2017 Summit + SES MeetingJune 5th - 9th@ Colorado State UniversityFort Collins, Colorado

Welcome to the Ecology of Soil Health Summit and the biennial meeting of the Soil Ecology Society. This meeting comes at a time when interest in soil health–a concept that embraces not only the importance of

soil organic matter content and physical structure, but also the key role of soil biology for productive and efficient agroecosystems–is rapidly growing. In parallel, our scientific understanding of the ecology of the soil system has advanced tremendously in recent years, in many cases challenging longstanding paradigms. This international summit provides a unique opportunity to advance the development and implementation of science-based programs that enhance Soil Health. I hope that all meeting participants come away with a broader perspective, new ideas and new collaborators. It has been my pleasure to help organize this meeting, and I thank you for joining us.

Matthew Wallenstein, PhDPresident, Soil Ecology SocietyDirector, Innovation Center for Sustainable Agriculture

Chairman

Program Assistant

Soil Ecology Society Conference Committee

Ecology of Soil Health Summit Committee

Local Conference Committee

Matthew Wallenstein

Laurie Richards

Loren Byrne

Samantha Chapman

Jen Krumins

Michael Weintraub

Nicholas Goeser

Mary Beth Miranda

Whendee Silver

Allison Thomson

Charlotte Alster

Courtland Kelly

Yamina Pressler

Acknowledgements

Summit Supporters

Summit Advocates

The Soil Ecology Society (SES) is an international professional organization dedicated to furthering the science, education and awareness of soil ecology and the importance of soils for human and environmental well-being.

Just as healthy soils rely on interactive networks of incredibly diverse organisms, SES depends on all dimensions of human diversity. SES actively promotes participation and inclusion of all individuals regardless of age, gender, gender identity, race, cultural background, religion, physical ability, sexual orientation, professional status, geographic location, and all other characteristics that make our members unique. We strive to cultivate a scientific society of excellence built on mentorship, encouragement, tolerance, and mutual respect. SES is committed to proactively rejecting and denouncing prejudice and stereotyping whenever it is encountered in the Society or the profession.

Commitment to Divers i ty

Soi l Ecology Society Awards 2017 (sub-committee chair, Becky Bal l )

Career Achievement Award- Mary Firestone,

Service Award- Deborah Neher

Early Career Research Award- Thomas Crowther

Parkinson Travel Awards(sub-committee chair, Sam Chapman)

Lea Carlesso, Roberto Carrera-Martinez,

Martha Mary Gebhardt, Brittany

McAdams, Daniel Kane, Matthew Reid

Board of Directors 2015-2017

Matthew Wallenstein (President)

Stuart Grandy (Past-President)

Michael Weintraub (President Elect)

Becky Ball (Secretary)

Emma Aronson (Treasurer)

Cathy Stewart (Former Treasurer)

Samantha Chapman (At-Large)

Felicty Crotty (At-Large)

Jennifer Krumins (At-Large)

Loren Byrne (Communications)

Amanda Daly (Student Member)

Soi l Ecology Society Awards 2017 (sub-committee chair, Becky Bal l )

To feed increasing global populations, global crop production will need to double in the coming decades while minimizing environmental impacts. New innovations are needed to meet emerging sustainability metrics related to nutrient use efficiency, greenhouse gas emissions, soil carbon sequestration without sacrificing yield and farmer profit. To advance truly sustainable agriculture, new technologies and practices must be not only developed, but also broadly adopted.

Healthy soils are critical to sustainable farming systems, yet 40% of our agricultural soils are degraded. Agronomic practices and technologies that rebuild our soils can enable enhanced productivity with decreased inputs. Healthy soils are teaming with microbes that enhance nutrient use efficiency and improve plant health—harnessing this natural plant-microbe interaction can hold the key to enhanced farm productivity and sustainability. ICSA’s objective is to catalyze innovations that advance sustainable agriculture and soil health through partnerships with industries, governments, grower organizations, and other academic institutions.

The hallmark of our unique approach is an integrated systems view of agricultural technology development, adoption and implementation. We combine cutting-edge scientific expertise in soil science, plant biotechnology, the microbiome, and big-data analytics with rigorous socioeconomic analyses. Examples of our current initiatives: Integration of cutting-edge crop and economic models to optimize production systemsApplication of biogeochemical models to optimize nutrient use efficiency and minimize greenhouse gas emissions

An integrated economic and biophysical assessment of organic waste products for soil quality;Development of training programs for the next generation of agricultural innovation scientists;Development of below-ground sensor technologies to improve understanding of plant-soil-microbe interactions.

We seek to expand and strengthen our partnerships with corporations and NGO’s in order to incorporate the scientific best practices into sustainability incentive programs, to provide training, and to commercialize new innovations. ICSA aims to be the premier global center for practical innovations in sustainable crop production.

Event AgendaJune 5th - 7th@ Colorado State UniversityFort Collins, Colorado

Monday June 5th

Lory Student Center, Ballroom 350 C & D, Colorado State University

Welcome: Matthew Wallenstein, Director, Innovation Center for Sustainable Agriculture;President, Soil Ecology Society; Associate Professor, Colorado State University

Plenary session: Overview of Soil Health Science & Challenges

Michael Doane, The Nature Conservancy

Wim van der Putten, Head, Depart of Terrestrial Ecology, Netherlands Institute of EcologySoil health: from ecological concepts to the Holy Grail of sustainability

Esther Ngumbi, Auburn UniversityHarnessing science-based soil solutions to revolutionize African Agriculture: Challenges and opportunities.

Moderated Panel Discussion: What is soil health? How do we manage it?

Miles O’Brien, Moderator

Keynote panel discussion moderated by Miles O’Brien, Emmy-award winning veteran independent journalist who focuses on science, technology and aerospace. He is the science correspondent for the PBS NewsHour, a producer and director for the PBS science documentary series NOVA, and a correspondent for the PBS documentary

series FRONTLINE and the National Science Foundation Science Nation series

2:00

2:30

3:00

3:30

4:00

Monday June 5th (Continued)

Lory Student Center, Ballroom 350 C & D, Colorado State University

IGNITE Session 1: The Science of Soil Health 5 minute lightning talks; selected from submitted abstracts from The Soil Ecology Society

Jessica Gutknecht Is your farm ready for the next storm? Soil health as a win-win for sustainability and resiliency to climate change

Stephen WoodCan different types of organic matter can have contrasting effects on soil health?

Matt RuarkWhy isn’t soil ecology considered when developing nitrogen fertilizer recommendations?

Loren ByrneSoil health fosters student engagement and deepens environmental literacy in soil ecology education

Poster Session and reception (appetizers and open bar)

4:30

5:00

S1.1 Kerri Steenwerth, Rachel Greenhut, *Francisco CalderonFine soil organic matter fractions in wine grape vineyards (Napa, CA) reflect distinctions in soil microbial community composition

S1.2 Lisa Windom, Maria Dragila, Noam WeisbrodCarbon dioxide sequestration in karst micro-fissures: the solution of a droplet

S1.3 Catherine Stewart, Damaris Roosendaal, Karolien Denef, Louise Comas, Gautam Sarath, Virginia L. Jin, Marty SchmerSeasonal switchgrass ecotype contributions to soil organic carbon, deep soil microbial community composition and rhizodeposit uptake during an extreme drought

S1.4 Adi OrenExamination of residual chloroform interference in the measurement of microbial biomass C by fumigation-extraction

S1.5 Michael Allen, Michael Taggart, George Rothbart, Thomas Harmon, Rebecca Hernandez, Philip RundelPeering into the Soil Black Box: A soil ecosystem observatory by rhizosystems, LLC.

S1.6 Emily Webster, Amélie Gaudin, Mirjam Pulleman, Pablo Siles, *Steven FonteEstablishment of improved pastures supports early indicators of soil restoration in low-input agroecosystems of Nicaragua

S1.7 Adam Cobb, Gail Wilson The influence of agricultural practices on the abundance of arbuscular mycorrhizal fungi in rural eastern Zambia

S1.8 Terry Woodford-thomas, *Sandra Arango-Caro MO DIRT - Missourians Doing Impact Research Together - A citizen science project to monitor soil health in the state of Missouri

S1.9 Cam Gudmundson, Louise Egerton WarburtonSoil aggregation and organic matter stabilization in green roof systems and implications for C sequestration

S1.10 Daniel Kane Estimating soil carbon with open-source VNIR spectroscopy

POSTER SESSION IBallroom B, Lory Student Center5:00 – 7:00 PM

S1.11 Edward Ayres, Natchaya Durden, David Durden, Monique Leclerc, Josh RobertiMitigating the impact of slow sensor response times on calculating soil CO2 fluxes from NEON’s soil CO2 measurements

S1.12 Adam von Haden, Christopher Kucharik, Randall Jackson, Erika Marín-SpiottaChanges in physical protection of soil organic matter following five years of biofuel cropping system cultivation: soil texture matters

S1.13 Phil Murray, Jennifer Dungait, Umran Akkan, Stuart Norris Long-term land use change and impacts on soil faunal diversity

S1.14 Sudan Kariuki, Mitch Mcclaran, Rachel Gallery How does recreational camping affect cover mediated soil microbial activity?

S1.15 Daniel Almeida Melman, Courtland Kelly, Joel Schneekloth, Francisco Calderon, Steven Fonte Conservation agriculture enhances soil quality and function in an irrigated cropping system of Eastern Colorado

S1.16 Courtland Kelly, Meagan Schipanski, Wilma Trujillo, Daniel Melman, Angie Moore, Steven Fonte Soil health implications of grazed vs. ungrazed cover crops in the U.S. high plains

S1.17 Tucker Andrews, *Deborah Neher, Thomas Weicht Microbial ecology of composting bedded pack

S1.18 Emmanuel Deleon, Troy Bauder, Steven Fonte, Erik Wardle Conservation tillage impacts on soil quality parameters under furrow irrigation

S1.19 Diana Vargas-Gutierrez, John Zak, Veronica Acosta-Martinez, Bobbie McMichael Reduction in daily soil temperature range increase microbial community dynamics in a dryland cotton production system in west Texas

S1.20 Lea Carlesso, Graham Hartwell, Karl Ritz, Phil MurrayResponses to soil mesofauna to agricultural practices and arable field-margin management

S1.21 Lea Carlesso, Andrew Beadle, Graham Hartwell, Debbie Sparkes, Karl Ritz, Lianhai Wu, Phil MurrayImpact of compaction on decomposition in an arable field and possible improvement by managing the headland.

S1.22 Sarah EvansEmpirical evidence that passive microbial dispersal maintains soil community and ecosystem function

S1.23 Pablo Tovar, Veronica Acosta-Martinez, John Zak Soil microbial dynamics in a long-term sustainable cotton for semi-arid West Texas

S1.24 Gordon Custer, William Stump, Linda van Diepen Rhizosphere and bulk soil microbial dynamics in Engelmann Spruce stands in response to Spruce beetle attack

S1.25 Kholoud GhanemHow bed design in a dryland cotton system can influence subsequent microbial dynamic

S1.26 Bethany Avera, Charles Rhoades, Francesca Cotrufo Investigating changes in soil organic matter pools following bark-beetle outbreak and salvage logging: Implications for soil organic matter formation

S1.27 Brittany McAdams, Sylvie Quideau, Mathew Swallow, Lisa Lumley The influence of invasive earthworms on oribatid mite assemblages in a boreal aspen stand

S1.28 Luci Wilson, Gail Wilson, Karen Hickman Consequences of invasion by Bothriochloa bladhii and implications for tallgrass prairie restoration

S1.29 Joanna Carey, Jianwu Tang, Kevin Kroeger, Pamela Templer Uniform response of soil respiration to experimental temperature manipulation

S1.30 Noelle Espinosa, *Rachel GalleryStability of microbial activity in an experimentally warmed dryland

S1.31 Paul Brewer, Francisco Calderon, Merle Vigil, Joseph von Fischer, Impacts of moisture, soil respiration, and agricultural practices on gross CH4 production in upland soils measured by stable isotope pool dilution

S1.32 Lisa Tiemann, Nzube EgbolucheLong- and short-term nitrogen additions increase decomposition of cover crop residues in agricultural soils

S1.33 Emily Kyker-Snowman, Will Wieder, Stuart GrandyThe MIcrobial-MIneral Carbon Stabilization model with coupled N cycling (MIMICS-CN) simulates litter decomposition and soil organic matter dynamics at landscape scales

S1.34 Daniel Revillini, Bo Stevens, Kara Gibson, Aradhana Roberts, Peter Motyka, Nancy C. JohnsonCommittee for Evidence-Based Action: Educating the public and policy-makers for a scientifically sound future

S1.35 Martha Gebhardt, Elizabeth Sparks, Rachel GalleryInquiry-based STEM education for high school students: strengths, possibilities, and opportunities to get involved

S1.36 Martha Gebhardt, Rachel GalleryWoody shrub encroachment alters ecosystem processes: Linking imaging spectroscopy and microbial biogeochemistry

S1.37 Caley GaschEarthworm distribution and demographics along a naturally occurring salinity gradient

S1.38 Ryan LancioneUnderstanding interactions between nitrogen-fixing bacteria and switchgrass for sustainable biofuel production

S1.39 Zander Venter, Samantha Luise Scott, Johann Strauss, Karin Jacobs, *Heidi HawkinsIncreasing crop diversity increased soil microbial activity, N-sourcing and crop N, but not soil microbial diversity

S1.40 William Salas, Stephen Hagen, Ian Cooke Operational tillage information system: Tracking conservation practices at field to watershed scales

S1.41 Rachel Bechtold, Anuradha GhoshBacterial Diversity of an Abandoned Coal Mine Soil in Southeast Kansas

S1.42 Na Yin, Roger Koide Mechanism of non-additive heterogeneous litter decomposition

S1.43 Antreas Pogiatzis, John Klironomos, Pat Bowen, Miranda Hart, Taylor HollandComparative response of six grapevine rootstocks to inoculation with arbuscular mycorrhizal fungi

S1.44 Adam Langley, Brendan Kelly, Samantha Chapman Realistically simulating the effects of oxidation on soil decomposition

S1.45 Megan Foley, Adam LangleyDoes microbial community composition influence decomposition in wetland ecosystems?

Tuesday June 6th

Steven Tucker, AgriForce Seed

Ami Gunasekara, Manager, Office of Environmental Farming and InnovationCalifornia Department of Food and Agriculture

Matt Carstens, Senior VP, SUSTAIN at Land O’ Lakes

Nick Goeser, Director of Soil Health and Sustainability, National Corn Growers Association

Break

Jennifer Moore-Kucera, USDA NRCS

Allison Thomson, Science & Research Director, Field to Market

Moderated Panel Discussion: What can we do now to enhance soil health?Moderator: Luke Runyon, Harvest Public Media

Lunch

Wayne Honeycutt, CEO, Soil Health Institute

LaKisha Odom, Director, Foundation for Food and Agriculture Research

Jacob Parnell, NovoZymes

Break

8:30

9:00

9:40

10:00

11:20

2:10

9:20

10:30

10:50

12:00

1:30

1:50

2:30

Lory Student Center, Ballroom 350 C & D, Colorado State University

Tuesday June 6th (Continued)

Innovations in Soil Health: Dan Morash, CEO, California Safe Soil Colin Bell, Co-Founcer & Chief Growth Officer, Growcentia, Inc. Brian Buege, Head of Technology, CoolPlanet, Inc Virgina Ursin, Indigo Ag Diane Wu, Co-Founder, Trace Genomics

Panel Discussion: What is the role of startups in enhancing soil health? Moderator:GregGraff,Associate Professor ofAgricultural Economics, CSU

IGNITE Session 2: The Science of Soil Health 5 minute lightning talks; selected from submitted abstracts from The Soil Ecology Society

Joseph Blankinship, Corey LawrenceNurturing a mechanistic view of soil health

Aradhana Roberts, Michelle Mack, Nancy C. JohnsonEighteen years of mob-grazing increases soil carbon in a semi-arid grassland

Steven FonteSoil macrofauna as drivers of soil and ecosystem functionIgnite Sessions

Felicity Crotty, Chris StoateUnderstanding how to harness the power of underground livestockIgnite Sessions

Rachel Rubin, Kees Jan Van Groenigen, Bruce Hungate Plant growth promoting rhizobacteria are more effective under drought: a meta-analysis

3:00

4:00

4:30

Lory Student Center, Ballroom 350 C & D, Colorado State University

Tuesday June 6th (Continued)

5:00

7-10

Lory Student Center, Ballroom 350 C & D, Colorado State University

Poster Session II and Mixer

Ecology of Soil Health Summit Banquet Ballroom 350 CD

SII.1 Thomas Forge, Tristan Watson, Paige Munro, Denise Neilsen, Gerald Neilsen, Louise NelsonSoil management practices to enhance soil health and early growth of sweet cherry planted into old orchard land

SII.2 Maxwell Helmberger, Kyle Wickings Microarthropod response to foot traffic in sports turf

SII.3 Pingting Guan, André L.C. Franco, Osvaldo Sala, Diana Wall Community composition of free-living soil nematodes under anomalous precipitation across sites

SII.4 Kevin Butt, *Mac CallahamEarthworms from soils developed below long term experimental plantations at Holt Down, Southern England

SII.5 Mac Callaham, Sophia Bonjour, Brent Brock, Clinton Meyer, Bruce Snyder, Matt WhilesPeriodical cicada expansion lags, but matches, woody plant encroachment in tallgrass prairie landscapes

SII.6 Daniel Revillini, Peter B. Reich, Nancy C. Johnson Elucidating the importance of bacterial network connectivity from a long-term environmental change experiment

SII.7 Newton Lupwayi, Derrick Kanashiro, Andrea Eastman, Xiying Hao Manure but not N fertilizer improved biological soil health after 38 annual applications

SII.8 Ryan Byrnes, Leslie Roche, Kenneth TateDo livestock grazing regimes influence soil biogeochemical processes and function? A global analysis of grazing effects on soil nitrogen and carbon dynamics.

SII.9 Cynthia Kallenbach, Fnu Junaidi, Steven Fonte, Patrick Byrne, Mathew WallensteinWheat genotypic and phenotypic effects on microbial-mediated nitrogen cycling

SII.10 Kurt Reinhart, Lance VermeirePower and limitation of soil properties as predictors of rangeland health and ecosystem functioning in a Northern mixed-grass prairie

SII.11 Kalyn Diederich, Kavya Krishnan, Erin Silva, Matt Ruark Increasing labile carbon and nitrogen pools in agricultural soils requires a change in system, rather than practice

POSTER SESSION llBallroom B, Lory Student Center5:00 – 7:00 PM

SII.12 Grace Crain, Eva Dettweiler-Robinson, Anthony Darrouzet-Nardi, Jennifer Rudgers, Robert SinsabaughMixed evidence for carbon transfer between biocrust cyanobacteria and plants in multiple dryland ecosystems using natural abundance δ13C

SII.13 Rachel Brockamp, *Sharon Weyers, Margaret Kuchenreuther, John Zaharick, Alan WiltsInfluence of fertilization on mycorrhizal dynamics in a perennial biomass production system

SII.14 Chelsea Carey, Rachel Sullivan, Doug Millar, Mel Preston, Nathaniel Seavy, Thomas GardaliMonitoring biotic and abiotic soil parameters to inform regenerative grazing practices across California’s coastal range

SII.15 Natalie Bray, Grant Thompson, Jenny Kao-Kniffin, Kyle WickingsSoil macrofauna modify soil microbial community composition and function and alter belowground carbon inputs

SII.16 Colin Tucker, Sasha Reed, Anita Antoninka, Matthew BowkerRestoration of biological soil crust on the Colorado Plateau in a warming climate.

SII.17 Tahir Zaman, Timothy Fegel, Paula Fornwalt, Charles RhoadesAre soil changes responsible for persistent, non-forested burn scars in Colorado forests?

SII.18 Landon Gibbs, Mark Coyne Cover crop mixes differentially stratify mineralizing microbes and residual nitrogen.

SII.19 Tyler Poppenwimer, Louis Gross, Joseph Bailey, Megan RúaModelling the root age structure of perennial woody plants

SII.20 Meghan Midgley The Tollway Trees Initiative: From right tree, right site to right soil, right tree

SII.21 Thomas Ducey, Phil Bauer Effect of tillage and cover crops on the cotton rhizosphere

SII.22 Emm Fulk, Jonathan J. Silberg, Caroline MasielloMicrobial genetic memory to study heterogeneous soil processes

SII.23 Carl Wepking, Brian Badgley, John Barrett, Matthew Hedin, Katharine Knowlton, Kevan Minick, Partha RayEcological effects of livestock antibiotics on agricultural soils

SII.24 Deirdre Griffin, Daoyuan Wang, Sanjai Parikh, Kate ScowEffects of walnut shell biochar on soil microbial communities in a long-term field experiment.

SII.25 Paulina Beatriz Ramírez, Sebastián Fuentes, Beatriz Díez, Carlos A. Bonilla Bacterial composition patterns distinguish two contrasting soils in organic carbon content: andisols and inceptisols

SII.26 Di Liang, G. Philip Robertson Management intensities and seasons affect the relative contribution of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) to nitrification across a Midwest management gradient

SII.27 Tye Morgan, Matthew O’neill, Robert Blank, Edith Allen, Michael Allen Why is Taeniatherum caput-medusae (medusahead) Invasive in North America and not in its Native Eurasia?

SII.28 Jessica Susser, Shannon L. Pelini, Michael Weintraub Can we reduce phosphorus runoff potential by stimulating decomposers with carbon and sodium?

SII.29 Jayprakash Singh, Nina Goodey, Jennifer KruminsVariation in microbial community composition may explain soil functioning in an urban brownfield

SII.30 Michala Phillips, Andrew Krohn, Edith Allen Invasion shifts soil fungal community composition in California chaparral

SII.31 Jennifer Schmidt, Clare Casteel, Rachel Vannette, Christian Nansen, Scott Park, Kate Scow, Amélie GaudinSoil health mediates tomato resistance to insect vectors and viral pathogens

SII.32 Amisha Poret-Peterson, Natalia Ott, Greg BrowneBacterial communities associated with Prunus replant disease

SII.33 Kaiyue Zhou, Louise Egerton WarburtonPlant species and functional group effects on soil properties in a green roof community

SII.34 Megan RúaDisturbance history and environmental characteristics shape the ectomycorrhizal fungal community of two varieties of Pinus clausa

SII.35 Eric Vukicevich, José Ramon úRbez-torres, Pat Bowen, D. Thomas Lowery, Miranda HartThe effect of ground cover management on vine performance and fungal root endopyte communities

SII.36 Chen Ning, Gregory Mueller, Louise Egerton Warburton Profiling ectomycorrhizal fungal diversity and function in seedlings of south China native masson pine and introduced slash pine

SII.37 Ilenne Del Valle, Tara M. Webster, Caroline Masiello, Jonathan J. Silberg, Johannes Lehmann Environmental multi-input circuit to understand plant-microbe communication

SII.38 Akihiro Koyama, Teresa Dias, Angela Dukes, Pedro AntunesSoil microbial feedback in agricultural crop rotation

SII.39 Natalia Ott, Amisha Poret-Peterson, Hossein Gouran, Greg BrowneOomycete and fungal root communities associated with Prunus replant disease and its control in conventionally fumigated or anaerobically disinfested soil

SII.40 Ma. Lourdes Edano, Gail Wilson, Karen Hickman, James BeverWill the use of nurse plants inoculated with native AM fungi help restore the native plant community after eradication of invasive grasses?

SII.41 Franz Lichtner, Kirk BrodersEcology of temperate belowground fungi through ITS sequence analysis over four years in mixed successional perennial systems

SII.42 John DightonComparisons of mycorrhizae and plant growth between the NJ pine barrens and serpentine barrens

SII.43 Tom Bolger, Tara Dirilgen, Edite Jucevica, Pascal Querner, Viesturs Melecis Analysis of spatial patterns informs community assembly and sampling requirements for Collembola in forest soils

*Denotes presenting author if other than first author

Wednesday June 7th

Kate Scow, Professor of Soil Science and Soil Microbial Ecology, University of California, Davis

Stuart Grandy, Associate Professor of Sustainable Agriculture and Food Systems, University of New HampshireRevising Paradigms of Nitrogen Mineralization and Availability in Agroecosystems

Lynne Macdonald, CSIRO

Panel Discussion: What are the most important research needs to advance soil health?

Break

IGNITE Session 3: The Science of Soil HealthEmily Oldfield, Mark Bradford, Stephen WoodIncreasing soil organic matter can reduce global yield gaps

Kelly Gravuer, Kate ScowCan “macrobial” diversity and invasion theories explain microbial outcomes of compost addition to agricultural soils?

Brendan O’Neill, Christine Sprunger, John Kerr, G. Philip RobertsonAligning Soil Health Testing and Farmer Knowledge for Improved On-farm Soil Management

Michael Lehman, Shannon OsborneMeasuring and Managing Soil Health – Multidimensional Solutions

8:30

8:50

9:10

9:30

10:30

10:00

Lory Student Center, Ballroom 350 C & D, Colorado State University

Wednesday June 7th(Continued)

Phillip TaylorThe Jury is Out on Carbon Farming

Moving forward: Building Bridges Between Industry, Scientists, and Practitioners Bill Buckner, President, Noble Foundation LaKisha Odom, Scientific Program Director, Foundation for Food and Agricultural ResearchKeith Paustian, Professor, Dept of Soil and Crop Sciences, Colorado State University

Wrap-Up Lunch: Box lunches served – please select your box lunch and enjoy it outside or in another area of the Lory Student Center to allow for reconfiguration of ballroom for afternoon SES meeting

11:00

12:00

Lory Student Center, Ballroom 350 C & D, Colorado State University

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HOOH

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Event AgendaJune 7th - 9th@ Colorado State UniversityFort Collins, Colorado

SES Meeting Sess ion AWednesday June 7th

PARALLEL ORAL SESSION ABALLROOM C

Michael Allen, Amanda Swanson, Emma Aronson, Thomas Harmon, Robert Johnson, Diego Dierick, Zhan Chen, Steve Oberbauer, Adrian Pinto, Tamara Zelikova, Luitgard Schwendenmann, Philip Rundel, Angel FernandezSoil Net Primary Production and Carbon Emissions in a Tropical Rainforest: Effects of Leaf Cutter Ants through an ENSO cycle

Racheal Upton, Kirsten HofmockelSoil fungi response to seasonal and annual variance in three agroecosystems

Michael Remke, Matthew Bowker, Nancy C. Johnson, Matthew Williamson, Karen HaubensakMycorrhizal allocation determines their function across varying environmental contexts

Eldor PaulQuantifying the controls on SOM characteristics by MAT, disturbance, vegetation, depth and the soil matrix: An Opus approach

Steven Rosenzweig, Meagan Schipanski, Steven Fonte, Mary StrombergerCrop rotation impacts on AMF, P acquisition and C sequestration in semi-arid agroecosystems.

Noah Sokol, Mark Bradford Is root carbon better stabilized than shoot carbon? Testing features of the above- versus below-ground pathway

2:00

2:15

2:30

2:45

3:00

3:15

SES Meeting: Sess ion A (continued)

PARALLEL ORAL SESSION ABALLROOM C

3:30

3:45

4:00

4:15

Elizabeth Porzig, Chelsea Carey, Nathaniel SeavyPlant community composition and variation in soil organic carbon in California rangelands

Sarah Castle, Zewei Song, Stuart Grandy, Linda KinkelDoes climate warming alter plant diversity-soil carbon relationships and associated soil microbial communities?

Daniel Maynard, Thomas Crowther, *Mark BradfordCompetition reduces microbial carbon use efficiency

Cameron McMillan, *Michael Weintraub How do plant seasonal dynamics drive root carbon inputs to the soil and their distribution?

SES Meeting: Sess ion A (continued) SES Meeting Sess ion BWednesday June 7th

PARALLEL ORAL SESSION BBALLROOM D

Steven Fonte, Steven Vanek, Katherin Meza, Anne De Valenca, Raul Carlos Ccanto Retamozo, Edgar Olivera, Maria Scurrah Land-use impacts on soil biodiversity and ecosystem services in an Andean farming community

Yamina Pressler, John Moore, Francesca Cotrufoire reduces soil biota biomass and diversity: a cross-biome meta-analysis

Emma Aronson, Denise Jackson Soil Microbial dispersal by way of terrestrial slugs

Charlotte Alster, Joseph von Fischer Characterizing Temperature Sensitivity as a Microbial Trait: A Meta-Analysis Using Macromolecular Rate Theory

Eric Duell, Anna O’Hare, Gail WilsonImproving grassland restoration efforts: the power of soil amendments

Maria Soledad Benitez, Shannon L. Osborne, Michael LehmanRotation history effects on soybean plants and rhizosphere microbiome

Parker Coppick, Gail Wilson Soil biotic and abiotic properties following Bothriochloa ischaemum invasion into native tallgrass prairie

Matthew Reid, Sarah EmeryLeymus arenarius invasion alters belowground interactions with mycorrhizae and nematodes without altering nematode community structure

2:00

2:15

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2:45

2:45

3:00

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3:45

SES Meeting: Sess ion B (Continued)

PARALLEL ORAL SESSION BBALLROOM D

4:00

4:15

5:30

Gail Wilson, Tim ToddTallgrass prairie restoration: Does functional group matter?

Kyle Wickings, Huijie GanSoil ecological responses to pest management practices in turfgrass vary with pesticide use intensity, identity, and application program

David Knaebel, USDA ARS - USDA only meeting, Room 390, Lory Student Center

SES Meeting: Sess ion B (Continued) SES Meeting Sess ion CThursday June 8th

PARALLEL ORAL SESSION CBALLROOM C

Tamara Zelikova, Diego Dierick, Luitgard Schwendenmann, Thomas Harmon, Nicole Trahan, Michael AllenIndustrious leaf cutter ants and their big footprints in tropical soils

Roberto Carrera-Martínez, Mitchell J Greer, Bruce A SnyderInvasive Yellow Bluestem and European earthworms: Conspiracy for ecosystem domination?

Jessica Gutknecht, Cameron BlakeMicrobial C use in peat depth profiles under warming, as revealed with isotopic profiling

Felicity Crotty, Chris StoateUntangling the effects of individual cover crop species compared to mixes on soil ecology

Samantha Weintraub, Lee StanishUsing NEON data to explore continental-scale patterns in soil communities and processes

Stuart Grandy, Andrea JillingFrom where and how do plants and microbes get their nitrogen?

Break

Soil Ecology Society Business Meeting BALLROOM D Full Breakfast Served

8-8:45

9:00

9:15

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10:00

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10:30

SES Meeting: Sess ion C (Continued)

PARALLEL ORAL SESSION CBALLROOM C

11:00

11:15

11:30

Phillip Taylor, Pete Newton, Alan TownsendThe Future of Protein

Erika Foster, Matthew Wallenstein, Francesca CotrufoBiocarbon as an effective microbial inoculum carrier in an agricultural maize field trial

Kelly Ramirez, Wim Van Der Putten, Basten SnoekThe role of the belowground plant microbiome in climate change induced range shifts

François-Xavier Joly, Sylvain Coq, Mathieu Coulis, Stephan Hättenschwiler, Johanne NahmaniThe transformation of leaf litter into feces by millipedes reshuffles the control of litter traits on decomposition

11:45

SES Meeting: Sess ion C (Continued) SES Meeting Sess ion DThursday June 8th

PARALLEL ORAL SESSION DBALLROOM D

Megan Machmuller, Carsten Mueller, Jennifer Soong, Carmen Hoeschen, Claudia Boot, Francesca Cotrufo Advancing the understanding of organo-mineral interactions: Insights from nano-scale Secondary Ion Mass Spectrometry

Samantha Chapman, Chelsea Barreto, Ember MorrisseyWetland plant range shifts may alter soil microbial communities and carbon storage

Kara Gibson, Channing Laturno, Andrea Raya, Anita Antoninka, Nancy C. JohnsonEffect of restoration treatments and forest type on soil mesofauna, fungi, and physicochemistry in Valles Caldera National Preserve

Matthew Hedin, John BarrettEffects of antibiotic residues on extracellular enzyme activity in soils

Caroline Masiello, Jonathan J. Silberg, Hsiao-Ying Cheng, Ilenne Del Valle, Emm Fulk, George Bennett Spies and Bloggers: New Synthetic Biology Tools to Understand Soil Microbial Processes

Amanda Daly, Andreas Richter, Stuart GrandyInfluence of wet-dry cycles and organic management on gross nitrogen depolymerization in agricultural soils

Break

9:00

9:15

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10:30

SES Meeting: Sess ion D (Continued)

PARALLEL ORAL SESSION DBALLROOM D

11:00

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11:45

A. Peyton Smith, Malak Tfaily, Kent Rod, Vanessa Bailey, Ryan RenslowTemperature, moisture and mineral interactions alter the vulnerability of organic matter turnover

Colin Averill, Bonie Waring Nitrogen limitation of decomposition and decay: how can it occur?

Becky Ball, Suzanne Dietrich, Don GoelmanAn interactive learning module for teaching ecology students (and professors) about databases for managing and querying large datasets

Loren ByrneIntegrating soil biodiversity and soil ecology into non-soil-focused undergraduate courses

LUNCH12-1:30

SES Meeting: Sess ion D (Continued) SES Meeting Sess ion EThursday June 8th

PARALLEL ORAL SESSION EBALLROOM C

SES Ear ly Career Research Awardee: Tom CrowtherQuantifying global soil carbon losses in response to warming

Drew A. Scott, Sara G. BaerPartial support for the ‘environmental heterogeneity hypothesis’ in tallgrass prairie restorations

Mark Anthony, Serita Frey, Kristina StinsonFungal Responses to an Invasive Plant in a Warmer, Fertilized Forest

Nora Flynn, Louise Comas, Catherine Stewart, Steven FonteInvestigating deficit irrigation impacts on belowground processes and climate change mitigation potential

Joseph Blankinship, Kenneth Marchus, Joshua SchimelUsing extracellular polymeric substances (EPS) from bacteria to make soils more drought-adapted

Tyler Rippel, Pasquale Succi, Samantha ChapmanThe influence of Japanese stiltgrass on soil microbes, edaphic properties, and tree regeneration in a nitrogen saturated environment

BREAK

Kate Glanville, G. Philip RobertsonConsequences of Changing Rainfall Patterns on Nitrous Oxide Fluxes in Cropping Systems

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SES Meeting: Sess ion E (Continued)

PARALLEL ORAL SESSION EBALLROOM C

3:45

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Meghan Midgley, Quinn TaylorPrescription side effects: Controlled burning alters resource stoichiometry in a Midwestern forest soil

Brendan O’Neill, Thomas Schmidt, G. Philip Robertson, Sasha Kravchenko, Stuart GrandyLinking soil C and N cycling and trace gas fluxes with soil bacterial communities along a gradient of simple to complex crop rotations

Joni Baumgarten, John DightonEdaphic manipulation of the soil community of biofuel switchgrass (Panicum virgatum) in three soils

Darian Smercina, Lisa Tiemann, Sarah Evans, Maren FriesenEnvironmental Controls on Free-living Nitrogen Fixation and Nitrogen Mineralization

SES Service Awardee: Deborah NeherSoil health – what progress have we made in the past 25 years?

SES Meeting: Sess ion E (Continued) SES Meeting Sess ion FThursday June 8th

PARALLEL ORAL SESSION FBALLROOM D

Becky Ball, Kyle Wickings, Lynn ChristensonPathways and patterns of plant litter chemistry throughout decomposition

Monica Farfan, David WiseAugmentation of basal resources in a soil food web changes patterns of intraguild predation and decomposition rate

Michael LeDuc, Tucker Andrews, Thomas Weicht, *Deborah Neher Microarthropods in Bedded Pack: A Source for Biocontrol of Biting Fly Pests on Dairy Farms?

Rachel Hestrin, Maria Harrison, Johannes LehmannSoil Microbial Communities and Gas Dynamics Contribute to Arbuscular Mycorrhizal Nitrogen Uptake and Transfer to Plants

Huijie Gan, Chao Liang, Kyle WickingsInvasive root herbivores accelerate soil carbon inputs and soil organic matter decomposition

Brittany McAdams, Sylvie Quideau, Mathew Swallow, Lisa LumleyOribatid mites as a tool to assess soil recovery after oil sands mining

Break

1:30

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SES Meeting: Sess ion F (Continued)

PARALLEL ORAL SESSION FBALLROOM D

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Anthony Darrouzet-Nardi, Michael Weintraub, Jane Martinez, Daniela AguirreIs soil pore water an exchange depot for nutrients in Arctic tussock tundra soils?

Bo Stevens, Jeffrey Propster, Gail Wilson, Andrew Abraham, Chase Ridenour, Chris Doughty, Nancy JohnsonA Serengeti Without Arbuscular Mycorrhizas: Quantifying Interactions Between Migratory Mammals and Fungal Symbionts

François-Xavier Joly, Heather ThroopPulse size, frequency and soil-litter mixing alter the control of cumulative precipitation over litter decomposition in drylands

Ashley Keiser, Montana Smith, Sheryl Bell, Kirsten HofmockelPeatland microbial community response to altered climate tempered by plant – soil interactions

Anna Cates, Thea Whitman, Randall JacksonThe effect of C decomposition environment on plant detritus C in soil organic matter

Kirsten Hofmockel, Alison King Organic N cycling in agroecosystems

*Designates Presenting Author

Soil Ecology Society Banquet Award Dinner Agave Room, 149 W Mountain Avenue, Fort Collins, CO 80524

4:45

7-10

SES Meeting: Sess ion F (Continued) SES Meeting Sess ion FFr iday June 9th

Field Trip: Rocky Mountain National ParkMeeting place TBA Box lunch provided

8:30

Appendix l

ECOLOGY OF SOIL HEALTH SUMMITPOSTER SESSION ABSTRACTS

Monday June 5th

POSTER SESSION 1 5:00 – 7:00 PM

Bal l room B, Lory Student Center

#SI.1Finesoilorganicmatterfractionsinwinegrapevineyards(Napa,CA)reflectdistinctionsinsoilmicrobialcommunitycompositionKerriSteenwerth1,RachelGreenhut1,*FranciscoCalderon21USDA‐ARSCropsPathologyandGeneticsResearchUnit,UnitedStates2USDA‐AgriculturalResearchService,UnitedStatesRecently, Burns et al. (2015) demonstrated that soil‐borne microbial communities differentiatethemselveswith respect toAmericanVineyardAreas, defined for their distinguishing features ofclimate, geology, soils,physical features (topographyandwater), andelevation.Of these features,location (latitude, elevation, topography, precipitation) and edaphic variableswere the strongestdrivers of beta‐diversity of microbial communities at the landscape scale, especially total soilcarbon and nitrogen contents in the <53 µm and 53‐250 µm particulate organic matter (POM)fractions.Given that soilmicrobial communitiesmineralize, contribute to andpreserve these soilorganic carbon pools, we hypothesized that the chemical composition of the SOC pools wouldreflectthatofmicrobialcommunities.Twentyfourvineyardsweresampledfrom0‐5and5‐10cmforphysicalandchemicalattributes,CandNresourcesandlandusehistory.ThefinesoilOMthatisthoughttoreflectresiduesthathavebeenhighlydecomposedbysoilmicroorganisms(i.e.<53µmorganomineral fraction) was analyzed by diffuse reflectance Fourier transformed mid‐infraredspectroscopy(DRIFTS).Canonicalcorrespondenceanalysesof theFTIRoutputdemonstratedthatPOMchemical fingerprintsdidnot structure themselveswithrespect tocompostaddition, tillage,soil depth, and farming system (conventional vs. organic vs. biodynamic). Similar to drivers ofmicrobialcommunitystructure,locationattributes,soiltype,covercroptypestronglydifferentiatedclusters of FTIR fine soil OM fingerprints among samples. The correspondence between themicrobialcommunitystructureandthePOMchemicalfingerprintswillbediscussedfurtherinthispresentation.

#SI.2Carbondioxidesequestrationinkarstmicro‐fissures:ThesolutionofadropletLisaWindom1,MariaDragila1,NoamWeisbrod21OregonStateUniversity,UnitedStates2Ben‐GurionUniversityoftheNegev,IsraelThe concern for increased atmospheric carbon dioxide concentration calls for improvedunderstandingofnaturalsequestrationprocesses. Increasedcarbondioxidestorage insoilshowspromisebecausethenetstorageiscompromisedbylosstotheatmospherebutaidedbydownwarddrainage.Weaskhowthemechanismofinfiltrationintokarstaquifermicro‐fissuresbelowthesoilcanadditionallysequestercarbondioxide.Karstaquifersoccupyconduitsandcavernscarvedintolimestone (calciumcarbonate).These caverns formbyprolongederosionofmicro‐fissures in theepikarst, soil solution percolates down micro‐fissures (< 2 mm thick) in the form of thin films(~200microns).Therearethreegas‐liquidfluidmodesthatcanbesustainedinmicrofracturesandthat allow for a three‐phase interaction of carbon dioxide in the gas phase, water, and calciumcarbonate in the solid phase. Limestone erosion, commonly approached through calciumdissolution, is limited by the presence of dissolved carbon dioxide but accelerated by advectivecarbondioxidegasassimilation intosolution.Theprocess fixescarbonbyexchanging forcalciumwithin the limestone matrix; the kinetics of calcium dissolution is well‐defined but how it isimpactedbydifferentflowmodesremainstobestudied.Byunderstandingtheadvectivepotentialof naturallydevelopingmodesof flow,we canmore accuratelyunderstand the storageof carbondioxidegasintosubsurfacelimestone.

#SI.3Seasonalswitchgrassecotypecontributionstosoilorganiccarbon,deepsoilmicrobialcommunitycompositionandrhizodeposituptakeduringanextremedroughtCatherineStewart1,DamarisRoosendaal2,KarolienDenef3,LouiseComas1,GautamSarath4,VirginiaL.Jin5,MartySchmer51USDA‐AgriculturalResearchService,UnitedStates2USDA‐ARSSoilManagementandSugarbeetResearch,UnitedStates3ColoradoStateUniversity‐CentralInstrumentFacility,UnitedStates4USDA‐AgriculturalResearchServiceGrain,Forage,andBioenergyResearch,UnitedStates5USDAARSAgroecosystemsManagementResearch,UnitedStatesTheimportanceofrhizodepositCandassociatedmicrobialcommunitiesindeepsoilCstabilizationisrelativelyunknown.PhenotypicvariabilityinplantrootbiomasscouldimpactCcyclingthroughbelowground plant allocation, rooting architecture, and microbial community abundance andcomposition.Weusedapulse‐chase13Clabelingexperimentwithcompound‐specificstable‐isotopeprobingto investigatetheimportanceofrhizodepositCtodeepsoilmicrobialbiomassundertwoswitchgrass ecotypes (Panicum virgatum L., Kanlow and Summer) with contrasting rootmorphology. We quantified root phenology, soil microbial biomass (phosopholipid fatty acids,PLFA), andmicrobial rhizodeposit uptake (13C‐PLFAs) to 150 cm over one year during a severedrought.Thelowlandecotype,Kanlow,hadtwotimesmorerootbiomasswithacoarserrootsystemcomparedtotheuplandecotype,Summer.Overthedrought,Kanlowlost78%ofitsrootbiomass,whileSummerlostonly60%.RhizodeposituptakeunderKanlowhadahigherrelativeabundanceofgram‐negativebacteria(44.1%),andSummerrhizodeposituptakewasprimarilyinsaprotrophicfungi (48.5%). Bothmicrobial community composition and rhizodeposit uptake shifted over thedrought into gram‐positive communities. Rhizosphere soil C was greater one year later underKanlow due to turnover of unlabeled structural root C. Rhizosphere δ 13C was not significantlydifferent between the two ecotypes, suggesting greatermicrobial C input under the finer rootedspecies, Summer, whose microbial associations were predominately saprotrophic fungi. Root‐derived C inputs drive soil C processes and these data suggest that individual plant interactionswiththemicrobialcommunityandextremedroughteventsaffectsoilCsequestration.

#SI.4ExaminationofresidualchloroforminterferenceinthemeasurementofmicrobialbiomassCbyfumigation‐extractionAdiOrenInstitute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural ResearchOrganization(ARO),IsraelChloroform fumigation‐extraction (CFE) is by far the most widely usedmethod for determiningmicrobialbiomass insoils.UsingtheCFEmethod,apresumption is followed, i.e., thatchloroformbecomes fully evacuated from the fumigated soil before extraction. Otherwise, the C‐containingfumigant may comprise an unknown part of the extractable C flush, resulting in certainoverestimation of soil microbial biomass. A quantitative assessment of extractable residualchloroformlevelsinfumigatedsoilswasperformed,testingsoilsvaryinginclayandorganicmattercontents.Thetestswereperformedoverabroadrangeofsoilmoistureconditionsastofacilitateamechanisticinterpretationofpossiblechloroforminteractionsinthestudiedsoils(i.e.,dissolution,sorption). The results support the validity of the CFE method's application in agricultural soils,demonstrating the insignificance of biomass overestimation arising from residual chloroform.However,attentionmustbegiventopotentialbiomassoverestimationinlow‐biomasssamples(e.g.,subsoil) where extractable‐C flushes are characteristically low, sorption of chloroform may berelatively high, and thus extractable chloroform‐C contribution to the extractable‐C flush can besignificant.

#SI.5Peeringintothesoilblackbox:Asoilecosystemobservatorybyrhizosystems,LLCMichaelAllen1,MichaelTaggart2,GeorgeRothbart2,ThomasHarmon3,RebeccaHernandez4,PhilipRundel51UniversityofCalifornia,Riverside,UnitedStates2Rhizosystems,LLC,UnitedStates3UniversityofCalifornia,Merced,UnitedStates4UniversityofCalifornia,Davis,UnitedStates5UniversityofCalifornia,LosAngeles,UnitedStatesUnderstandingsoildynamicsisacriticalstepinmanagingecosystemprocesses.However,toolsthatfacilitate temporal and spatial observations are constrained in that observations must occurbelowground,andmustoccurathighfrequenciestodelineaterapidchangeassociatedwithevents.Coringdisruptssoilstructure,andchangesthroughtimecanbeeithervariationintime,orvariationin space.These cannotbedifferentiated.A critical value, oftenmissing, is lifespan.Yet lifespan iscritical to calculating turnover, and turnover is just as important asproduction to estimatingnetprimaryproduction.Wedesignedanintegratednetworkofsensors,CO2,O2,H2O,andtemperature,placedinadepthprofile.Fromthese,concentrationscanbemeasuredandfluxescalculatedusingFick’sLaw.Embeddedwithin thesensornetworkareautomatedminirhizotronsthat imageroots,fungalhyphae, soil animals, soil structureup to four‐timesdaily, andmanualminirhizotrons thatcanbeusedatintervalsasdeterminedbytheuser.Automatedminirhizotronsallowforcontinuousobservationincreasingunderstandingoftemporalvariation.Manualminirhizotronscanprovideforevaluatingspatialvariationacrossasite.Herewewillshowexamplesoftheunits,andtestsystemsfrom a tropical rainforest to a hot desert, to a subalpine coniferous forest. Observations includeunder snow dynamics, carbonate crystallization along hyphae, root grazing, mycorrhizaldevelopment, root and hyphal regrowth into abandoned ant nests, and integration into a carbonfluxmodel.

#SI.6Establishmentofimprovedpasturessupportsearlyindicatorsofsoilrestorationinlow‐inputagroecosystemsofNicaraguaEmilyWebster1,AmelieGaudin1,MirjamPulleman2,PabloSiles3,*StevenFonte41UniversityofCalifornia‐Davis,UnitedStates2InternationalCenterforTropicalAgriculture,Colombia3InternationalCenterforTropicalAgriculture,Nicaragua4ColoradoStateUniversity,UnitedStatesPasture degradation hinders livestock production and ecosystem services that support ruralsmallholder communities. Silvopastoral systems, featuring improved pasture grass species, arepromising restoration strategies. However, studies evaluating the impact of such systems, inconjunctionwithcommonmanagementpractices,onindicatorsofsoilhealtharelacking.Wesoughtto evaluate the impactof low‐input, improvedpasture establishmenton soil health indicators, inactively grazed silvopastoral systems. In August 2013, paired pasture management treatments(improved vs. degraded)were established onnine farmswith similarmanagement histories andedaphiccharacteristicsintheMatagalpadepartmentofNicaragua.Oneachfarm,onetreatmentwasleft asdegradedpasturewithnaturalized grass speciesHyparrhenia rufawhile the adjacent areawas sown with the improved Brachiaria brizantha cv. Marandu species without fertilizer. Wemeasuredasuiteofsoilchemical,biological,andphysicalvariablesaswellasstandingbiomassinAugust2015,2 years after establishmentof the trial.The improved (B.brizantha)pastureswerefoundtoproducemorestandinggrassbiomassandsupporthigherlevelsofearthwormpopulationsand permanganate oxidizable carbon (POXC) compared to the degraded control. CorrelationanalysisrevealedthatearthwormsandPOXCwereassociatedwithincipient improvementstosoilstructureandwaterholdingdynamics.Wereportmeasurable improvements tosoilhealthwithinjust two years following the establishment of improved silvopastoral systems under commonsmallholdermanagementpracticesandsuggestthatpromotionofthesesystems,evenwithminimalfertilityinputs,hasthepotentialtoenhancesustainabilityinthisregion.

#SI.7TheinfluenceofagriculturalpracticesontheabundanceofarbuscularmycorrhizalfungiinruraleasternZambiaAdamCobb,GailWilsonOklahomaStateUniveristy,UnitedStatesZambia and many developing countries are struggling to protect natural resources, such asproductive soils. Fortunately, symbiotic partnerships between agronomic crops and arbuscularmycorrhizal (AM) fungi can help make agricultural systems more sustainable and improve soilquality.While theeffectsof industrialagricultureonAMfungihavebeenstudied in theUS,muchless isknownaboutconsequencesof farmmethods inAfricansoils.Wecomparedsoils fromfourfarms in Zambia with soil from nearby grassland (control) to assess microbial abundances,includingAMfungi,usingphospholipidandneutrallipidfattyacid(PLFA/NLFA)analyses.Wealsomeasured soil pH, soil organic matter, and nutrients, and categorized farms to link microbialabundances with agricultural practices including: low and high input cultivation; conservationfarming;andagroforestry.Soilorganicmatterwassignificantlygreater ingrassland,compared tofarms.TheconcentrationsofN,P,andKweregreaterinfarmsoilscomparedtograsslandsoil,butFeandZnweresignificantlydiminishedonallfarms.AMfungalabundance(PLFA)wassignificantlygreater in grassland compared to the farms, and grassland containedmore thandouble the totalmicrobial biomass compared to any farm. Abundance of AM fungal storage biomass (NLFA; e.g.spores)didnotdiffer between grassland soil and the conservation farm; however, all other farmpracticesreducedabundanceofAMstoragebiomass.Ourresults indicateagriculturalpractices ineastern Zambia are negatively affecting AM fungi as well as other soil microbes. However,conservationfarmingshowspromiseinfacilitatingAMfungalrecovery.

#SI.8MODIRT‐Missouriansdoingimpactresearchtogether‐AcitizenscienceprojecttomonitorsoilhealthinthestateofMissouriTerryWoodford‐thomas,*SandraArango‐CaroDonaldDanforthPlantScienceCenter,UnitedStatesMO DIRT – Missourians Doing Impact Research Together, an NSF‐supported citizen scienceinitiative,educatesindividualsonsoilscienceandsoil‐climateinteractions.OnecomponentofMODIRTismonthlysoilhealthsurveys(February‐November)conductedbyvolunteersattestsites.Acohort of170 citizenshasbeen trained, ofwhich61have received soil surveykits. Currently, 45sitesrepresenting forest (13),woodland(4),prairie(8),grassland(11),pasture(4)andcropland(5)habitatsareactivelymonitored.Thedatacollectedisstoredinanon‐linedataportalthatwillsoonbeopen‐access(modirt.missouriepscor.org).Participantsareexposedtothescientificprocessbycollectingandmanagingsoilhealthdatawhiledevelopingasenseofstewardship forMissourisoils. Citizen‐collected data on the temporal relationship between soil respiration (SR) and soiltemperature (ST) are presented. SR, an indicator of soil microbial activity, is expressed aslb/acre/dayofCO2‐CandmeasuredusingtheSolvitamethod.In2016,SRincreasedinallhabitatsstudied from February to a peak in July and declined until November indicating a response toseasonalchanges.ThiswassupportedbyapositiverelationshipbetweenSRandSTinallhabitats.Grasslands showed the highest levels of SR, followed by forests and prairies. Site‐specificityinfluenced these results as sites of the same habitat differed in history of management, naturaldisturbances, soil types, etc. The inclusion of additional survey sites and analytical results willimproveourunderstandingofSRanditsinterplaywithchangesinweatherpatternsandclimate.

#SI.9SoilaggregationandorganicmatterstabilizationingreenroofsystemsandimplicationsforCsequestrationCamGudmundson1,LouiseEgertonWarburton21LakeForestCollege,UnitedStates2ChicagoBotanicGarden,UnitedStatesGreenroofsystemsarepurportedtooffseturbanCO2emissionsbysequesteringCinsoilsubstrates.However, few studies have examined C sequestration in green roof systems, meaning that it isequallyplausiblethatroofsubstratescouldactassinksorsourcesofCO2.Innaturalsoils,physicalprotectionof soil organic carbon (SOC)within aggregates is considered tobeoneof themajorCstabilizationmechanisms.Inthisstudy,wequantifiedSOCinsoilaggregatefractionsingreenroofsto determine if: a) physical stabilization of SOC in soil aggregates occurred, and b) stabilizationresultedinsimilarSOClevelstonaturalsoils.SoilswerecollectedundernativetallgrassspeciesandSedum in a seven year‐old green roof and in natural soils, wet‐sieved, and each aggregate sizefractionanalyzedforCbycombustion.Wefoundthatwater‐stableaggregateswereformedingreenroofsaswellasnaturalsoils,andthatmicroaggregatesweremoreabundantthanmacroaggregates.However,theabundancesofbothaggregatesizeclasseswereloweringreenroofthannaturalsoils.Microaggregateswerealso relatively enriched in total SOC compared to themacroaggregatesbutagain,aggregateSOCandparticulateorganicCweresignificantlyloweringreenroofthannaturalsoils.Takentogether,theseresultsindicateareducedcapacityforSOCstabilizationingreenroofsincomparison tonatural soils. Possibly, Cmineralization exceedsnewC inputs, or there is reducedbindingofmineralandorganicparticlestoformstableaggregatesingreenroofs.

#SI.10Estimatingsoilcarbonwithopen‐sourceVNIRspectroscopyDanielKaneYaleSchoolofForestry&EnvironmentalStudies,UnitedStatesStudies have found that visible/near‐infrared (VNIR) spectroscopy can be successfully used toestimate soil carbon concentrations instead of more expensive GCMS analyses. But standardbenchtopandspectrometersarestillexpensiveandrequireexpertisetooperate.Wehaverecentlydevelopedaprotocolthatmakesuseoflow‐costfieldspectrometersbuiltonthePhotosynQopen‐source hardware/software platform to estimate soil carbon content. First, we sample soilthroughoutagivensitetocapturearangeofsoilcarboncontentsusingtraditional,highlyaccuratelab‐based techniques. Thosedata are thenused to build statisticalmodels relating lab‐measuredsoil carbon levels to the spectral data collected with the field spectrometer. These models arefurther improved by integrating different data types thatmay be predictive of soil carbon levelsfromspatiallyexplicitdatasets,suchassoiltypeornetprimaryproductivity.Aftertheinitialsite‐specificcalibration,carboncontentcanbedeterminedinthefieldusingonlythespectrometerandthe sitemodel, dramatically reducing sample collection time and cost and allowingmanagers tosamplemore frequently in the futureandoverbroaderareas.Furthermore, thedevice integrateswithasimpletouseappthatallowsseveraluserstocoordinateadatacollectioneffortatthesametime, creating theopportunity forparticipatory, citizenscienceprojects.With these reductions incostandstreamliningofsampleefforts,managerscanworkwithresearcherstoquantifysoilcarbonat landscape scales and at more frequent intervals, allowing them to inexpensivelymonitor soilcarbonresponsesasnewmanagementpracticesareadopted.

#SI.11MitigatingtheimpactofslowsensorresponsetimesoncalculatingsoilCO2fluxesfromNEON’ssoilCO2measurementsEdwardAyres1,NatchayaDurden1,DavidDurden1,MoniqueLeclerc2,JoshRoberti11NEON,UnitedStates2TheUniversityofGeorgia,UnitedStatesThe National Ecological Observatory Network (NEON) is measuring vertical profiles of soil CO2concentrationat47 sites toallowcalculationof soilCO2 fluxesusing thegradientmethod.NEONdesignedasoilCO2assemblytoprotectthesensorsfromthesoil,whileensuringtheyareremovablefor calibration without disturbing the surrounding soil. However, the assembly’s relatively largevolume slows the sensor’s response time. In this study, we quantify the response time of CO2sensors installed in these assemblies, as well as the response time’s impact on soil CO2 fluxcalculations. We used a controlled environmental chamber to determine the response time ofsensors in assemblies following a rapid increase in CO2 concentration. We then combined theresponsetimederivedfromthechamberdatawitha10‐daytimeseriesofCO2concentrationsmadeby sensors installed directly in the soil to approximate the impact of NEON’s assembly, andcalculatedtheCO2fluxforbothtimeseries.Initialresponsetimetestsindicated95%ofthesensorresponse occurred within 2.5±0.3 hours. Mean CO2 fluxes over the time series were similar forsensors outside and inside the assembly (2.30±0.36 and2.30±0.33µmolm‐2s‐1, respectively), butthemeasurementrangewassmallerforsensorsintheassembly(0.98‐3.06versus0.59‐3.15µmolm‐2s‐1). The temporal pattern of fluxes outside and inside the assembly were similar, but theassembly caused a ~30 minute lag. Accounting for the lag improved the Pearson correlationbetweenthetimeseriesfrom0.95to0.98.

#SI.12Changesinphysicalprotectionofsoilorganicmatterfollowingfiveyearsofbiofuelcroppingsystemcultivation:soiltexturemattersAdamvonHaden,ChristopherKucharik,RandallJackson,ErikaMarın‐SpiottaUniversityofWisconsin‐Madison,UnitedStatesPhysical protection of soil organic matter (SOM) within aggregates is regarded as an importantmechanismof SOMaccrual, but the efficacy of SOMprotection is thought to vary by soil texture.WhiletheconversionofannualrowcropstoperennialsystemshasbeenshowntobuildSOM,itisnotclearwhethersoiltexturemodifiesshort‐termSOMstoragepotentialthroughitseffectonsoilaggregation.Weexaminedchanges intheunprotectedfree light fraction(FLF)andtheaggregate‐protectedoccludedlightfraction(OLF)afterfiveyearsofbiofuelcropcultivationontwosoilswithcontrastingtextures.ThecroppingsystemswereestablishedattheArlingtonAgriculturalResearchStation in Wisconsin and the Kellogg Biological Station in Michigan and included no‐till maize,switchgrass,popular,andprairie.Preliminaryresults indicate that the initial sizesof theFLFandOLFweresimilarbetweensoiltextures.However,afterfiveyearsofcultivation,theOLFtendedtoremain similar or increase in the fine‐textured soil but decreased dramatically in the coarse‐texturedsoilinalltreatmentsexceptpoplar.AtbothsitestheperennialcroppingsystemstendedtohavegreaterOLFandlessFLFthantheannualcornsystem.Notably,thepoplarsystemcontainedthe largestOLFandsmallestFLF, suggesting rapid comminution and incorporationofplant litterintoaggregates.Overallourpreliminaryresults indicatethatperennialsystemsaremore likely tostoreaggregate‐protectedSOMthanannualrowcropsystemsintheshort‐term,butinitiallossesofaggregateSOMmightbeexpectedincoarse‐texturedsoils.

#SI.13Long‐termlandusechangeandimpactsonsoilfaunaldiversityPhilMurray1,JenniferDungait1,UmranAkkan2,StuartNorris11RothamstedResearch,UnitedKingdom2DirectorateofPlantProtectionResearchInstituteBornova‐Izmir,TurkeyHerewefocusontheeffectofhistoricalmanagementchangesinaverywelldocumentedmanagedareascoveringasmallgeographicaldistancetocontrolforconfoundingfactorssuchasdifferingsoiltype and climate. This approach allowed us to decouple the impacts of climate and otherenvironmental factors from managed, vegetation‐imposed effects. Ultimately this will tell uswhethertherearecontextualrelationships,orwhetherwecanmakegeneralrulesonhowsoilbiotarespondtolongertermanthropogenicchangeandtherelativeresilienceofthesesystemstochange.This investigationassessedthediversityandabundanceofarthropodsalongachronosequenceoflandusetypes.Thehabitatscomparedandtheapproximateagessinceanthropogenicdisturbancewere; ancient woodland (>200y), old woodland (<200y), unimproved semi‐natural grassland(>50y), willow/poplar coppice (>30y), unimproved permanent pasture (<20y), improvedpermanentpasture(<10y)andrecentlygrazedandreseededgrassland(>2y),allhabitatswereonthesamesoiltypeandwithina5kmradius.Landusetypeandagesinceanthropogenicdisturbancesignificantly influenced (p<0.05) the community composition of soil fauna.Woodlands generallycorrelated with lower pH and were richer in arthropods compared with recently managedgrassland.Thisstudyhasconfirmedasignificanteffectoflandusetypesandagesincedisturbance,clarifyinghowunderlyingabioticfactorsalterabundance,richnessanddiversityofsoilarthropods.

#SI.14Howdoesrecreationalcampingaffectcovermediatedsoilmicrobialactivity?SudanKariuki,MitchMcclaran,RachelGalleryUniversityofArizonaSchoolofNaturalResourcesandtheEnvironment,UnitedStatesRecreationmanagement of popular outdoor activities such as camping is becoming increasinglyimportant in natural areas of the United States. Likewise, recreation ecologists are tasked withinvestigating how these activities affect ecological processes. This case studyuses the SantaRitaExperimentalRange(SRER)inSouthernArizonatoinvestigatehowrecreationalcampinginfluencestherelationshipbetweensoilmicrobialactivityandlocalplantcompositioninadesertgrassland.In2013, fences were installed to limit the spread of frequently used campsites. Therefore, thesecampsites each provide a direct comparison of recently disturbed, formerly disturbed, andundisturbed areas within a 10 meter radius. Previous research shows that soil beneath treesexhibitsgreatermicrobialactivitythansoilinbareareas.Stratifiedgroundcover,microbialbiomassassay,andenzymeassaydatawillbecollectedintheserespectiveareasinordertostudytheeffectsofcamping‐relateddisturbancesonplant‐soilinteractions.Expectedresultsincludecorrespondinglow herbaceous and litter ground cover, enzyme activity, and microbial biomass in currentlydisturbedareasrelativetoundisturbedareas,andhighenzymeactivityinbothundisturbedshadedareas and disturbed shaded areas. Trampling reduces cover and limits plant litter available formicrobialdecomposition.However,campersarelikelytodepositnutrient‐richwasteintheshadeoftrees, which may stimulate microbial activity. Camping introduces complex changes to ongoingecological processes, but does not necessarily eliminate potential for healthy active soils andrevegetation.

#SI.15ConservationagricultureenhancessoilqualityandfunctioninanirrigatedcroppingsystemofEasternColoradoDanielAlmeidaMelman1,CourtlandKelly2,JoelSchneekloth3,FranciscoCalderon4,StevenFonte21UniversityofSaoPaulo,Brazil2ColoradoStateUniversity,UnitedStates3ColoradoStateUniversityExtension,UnitedStates4USDA‐AgriculturalResearchService,UnitedStatesTillage and stover harvest are common management practices in corn‐based cropping systemsaroundtheglobe. However,giventhat frequentsoildisturbanceandbiomassexportare likely tohavenegativelong‐termimpactsonsoilfertility,soilstructureandbelowgroundbiologicalactivity,there is great concern surrounding the sustainability of these practices. To address this issue,experimentalplotswereestablishedinApril2014inAkron,Coloradotounderstandtheimpactsofconservation agriculture practices, no‐tillage and residue retention, in a full factorial designwiththe following treatments: no‐till + residue retention (NT/R); no‐till + residue removal (NT/NR);conventionaltillage+residueretention(T/R);andconventionaltillage+residueremoval(T/NR).In year threeof the experiment soil healthparameterswere assessed including: soilmacrofaunacommunities,enzymeactivity,aggregatestability, infiltration,andchemicalfertilitymeasures.Thecombined practice of residue retention with no‐tillage (NT/R) greatly enhanced macrofaunacommunities, but thiswasespecially apparentwith a five‐fold increase in earthwormabundanceandbiomass.Greaterearthwormpopulationswerealsostronglyrelatedtoanincreaseinaggregatestability under NT/R and a trend for greater water infiltration. Enzyme and soil chemicalparametersindicatedrelativelylessdramaticdifferencesbetweentreatments.Ourfindingssuggestthat no‐till and residue retention practices offer great promise for improving soil structure andhydrologic function,and that theseeffectsare largelymediatedbygreaterearthwormabundancewhenthesetwopracticesarecombined.

#SI.16Soilhealthimplicationsofgrazedvs.un‐grazedcovercropsintheU.S.highplainsCourtlandKelly1,MeaganSchipanski1,WilmaTrujillo2,DanielMelman3,AngieMoore1,StevenFonte11ColoradoStateUniversity,UnitedStates2ColoradoStateUniversityExtension,UnitedStates3UniversityofSaoPaulo,BrazilCover cropping is an important agroecologicalmanagementoption for improving soil health, butadoption in the High Plains region has been slow due to water/economic concerns. Our studyinvestigatestheimpactsofgrazedvs.un‐grazedcovercropsonarangeofsoilqualityparametersindryland wheat‐based rotations. On‐farm trials were established at five sites across easternColorado,WesternKansasandWesternNebraskabyplantingaseedmixture(eightspeciesofwarmandcoolseasongrasses,legumeandbroadleafspecies)intheSpringof2016.Theplantedfields(>20ha)weredividedintofourblocksandgrazingexclosureswereestablishedtogetherwithfallowplots(maintainedwithminimalvegetation)tocreatethreetreatmentsperreplicateblock.Soilwassampled in Summer 2016 at cover crop termination (by herbicide) for evaluation of soilcompaction, aggregate stability, nutrient availability, and water storage in the soil profile.Preliminaryresultssuggestgreatersoilmoisturedowntoadepthof100cminthefallowvs.covercroptreatmentsatthetimeofcovercroptermination,butmoistureatshallowerdepths(0‐60cm)in the cover‐cropped treatments recovered to fallow levels by wheat planting in Fall 2016.Preliminary results suggest that impacts on aggregate stability, bulk density, and nutrientavailability appear tobe lessdramatic . These results indicate that grazingdoes not significantlyaffectsoilstructureorotheraspectsofsoilhealth,butthatsoilwaterusemaybeacriticaldriverofadoption.

#SI.17MicrobialecologyofcompostingbeddedpackTuckerAndrews,*DeborahNeher,ThomasWeichtUniversityofVermont,PlantandSoilScience,UnitedStatesBedded pack dairy systems use carbon rich substrate such as straw orwood chips to bed cowsthroughoutthecoldVermontwinter.Ratherthanremovethebeddingandmanure,itissimplyre‐beddedwithmoresubstrateandlefttoaccumulateforupto8months.Decompositionwarmsthelower levels of the bedded pack as the cows happily congregate on the freshly bedded surface.Whenspringweatherallowscowstoreturntopasture,barnsarescrapedclean,andthebeddingisspreadinthefield. AsthesesystemsgainpopularitywithdairiesthroughoutVermont,ourgroupnotedtheimportantpotentialofbiologicalinteractionbetweenthebeddedpackandotherpartsoftheagro‐ecosystemsuchasbovinemastitisandbitingflypests.Weuseamicrobiomeapproachtostudy the disease cycle of mastitis of dairy cows by exploring 16S/ITS DNA sequencing of themicrobiome of cows, flies and bedded pack. Highly abundant fungal taxa include Aspergillus,Candida and Thermomyces. Highly abundant bacterial taxa include families Moraxellaceae,PseudomonadaceaeandSphingobacteriaceae. Beddedpackmicrobial taxaobserved tohavetwo‐fold shift in relative abundance in the presence of clinical mastitis include Comamonadaceae,Flavobacteriaceae,Moraxellaceae,Sphingomonadaceae,andRuminoccaceae.Fungaltaxaingreaterthan1%abundanceinbeddedpackthatwerealsogreaterinmastiticmilkincludedDebaryomyces.Sampling at five farms revealed that management practices and choice of bedding materialinfluencethemicrobialcommunityofbeddedpack.

#SI.18ConservationtillageimpactsonsoilqualityparametersunderfurrowirrigationEmmanuelDeleon,TroyBauder,StevenFonte,ErikWardleColoradoStateUniversity,UnitedStatesFurrowirrigationiswidelypracticedinColoradoandit’sexpectedtocontinueacrossmuchoftheState. Under furrow‐irrigated systems, conventional tillage practices are common, but suchpractices canhave adverse environmental impact anddegrade soil quality. Theproject sought toexamine the effects of conservation tillage on soil health at a production scale, understandrelationships between soil parameters, and to evaluate the economic feasibility of conservationpractices. Soil biological, physical, and chemical parameters were evaluated during the fifth andsixthyears(2015and2016)ofastudycomparingtwodifferentmanagementsystems,minimumtill(MT), and strip‐till (ST), vs. a conventional tillage (CT) control. Measurement included activecarbon,macrofaunacommunities,aggregatestability,infiltration,andtotalsuspendedsolids(TSS),and residue cover. Active carbon was significantly higher for minimal tillage when compared toconventionalandstriptill.Resultsfrombothyearssuggestthatconservationtreatmentsincreasedmacrofauna abundance, especially earthworms, and diversity (richness) relative to the control.Aggregate stability was significantly higher in the conservation treatments for 2015, but not in2016. Infiltration rates were slightly higher under strip‐till, while TSS in runoff water weresignificantlyreducedinbothconservationtreatments.ResiduecoverwasstronglycorrelatedwithmacrofaunaandearthwormabundanceandTSSloss.Whencomparingeconomiccost,andreturnsamong systems, strip till had a16%greater returnwhen compared to conventional tillageplots.These preliminary results show potential for conservation tillage under furrow‐irrigation toimprovesoilqualityparametersaswellasincreasingnetincome.

#SI.19ReductionindailysoiltemperaturerangeincreasemicrobialcommunitydynamicsinadrylandcottonproductionsysteminWestTexasDianaVargas‐Gutierrez1,JohnZak1,VeronicaAcosta‐Martinez2,BobbieMcMichael11TexasTechUniversity,UnitedStates2USDA‐ARS,UnitedStatesSustainabilityofagricultureintheSouthernHighPlainsofWestTexasfaceschallengesduetotheclimate change variability is imposing on soil health, microbial dynamics, water use and plantproductivity.Soiltemperatureiscrucialforplantgrowth,andtheabilityofmicroorganismtocarryout fundamental process. Variation in Daily Temperature Range (DTRsoil) has a large impact onmicrobial activity in arid and semi‐arid environments. Thus, it is imperative to understand howtemperature variability at the daily scale influences microbial communities and their roles innutrientcycling,andcarbonstorage. Weevaluatedthe impactsofmodifyingDTRsoilonmicrobialresponses.For2014‐2015growingseason,3treatmentswereestablished:Control,ReducedDTRsoilusing erosion blankets (shade), and Reduced DTRsoil using sorghum residue (stubble) tomodifyDTRsoil,withsixplots(4x3m)ineachtreatment.Soilsampleswerecollectedmonthlytoevaluateedaphic parameters, extractableNH4+‐N andNO3‐‐N, andmicrobial parameters. The stubble andshadereducedtheDTRsoilby6°Conaverageatthesoilsurfaceand2°Cat15cmduringthehottestmonths. Microbial biomass carbon increased in stubble by 43% on average irrespective of anychanges to soil moisture while extractable nitrogen levels were higher under control plots incomparison with reduced DTRsoil plots. The reduction in DTRsoil in these semi‐arid systemspositively affectedmicrobial dynamics and their contributions to soil productivity, this will helpcottonproducersmitigateclimatevariabilityimpactsandimprovesoilhealthleadingtosustainablecottonproductioninWestTexas.

#SI.20Responsestosoilmesofaunatoagriculturalpracticesandarablefield‐marginmanagementLeaCarlesso1,GrahamHartwel2,KarlRitz3,PhilMurray11RothamstedResearch,UnitedKingdom2BASF,UnitedKingdom3TheUniversityofNottingham,UnitedKingdomSoil health is a key factor controlling crop quality and yield in which soil fauna underpin soilprocessesinrelationtoorganicmatterdecompositionandnutrientcycling.Abetterunderstandingof abundance and composition of soil faunal populations is therefore essential in determiningagricultural ecosystem health and preserving soils and their functions. Over two seasons, westudiedsoilinvertebratepopulationsinanarablefieldanditsassociatedgrassmargin.Theaimofthestudywastounderstandwhetherfieldmarginsaffectpopulationstructure,andifsucheffectsextended into the field. Results showed that distribution of soil fauna varied depending on bothenvironmental and seasonal factors. In comparison to the crop, margin did not strongly modifypopulations of soil invertebrates. However, this populations were reduced in the fallow areabetween fieldandmargin,and in the tramlines further into the field.Someofsoilpropertiesandfaunaldistributionsshowedaspatiallydiagonalorientationtothemargin. Agriculturalactivities,suchas trafficking,couldbetheoriginofnon‐conduciveconditions forsoil faunabutnoneof thecurrentfieldactivitiesexplainthediagonalpatternandatthepresenttime,onlyassumptionscanbe made about it. Digging in the landscape history of Rawcliffe Bridge suggested that far olderagriculturalmanagementsmay still affect soil properties. The study showed that field activitiesmay mask inherently effects of landscape diversity. It also raises possible issues about the'agricultural footprint' on soils and the necessity to care about the potential long‐term legacy ofmanagementpractices.

#SI.21ImpactofcompactionondecompositioninanarablefieldandpossibleimprovementbymanagingtheheadlandLea Carlesso1, AndrewBeadle2, GrahamHartwell2, Debbie Sparkes3, Karl Ritz3, LianhaiWu1, PhilMurray11RothamstedResearch,UnitedKingdom2BASF,UnitedKingdom3TheUniversityofNottingham,UnitedKingdomSoil compaction is amajor threat on agricultural soil and heavymachineries are responsible fordamagingsoilchemical,physicalandbiologicalproperties.Amongthese,soildecompositionisthenecessary process to nutrient cycling that transformed organic matter into mineral nutrients.Becausenutrientturnoverisessentialtocropproduction,understandingwhatfactorsimpactsoilbiota,andaffectitsfunctionality,isafirststeptobetteragriculturalpractices.Inapreviousstudy,weassessedwhethermarginsaffectsoilbiotainfieldscloseby.Resultsshowedthatsoil faunawashighlyreducedwithin the firstmetersof field,where tramlinesandwheelingwere situated. To understand in which extent compaction affects soil ecology, we assesseddecompositioninthreedistinctfieldareas:themargin,thetramlinesandthecrop.Threetypesoflitter in two differentmesh sizes litter bagswere buried for 1, 2, 4 and 6months. Soil physicalpropertiesweremeasured,andasexpectedbulkdensitywas lower inthecompactedtramline. Italsoconfirmedthatthegrassmarginimprovedsoilstructurecomparedtothefield.Resultsshowedthehighestmasslossoccurredinthegrass,andthelowestinthetramlineanddifferencesbetweentreatmentsincreasedwithburialtime.Nosignificantdifferenceofmasslossbetweenthetwomeshsizeswasdetectedbeforethefourthmonth, implyingthatmicrobialdecompositionwasthemainprocess involved at the beginning. Decomposition in the tramline was clearly affected by thestructuredegradationandlimitationofwaterandnutrientsuppliesduetoheavycompaction.

#SI.22EmpiricalevidencethatpassivemicrobialdispersalmaintainssoilcommunityandecosystemfunctionSarahEvansMichiganStateUniversity,UnitedStatesDispersal rate is increasingly recognized as an important determinant of microbial communitycompositionandfunction.Themechanismsthatunderlietheeffectofdispersalonfunctionarealsorelevant to efforts to optimize soil function by application of biological inocula (or colonists).However, knowledge of the ecological role of microbial dispersal in situ is limited. Rain hosts adiverse community ofmicroorganisms,making it a proportionally small but consistent source ofmicroorganisms tosoil.Toassess theecological impactofpassivedispersalonsoilprocesses,weestablishedmesocosmsof intactsoil coresatKelloggBiologicalStation.Afterrain, coresreceivedeither filter‐sterilized rain (nodispersal) or ambient rain (dispersal).We alsooverlaid adroughttreatment on these cores to test whether zero dispersal constrained community and functionalresilience under stress. We found that excluding rain immigrants significantly altered microbialcommunity composition and substrate utilization, as well as soil properties. Soils experiencingdispersallimitationhadlowerwaterholdingcapacityandhighernitrateexport.Althoughmicrobialbiomasswassimilaramongdispersallevels,wefoundthatfunctionaldiversitywasreducedunderdispersal limitation. Drought treatments also had reduced functional capacity and diversity, butwereunaffectedbydispersaltreatment.Overall,weobservedaninteractionbetweendroughtanddispersal, but saw no evidence of dispersal rescuing function. Our data demonstrate that rain‐dispersedmicrobesmaintainsoilmicrobial function,but thedisturbance stateof soilsmodulatesthe effect of dispersal. Ultimately our understanding of dispersal and colonization can informstrategiesformanagingmicrobiomesforecosystemfunction.

#SI.23Soilmicrobialdynamicsinalong‐termsustainablecottonforsemi‐aridWestTexasPabloTovar1,VeronicaAcosta‐Martinez2,JohnZak11TexasTechUniversity,UnitedStates2USDA‐ARS,UnitedStatesSustainableagriculturepracticescan improvemicrobialcapabilities tocarryout fundamentalsoilprocesses. Understanding microbial dynamics in soils within long‐term sustainable practices iscriticalforaddressingimpactsofincreasingclimatevariabilitywithinasemiaridsystem.Thisstudydescribes microbial dynamics from a 10‐year‐old sustainable cotton production system on theSouthern High Plains of West Texas (no‐till and stubble application). In 2016, 8 replicate plotswhere randomly selected from a full section center pivot irrigated cotton field. A layer of cornstubblefromthepreviousgrowingseasonalongwithterminatedwinterwheatcoveredthesoil.Soilsampleswerecollectedandanalyzedmonthlytoevaluateedaphicparameters,nutrientlevels,andmicrobial communitystructure. Inaddition,eachplothadadata logger to recordhourlydataontemperature and volumetric water content (VWC) through the growing season. Soil microbialbiomass decreased over the growing season irrespective of soil moisture levels. However, usingFAME analyses, relative abundances of saprophytic fungi and arbuscular mycorrhizae weredominant (27.4% and 30.9%) with Gram positive, Gram negative and Actinomycetes, relativeabundancewasbetween26.4%and27.6%acrossthegrowingseasonwithlittleseasonalchanges.Between 0.8% and 1.7% of the FAME signatures were assigned to protozoans. Lastly, 40.9% to45.1%thetotalFAMErelativeabundanceswereassignedasunidentified.Nutrientanalysesshoweda general decrease across time.Nonmetricmultidimensional scaling analysis indicated that dailytemperaturerange(dailyTmax–dailyTmin)andVWCwerethetwomostimportantabioticvariablesshapingmicrobialcommunitystructure.

#SI.24RhizosphereandbulksoilmicrobialdynamicsinEngelmannSprucestandsinresponsetoSprucebeetleattackGordonCuster,WilliamStump,LindavanDiepenUniversityofWyoming,UnitedStatesThecurrentoutbreakof sprucebeetle in theColoradoandWyomingmountain forests is causingwidespreadtreedeath. Astreesdie,theassociatedmicrobialcommunityislikelytochange.Withnew advances in genomic technologies, scientists are beginning to understand the intricacies ofthese plant‐microbe interactions. The phytobiome includes themicrobes that are on or in closeproximitytotheplantandareresponsibleformanybeneficialplantandecosystemfunctions.Oneofthemoststudiedphytobiomecomponents, therhizosphere, is likelymost importantduetotheadvantages a healthy functioning rhizosphere coveys. To understand how the rhizosphere ofEngelmannspruce,aswellas thesurroundingbulksoil,changes inresponsetobeetleattackandcolonization of blue stain fungi, a chronosequence of beetle infestation was utilized. Therhizosphereandbulksoilof threephases;healthy, infestedanddead tree clustersweresampled.Significantdifferencesinsoilgravimetricwatercontentwereobservedbetweenallthreephases,aswellasanincreasedsoilpHandECinthedeadandinfestedphasecomparedtothehealthyphase.These physical and chemical changes, based on previous studies, are predicted to have directimpactsonthemicrobialcommunitystructure.Usinghigh‐throughputsequencingofthefungalandbacterialcommunitiesintherhizosphereandbulksoilassociatedwitheachofthethreephaseswewillanalyzetheimpactsofbeetle infestation.Weexpectto finddistinctmicrobialcommunitiesateachphase,withmoresaprotrophsinthedeadphaseandmorepathogensinthediseasedphase.

#SI.25HowbeddesigninadrylandcottonsystemcaninfluencesubsequentmicrobialdynamicKholoudGhanemTexasTechUniversity,UnitedStatesSoil temperature indry‐landcottonproduction systemscan influence soilmicrofloraactivityandnutrientavailability,andplantproduction.Fieldmaintenancepracticesandsoiltemperatureneedsatplantingcouldresult inalteredmicrobialdynamicsas the seasonprogresses.Forconventionaltilled cotton system on the Southern High Plains pitched beds are used to reduce erosion andincrease temperatures at planting. However, bed design could influence soil heat dynamics, byincreasing the Daily Temperature Range (DTR) of the soil. The goals of this project were toinvestigatetheimpactsofbeddesign(pitchedvsflat)onDTRsoildynamicsandmicrobialresponses,six4meterplotswith five rowsperplotwereestablished in2014and2015at theTTU farm inLubbock, TX. Soil samples to 15 cm depthwere collected starting inMay and followedmonthlythrough November. Microbial biomass carbon, enzymatic activities, FAME, and carbon usage bybacteriaandfungialongwithnutrientdynamicsandsoilmoisturewereevaluated.Beddesigndidimpact soil temperature dynamics and moisture status, especially during the hottest and driestportions of the growing season. Pitched beds were warmer than flat beds at both depths, andexperienced a higher DTRsoil through the growing season Subsequently flat beds contained 26%more microbial biomass carbon than the pitched across the growing season. Bed design is onemanagement tool that could be employed in cotton production systems across the SHP toamelioratesoiltemperaturevariabilityandthehighDTRsoilthatoccursintheregion.

#SI.26Investigatingchangesinsoilorganicmatterpoolsfollowingbark‐beetleoutbreakandsalvagelogging:ImplicationsforsoilorganicmatterformationBethanyAvera1,CharlesRhoades2,FrancescaCotrufo11ColoradoStateUniversity,UnitedStates2USForestService,RockyMountainResearchStation,UnitedStatesContinent‐scaleforestdisturbancecausedbyrecentbarkbeetleoutbreaksrenewedconcernaboutthe implications of forestmanagement on soil organic matter (SOM) formation and persistence.Decomposition of plant residue creates a range of physically‐distinct SOM pools with uniquecontributions toSOMdynamics.To investigate theconnectionbetweenmanagementofdisturbedforestecosystemsanddistributionSOMpools,wefractionatedmineralsoils(0‐10cm)from12sitesinColorado,subjecttothreemanagementtreatments:(1)uncutbarkbeetle‐infestedforestand,(2)adjacentsalvage‐loggedstandswitheither loggingresidueretentionor(3)removal.Mineralsoilswere fractionated into three SOMpools: light (<1.85 g/cm‐3), sand‐sized (> 53μm) andmineral‐associatedorganicmatter(MAOM,<53μm).Loggingwithresidueretentionincreasedthemassofthesurface,Oi,organichorizon(P<0.05);however,increasedOididnotresultinincreasedcarbon(C)inthedeeper,moredecomposedorganichorizons(OeandOa)orthemineralsoil.Incontrasttoexpectations, logging followed by residue removal increased mineral soil C compared to uncutstands(P<0.10).NodetectedchangesintheMAOMmeantherearenochangestothepersistentsoilC pool with the logging residue treatments. Therefore, the light and sand‐sized fractions,particularly thesand‐sized (p<0.05), largelydrove thechange inwholesoilC.FurtheranalysisofchangesintheMAOMfraction,aswellasofthecompositionandrecalcitranceofthelightandsand‐sized fractionsmayhelp elucidatewhichmechanisms linkOM inputs following logging and SOMformationandpersistenceincoarse‐texturedforestsoils.

#SI.27TheinfluenceofinvasiveearthwormsonoribatidmiteassemblagesinaborealaspenstandBrittanyMcAdams1,SylvieQuideau1,MathewSwallow2,LisaLumley31UniversityofAlberta,Canada2Mt.RoyalUniversity,Canada3RoyalAlbertaMuseum,CanadaNon‐nativeearthwormspecies,specificallyLumbricidae,areinvadingareasoftheboreal forest inAlberta, Canada. Lumbricidae species are ecosystem engineers, andwhen introduced into a newenvironmentmaystronglyaltersoilbiogeochemicalcycling.Earthworminvasionhasbeenstudiedin Southwestern Alberta with only a small series of studies conducted in Northern Alberta.NorthernAlbertasoilshaveathickforestfloorthatstores~24%ecosystemcarbonandhousesthemajority of soil biological interactions. Oribatidmites are key detritivores in these soils as theyinitiate litter decomposition and maintain forest floor structure. Earthworms also function asdetritivores, and when introduced into non‐endemic environments, can have adverse effects onoribatid mite composition. However, there is a dearth of field studies in the Northern Albertaregarding invasive earthworm disturbance on oribatid mite assemblages. The objectives of thisstudywereto(1)characterizeearthwormandoribatidmiteassemblagespresentinaborealaspenstand and (2) assess how oribatid mite assemblages respond to changes in soil biogeochemicalpropertiesasaresultofearthwormdisturbance.ThecasestudywasconductedinaborealaspenstandnearWolfLake,Alberta.Fourplotswereestablishedinareasofbothhighandlowearthwormdensity and sampled for earthworms and oribatidmites, whichwere identified to specieswhenpossible.Earthworminvadedplotshadsignificantlylowerforestfloorcarbon,thinnerforestfloor,and lower oribatid mite abundance. Further work will use a multivariate approach to analyzeoribatid mite species composition as a function of earthworm density and environmentalcharacteristics.

#SI.28Consequences of invasion by Bothriochloa bladhii and implications for tallgrass prairierestorationLuciWilson,GailWilson,KarenHickmanOklahomaStateUniversity,UnitedStatesGrasslandscover35%ofearth’slandsurface,providemanyessentialecosystemservices,andplayan important role indrivingglobalbiogeochemical cycles. Oneof thegreatest current threats tothese ecosystems is invasion by non‐native plant species. While the underlying biologicalmechanismsfacilitatingnon‐nativespeciesinvasionarestillunknown,thereisgrowingrecognitionthatalterationsinbelowgroundprocessesmayplayfundamentalroles intheirsuccess.OurstudywasconductedatKonzaPrairieBiologicalStation,Manhattan,KS,USA.Theobjectivesofourstudyare twofold;1)assessabove‐andbelowgroundconsequencesof invasionbyanon‐nativewarm‐season grass,Bothriochloabladhii, and 2) eradicate the invasive and assess potential restorationmanagement practices. Replicate plots were established in invaded and adjacent non‐invadednative grassland. Above‐ and belowground biomass, plant species composition, and soil biotic(relative abundance of soil microbial functional groups and intra‐radical mycorrhizal hyphalabundance), and abiotic parameters (plant‐available N/P, soil aggregate distribution) wereassessed. Aboveground biomass of the invasive grass was significantly greater than that of thenative prairie,while root biomass and soil organicmatterwas reduced. Eradication ofB.bladhiiusingsolarizationwasinitiatedspring2016.TarpswereremovedattheendofthegrowingseasonwithsuccessfuleradicationofB.bladhii. Thisupcomingfieldseason,wewillestablishrestorationtreatmentstoassessifinoculationwithnativeAMfungiimprovestheestablishmentofnativeplantspecieswhilesimultaneouslysuppressingre‐establishmentoftheinvasivegrass.

#SI.29UniformresponseofsoilrespirationtoexperimentaltemperaturemanipulationJoannaCarey1,JianwuTang2,KevinKroeger3,PamelaTempler41BabsonCollege,UnitedStates2MarineBiologicalLaboratory,UnitedStates3USGeologicalSurvey,UnitedStates4BostonUniversity,UnitedStatesThe respiratory release of carbon dioxide (CO2) from soil is one of the primary determinants ofatmospheric CO2 concentrations1. Climatic warming is hypothesized to increase soil respiration,potentially fueling further increases in global temperatures2. However, despite considerablescientific attention in recent decades, the response of soil respiration to anticipated climaticwarming remains unclear3. Here we synthesize >3800 observations from 27 temperaturemanipulation studies spanning nine biomes to reveal shared responses of soil respiration toexperimental warming. Contrary to the results from numerous single‐site studies4–6, we find nodifferences in the temperature responseof soil respirationbetween control andwarmedplots inseveralbiomes; temperaturesensitivitybetweencontrolandwarmedplotswasonlysignificantlydifferent indesertsandboreal forests.Thus,ourdataprovides limitedevidenceofacclimationofsoilrespirationtowarming.Acrossallnon‐desertbiomes,respirationratesincreasedexponentiallywithsoiltemperatureuptoathresholdof~25°C,abovewhich,therelationshipbetweenrespirationandtemperaturebecameneutralornegative.Thisconsistentdeclineinthetemperaturesensitivityathighertemperaturescouldnotbeattributedtochangesinsoilmoistureavailabilityatelevatedtemperatures. Our analysis highlights that rising global temperatures will result in regionallyvariableresponsesinsoilrespiration,withcolderclimatesbeingconsiderablymoreresponsivetoincreasedambienttemperaturescomparedtowarmerregions.

#SI.30StabilityofmicrobialactivityinanexperimentallywarmeddrylandNoelleEspinosa,*RachelGalleryUniversityofArizonaSchoolofNaturalResourcesandtheEnvironment,UnitedStatesDrylandecosystemscoverabout40%ofthegloballandsurfaceandplayasignificantroleinglobalwaterandbiogeochemicalcycles.Encroachmentofwoodyshrubsintodrylandgrasslandsisaglobalphenomenonthatalterstheecohydrology,plantbiodiversity,fireregimes,andproductivityofthesesystems.Theprojectedwarmeranddrierconditionsintheseregionsmayfurtheralterthefunctionand stability of these ecosystems through direct effects on soil microbiota and plant‐microbeinteractions. In drylands, microbial activities are regulated by nutrients and pervasive, seasonalwaterlimitation.Inmesicecosystems,warmingresultsinincreasedextracellularenzymepools,butthese resultsmight not apply to drylands.We used a long‐term passivewarming experiment toexplore the effects of warming and nutrient supply on extracellular enzymes after summer andwintermonsoons.Wemonitoredplantbiomass,soilrespiration,andenzymeactivityovertwoyearsinsoilscommontotheArizonaSonorandesert.Soilswereamendedwithbiocharandwoodchipstomimic woody shrub encroachment. We hypothesized that warming would increase carbonacquisition extracellular enzyme pools and create a positive feedback on carbon mineralizationfollowingbi‐annualmonsoons.Soilrespirationrespondedpositivelytowarmingforcertaincarbonadditionsandseasons.Forsevenhydrolyticenzymes,therewasnosignificantresponsetowarmingregardless of soil moisture and temperature. These results are consistent with other drylandwarmingexperimentsandsuggestcomplexresponsesofdrylandsoilmicrobialactivitytoclimatewarming.Analysisof themicrobialcommunitycomposition isunderwayandwillprovide furtherunderstandingofsoilmicrobialcommunitystability.

#SI.31Impactsofmoisture,soilrespiration,andagriculturalpracticesongrossCH4production inuplandsoilsmeasuredbystableisotopepooldilutionPaulBrewer1,FranciscoCalderon2,MerleVigil2,JosephvonFischer31SmithsonianEnvironmentalResearchCenter,UnitedStates2USDA‐AgriculturalResearchService,UnitedStates3ColoradoStateUniversity,UnitedStatesMethanogenesis that occurs in upland, unsaturated soils indicates the likely presence of anoxicmicrositeshostingother anaerobic activities.Theseactivities affectprocesses that are critical foragriculturalproductionandnaturalecosystemssuchasnutrientcyclingandgreenhousegasfluxes,however, little is known about the controls of anoxic microsite formation, persistence, andbiogeochemical impact. Agricultural practicesmay alter anoxic microsites and related processesthrough changes to soil properties. We hypothesized that methanogenesis, as an indicator ofanaerobicactivityinmicrosites,isprimarilyaffectedbysoilmoistureandrespiration.Totestthis,we examined relationships between soil properties, methanogenic microsite dynamics, andbiogeochemicalresponsesinafullfactoriallaboratoryexperimentoversoilsource(semi‐aridandmesic ecosystems), agricultural practice (conventional, no‐till, and organic), andmoisture (10 to95% water‐filled porespace, WFPS) in a five month intact core incubation. We found thatorganically‐managedsoilshadhigherratesofmethanogenesisthanconventionallytilledsoils,andsoilswithmorethan60%WFPSwerethreetimesas likely tohostmethanogenesisasdriersoils.Ratesofmethanogenesisvariedtemporally,withearlymethanogenesis(6thweek)correlatedwithhigher soil respiration andWFPSwhile latermethanogenesis (21stweek)was only predicted byWFPS. The importance of soil respiration andWFPS in our soils is similar to findings in betterstudied wetland systems, suggesting that upland anaerobicity can also arise from increased O2demandordecreasedO2diffusion.HigherratesofmethanogenesiswereassociatedwithhighersoilNH4+,lessNO3‐,andgreaterN2Oemissions.

#SI.32Long‐andshort‐termnitrogenadditionsincreasedecompositionofcovercropresiduesinagriculturalsoilsLisaTiemann,NzubeEgbolucheMichiganStateUniversity,UnitedStatesRecentstudieshaveshownincreasesinmicrobialbiomassandactivitynitrogen(N)amendmentsinannualcroppingsystems.Hereweexploretheeffectsofshort‐andlong‐termfertilizerNadditionson the decomposition cover crop residues in soils from a corn‐soy‐wheat cropping system. Ourstudy site at the Kellogg Biological Station in Michigan is an experiment started in 2000 thatincludesagradientofNfertilizer.WesampledsoilsinNovember2015withNadditionsof134and291kgha‐1Nduringyearsincorn.Duplicatesetsofsoilswereamendedwith5mgg‐1soilresiduefrom four different cover crops:millet, rye, hairy vetch and field pea.One setwas also amendedwith urea equivalent to 134 kg ha‐1. Soils and residues were incubated for 360 days, and sub‐sampledfourtimestomeasureextracellularenzymeactivities,inorganicNandmicrobialbiomassand net Nmineralization and nitrification rates. The short‐term (lab) N additions had a greaterimpactonNtransformationsthanlong‐term(field)Nadditions.Nmineralizationandnitrificationprocesseswerebothincreasedbyshort‐termNaddition,butonlyinsoils thatalsoreceivedlong‐termN.Thiswastrueregardlessofthedifferentcovercropresidues.Long‐termNadditionaffectedthetimingofnetpositivemineralizationandnitrificationandthereforeplantNavailability.Thesedataprovideevidenceforinteractionsbetweenlong‐andshort‐termNadditionstosoilsthathaveimplicationsformicrobialactivitiesrelatedtoresiduedecompositionandthetimingandmagnitudeofplantavailableNpools.

#SI.33TheMIcrobial‐MIneralCarbonStabilizationmodelwithcoupledNcycling(MIMICS‐CN)simulateslitterdecompositionandsoilorganicmatterdynamicsatlandscapescalesEmilyKyker‐Snowman1,WillWieder2,StuartGrandy11UniversityofNewHampshire,UnitedStates2NationalCenterforAtmosphericResearch,UnitedStatesMicrobesareincreasinglyrecognizedascriticalmediatorsofclimatechangeeffectsonsoilcarbon(C)andnitrogen(N)transformations,bothinfieldstudiesandtheoreticalmodels.TheMIcrobial‐MIneral Carbon Stabilization model with coupled nitrogen cycling (MIMICS‐CN) uses explicitmicrobial dynamics andmicrobe‐mineral interactions to simulatemeasured patterns of C andNcyclingatlandscapescales.ThemodelsimulatesCandNlossesfromlitterbagsintheLIDETstudy(6littertypes,10yearsofobservations,14sitesacrossNorthAmerica)withreasonableaccuracy(C: R2=0.59; N: R2=0.33). MIMICS‐CN simulations of litterbag N dynamics are better thanCommunity Land Model (CLM‐cn) simulations of the same data and as good or better thanDAYCENT simulations. Across the 14 simulated LIDET sites, MIMICS‐CN produces reasonableequilibriumvaluesfortotalsoilCandN,microbialbiomassCandN,respiration,inorganicN,andNmineralization rate. Parameter sensitivity analysis indicates that carbon use efficiency andmicrobial turnover are critical controls over model behavior that are poorly constrained byexperimentaldata.WealsosimulatedatheoreticaldoublelitteradditionexperimentatoneoftheLIDETsites (KelloggBiologicalStation) toexplore transientmodelbehavioracrossmicrobialandmineral pools. Unlike first‐order models where added litter can only result in increases in soilorganicmatter(SOM)pools,MIMICS‐CNallowsfreshlitteradditionstostimulatemicrobe‐mediatedClossesandNreleasefromSOMpools.

#SI.34Committeeforevidence‐basedaction:Educatingthepublicandpolicy‐makersforascientificallysoundfutureDanielRevillini,BoStevens,KaraGibson,AradhanaRoberts,PeterMotyka,NancyC.JohnsonNorthernArizonaUniversity,UnitedStatesThe role of critical, scientific thinking in the future of American society is uncertain, and thedisregardofevidenceisdetrimentalatmultiplelevelsofsociety.TheCommitteeforEvidence‐BasedActionisanewgraduatestudentgroupatNorthernArizonaUniversitywiththegoalofintroducingevidence‐based decision making as a platform to be adopted at the individual, local, state, andfederal levels. Our mission is to (1) advocate the use of evidence‐based decision making to thepublicandpolicy‐makers,(2)opendirectlinesofcommunicationbetweenscientistsandthepublicthroughopen‐access forumsand community events, and (3)promoteopen,public discourseandimplement coordinated actions that disseminate committee ideals.We have initiated communityforums to provide the public with direct access to scientists, and also to learn how scientificthinking helps us develop our stance on issues. We have presented issue‐focused seminars oncampus across multiple departments, and disseminated educational materials to help scientistsdeveloptheirwritingandspeakingskillsforbroadaudiences.We’vealsodevelopedonlinetraininganddiscussionworkshopstohelpincreasescientificoutreachtothepublic,policy‐makers,andthemedia.Ourgoalisnotonlytoinfluencepolicy,butthecollectiveconsciousofthepublictobringtheroleofscienceandevidence‐basedthinkingtotheforefrontofourdailylives.Onlythencanwe,asanation, influence the decisions made by legislators to protect human‐health, education, and theenvironmentinascientificallysoundmanner.

#SI.35Inquiry‐basedSTEMeducationforhighschoolstudents:strengths,possibilities,andopportunitiestogetinvolvedMarthaGebhardt,ElizabethSparks,RachelGalleryUniversityofArizona,UnitedStatesAlthoughmany high school science teachers incorporate climate science into their courses, theireffectivenessof teaching thesetopicsmaybehinderedby lackof trainingandconfidence in theirown understanding of these concepts. Educators with a greater appreciation and knowledge ofscience literacywill bemore successful at encouraging students to enjoy science andmotivatingthem to pursue science careers. Inquiry‐based science learning engages students in hands‐onactivitiesandcooperativelearningstrategies,whichhavebeenproventoincreasetheirknowledgeand interest of scientific concepts. To help overcome obstacles teachers encounter with scienceeducation, and engage and excite students in STEM, I worked with high school teachers andscientific experts in school districts in SoutheasternArizona todevelop a series of inquiry‐basedlessonsandvideosfocusedonclimateandhumanimpactsonvegetationabundanceanddiversityacrossspatialandtemporalscales.Studentsusethescientificmethodtoexaminevegetationattheirownschool,comparethesetrendstopatternsofvegetationacrossspaceandtimeattheSantaRitaExperimental Range, and relate these patterns to climate and cattle grazing data to study theirpotential impactonvegetation.Allmaterialsdeveloped,whicharepubliclyavailableonline, alignwitheducationalstandardsandprovidethetoolsandresourcesneededtomakeanyeducatorfeelconfident they can incorporate them into their classroom. Here I outline the successes andchallengesfacedinimplementingthisproject.Aslessondevelopmentcontinues,Ihopetoexpandscientificconceptsandbothresearcherandeducatorparticipation.

#SI.36Woodyshrubencroachmentaltersecosystemprocesses:LinkingimagingspectroscopyandmicrobialbiogeochemistryMarthaGebhardt,RachelGalleryUniversityofArizonaSchoolofNaturalResourcesandtheEnvironment,UnitedStatesArid and semi‐aridgrasslandsareundergoingprolific changes invegetationdue towoody shrubencroachment that causes large‐scale shifts in biogeochemistry. Nitrogen‐fixing mesquites, acommonshrubtoinvadetheseareas,fundamentallyaltersecosystemprocessesbychangingplantcommunity diversity, net primaryproductivity, and soil functioning.Although theproliferation ofthese shrubs is well documented, uncertainties related to landscape‐scale biogeochemicalconsequences and spatial patterns associated with shrub invasion remain. This information isneeded to quantify the effects of vegetation changes on ecosystem processes and services. Thisstudy combines hyperspectral foliar chemistry data with soil biogeochemical and microbialparameterstoquantifytheimpactsofshrubencroachmentonnutrientdynamicsatTheSantaRitaExperimentalRange (SRER) in southeasternArizona.Wepropose that hyperspectral data canbeused to quantify changes in ecosystem services due to differences in vegetation chemistry andassociatedbelowgroundprocessesacrossa landscape.Thesedataareusedto investigate the linkbetweensoilnutrients,topographyandtheabundanceofshrubsandgrasses;thepotentialeffectsof shrub encroachment on landscape‐scale nutrient dynamics; and the utility of imagingspectroscopytoinformmanagementpracticesthroughremotemonitoring.SRERisanideallocationto investigate these questions because long‐term data on vegetation dynamics across SRER ispublicly available and the proposed National Ecological Observatory Network (NEON) airborneobservationplatformoffersauniqueopportunitytomappatternsofplantspecies,litterinputsandmicrobial‐mediatedbiogeochemicalcyclingacrossthelandscape.

#SI.37EarthwormdistributionanddemographicsalonganaturallyoccurringsalinitygradientCaleyGaschNorthDakotaStateUniversity,UnitedStatesOver 90% of crop producers in North Dakota are affected by naturally occurring soluble salts(primarily sodium, calcium, andmagnesiumsulfates),whichoriginate in theparentmaterial andmigratetothesoilsurface.Salinitylevelscanbehighenoughtolimitcropproductionandinfluencesoil management decisions. Our objective was to examine the distribution and demographics ofearthworms in an annual cropping field that is affected by surface salinity, and that is currentlyundergoingmanagementtolimitsaltmigrationandimprovesoilhealth.Weestablishedatransectto capture increasing levels of soil electrical conductivity (EC), and collected intact soil cores forwormcountsandsoilsamplesforchemicalanalyses.Withincreasingsalinitylevels,weobservedadecrease in soil organic matter content and total worm counts for all worm age classes. Wormcocooncountswerenotdifferentacrosssalinitylevels.Juvenilewormswerethemostabundantageclass innon‐salinesoils,butwas thegroupmost reducedby increasingsalinity levels.Consistentcocoon counts and decreasing juveniles across the salinity gradient indicate that adult wormsmigrate into saline areas, but are not able to establish a viable population. Earthworm speciespresent in the studywere predominatelyAporrectodea trapezoides andAporrectodea tuberculatawith Octolasion tyrtaeum present. Worm occurrence and age classifications may be an easyindicatorforproducerstomonitorsalinitylevelsandsoilhealth.

#SI.38Understandinginteractionsbetweennitrogen‐fixingbacteriaandswitchgrassforsustainablebiofuelproductionRyanLancioneNorthernArizonaUniversity,UnitedStatesSwitchgrass(Panicumvirgatum)hasbeenrecognizedtohavegreatpotentialasabiofuelfeedstock.Switchgrasscanfunctionasanagriculturalcashcroponmarginalfarmlands,asoilrestorationtool,andasustainable,renewableenergysource.Bacteriathatliveonoraroundswitchgrassrootshavebeenshowntofixnitrogen(N)andimprovethenutritionalstatusofswitchgrass.Thenifgenescodefor enzymes involved in atmosphericN fixation.We usedquantitative polymerase chain reaction(qPCR) to determine the absolute abundance of the nifH gene found in the rhizosphere ofswitchgrassfromalong‐termexperimentalresearchsiteatArgonneNationalLaboratory.ThissiteteststhedifferencesbetweenthreeswitchgrasscultivarsandtheeffectofNfertilizationonbiomassproduction.WeidentifiedtrendswherethenifHgenewaslowerinN‐fertilizedplots,butcontrarytoourhypothesiswe foundnovariation innifHgeneabundancebetween the three cultivars. If thebeneficialrelationshipbetweenswitchgrassandN‐fixerscanbeoptimizedtominimizefertilizeruseandsustainorpromoteplantbiomassproduction,itcouldlowerthecostofswitchgrassproductionsubstantiallyandincreasethesustainabilityofnationalrenewableenergyproduction.

#SI.39Increasingcropdiversityincreasedsoilmicrobialactivity,N‐sourcingandcropN,butnotsoilmicrobialdiversityZanderVenter1,SamanthaLuiseScott2,JohannStrauss3,KarinJacobs4,*HeidiHawkins21UniversityofCapeTown/UniversityofStellenbosch,SouthAfrica2UniversityofCapeTown,SouthAfrica3WesternCapeDepartmentofAgriculture,SouthAfrica4UniversityofStellenbosch,SouthAfricaTherelationshipsbetweencropdiversity,soilmicrobialdiversity,andagro‐ecosystemfunctioning(N‐sourcing)were compared inwheatmonoculture versus twowheat‐legume rotationswithin a19‐yearoldtrialinSouthAfrica.Therelativeincreaseinhistoricalwheatyields(28%)andfoliar[N](106%) of wheat‐legume rotations compared to wheat monoculture was related to increasedmicrobialactivitybutnotgeneticdiversityasmeasuredbyCommunityLevelPhysiologicalProfilingand automated rRNA intergenic spacer analysis, respectively. Soil microbial diversity was ratherrelated to known abiotic drivers. A 15N‐13C dual isotope mixing model supported the idea thatenhancedNcyclingandyieldincrop‐legumerotationswasnotaresultofmicrobialdiversityperse,butratherincreasedmicrobialactivitywhenkeystonelegumespeciesandtheirassociatedN2‐fixingsymbiontswerepresent.

#SI.40OperationalTillageInformationSystem:TrackingconservationpracticesatfieldtowatershedscalesWilliamSalas,StephenHagen,IanCookeAppliedGeoSolutions,LLC,UnitedStatesApplied GeoSolutions (AGS) has developed and deployed a system for operational mapping oftillage practices and cover crops overwide areas. The system, known as theOperationalTillageInformationSystemorOpTIS,produces spatially comprehensivemapsof crop residuecover andcovercropsusing information integratedfrommultipleearth‐observingsatellites.Thesedetailed,retrospective(1984topresent)andon‐going,largeareamapsofconservationagriculturepracticesare produced at the farm‐field level, but are often used to produce summaries at aggregatedpolitical or natural scales. These data are used to driveDNDC, a soil biogeochemicalmodel thatsimulates crop growth, nutrient cycling, GHG emissions, and soil carbon dynamics, for field towatershedmodelingonimpactofconservationagricultureonsoilhealth.Theintegrationofthesetechnologies facilitates the estimation of ecosystem services associated with the adoption ofconservation agriculture management practices. We propose to present a poster on the OpTISRemoteSensing–DNDCmodelingplatformformappingandmonitoringadoptionandperformanceofconservationpracticesatfieldandwatershedscales.

#SI.41BacterialDiversityofanAbandonedCoalMineSoilinSoutheastKansasRachelBechtold,AnuradhaGhoshPittsburgStateUniversity,UnitedStatesAcid mine drainage (AMD) occurs near abandoned coal mines in southeast Kansas, the wasteproductdecreasingpH.Soilbacteriaareuseful indicatorsofecosystemhealth in theseperturbedareas. The goal of the studywas to assessmicrobial diversity of anAMD site. In fall (2015) andsummer(2016),soilsampleswereasepticallycollectedfromfivetopographicallydiversesitesandphysico‐chemical characteristicswere evaluated. A total of 58morphologically different colonieswere typified using physiological and biochemical tests and were identified at the species levelthrough16SrRNAgenesequencing.Additionally,acidophilicbacterialstrainswerescreenedusingselectivemedia.SoilpHrangedfrom2.5‐6.8andvariedconcentrationsofarsenic,manganese,andiron were detected. Biochemical tests revealed a diverse metabolic potential of the bacterialpopulation.ThemajorityofbacterialspeciesbelongedtocommonsoilinhabitantphylaFirmicutesand Actinobacteria. A total of 17 acidophilic bacterial isolates were identified and would besubjected to small‐scale bioremediation process using lyophilization complemented with otherphysico‐chemical techniques.Abaselinemeasurementofbacterialdiversityandsoil chemistryofAMDsitesinthisregionisnovelinitskind.ThefindingshavepotentialuseinAMDremediationandrestorationofnaturalhabitatforplantsandanimals.

#SI.42Mechanismofnon‐additiveheterogeneouslitterdecompositionNaYin,RogerKoideBrighamYoungUniversity,UnitedStatesLitterdecomposition is a fundamental ecosystemprocess that stimulates energy flowanddrivesnutrientcycling.Thefactorsthatcontrolthedecompositionofhomogeneouslitterhavebeenwellresearched. Innature,however, litter isusuallyheterogeneous,consistingofeithermaterial fromthe same species in varying decomposition states, or material from multiple species.Heterogeneouslittermaynotdecomposethewayhomogeneouslitterdoes,whichmakesthefluxesassociated with decomposition impossible to predict. For example, heterogeneous litterdecomposition may be non‐additive. We focus on investigating the effect of litter mixing (oatstraw/clover system) on oat straw decomposition. None of the frequently‐evoked mechanisms(nutrienttransfer,increasedwatercontent)explainnon‐additivedecompositionofoatstrawwhenassociated with clover. Preliminary studies suggest that clover increases the rate of oat strawdecomposition by stimulating the activity of cellulase enzymes produced by decomposermicroorganisms, and that themechanism for this stimulation involves the availability of labile Cfromcloverlitter.

#SI.43ComparativeresponseofsixgrapevinerootstockstoinoculationwitharbuscularmycorrhizalfungiAntreasPogiatzis1,JohnKlironomos1,PatBowen2,MirandaHart1,TaylorHolland11UniversityofBritishColumbia‐Okanagan,Canada2Agriculture&Agri‐FoodCanada,SummerlandResearch&DevelopmentCentre,CanadaArbuscularmycorrhizalfungiaresoilfungithatformasymbioticassociationwithplantroots.Thesymbiosisislargelynutritional.Thefungidependontheplantsforcarbonresources,andtheplantsbenefitfromincreasedaccesstosoilnutrients.Themagnitudeofplantbenefit,however,canvarysignificantly. It has been suggested that root architecture is a key factor that determines plantresponsiveness to arbuscular mycorrhizal fungi, and some studies have been conducted andsupport this notion. However, a major limitation in such studies is the lack of control forphylogenetic constraints among tested plants, making it difficult to control for confoundingvariables that are not associated with root architecture. I explored the variation in plantresponsiveness among closely related species (grapevines) and investigated the potentialrelationshipbetweenrootarchitectureandresponsivenesstoarbuscularmycorrhizalfungi.Ifoundthatrootcolonizationbyarbuscularmycorrhizalfungicanimprovegrapevinegrowth,althoughthedegree of benefit differed among grapevine rootstocks. The magnitude of the benefit can bepartiallyexplainedbythepre‐colonizationrootarchitecture,andinparticular,byrootbranching,whichisassociatedwithplantnutrientforagingability.Inaddition,rootcolonizationbyarbuscularmycorrhizalfungicaninfluencetheexpressionofroottraits,byincreasingplantbiomassperunitofrootlengthandrootbranching.

#SI.44RealisticallysimulatingtheeffectsofoxidationonsoildecompositionAdamLangley,BrendanKelly,SamanthaChapmanVillanovaUniversity,UnitedStatesSoil oxygen availability strongly regulates microbial function and varies along sharp gradientsthroughspaceandtime.Moreover,soiloxygenstatus ischanging inmanyecosystemsasclimate,hydrologyandplantcommunitieschange,yetwe lackabasicunderstandingof theconsequencesfor processes like decomposition. The factor by which fully oxygenating previously anoxic soilsaccelerates decomposition (O:A ratio) varieswidely across studies, ranging from 1.3 to 22 evenwithinhighlycontrolledlab‐basedstudies.OurgoalsweretodeterminetheO:Aratioofpeatfromabrackishmarshandexplorewhat factorsmayexplaindisparities inestimatesacross studies.Weused three methods to experimentally oxygenate and deoxygenate soils for two months: (1)incubations with intact soil cores, (2) incubations with soil slurries and (3) flow‐throughmesocosms.Overtwomonths,thethreemethodsyieldedO:Aratiosof2.2,1.8and4.2,respectively.O:Aratioswerestablethroughtime.Wefoundthatevenonsmallmonoliths(roughly1cmcubes)of intact soil, headspace O2 treatments failed to fully oxygenate soils, likely leading to anunderestimate of the O:A ratio. Slurrying and shaking soil allows for precise and homogenoustreatment application but dramatically accelerates decomposition rates compared to static soil,again likely biasing the O:A ratio downward. The flow‐through mesocosms maintained soilstructureandsuccessfullyoxygenatedtheentiresoilprofile.Wemaybeunderestimatingtheeffectsofsoiloxygenationonsoildecompositionrates,whichcoulddramaticconsequencesforpredictingfuturecarbonfluxes,particularlyfromwetlands.

#SI.45Doesmicrobialcommunitycompositioninfluencedecompositioninwetlandecosystems?MeganFoley,AdamLangleyVillanovaUniversity,UnitedStatesMicrobialcommunitiesaregenerallyregardedtobefunctionallyredundantforgeneralecosystemprocesses,suchasdecomposition.However,microbialcommunitycompositionvariesdramaticallywith depth, particularly in wetland soils, where anoxic conditions dominate in deep soils. Weperformed a laboratory incubation experiment to test the functional redundancy of very distinctmicrobial communities from surface (0‐10 cm) and deep (50‐60 cm) soils in two wetlandecosystems. Surface and deep soilmicrobial communitieswere used to inoculate sterilized soilstakenfromtwodepths(0‐10cm,50‐60cm)intwotidalmarshesinBarnegatBay,NJ.Wefactoriallymanipulated oxygen availability to represent realistic “surface” and “deep”marsh environments.We estimated substrate‐induced respiration to evaluate the potential activity of initialmicrobialcommunities,andtherewerenodifferencesbetweensurfaceanddeepmicrobialcommunities.Weperformedtheincubationexperimentintwophases,andmeasuredC2productionweeklyforfourweeks in each phase. Mean microbial respiration did not differ between surface and deep soilmicrobial inocula under any condition. These results suggest even very distinct soil microbialcommunitiescanadaptrapidlytonewconditionsandmayexhibitredundancyinfunctionacrossawiderangeofenvironments.

Appendix l

ECOLOGY OF SOIL HEALTH SUMMITPOSTER SESSION ABSTRACTS

Tuesday June 6th

POSTER SESSION 25:00 – 7:00 PM

Bal l room B, Lory Student Center

#SII.1SoilmanagementpracticestoenhancesoilhealthandearlygrowthofsweetcherryplantedintooldorchardlandThomasForge1,TristanWatson2,PaigeMunro2,DeniseNeilsen1,GeraldNeilsen1,LouiseNelson21Agriculture&Agri‐FoodCanada,SummerlandResearch&DevelopmentCentre,Canada2BiologyDepartment,UniversityofBritishColumbia‐Okanagan,CanadaAnassemblageofsoil‐borneplantpestsincludingroot‐lesionnematodes(Pratylenchuspenetrans)buildsup inorchardsoils,causingpoorgrowthof juvenile treeswhenorchardsarereplanted. Intwo field experiments we assessed the efficacy, relative to fumigation, of using organic matterinputstoenhanceoverallsoilhealthandthereby improveearlygrowthofcherrytreesreplantedintooldorchardsoil.Specifically,westudiedtheeffectsofpre‐plantincorporationofcompost(50Mgha1)andbarkmulchonpopulationsofplant‐parasiticnematodesandkeyrhizospheremicrobialpopulations, inrelationtosoilhealthindicatorsandtreegrowthduringthefirstthreeyearsafterreplanting.Thecompostamendmentenhancedtotalandlabilefractionsofsoilorganiccarbonandnitrogenthroughatleastthreegrowingseasonsinbothfieldexperiments.Thecomposttreatment,particularlywhencombinedwithbarkmulch,suppressedroot‐lesionnematodepopulationswhileenhancinggrosspopulationsof fungiandbacteria,Pseudomonas., and theabundanceofbacterialstrains producing antibiotics pyrrolnitrin and 2,4‐diacetylphloroglucinol in the rhizosphere.Laboratoryassaysofbiologically‐mediatednematodesuppressionpotentialparalleledresultsfromthefield,withgreatersuppressivepotentialinamendedsoilthaninfumigatedoruntreatedsoil.Inone field experiment treegrowthwasgreatest in fumigatedplots at the endof the first growingseasonbutbytheendofthethirdgrowingseasonthelargesttreeswereinthecombinedcompostandbarkmulchtreatment,demonstratingthatsoilmanagementpracticesthatenhanceoverallsoilhealthcanhavegreatercumulativebenefitstoorchardestablishmentthanfumigation.

#SII.2MicroarthropodresponsetofoottrafficinsportsturfMaxwellHelmberger,KyleWickingsCornellUniversity,UnitedStatesUrban soil communities are importantdriversof keyecosystem functionsand services, yetmustcontend with numerous anthropogenic disturbances, including vehicle and foot traffic. Weinvestigatedtheeffectsoffoottrafficonauniqueurbansoilecosystem,thesportsfield.Wesampledmicroarthropod communities and measured soil compaction in the high‐traffic and low‐trafficareas of two central New York turfgrass soccer fields differing in soil type and managementpracticesduringfallof2016.Wefoundsignificantdifferencesbetweenfieldsandtrafficareasintheabundance of several common microarthropod taxa. Collembolan abundance differed betweenfieldsandwaslowerinhigh‐trafficareas.Oribatidmiteabundancedifferedbetweenfieldsbutnotbetweentrafficareas,andmesostigmatidmiteabundancevariedbytraffic,butnotbetweenfields.Astigmatidmitesweremuchmoreabundantinhigh‐trafficareas.Theobserveddifferencesinthehigh‐traffic areas could be due to soil compaction or to differing temperature and moistureconditionsat thesoilsurfacecausedbydegradationof theturf.Futuresurveys inthespring, latesummer,andfallof2017willproduceamorecompletepicture,astheywillallowustodeterminetheextentof thehigh‐trafficareas’ recoveryas fieldssit inactiveand theexactmagnitudeof anyshiftsincommunitycompositionuponinitiationofplay.

#SII.3Communitycompositionoffree‐livingsoilnematodesunderanomalousprecipitationacrosssitesPingtingGuan1,AndreL.C.Franco2,OsvaldoSala3,DianaWall11InstituteofAppliedEcology,ChineseAcademyofSciences,China2ColoradoStateUniversity,UnitedStates3ArizonaStateUniversity,UnitedStatesClimate changewill increase theoccurrenceof extremewet anddry events especially indrylandecosystems.Free‐livingsoilnematodesareimportantplayersindecompositionandnutrientcyclingprocesses.Wecompared thegenuscompositionof free‐livingnematodecommunitiesbetweenanaridandasemi‐aridgrassland,andstudiedtheeffectsofchangesinwaterprecipitationateachsiteon nematode community structure.Wemanipulated incoming precipitation (PPT), from extremeand intermediate reduction levels to intermediate and extremeaddition levels, in the ariddesertgrassland (Jornada Long Term Experimental Range, New Mexico) and semi‐arid (SemiaridGrasslandResearch Center, Colorado) grassland sites, and analyzed the diversity and communitycomposition of soil free‐living nematodes. Abundance, genus diversity and maturity index weresignificantlyhigherinthesemi‐aridthaninthearidsite(Shannon’sindexof2.03±0.03and2.18±0.03andmaturityindexof2.47±0.02and2.70±0.05forthearidandsemi‐aridsites,respectively).Thereweredistinctivecommunitiesatsites,withthemostrelativeabundantbacterialfeederswereCephalobusatthesemi‐aridsite,andAcrobelesatthearidsite.Thedominantomnivoregenerawere,Thonus at the arid site and Mesodorylaimus at the semi‐arid site. Abundance, diversity, andcommunitycompositionoffree‐livingnematodes,althoughdifferingbetweensites,didnotrespondat either site to precipitation manipulation. We conclude that free‐living nematodes are moreabundant and diverse in semi‐arid than arid grasslands, with communities in both sites notrespondingtochangesinwateravailability.

#SII.4EarthwormsfromsoilsdevelopedbelowlongtermexperimentalplantationsatHoltDown,SouthernEnglandKevinButt1,*MacCallaham21UniversityofCentralLancashire,UnitedKingdom2USDAForestService,SouthernResearchStation,UnitedStatesSeminalresearchfromthe1980sundertakenatHoltDown,Hampshire,showedthatthespeciesoftrees planted influenced subsequent soil development and understory vegetation. The workmonitoredplantationsofbeech(Fagussylvatica)andsmall‐leaved lime(Tiliacordata)plantedonidenticalsoilsthathadbeenusedforsheepgrazingforcenturiesprior.Afteraperiodof>50years,abrownpodzolicsoil(pH<4)andabrownforestsoil(pH>5)haddevelopedunderbeechandlime,respectively.Inthelatter,evidenceofearthwormpresencewasreportedbutnodetailprovided.Ona return to this site in 2013, we examined soils of these and an adjacent spruce (Picea abies)plantation, specifically sampling for earthworms. Soil and litter measurements were made, andearthworms collected by hand‐sorting soil in replicated 0.1m2 plots (20 cmdepth), followed byapplication of amustard vermifuge. Scant leaf litterwas present below lime, but large amountswere present below beech and spruce. Significantlymore earthwormswere present below lime,withmean(±SE)densityof29.2m‐2(±0.9),whencomparedwith1.7m‐2(±0.1)forbeech,and10.8m‐2 (±0.5) for spruce, with corresponding differences in biomass. Six species were collected.Dendrobaenaoctaedrawerecollectedexclusivelybeneathsprucetrees.AnecicAporrectodea longaandLumbricus terrestriswere foundbelow lime alongwith endogeicA.caliginosa andOctolasioncyaneum. Additional targeted sampling of L. terrestris middens also revealed A. rosea and S.mammalis in the lime plantation, where earthworm species richness was greater compared tobeechandspruce.

#SII.5Periodicalcicadaexpansionlags,butmatches,woodyplantencroachmentintallgrassprairielandscapesMacCallaham1,SophiaBonjour2,BrentBrock3,ClintonMeyer4,BruceSnyder5,MattWhiles21USDAForestService,SouthernResearchStation,UnitedStates2SouthernIllinoisUniversity,UnitedStates3HolosceneWild,Inc.4SimpsonCollege5GeorgiaCollegeandStateUniversity,UnitedStatesPeriodical cicadas are long‐lived soil invertebrates, and their spectacular emergences representsignificant fluxesofnutrientsandenergy frombelowgroundtoabovegroundpools. Becausetheyfeedexclusivelyontree‐roots,theyallowexaminationof long‐termdynamicsofwoodyvegetationwithin thegrass‐dominatedprairie landscape.Weusedemergencedata fromthe1998periodicalcicadaemergenceatKonzaPrairieBiologicalStation(KPBS),andcollectedemergencedatafromthe2015emergence to evaluatepatternsof emergence (and associatednutrient/energy fluxes)withrespect to woody vegetation expansion at KPBS. Results indicated that ~35.2 million cicadasemergedfromriparianforestsatKPBSin2015.Thisnumberrepresentsanincreaseoverthe1998emergencebya factorof1.8. Forestcover in thewatershed increasedbya factorof1.6over thesameperiod.Thesefigurescorrespondtototalemergencebiomassestimatesof59kgCha‐1,and7kgNha‐1withintheforestedareaatKPBS.Differencesbetweenemergenceestimatesof1998and2015 suggested that dispersal distances in 1998were potentially quite long and that areaswithhighestdensityin1998wereconsiderablyreducedin2015.Conversely,someareasthathadzeroemergence in 1998 had densities of 90‐100 individuals m‐2 in 2015. Our results show thatperiodicalcicadasemergedfromvirtuallyeveryareathathadforestcoverintheyearofemergence(when oviposition occurred), and suggest that continued expansion of forests in the region willlikelyresultinmorecicadabiomassthatwillberedistributedinperiodicresourcepulsesofenergyandnutrients.

#SII.6Elucidatingtheimportanceofbacterialnetworkconnectivityfromalong‐termenvironmentalchangeexperimentDanielRevillini1,PeterB.Reich2,NancyC.Johnson11NorthernArizonaUniversity,UnitedStates2UniversityofMinnesota,UnitedStatesEnvironmentalchangesincludingelevatedatmosphericCO2andincreasingnitrogendepositionarepredicted to influence the structure and function of soil microbial communities by altering theavailabilityofbelowgroundcarbon(C)andnitrogen(N),respectively.BacteriaarenotablyC‐limitedmicrobes, and have the potential to play a vital role in N‐cycling via N‐fixation or ammoniaoxidation.Theconnectivityamongbacterialcommunitiescanrevealthepotentialforniche‐sharing(modularity) andmay provide insight into keystone bacterial interactions. Using randommatrixtheory,weperformedbacterialnetworkanalysestoidentifytheeffectsofelevatedCO2(eCO2)andNfertilizationonbacterialcommunityco‐occurrencepatternsandmodularity fromtherhizosphereof‘diverse’prairieplotsfromtheBioCONexperiment.eCO2increasednetworkcomplexity,buthadnoeffectonmodularityoftherhizobacterialcommunities.Nfertilizationhadstrongpositiveeffectson both network complexity and modularity, indicating that the interactions as a result offertilization at this N‐poor site were likely driven by increased competitive or niche‐sharinginteractionsamongbacterial taxa.We foundan inverserelationshipwherediversitydecreasedasnetwork connectivity increased when comparing beta‐diversity to connectivity of the bacterialcommunities in N fertilized plots. These results are consistent with recent network studiesindicating increaseddevelopment of niches populatedbydominant taxa.Our study indicates theneed to understand both the connectivity of soil bacterial communities as well as the morecommonlystudiedalpha‐andbeta‐diversitymetricstodeterminethemultifunctionalresponsesofentirebacterialcommunities.

#SII.7Manure,butnotNfertilizer,improvedbiologicalsoilhealthafter38annualapplicationsNewtonLupwayi1,DerrickKanashiro1,AndreaEastman2,XiyingHao11Agriculture&Agri‐FoodCanada,LethbridgeResearch&DevelopmentCentre,Canada2Agriculture&Agri‐FoodCanada,BeaverlodgeResearchFarm,CanadaAddingcattlemanuretothesoilimprovesitsqualitybybuildingsoilorganicC,butmanureeffectsontheverticaldistributionofsoilmicrobialpropertiesarerarelyevaluated.Soilphospholipidfattyacid (PLFA) biomarkers and β‐glucosidase activityweremeasured down to 120 cm depth in anirrigatedfieldtrialthathadreceived38(1973‐2010)annualmanureor21(1990‐2010)annualNfertilizerapplications.Themanureapplicationrateswere0,60,120and180Mgha‐1.TheeffectofNfertilizer(ammoniumnitrate)appliedat100kgNha‐1wascomparedwiththatofmanureappliedat 60Mg ha‐1. Total PLFAs, fungal PLFAs, bacterial PLFAs andβ‐glucosidase activity inmanuredtreatmentswereabout3‐4xtheamountsinthecontroltreatment,butfertilizerNhadnoeffectsonthese soilmicrobialproperties. Thesemanureeffectsoccurredmainly in the0‐15cmsoildepthwhichcontained75%ofthetotalPLFAsand79%oftheenzymeactivity,withsmallereffectsinthe15‐30cmsoildepthwhichhad20%ofthetotalPLFAsand18%oftheenzymeactivity.Therewerenomanureeffectsinthe30‐60cmand60‐120cmsoildepths. Increasingmanureratesfrom0to180 Mg ha‐1 increased total PLFAs and bacterial PLFAs linearly, but quadratic increases wereobserved for fungalPLFAsandβ‐glucosidaseactivity. Therefore,manure improvedbiologicalsoilhealthbyincreasingsoilmicrobialbiomassandactivityinthetop30cmofsoil,butNfertilizerhadnoeffects.

#SII.8Dolivestockgrazingregimesinfluencesoilbiogeochemicalprocessesandfunction?AglobalanalysisofgrazingeffectsonsoilnitrogenandcarbondynamicsRyanByrnes,LeslieRoche,KennethTateUniversityofCalifornia‐Davis,UnitedStatesGlobally,grazedecosystemscompriseapproximately40%of terrestrial land.These landssupportnumerousenvironmentalandeconomicservices.Giventheprolificnatureoftheselandstheyalsohavethepotentialtoimproveordegradetheirgrazedenvironmentbasedonlivestockmanagement.Grazed lands, while diverse, are commonly less productive than their highly managed and highinputfieldandhorticulturalcropcounterparts.Asaresult,theselandshavethepotentialtobecomequickly degraded and may harm the broader environment they are in if they are not managedproperly. Soils in grazed lands serve as the backbone of stability and resilience in theseheterogenoussystemsandprovidenumerousecosystemservicessuchastheprovisionoffoodandfiber,filteringofpollutantsthroughthesoilprofileandthecyclingofnutrients.Ourobjectiveistoconductaglobalanalysisontheresponseofgrazingmanagementandintensityonnumeroussoilbiochemicalprocesses.The resultsof thisanalysiswillbeused todetermineglobal trends in theresponseof soil to grazingmanagement regimes andultimately,understandwhich environmentsmayrespondmorefavorablytocertainregimes.Ourresultswillhelpinformtheglobaldiscussionsurrounding the importanceof soilhealth, aswell, our resultswill inform thegrazingandpolicystakeholder communities as to how grazed lands, which have a massive global footprint cancontinue to be productive landscapes as well as supportive in providing positive environmentalhealthoutcomes.

#SII.9Wheatgenotypicandphenotypiceffectsonmicrobial‐mediatednitrogencyclingCynthiaKallenbach,FnuJunaidi,StevenFonte,PatrickByrne,MathewWallensteinColoradoStateUniversity,UnitedStatesModernagricultureandbreedingunderhighmineralnitrogen(N)fertilizationmayhavedisruptedplant‐microbecoevolutionaryrelationshipsthroughalterationstobelowgroundcarboninputsandassociated impacts on the soil microbiome. Consequently, modern crop cultivars may beconstrained by crop roots’ ability to effectively supportmicrobial‐mediatedNmineralization.WeinvestigatedhowdifferencesinroottraitsacrossahistoricalgradientofwheatgenotypesinfluencetherhizospheremicrobialcommunityandtheeffectsonsoilN.Fivegenotypes,representingwild(Wild), pre‐GreenRevolution (Old), andmodern (Modern)wheatwere grownunder greenhouseconditions. Wheat was grown in soils with and without compost to also compare how thesegenotypes respond to inherent difference in native soil microbiomes and organic resourceavailability.Weanalyzedrhizospheresoilsatthreewheatgrowthstagesforsoilenzymeactivities,inorganicN,andmicrobialbiomass.Wheatyield,Nuptake,androottraitsweremeasuredatwheatharvest.Rootlengthandfinerootdensitywere6timeshigherinWildwheatcomparedtoOldandModerngenotypes.Genotypicdifferences in enzymeactivities and soil inorganicNonly emergedwithcompostamendments,whereoldergenotypeshadrelativelygreatersoilnitrateandN‐cyclingenzymeactivities compared toModern.Wealsoobserved thatWildandOldwheathad themostpositiveN‐cyclingresponsestocompostamendments,indicatingastronggenotypeXenvironmentinteraction influencing organic N turnover. Thus, genotype selections that enhance beneficialinteractions between roots and their rhizospheremicrobiome should be considered to optimizecropNavailabilityfromorganicsources.

#SII.10PowerandlimitationofsoilpropertiesaspredictorsofrangelandhealthandecosystemfunctioninginaNorthernmixed‐grassprairieKurtReinhart,LanceVermeireUSDA‐ARSFortKeoghLivestock&RangeResearchLab,UnitedStatesSoil properties are thought to affect rangeland ecosystem functioning (e.g., primary productivity,hydrology), and thus soil variables that are consistently correlatedwith key ecosystem functionsmay be general indicators of rangeland health. We summarize results from several studies inmixed‐grassprairieoftheNorthernGreatPlains.Wetestedmanywould‐bepredictorvariablesoflocalvariationinpeakabovegroundbiomassandwaterinfiltration.Individualpropertiesexplainedamoderate amount of variation in plant biomass (≤18%) and infiltration (≤15%). For example,plant biomass was positively correlated with field‐saturated infiltration, subsurface microbialbiomass,andsomeplantavailablenutrients(boron,manganese,andphosphorus). Plantbiomasswasnegativelyassociatedwithtwosoilproperties,subsurfacesoilcarbonateconcentrationandthestability of soil macroaggregates near the soil surface. Many popular indicators of soil andrangeland health, such as soil organic carbon, organicmatter, andwater‐stable aggregates,werefoundtobepoorpredictors.Forexample,waterinfiltrationwasunrelatedtoaggregatestabilitybutwasrelated toplantbiomass. Wehypothesize thatotherplantandsoilproperties(i.e., litterandbaregroundcover)explaingreateramountsofvariationininfiltration. Whileprotectionofsoiliscritical to overall rangeland ecosystem functioning, our findings suggest that the relationshipbetween soil properties and plant biomass (or infiltration) in natural grasslands is complex. Amajorchallengeistouncoverindicatorvariablesthatconsistentlyexplainappreciablevariationinpeakgrasslandbiomass,especiallyvariationwithinanecosystemindependentofprecipitation.

#SII.11Increasinglabilecarbonandnitrogenpoolsinagriculturalsoilsrequiresachangeinsystem,ratherthanpracticeKalynDiederich1,KavyaKrishnan1,ErinSilva2,MattRuark11UniversityofWisconsinMadisonSoilsDepartment,UnitedStates2UniversityofWisconsinMadisonPlantPathologyDepartment,UnitedStatesLabilesoilcarbon(C)andnitrogen(N)dynamicsarekeyvariablesinsoilhealthassessmentsandarecriticalforsoilecosystemservices.UnderstandingthesedynamicswillprovideinsightintohowseasonalityandfarmmanagementpracticeswithinforageanddairycroppingsystemsinfluencesoilC andN. The objective of this research is to study the effects of six different long‐term croppingsystemsonpotentiallymineralizablenitrogen(PMN),permanganateoxidizablecarbon(POxC),andpotentiallymineralizablecarbon(PMC);indicatorsoflabileCandNpools.Theselabilepoolswereevaluated using incubation and chemical extraction methods at two soil depths and five timesduringthegrowingseasonattheWisconsinIntegratedCroppingSystemsTrial.Preliminaryresultsindicate POxC and PMNwere greater in the forage‐based systems (FBS) compared to the grain‐basedsystems(GBS),andthatFBShadmineralizableNpoolssteadilyreplenishedthroughoutthegrowingseasonuntilSeptember.GBSexperiencedasignificantdecreaseinPMNmid‐season(akeypoint in plant growth), and had significantly lower POxC values in the beginning of the growingseason. PMC analysis is currently underway. The significant differences in these biologicalindicatorsofsoilhealthmetricsbetweenGBSandFBSare likelydue to reducedsoildisturbance,frequentmanure additions, and the incorporation of a perennial legume phase in the FBS. Sincemanagementpracticeshiftswithinacroppingsystem(GBS/FBS)inthecontextofthisstudywerenotenoughtoaffectlabilepools,systemchangessuchascompletetillagereductioncombinedwithannualcovercroppingisrequired.

#SII.12Mixedevidenceforcarbontransferbetweenbiocrustcyanobacteriaandplantsinmultipledrylandecosystemsusingnaturalabundanceδ13CGrace Crain1, Eva Dettweiler‐Robinson2, Anthony Darrouzet‐Nardi1, Jennifer Rudgers2, RobertSinsabaugh21UniversityofTexasatElPaso,UnitedStates2UniversityofNewMexico,UnitedStatesIndrylands,plant‐biocrustmutualismsare importantdriversofnutrient cycling.Recentdatahasshown that biocrust cyanobacteria are able to incorporate plant‐derived carbon into theirstructures.Specifically,biocrustshavebeenfoundtoshowδ13CsignaturesofrespectivenearbyC3andC4plants.Usingthenaturaldifferenceinδ13Csignaturebetweenphotosyntheticpathways(C3average ‐28%andC4 average ‐14%),wehypothesized that if biocrusts incorporateplant‐derivedcarbon, the cyanobacterial filaments would reflect the signature of the nearby plant. Weinvestigatedthispatternbycollectingpairedleafandbiocrustsamplesfromundertheplant(0cm)totheinterspace(25cm)nearC3andC4individualsfoundintheChihuahuanDesertandColoradoPlateau. δ13C of cyanobacterial filaments near C3 plant species were depleted by ~2‰ per milundertheplantincomparisontotheinterspace.δ13CoffilamentsneartwoC4plantspeciesdidnotdifferbetweendistances.However,filamentsnearoneC4grassshowedadepletionof~3‰permilbetween distances. This result was unexpected as we hypothesized that all C4 plants would notdiffer. While δ13C signatures of cyanobacterial filaments near C3 plants is consistent withinteractionsbetweenbiocrustcommunitiesandplants,wearecarefultonotethattranslocationisnottheprovenmechanism.TheunexpectedresultsintheC4grasssuggeststhatthesepatternsmaynothold true for all plant species. If themechanisms canbe shownusingmoredetailed isotopictracerstudies,naturalabundancedatacouldprovideameansforquickassessment.

#SII.13InfluenceoffertilizationonmycorrhizaldynamicsinaperennialbiomassproductionsystemRachelBrockamp1,*SharonWeyers1,MargaretKuchenreuther2,JohnZaharick1,AlanWilts11USDA‐ARSNorthCentralSoilConservationResearchLab,UnitedStates2UniversityofMinnesota,Morris,UnitedStatesInterest among landowners in diversified production systems is growing in the UpperMidwest.Diversification in the form of perennial biomass production systems from converted cropland issupported by developments in livestock integration as well as cellulosic and gasification energyplatforms.Managementstrategiesareneededthatbalanceproductivitywiththeecosystemservicesperennial systems often offer. Within a low‐diversity, native perennial production system, weestablished a randomized block experiment to evaluate the impact of four whole plot fertilizertreatments(zero,compostedcattlemanure,halfrate(30‐10‐30NPK)andfullrate(60‐20‐60NPK))and two split‐plot harvest rates (annual fall harvest versus no‐harvest) on biomass productiondynamics, soil health, and associated ecosystem services. Mycorrhizal inoculum potential (MIP)wasevaluatedasanindicatorofsoilhealthbenefits. Bigbluestem(Andopogongerardii)seedwasused to bioassay the MIP of soil collected within the four different fertilizer treatments underannual fall harvest. To support bioassay results field collected roots were also assessed formycorrhizal colonization. The MIP, measured as fraction of infection in the bioassay roots, wassignificantly lower in treatments that had received fertilizer at the recommended rate thantreatmentsreceivingnofertilizerorcompostedcattlemanure.Infieldcollectedbigbluestemroots,mycorrhizalcolonizationwasnotsignificantlydifferentamongfertilizertreatments,butdidreflecta trend similar to the bioassay. Despite colonization of field‐grown hosts, the bioassay results inconjunction with established reduction in plant diversity, suggest that recommended fertilizermanagementmayhaveunforeseenconsequencesformycorrhizaldiversityandabundance.

#SII.14MonitoringbioticandabioticsoilparameterstoinformregenerativegrazingpracticesacrossCalifornia’scoastalrangeChelseaCarey1,RachelSullivan2,DougMillar3,MelPreston1,NathanielSeavy1,ThomasGardali11PointBlueConservationScience,UnitedStates2CornellUniversity,UnitedStates3TomKatRanch,UnitedStatesRegenerative agriculture aims to restore healthy, robust, and resilient agro‐ecosystems. Soils –which provide nutrients to plants, harbor diverse macro and microbiota, and mediate criticalbiogeochemical cycles – play a central role in regenerative agriculture. Thus, soils must bemonitoredconcurrentlywithmoretraditionalmetrics likeplantcommunitycomposition inordertoensurethatpracticesaretrulyregenerative.In2016wesampledsurfacesoil(0‐10cm)fromtworanches (Paicines, n = 12; TomKat, n = 8) practicing regenerative agriculture along California’scentral coast with the goal of providing baseline data from which future changes could bebenchmarked. The soil was analyzed for phospholipid fatty acid analysis, cations, total C and N,inorganicN,P,pH,andsoilorganicmatter(SOM).Soilabioticparameters(e.g.,pH,organicC),totalmicrobialbiomass,andmicrobialcompositiondifferedsignificantlybetweenranches–andcompostapplicationatonesitealteredmicrobialcompositiondramatically.Despitethesedifferences,fungito bacteria ratios remained consistent across sampling points at both ranches, highlighting theimportance of carefully identifying dynamic indices of soil health at regional or local scales. Inaddition,distance‐basedredundancyanalysisshowedthatsoilpH,SOM,K,Ca,andinorganicPbestexplained the variation in soil microbial community composition across all sampling locations.Thesepreliminaryfindingssuggest thatregenerativeagriculturalpracticesmaybeabletomodifymicrobialdynamicsbyinfluencingtargetedsoilparameterssuchasorganicmattercontentandpH.

#SII.15SoilmacrofaunamodifysoilmicrobialcommunitycompositionandfunctionandalterbelowgroundcarboninputsNatalieBray,GrantThompson,JennyKao‐Kniffin,KyleWickingsCornellUniversity,UnitedStatesSoilanimalscanhaveimpactsonmicrobialprocessesbyfragmentingorganicmatterandgrazingonmicrobialcommunities;however,theimportanceofsoilanimalsinshapingsoilmicrobialfunctionis not fully understood. Our experiment aims to assess soil animal community impacts on soilmicrobialcommunitycompositionandfunctionanddetermineiftheireffectsinfluencethefateofcarboninsoil.Inordertomodifysoilanimalcommunitiesinsitu,weusedmesocosmsconstructedfromdifferentmeshsizesto includeorexcludemacrofauna.Wemeasuredsoilanimalcommunitycompositionandsoilmicrobialbiomassandquantifiedshiftsinsoilcarbonpoolsbothwithinandoutsidethemesocosms.Finemeshmesocosmssuccessfullyexcludedsoilmacrofaunaanddifferedfromthemacro‐meshmesocosms inmicroarthropodcomposition.Mesocosmswheremacrofaunawereexcludedalsohad lowermicrobialbiomassnitrogen than inmesocosmswheremacrofaunawere present. Soil carbon fractions such as macroaggreagtes, microaggregates and particulateorganicmatterwillalsobeevaluatedacrosstreatments.ChangestothemicrobialcommunitywillbefurtherinvestigatedthroughIlluminasequencingforbacteriaandfungi.Ourresultsindicatethatalterationstosoilanimalcommunities,particularlytheexclusionofmacrofauna,canhaveeffectsonbelowgroundcommunitiesandprocesses.

#SII.16RestorationofbiologicalsoilcrustontheColoradoPlateauinawarmingclimateColinTucker1,SashaReed2,AnitaAntoninka3,MatthewBowker31USGeologicalSurveySouthwestBiologicalScienceCenter,UnitedStates2USGS,UnitedStates3NorthernArizonaUniversity,UnitedStatesBiologicalsoilcrusts(biocrusts)aresoilsurfacecommunitiesofbryophytes,lichen,cyanobacteria,algae and associated heterotrophs, which cover a large fraction of many dryland ecosystems.Biocrustscontributemanyecosystemfunctionsincludingsoilstabilization,waterregulation,carbonand nitrogen cycling, andmay be important for co‐occurring vegetation communities. Yet acrossdrylandsglobally,andinparticularinthesouthwestUS,biocrustshavebeenseverelyimpactedbyanthropogenicdisturbances, includinglivestockgrazingandassociatedtrampling,off‐roadvehicleuse, industrial development. Because biocrusts are composed of slow growing organisms, withlimiteddispersaldistances,oneperspectivehasbeen thatdegradedbiocrustwillonlyrecoveronlong timescales (i.e., decades to centuries), and thus thatminimizing disturbance is the primarymethod for preserving biocrusts. Yet, because of the scale of biocrust degradation across thesouthwestUS,andthecriticalityof theecosystemfunctionsbiocrustsprovide, increasing interestand effort has been placed on methods of biocrust restoration. In general, restoration practicesrevolvearoundprotectinganareafromrepeateddisturbanceandinoculatingthesoilsurfacewithtargetorganismsorcommunities.Onepotentialproblemwiththisapproachisthatrecentclimatemanipulationexperiments(warmingandalteredprecipitation) indicateextremenegative impactsof warming and subtle precipitation shifts on key late‐successional elements of biocrustcommunities. In this studyweevaluate theuseof biocrust communities fromwarmer regions topromoteecosystemfunctionofadegradedrangelandsiteontheColoradoPlateaunearMoab,UT,specificallyconsideringtheresponsetoawarmerclimateasanexperimentaltreatment.

#SII.17Aresoilchangesresponsibleforpersistent,non‐forestedburnscarsinColoradoforests?TahirZaman1,TimothyFegel2,PaulaFornwalt2,CharlesRhoades21ComsatsInstituteOfInformationTechnology,Abbottabad,Pakistan2USDAForestService,RockyMountainResearchStation,UnitedStatesPileburning is themostcommonmethodofdisposing loggingresidue inRockyMountain forestsyetthepracticeisknowntoalterandpotentiallydegradesoilproperties.Thoughextremeheatinghas short‐term effects on soils beneath burn piles, it is uncertain if the practice has long‐term,ecologically‐relevantconsequences.InColorado,lodgepolepineecosystemswehaveestablisheda50‐year time series of pile burn scars located within pine stands regenerating after clear cutharvesting.Theburnscarssupportherbaceousvegetationbuthaveresistedtreecolonization.Wehypothesize that lasting changes in 1) soil resources (i.e., nutrients, water relations or plantsymbionts),2)treeseedavailability,3)herbaceousplantcompetition,or4)herbivorymayexplainthescarcityofpinerecruitmentwithinpileburnscars. Toevaluatethesefactorswecombinesoilnutrientandectomycorrhizalanalysis,greenhousebioassays,andinsituplantestablishmenttrialsto evaluate the probable causes.Herewe present preliminary soil‐related findings. Pile burningincreasedmineralsoilpH(upper10cmdepth)anda0.8pHunitdifferencepersistedthroughoutthe 50 year chronosequence. Total soil carbon and nitrogen in burn scarswas twice as high onaverageasthesurroundingforest.Ourpreliminaryanalysesdonotsupporttheexistenceofasoilnutrientorchemicalbarriertoforestrecoveryandsuggestthatsomeabove‐orbelowgroundbioticfactormayberesponsibleforpreventingtreesfromrecolonizingburnscars.

#SII.18CovercropmixesdifferentiallystratifymineralizingmicrobesandresidualnitrogenLandonGibbs,MarkCoyneUniversityofKentucky,UnitedStatesThere have been very few studies on the benefits of various legume species mixtures with ryeconcerning the stratification and composition of microbial communities and soil nutrients. Asindustrial hemp grows as a Kentucky agricultural commodity, there have been no studiesconcerning cover crop addition in hemp production. The objectives of this study are: (1)demonstrate the extent that differing cover crops and cover crop mixes containing grasses andlegumesstratifynitrogen,carbon,andphosphorustoadepthof45centimeters;(2)determinethechange ofmicrobial communities in soils plantedwith these specific cover crops and cover cropmixes;(3)showthatcovercropusewithoilseedhempproductionenhancesyieldandquality;(4)determinethechange(ifany)thathemphasonmicrobialcommunitiesandnutrientstratificationfollowing cover crops. Baseline sampleswere collected at depths of 0‐15 centimeters and 15‐30centimetersfollowingaseasonalfallowandthenfollowingasummerannualmaizecrop.Initialdataof yield, chlorophyll content, nutrient analysis, and labile carbon show no significant differencesfollowingmixes. The plots have been replanted to collect data immediately following cover croppresencebecauseinitialcovercropswereplantedtwoyearspriortoanalyses.Wepredictthatryetreatmentswillstratifycarbondeeperintothesoilprofilethanlegumes,buttotalresidualnitrogenwillbestratifieddeeperinmixes.Thesemixeswillmoreprofoundlydiversifymicrobialcommunitystructurebyimprovingsoilnitrogenmineralization.Oilyieldinsummerhempcropswillbenefit.

#SII.19ModellingtherootagestructureofperennialwoodyplantsTylerPoppenwimer1,LouisGross1,JosephBailey1,MeganRua21UniversityofTennessee,UnitedStates2WrightStateUniversity,UnitedStatesRootageandnutrientuptakeefficiencyaretypicallyinverse.Ithasbeensuggestedoverallgrowthis enhanced by maintaining a large population of younger roots while minimizing biomassallocation to older roots which have low efficiency. However, there are trade‐offs in senescingscheduling fornewrootsanda rootagedistributioncouldbeskewed towardsolder roots. Rootturnoverandrootproductionhavebeenproposedastwomethodsbywhichplantscontroltheagedistributionof roots.Unfortunately, direct examinationof thesehypotheses isnot experimentallytractable as measuring root age can be difficult. However, an age based theoretical model withvaryingcost‐benefitratiosforrootsofdifferentagescouldbeusedtoexaminetheimpactonoveralluptake of alternative root age distributions. The ability of this model to analyze how root agedistribution affects growth may enhance our capability to project whole‐plant growth. To ourknowledge,nosuchmodelhasbeenconstructed.Weapplyanintegralequationapproach,similartomany structure populationmodels, using varying death, survivorship, and cost‐benefit curves toanalyze the age distribution of the roots. To simulate growth and aging, we include feedbacksbetweenrootsandshoots to incorporate theadditional influxofnutrients fromrootsandcarbonfromshootsastheplantages.Anobjectiveistoobservetheimpactsonplantgrowthofchangingroot age structure throughout the life cycle and determine conditions forwhich age distributiondynamicstendstowardsasteadystate,acycle,oriftheagedistributionfluctuates.

#SII.20TheTollwayTreesInitiative:Fromrighttree,rightsitetorightsoil,righttreeMeghanMidgleyTheMortonArboretum,UnitedStatesTheIllinoisTollwayisundertakingathree‐yearinitiativetoplant58,000treesalongtheir292mileright‐of‐way to increase the regional forest canopy in the Chicagoland area. Soils in the sitesavailable for this project are likely of poor quality: compacted, nutrient‐poor, and saline due totopsoilremoval,grading,andcompactionthatoccurredduringTollwayconstructionandpollutionbyde‐icingsalts.Twobroadstrategiesarecommonlyusedtomaximizetreesurvivalandhealthinsuchanextremeenvironment:1)extensivesoilpreparation tomimicnatural forest soil– that is,withhorizons,higherporosityandaggregation,andincreasedorganicmatter,and2)choosingthe“righttree”forthe“rightsite”–thatis,selectingtreespeciesthataresalt‐,pollution‐,anddrought‐tolerant.However,theTollwayseekstonotonlyincreasethenumberoftrees,butalsothediversityof trees in theregion.Furthermore, there isnotone “forest soil,”but rathermany typesof forestsoils than varywith tree community composition.Here, I propose a newparadigmand researchproject toevaluate theextent towhichorganicmatteramendments thatbestmatch thechemicalpropertiesofatreespecies’naturalenvironmentmaximizetreegrowthandsurvivalaswellassoilecosystemfunctioning.Inotherwords,canweenhancethediversityoftreespeciesthatcanpersistinaroadsideenvironmentbymovingfrom“righttree,rightsite”to“rightamendment,righttree”?

#SII.21EffectoftillageandcovercropsonthecottonrhizosphereThomasDucey,PhilBauerUSDepartmentofAgriculture,AgriculturalResearchService,UnitedStatesCover crops and tillage (conservation vs. conventional) management practices are frequentlyutilizedtoincreasesoilfertility,bothintermsofplantproductivityandbuildingsoilcarbon.Thesemanagementpracticescanalsohavesignificantimpactsonsoilmicrobialcommunities.Sincethesemicrobialcommunities(bothbacterialand fungal)canbothdirectlyand indirectlyprovideplantswithnutrientsandwater,understandingtheirresponsetoagriculturalmanipulationsmayhelpusoptimize management practices such that they spur microbial activity beneficial to cottonproduction.Wewillreporttheresponseofthecottonrhizospheretobothtillagemanagementswithor without winter cover crop additions. Soil enzymatic assays demonstrate an influence onmicrobialpopulationsbybothtillageandcovercrop.

#SII.22MicrobialgeneticmemorytostudyheterogeneoussoilprocessesEmmFulk,JonathanJ.Silberg,CarolineMasielloRiceUniversity,UnitedStatesMicrobes canbeengineered to senseenvironmental conditionsandproduceadetectable output.Thesemicrobialbiosensorshavetraditionallyusedvisualoutputsthataredifficulttodetectinsoil.However, recently developed gas‐producing biosensors can be used to noninvasively monitorcomplex soil processes such as horizontal gene transfer or cell‐cell signaling. While thesebiosensors are suitable for reporting onwhat fraction of amicrobial population is exposed to aprocess or chemical signal at the time of measurement, they do not record a “memory” of pastexposure. Synthetic biologists have recently developed a suite of genetically encoded memorycircuitscapableofreportingonhistoricalexposuretothesignalratherthanjustthecurrentstate.Wewill provide an overviewof themicrobialmemory systems thatmayproveuseful to the soilecology community, including both “software” memory that can be re‐written and “hardware”memory that ispermanently encoded into themicrobialDNA.Simplememorycircuits cangiveayes/noreportofanypastexposuretothesignal(forexampleanaerobicconditions,osmoticstress,orhighnitrateconcentrations).Morecomplicatedsystemscanreportontheorderofexposureofapopulationtomultiplesignalsortheexperiencesofspatiallydistinctpopulations,suchasthoseinrootvs.bulksoil.Wewillreportonproof‐of‐conceptexperimentsshowingthefunctionofasimplepermanentmemorysysteminsoil‐culturedmicrobes,andwewillhighlightadditionalapplications.Finally, we will discuss challenges still to be addressed in applying these memory circuits forecologicalstudies.

#SII.23EcologicaleffectsoflivestockantibioticsonagriculturalsoilsCarlWepking1,BrianBadgley1,JohnBarrett1,MatthewHedin1,KatharineKnowlton1,KevanMinick2,ParthaRay31VirginiaTech,UnitedStates2NorthCarolinaStateUniversity,UnitedStates3UniversityofReading,UnitedKingdomAntibioticuseisunderincreasedscrutinyduetotheirdecliningeffectiveness;thisincludestheuseof antibiotics in livestockproduction,whichaccounts for80%ofnational antibioticuse.Muchofthis80%passesthroughlivestockviamanure,withhighestimatesatapproximately14‐millionkg‐yr‐1. Studies have shown that additions of manure from cattle treated with antibiotics can haveeffects on soil microbial community composition, antibiotic resistance gene abundance, andecosystem functioning. However, studies have also shown that additions of manure from cowsreceivingnoantibioticscanalsocauseincreasesinantibioticresistancegenes.Tobetterunderstandtherelativecontributionofmanureandantibiotics,acommongardenexperimentwasestablishedwhere plots were amended with manure from cattle either treated with one of two types ofantibiotics,oruntreatedcattle.Manurewasaddedmonthlyforthreeyears.Eachspring,plotswerepulse‐labeled using 13C and 15N. Soils and plant biomass from these plots were collected andanalyzed using a range of assays to better understanding how soil microbial communities areimpactedbymanureaswellasantibiotics.Wehavefoundthatmanuretypedoeshaveanimpactona number of importantmicrobial parameters. For instance,manure from cattle treatedwith theantibioticpirlimycinelicitedan~6,000kgha‐1y‐1increaseinrespiredcarboncomparedtomanurefromcattle treatedwith cephapirin.Although further analysisneeds tobe completed, the resultsfromthisfieldstudyhighlightthepotentialinfluenceantibioticsandthetypeofantibioticshaveonsoilandecosystemprocesses.

#SII.24Effectsofwalnutshellbiocharonsoilmicrobialcommunitiesinalong‐termfieldexperimentDeirdreGriffin,DaoyuanWang,SanjaiParikh,KateScowUniversityofCalifornia,Davis,UnitedStatesSignificant biochar research has elucidated that biochar amendment to soils can influencemicrobially mediated nutrient cycling. Increases in microbial abundance and plant‐availablenutrients have been reported after biochar application, particularly inmorenutrient‐poor, acidicsoils.However,lessisknownabouthowbiocharaffectsmicrobialandnutrientdynamicsinfertilesoilsoftemperateagroecosystems,suchasthoseinCalifornia.Additionally,themajorityofstudieshavetakenplaceinlabincubationsoverashort‐termtimeframe;morelong‐termfieldstudiesareneeded toexaminetherelationshipsbetweenbiocharandmicrobialecology insoilsonthe farm‐scale.Weinvestigatedthelastingeffectsofwalnutshell(WS)biocharonmicrobialcommunitiesandmicrobiallymediatednutrient cycling over four years in a field experiment. Long‐termplots of atomato‐cornrotationwereestablishedina2x2factorialdesignoftreatmentsi)withorwithoutWSbiochar amendment (10 t ha−1) and ii) fertilized with mineral fertilizer or composted poultrymanure.Soilsampleswerecollectedthroughouteachgrowingseason,andphospholipidfattyacidanalysis(PLFA)wasusedtoevaluatechangestosoilmicrobialcommunitycompositionasaresultof WS biochar application. In addition, quantitative PCR (qPCR) was used to analyze how WSbiocharaffectedtheabundanceofbacterialandarchaeal16srRNAgenesandnitrogen(N)cyclinggenesamoA.BothPLFAandqPCRanalysesshowedthatmicrobialcommunitiesweremuchmoreaffectedbythefertilizertypeusedthanthepresenceofbiochar.Similarly,nitrogentransformationswereaffectedbyfertilizerbutnotbybiocharapplication.

#SII.25Bacterialcompositionpatternsdistinguishtwocontrastingsoilsinorganiccarboncontent:andisolsandinceptisolsPaulinaBeatrizRamırez,SebastianFuentes,BeatrizDıez,CarlosA.BonillaPontificiaUniversidadCatolicadeChile,ChileThesoilorganiccarbon(SOC)iscrucialtomaintainandimprovemanyecosystemservicesprovidedbysoils.Chileansoilsderivedfromvolcanicmaterial(Andisols)haveahighSOCcontent,reachingvaluesup to12%.These soils enclose important agroecosystemsasa resultof theirhighnaturalfertilityandphysicalproperties(lowbulkdensity,highavailablewaterandaggregatestability).Thegoal of this study was to determine the bacterial structure and composition in soils with highorganic carbon (8‐11%) Andisols compared with lower organic carbon (1‐3%) Inceptisols. Wecharacterized the bacterial communities by 16S rRNA gene sequencing (Illumina) in native andcropped land use under the same climate conditions at 10 cm depth. Our results showed novariation in soil bacterial richness or diversity as SOC increased. However, differences wereobservedinbacterialcompositionbetweenthetypessoilsstudied.Thecommoncoreofoperationaltaxonomicunits(OTUs)wasrepresentedbylessthan0.5%overthetotalOTUs.Regardingcommoncore taxonomy, phylaAcidobacteria (28%),Proteobacteria (26%) andActinobacteria (14%)weredominant. Interestingly, major differences between soils were found within the most abundantOTUs(>1%)thatrepresent10%approximatelyofthetotalbacterialcommunity.AmongdominantOTUs,phylaWD272,FirmicutesandPlanctomyceteswereonlyobservedinInceptisols.MinorityandrareOTUs (90%of the total community) showed less differences at taxonomic level.Our resultsprovide additional insights into how soil bacterial communities may relate to SOC content,becoming potential indicators of soil quality for improving carbon restoration and conservationpractices.

#SII.26Managementintensitiesandseasonsaffecttherelativecontributionofammoniaoxidizingbacteria(AOB)andammoniaoxidizingarchaea(AOA)tonitrificationacrossaMidwestmanagementgradientDiLiang,G.PhilipRobertsonMichiganStateUniversity,UnitedStatesSoilammoniaoxidizingbacteria(AOB)andammoniaoxidizingarchaea(AOA)arethetwomaintaxainvolvedinnitrification,whichconvertsammoniatonitratewithnitrousoxide(N2O)releasedasabyproduct.PreviousstudieshaveshownthatAOBthriveinhighammoniumconditionswhileAOAaremoreadaptedtoacidicsoilenvironments.LittleisknownabouthowAOAandAOBrespondtomanagementintensitiesandseasons.Inthisstudy,weexploredtheseasonalcontributionsofAOAand AOB to nitrate accumulation and nitrification‐derived N2O emission from seven ecosystemsalongamanagementintensitygradient:twoannualcropecosystems,oneperennialcropecosystemand four native successional ecosystems including a late successional forest. Our results showedthat AOB were the major contributor to both nitrate and N2O production across managementintensities and seasons. AOA and AOB did not respond differently to changing seasons inconventional and biologically fertilized wheat ecosystems. However, for native successionalecosystems,nitrificationcontributedbyAOBinwinterwastwiceashighasinsummer,whileAOAdemonstratednoseasonalresponse.Inpoplaranddeciduousforestecosystems,bothAOAandAOBexhibitedhighernitrificationratesinwinterthansummer.Ourresearchsuggestsdistinctdynamicsofsoilnitrifiercommunitiesaffectedbydifferentmanagementintensitiesandseasons.

#SII.27WhyisTaeniatherumcaput‐medusae(medusahead)invasiveinNorthAmericaandnotinitsnativeEurasia?TyeMorgan1,MatthewO'neill2,RobertBlank1,EdithAllen2,MichaelAllen21USDA‐ARS‐GreatBasinRangelandsResearchUnit,UnitedStates2UniversityofRiverside,California,UnitedStatesTaeniatherum caput‐medusae (medusahead grass) is an exotic annual grass introduced to NorthAmerica(NA)thathasinvaded~4millionhaofwesternrangelands.Incontrast,innativerangesofEurasia(EA),medusaheadisnotconsideredtobeinvasive.WhyismedusaheadinvasiveinNA,butnot in its native lands in EA?We considered two prominent hypotheses: enemy release and soilresource availability.We hypothesized: 1)Medusahead‐invaded soils of NA aremore fertile thannativesoilsinEAandthussupportinvasion;2)InvadedsoilsofNAhavealowerrateofinfectionofpathogenic organisms, which in native environments reduce the growth and invasiveness ofmedusahead.Wedesignedaprojecttotesttheeffectsofsoil,seedsource,inoculumtreatmentsonbiomass, arbuscularmycorrhizae, and pathogen root counts ofmedusahead. In general, NA soilshad higher levels of nutrients than the EA soils. The NA populations, regardless of soil origin,generally had higher biomass responsiveness to both filtrate and whole soil inoculum. EApopulationstendedtohavehigherorequalbiomassinsterilesoilsthaninoculatedorfiltratesoils.ForbothNAandEApopulations,biomass insterilesoilswasrelatedtosoilnutrientsratherthancontinent of origin.Microscopic observations showedhigher pathogen counts in EA populations.MicrobialcommunitiesfromfiltrateandwholesoiltreatmentsinNAsoilsenhancedplantgrowth,whilemicrobialcommunitiesinEAsoilshadreducedorneutralgrowth.ResultsconcludethatbothresourceavailabilityandenemyreleasehypothesessupportmedusaheadinvasionsinNA.

#SII.28Canwereducephosphorusrunoffpotentialbystimulatingdecomposerswithcarbonandsodium?JessicaSusser1,ShannonL.Pelini2,MichaelWeintraub11UniversityofToledoDept.ofEnvironmentalSciences,UnitedStates2BowlingGreenStateUniversity,UnitedStatesLossofphosphorus(P)fromagriculturalfieldsintowaterbodiesrepresentsaninefficiencyinthecycling of fertilizer P from soils to plants. Stimulation of biological microbial and faunaldecomposers may help to maintain P availability while decreasing P application rates, therebyincreasing P application efficiency while reducing runoff potential. Although soil microbes (e.g.bacteriaandfungi)andfauna(e.g.beetlesandmillipedes)acceleratePcyclinginnaturalsystems,theircombinedeffectsonPavailabilityinagriculturalecosystemsarelargelyunknown.Wetestedthe hypothesis that stimulating soil fauna with sodium (Na) and microbes with carbon (C) willincrease soil P availability to plants. We added corn stover and Na solution to plots inconventionally‐managed corn fields in Northwest Ohio. Stover treatments increased microbialbiomassandactivitybutNatreatmentshadlittleeffectonmicrobesandsoilfauna.Thefieldstestedhadrelativelylowlevelsofdecomposeractivity–likelypartiallyduetotheirlowbiomassinthesesystemsandexacerbatedbydroughtconditionsin2016.Inthisdepuratesoil,decomposeractivitywasnot correlatedwithP availability.Therefore, in fieldswith low levels ofdecomposer activity,organismsmay play a limited role in soil P cycling. In these types of ecosystems, treatments tostimulatedecomposersalreadyinthosesystemsmaybeineffectiveinreducingPrunoffpotential,atleastintheshortterm.

#SII.29VariationinmicrobialcommunitycompositionmayexplainsoilfunctioninginanurbanbrownfieldJayprakashSingh,NinaGoodey,JenniferKruminsMontclairStateUniversity,UnitedStatesPhosphatase activity (PA) is sometimes used as a proxy for soil function, especially in metalcontaminated soils where PA can be depressed. We measured PA to investigate soil function inLibertyStatePark(LSP),anurbanbrownfieldinnorthernNewJersey,usingPAasaproxyforsoilhealth.WemeasuredPAfromfourdifferentsitesatLSPofknownheavymetalcontamination,twoof them represented high heavy metal load (LSP 146 and 25R) and the other two displayedrelatively lower heavy metal loads (25F and 43). We compared the PA of sites at LSP with anuncontaminatedsiteofthesimilarsuccessionalstatethatisexposedtosimilarclimaticconditions,HutchesonMemorialForest(HMF).Asexpectedbasedonpriorexperiments,wefoundalmostnoPAat25R.However,wefoundrelativelyhighlevelsofPAatLSP146and25F.Thisledustohypothesizethatmicrobial communitycompositionmightbedriving thenotablyhighPAatLSP146and25F.Wethereforesequencedthe16srRNAandITSgenesfromwholecommunityDNAandfoundthatthebacterial community isdistinctlydifferentat25R. Incontrast to thebacterial community, thefungalcommunityatHMFseemedtobedistinctlydifferentfromtheLSPsites.Further,CCAanalysisshowedthatPAandmoistureaccountedforthevariationassociatedwiththemicrobialcommunityatLSP146,andpHat25R.Resultsfromthestudysuggestitspotentialimplicationinimprovingsoilfunctionviamicrobialtransplantationinsoil.

#SII.30InvasionshiftssoilfungalcommunitycompositioninCaliforniachaparralMichalaPhillips1,AndrewKrohn2,EdithAllen11UniversityofCaliforniaRiverside,UnitedStates2NorthernArizonaUniversity,UnitedStatesInvasion persistence is likely driven by multiple interacting mechanisms, such as the a prioripresence of both mutualistic and parasitic soil organisms or alteration of the belowgroundcommunity by the invasive species. Invasive neighborsmay alter the community composition ofarbuscular mycorrhizal fungi (AMF) found colonizing native roots. We hypothesized that (1)invasive annuals will associate with an ‘early successional’ AMF community; and (2) invasivegrasseswillhavearelativelylowerpathogenabundance.WecollectedrootsandsoilsinMarch2016from two sites underneath individuals of a native shrub (Adenostoma fasciculatum) and invasivegrasses(BromusdiandrusandAvenafatua).WeextractedDNAfromrootsandsoils,amplifiedITS2andSSUrDNAusingusingprimersspecifictoallfungi(ITS2)ortoAMF(SSU),sequencedampliconson an Illumina MiSeq, and processed reads through QIIME. ITS2 sequences were aggregated tofunctional guilds using FUNguild. Host‐plant identity drove differences in fungal communitycomposition.NMDSordinationshowsgroupingoftotalfungalandAMFcommunitiesbyhost‐plantidentity. Invasion increased abundance of Acaulosporaceae, in support of the first hypothesis. Incontrasttothesecondhypothesis,invasiveshadagreaterrelativeabundanceofpathotrophicOTUs,whereasnativeshadagreaterrelativeabundanceofsymbiotrophicOTUs. Invasionresulted inanincrease of ‘early successional’ AMF that primarily have intra‐radicle colonization, which maydecrease the presence of extra‐radicle foraging hyphae in the soil. These natives depend onassociations with foraging hyphae to increase access to resources; a loss of this inoculum mayreducesuccessofre‐establishment.

#SII.31SoilhealthmediatestomatoresistancetoinsectvectorsandviralpathogensJennifer Schmidt1, Clare Casteel1, Rachel Vannette1, Christian Nansen1, Scott Park2, Kate Scow1,AmelieGaudin11UniversityofCalifornia‐Davis,UnitedStates2ParkFarmingOrganicsExploitingmultitrophic interactions between soilmicrobial communities, crops, insect pests, andpathogenshasthepotentialtoincreasesoilandplanthealthandbuildbroadresiliencetomultipleenvironmentalstresses.However,theunderlyingmechanismsareunclearandthepotentialofsoilhealth‐building management practices to increase pest and virus resistance remains to bequantified in economically relevant crops. Processing tomato (Solanum lycopersicum) is a majorcrop inCalifornia,whereproduction is limitedby insect‐vectoredviruses suchasBeetCurlyTopVirus (BCTV), transmitted by the beet leafhopper (Circulifer tenellus), and Potato Virus Y (PVY),transmittedbyaphid(Myzuspersicae).Twogreenhouseexperimentsusingfieldsoilrepresentingasoilhealthgradient from farmer fieldsand theCenturyExperimentatRussellRanch investigatedthe effect of soil health andmicrobial community compositiononplant growth, attractiveness toinsectvectors,inductionofdefensecompounds,andresistancetoviralpathogens.Resultssupportakeyroleofthemicrobialcommunityinplantnutritionandattractivenesstovectors:plantsgrowninorganicallymanagedsoils respondeddifferently tosoil sterilizationandwere lessattractive toleafhoppersthanplantsgrowninsoilsfromconventionalorintegratedmanagement.Microbesfromorganicallymanagedsoilalsoconferred increasedresistance toaphidvectorsand inducedhigherlevels of the defense hormone salicylic acid (SA), suggesting possible mechanisms. As tomatoproduction expands into marginal soils, a better understanding of the role of soil health inmultitrophic interactions affecting plant health can inform management decisions to improvepathogenresistanceandproductivityoverthelongterm.

#SII.32BacterialcommunitiesassociatedwithPrunusreplantdiseaseAmishaPoret‐Peterson,NataliaOtt,GregBrowneUSDepartmentofAgriculture,AgriculturalResearchServicePrunus replant disease (PRD) is a soil‐borne complex that suppresses productivity of replantedstone fruit andnutorchards. Symptomsof thedisease include reductionof fine root growth andaboveground biomass. PRD is likely microbially‐mediated, as pre‐plant soil fumigation orpasteurizationpreventssymptomexpression.Previousstudies implicated fungiandoomycetesaspotential contributors to PRD. Here, we characterize bacterial communities from roots of peachseedlingsexhibitingvariouslevelsofPRDseverityinsoilsfromCalifornia’sCentralValley.Thesoilswere left untreated or subjected to chemical fumigation or pasteurization before planting withseedlings.After2months,wemeasuredseedlingbiomassandsequenced16SrRNAgeneampliconsfrom combined root and rhizosphereDNAextracts. Seedlings accumulatedmuch less biomass inuntreated PRD‐conducive soils than in non‐conducive or treated soils. In all treatments, thebacterialcommunitiesconsistedmostlyofProteobacteria,Actinobacteria,andBacteroidetes.NMDSanalysis showed that the communities from roots in PRD‐conducive and non‐conducive soilsdifferedcompositionallyfromeachotherandfromthoseofthecognatefumigatedandpasteurizedsoils.WeappliedtheDirichletMultinomialMixturemodeltoclusterOTUsintometa‐communities,assign samples to particularmeta‐communities, and identify potential contributors to PRD. Thisanalysis revealed four meta‐communities within the dataset consisting of (1) fumigated andpasteurized soils (regardless of PRD potential), (2) fumigated soils from the most severe PRD‐conducive sites, (3) mostly non‐PRD‐conducive soils, and (4) mostly PRD‐conducive soils. OTUsclassified as Streptomycetaceae and Steroidobacter were diagnostic of this lastmeta‐community,suggestingapotentialroleofthesebacteriainPRD.

#SII.33PlantspeciesandfunctionalgroupeffectsonsoilpropertiesinagreenroofcommunityKaiyueZhou1,LouiseEgertonWarburton21NorthwesternUniversity,UnitedStates2ChicagoBotanicGarden,UnitedStatesGreen roofs are increasingly used to compensate for the loss of green space and biodiversity inmanycities.Theecosystemservicesandabovegroundplantperformanceongreenroofhavebeenextensively studied.However, there is surprisingly little informationon thebelowgroundhabitat,eventhoughthegrowingmediamakesalargeandindispensableproportionofgreenroofsystem.In this study,weasked:what is theeffectof individualplant speciesor functional groupson soilabioticandbioticpropertiesingreenroofversusnaturalsoils?Weindexedtheabiotic(nutrients;organicmatter;pH)andbioticproperties (enzymes linked toC,N,Pcycling;microbialsubstrate‐inducedrespiration)of rhizospheresoils in12nativeprairieplants (forbs, legumes,grasses)andSedum(genericroofplant)inagreenroofandarestoredprairieinnaturalsoil.Plantspeciesandfunctional groups differentially partitioned abiotic properties in both natural (NO3, P) and greenroof(NH4,NO3)soils.Plantidentityalsoplayedakeyroleinshapingthebioticpropertiesinnaturalsoils.Microbialrespirationandenzymeactivitydifferedmarkedlyamongplant functionalgroups,especially between forbs and grasses, and native plants and Sedum. Conversely, microbialrespirationandenzymeactivityweresimilarbetweenplantspeciesor functionalgroups ingreenroofsoils,meaningthatrhizospheremicrobialactivityandnutrientlevelswerenotcloselycoupled,or that abiotic factors (e.g., N) overruled microbial functioning in green roof communities.Understanding these responses and their underlying mechanisms will be important for thesustainedhealthofroofsoilcommunities.

#SII.34DisturbancehistoryandenvironmentalcharacteristicsshapetheectomycorrhizalfungalcommunityoftwovarietiesofPinusclausaMeganRuaWrightStateUniversity,UnitedStatesThe soil biota is diverse, yet the ecological and evolutionary processes that regulate speciesdiversityandabundanceofsoilmicroorganismsacrossspaceand timeremainselusive. In forestecosystems, periodic disturbances which operate at different time scales represent one possibleavenuebywhichdiversity in the soil biotamaybemaintaineddue to their effecton genetic andphenotypic characteristics of the host and associated environment. To investigate the degree towhich host variety and environmental characteristics shape the belowground ectomycorrhizal(ECM)fungalcommunity,wesampledtenpopulationsofasinglepinespeciesthathasdivergedintotwo genetically distinct varieties as a result of disturbancehistory (Pinus clausa var. immuginataandvar.clausa) andusedmultivariateanalysis to relate the communitymatricesofECM fungi tohostandenvironmentalcharacteristics.HostvarietywasanimportantdeterminantofECMfungalcommunity structure and diversity at both the species level and when fungi were grouped intocategoriesbasedontheirsubstrateexplorationandnutrientacquisitionstrategiesindependentofenvironmentalcharacteristics.Overall,ourresultssuggestthatperiodicdisturbanceswhichshapethehostpopulationsarealsoimportantforstructuringtheECMfungalcommunityindependentofenvironmentaleffects.

#SII.35TheeffectofgroundcovermanagementonvineperformanceandfungalrootendopytecommunitiesEricVukicevich1,JoseRamonuRbez‐torres2,PatBowen2,D.ThomasLowery2,MirandaHart11UniversityofBritishColumbia,Okanagan,Canada2Agriculture&Agri‐FoodCanada,SummerlandResearch&DevelopmentCentre,CanadaThepurposeofthisstudywastodetermineifdifferentgroundcovermanagementstrategiescouldinfluence vine disease resistance via changes in soil fungal communities. We used whole soilinoculum collected from a field trial of groundcover management schemes in a greenhouseexperiment planted to grapevine rootstock Vitis riparia x rupestris 101‐14. We introducedIlyonectrialiriodendri,acausalagentofblackfootdiseaseofgrape,toobservetheprotectiveeffectofeachmicrobialcommunity.Aftereightmonths,vineperformancedifferedbasedongroundcovertreatment and was correlated with differences in fungal communities isolated from vine roots.Therewerealsocommunitydifferencesbetweenhealthyandnecroticroots.Totalcolonizationbyarbuscularmycorrhizal fungididnotdifferamonggroundcover treatments. However,differenceswere seen in the proportion of different fungal structures (hyphae, arbuscules, vesicles) amongsome treatments and between healthy and necrotic roots. Our results indicate that in the earlystages of pathogen infection vine performance may depend on ground cover management andinvolveinteractionsbetweenthesoilcommunitytrainedbythegroundcoverandendophyticfungipresentinvineroots.

#SII.36Profiling ectomycorrhizal fungal diversity and function in seedlings of south ChinanativemassonpineandintroducedslashpineChenNing1,GregoryMueller2,LouiseEgertonWarburton21NorthwesternUniversity,UnitedStates2ChicagoBotanicGarden,UnitedStatesIt hasbeenproposed thatnon‐indigenouspine trees canovercomesymbiont limitation and thusadapt in a new ecosystem. However, the process that exotic plants choose their obligate soilmicrobialcommunitiesandtheassociatedfunctionremainspoorlyunderstood.WetookadvantageofalargeforestsiteinGuizhou,Chinathatincludesbothconservednativepine(Pinusmassoniana)forestsandintroducedpine(Pinuselliottii)plantations.Pineseedlingbioassayswereemployedtoexamine ectomycorrhizal (ECM) fungal root tip communities using both high‐throughputsequencing of pooled roots and single root tip enzyme assays. Field‐collected soil cores weretreatedoneofthreeways,keptintact(undisturbed),homogenized,orautoclaved.Wefoundthatthepattern of recovery of ECM fungal communities differed from the original soil spore bank: a)pioneercolonizerssuchasRhizopogonandTomentelladominatedthebioassaycommunitiesinalltreatments;b)intactsoiltreatmentincreasedthesurvivorshipforshortdistanceexplorationtypeECM fungal species such as Russula; c) ECM fungal community of the introduced pine wascomprisedoffewerfungalpartnersthanthenativepine.EnzymeactivityofthetwomostabundantpioneerRhizopogon speciesdidnot significantlydiffer acrosshost associationsor soil treatment.Thus,ourresultsshowthatevenaftersoildisturbance,thelow‐richnessECMfungalcommunityofalien pines retains adequate enzyme function, suggesting that functional redundancy exists forexoticpinesduringtheearlyestablishmentprocess.

#SII.37Environmentalmulti‐inputcircuittounderstandplant‐microbecommunicationIlenneDelValle1,TaraM.Webster2,CarolineMasiello1,JonathanJ.Silberg1,JohannesLehmann21RiceUniversity,UnitedStates2CornellUniversity,UnitedStatesMany interactions between plants and microorganisms depend on communication throughextracellular signalingmolecules,whose bioavailable concentrations and half‐lives can varywithsoil conditions.Microbessynthesize chemical signals thatdiffuseacrosscellmembranes tosensepopulationdensity(quorumsensing).Theaccumulationofthesemoleculesactivatestheexpressionof genes that regulate keybiogeochemical processes such as nitrogen fixation.Microbes can alsosense different plant produced signals found in root exudates to coordinate plant microbecommunication. Flavonoids are one type of plant produced signal necessary for the symbiosisbetween legumes and nitrogen fixing bacteria. Flavonoids and quorum sensing molecules havestructureswitharangeofelectrostatic interactionpotential andhydrophobiccharacteristics.Ourunderstandinghowdynamicsignalingcontributestosymbiosesdevelopmentindifferenttypesofsoils is not yet complete. The objective of this study is to understand how the soil mineral andorganicmattermatrixinteractswiththemultiplesignalingmoleculesthatplayakeyroleinplantmicrobe symbiosis formation. One flavonoid based sensor linked to green fluorescence protein(GFP)andanacylhomoserine lactone(AHL)biosensor linkedtoared fluorescenceprotein(RFP)werechromosomallyintegratedintoE.coli.Theeffectofdifferentsoilamendmentsincludingplantmaterials,pyrolyzedorganicmatter,claysandcompostwereanalyzedusingthisbiosensor.Resultshaveshownthatdifferentsoilamendmentscanhaveoppositeeffectsonthesetwochemicalsignals.pHappears toplayamore importantroleonAHLbioavailability,whilenaringeninbioavailabilitycanbereducedthroughcomplexationwithtanninspresentinplantbiomass.

#SII.38SoilmicrobialfeedbackinagriculturalcroprotationAkihiroKoyama1,TeresaDias2,AngelaDukes1,PedroAntunes11AlgomaUniversity,Canada2CentreforEcology,EvolutionandEnvironmentalChanges,PortugalPlant‐soil feedback can be a major driver to determine plant community dynamics. AlthoughfeedbackwithpestshasbeenappliedasabasisforcroprotationsincetheRomanTimes,plant‐soilfeedback has rarely been considered. Potential benefits of crop rotation via plant‐soil feedbackinclude nutrient use optimization and pathogen reduction, but contributions of the twomechanismshavenotbeenwellunderstood.Weinvestigatedthesemechanismsinagreenhousepotexperiment,usingfivecropscommonlycultivatedinOntario,Canada(alfalfa,canola,maize,soybeanandwheat).Wetrainedsoilbyeachofthefivecropsinthefirstphase,andreciprocallyplantedthefivecropsinthetrainedsoilsinthesecondphase.Toteaseoutnutrientvs.soilmicrobialfeedback,weestablishedthreetreatments;soilbiota(autoclavedsoils+microbialinoculationfromthefirstphase),nutrient(autoclavedsoilinthebothphases),andcontrol(fieldsoilwithoutautoclaveintheboth phases). We measured total biomass of each crop at the end of the second phase, andcalculated feedback by comparing total biomass of each crop grown in soils trained by the fourothercropsagainstbiomassinself‐trainedsoil.Thetwolegumecropstendedtoreducethebiomassof subsequent crops due to soil microbial feedback, whereas microbial feedback of canola andwheat was mostly neutral. The three non‐legume crops mostly benefited subsequent crops vianutrient feedback.Ourresultsdemonstratedifferent rolesofnutrientsandmicrobes inplant‐soilfeedback,whichcanbeusedtoimprovesequenceincroprotations.

#SII.39OomyceteandfungalrootcommunitiesassociatedwithPrunusreplantdiseaseanditscontrolinconventionallyfumigatedoranaerobicallydisinfestedsoilNataliaOtt1,AmishaPoret‐Peterson1,HosseinGouran2,GregBrowne11USDepartmentofAgriculture,AgriculturalResearchService,UnitedStates2JointGenomeInstitute,UnitedStatesEveryyear,Californiagrowersreplacethousandsofhectaresofoldstonefruitandnutorchardstorenewproductivity.However,therenewalscanbecompromised,initiallybyPrunusreplantdisease(PRD)and laterbyphytopathogenicnematodes.Our focuswasonPRD, aPrunus‐specific growthsuppressionapparentlymediatedbyanill‐definedsoilbornemicrobialcomplex.PRDoftenoccursin absence of phytopathogenic nematodes. Conventional soil fumigation (CSF)with chloropicrin‐containingfumigantseffectivelymanagesPRD,yetduetoenvironmentalconcernsdevelopmentofnon‐fumigant approaches is needed. In two field trials, both anaerobic soil disinfestation (ASD;driven by available carbon,moisture, and heat under tarp) and CSF prevented PRD, greatly andequally stimulating tree growth. Here,we report on oomycete and fungal root community shiftsassociatedwiththetrialtreatments.OomyceteandfungalITSampliconsequencingwascompletedforthecontrol,SF,andASDtreatmentsusingtotalDNAsampledfromfinerootsandrhizospherestwiceperyearperexperiment.AmongOTUsgeneratedwithoomyceteprimers,PERMANOVAandNMDSrevealed significant community shifts in all treatmentsofboth trials, andCCAconstrained42%to58%ofthevariationtosoiltreatment,samplingmonth,andtreegrowth.OTUsconsistentlyassociated with reduced tree growth in the control treatment included Pythium ultimum,Phytopythium vexans, Ceratobasidum sp., and an unknown ascomycete. Less‐consistent shiftsoccurred among OTUs generatedwith fungal primers. Both CSF and ASD can effectively preventPRDandreduceincidenceofcertainPRD‐associatedspecies,yeteachtreatmentgeneratesdifferentrootcommunitiesthatmaybeworthyoffurtherstudy.

#SII.40WilltheuseofnurseplantsinoculatedwithnativeAMfungihelprestorethenativeplantcommunityaftereradicationofinvasivegrasses?Ma.LourdesEdano1,GailWilson1,KarenHickman1,JamesBever21OklahomaStateUniversity,UnitedStates2KansasUniversity,UnitedStatesInvasionbynon‐nativeplantscanaltersoilmicrobialcommunities,furtherpromotinginvasionandreducingmutualisticsoilmicroorganismssuchasarbuscularmycorrhizalfungi(AMF).Weassessedrestoration success following establishment of nurse plants inoculated with AMF, compared tonurseplantswithout inoculation.Our studywas initiated in2013atFortRileyArmyBase inKS,USA.LargeareasofthebaseareinvadedbyBothriochloabladhii,anon‐nativewarm‐seasongrass.Weeradicated the invasive grasses in4mx4mexperimentalplotswith seven replicates.Nurseplants Andropogon gerardii, Amorpha canescens, Allium canadense, Echinacea augustifolia wereinoculated with whole soil from nearby native sites, AM fungal spores, or not inoculated, andtransplantedalongthecenterofeachplot.Onemonthaftertransplanting,allplotsweresownwitha diverse prairie seedmix. Plant species compositionwas assessed in late summer of 2014 and2015atdistancesof0.5,1.0,and1.5mfromnurseplants.Percentcoverbytheinvasivegrasswasalmost twice as high in plotswithnon‐inoculatednurseplants, compared toplots receivingAM‐inoculated plants. However, native species such as Bouteloua curtipendula and Schizachyriumscoparium increasedinrelativeabundanceinplotswithAM‐inoculatednurseplants,comparedtoplotswithnon‐inoculatednurseplants. Inaddition,nurseplants inoculatedwithnativeAM fungiincreasedinsurvivalandgrowth,comparedtonon‐inoculatedplants.OurresultsindicatethatAM‐inoculatednurseplantsandnativeseeding inpost‐invadedsoilmaysuppressthereinvasionofB.bladhiiandencouragethereestablishmentofnativegrasses.

#SII.41EcologyoftemperatebelowgroundfungithroughITSsequenceanalysisoverfouryearsinmixedsuccessionalperennialsystemsFranzLichtner,KirkBrodersColoradoStateUniversity,UnitedStatesFungal speciesdiversity changes over timedependingonbothbiotic and abiotic influences. ThisstudymeasuredthefungalITSsequencediversityattwosites,PennsylvaniaandNewHampshire,where the above ground plant diversity was manipulated through perennial rye grass cultivarmixtures. Over the course of the four years, cultivars and cultivar mixtures led to increased ordecreasedmeasuresofspecificfungaloperationaltaxonomicunits(OTUs).Specifically,membersofthe Glomeromycota responded uniquely to location, existing in significantly higher numbers anddiversity ofOTUsdepending on location. Glomeromycetes increased in an exponential fashion inPennsylvaniawhileinNewHampshiretheabundanceanddiversityoscillatedyeartoyear.ShannonandSimpsondiversityshowedspecificcultivarmixture treatmentscorrelatedwithgreater fungaldiversity than others. Phylogenetic analyses showed that there was specificity of compositionwithincommunitiesinassociationwithcultivarmixtures.Thisanalysisutilizedthemodern‘dada2’bioinformatics package in R which reaches single nucleotide resolution through unique errorinferencemethods. Thismethod allows for accurate amplicon analysiswith fewer false positivesthan other commonly utilized amplicon analyses pipelines. This work utilizes currentcomputationaladvancestointerpretbelowgroundecologicalfungalsuccessionatahighdegreeofprecision and fine resolution, allowing for a more accurate view of belowground plant fungalinteractions in a unique chronosequence. Understanding below ground community dynamicsrelatedtoabovegroundgenotypicvarianceiscrucialtoensuringsustainablecroppingsystemsandresilienceacrossbroadtemperategradients.

#SII.42ComparisonsofmycorrhizaeandplantgrowthbetweentheNJpinebarrensandserpentinebarrensJohnDightonRutgersUniversity,UnitedStatesIn a comparison of the growth of the two grass species Schizachyrium scoparium and Panicumvirgatumgrowingonpinebarrensandserpentinebarrenssoils, thecolonizationof rootsbybotharbuscularmycorrhizae anddark septate hyphaewas significantly higher in serpentine soil. In areciprocaltransplantexperimenttoassesssitespecificadaptationsbytheseplants,survivaloflittlebluestemdeclinedsignificantlywhenplantedintosoilnotofitsorigin,howeverthisonlyoccursinswitchgrasswhenserpentineseedsourcewasplantedintopinebarrenssoil.Overallplantbiomasswas greater in serpentine soil for both plant species, along with greater mycorrhizal and DSEcolonization. Preliminary data suggests there are significant differences in the ectomycorrhizalcommunityofpitchpinebetweenthetwosoiltypes.Ourdatasuggestssomeevolvedadaptationofbothplantspeciestoitslocaledaphicenvironment.

#SII.43AnalysisofspatialpatternsinformscommunityassemblyandsamplingrequirementsforCollembolainforestsoilsTomBolger1,TaraDirilgen1,EditeJucevica2,PascalQuerner3,ViestursMelecis21UniversityCollegeDublin,Ireland2UniversityofLatvia,Latvia3InstituteofZoology,Vienna,AustriaThe relative importance ofniche separation, non‐equilibrial and neutral models of communityassembly has been a theme in community ecology formany decadeswith none appearing to beapplicable under all circumstances. In this study Collembola assemblageswere recorded overelevenconsecutiveyearsinaspatiallyexplicitgridandusedtoexamine(i)whetherobservedbetadiversitydiffered fromthatexpectedunderconditionsofneutrality, (ii)whethersamplingpointsdiffered in their relative contributions to overall beta diversity, and (iii) the number of samplesrequiredtoestimatethespeciesrichnessintheforestsites.Thisstudyexaminesdataoverseveralyears and is therefore not merely a snapshot in time as is the case in many studies of spatialpatterns.Neutralitycouldnotberejectedonmostoccasionsandthedatasuggestthatstochasticitycannotberuledout.Notaloneisbetadiversityconsistentwiththosepredictedunderassumptionsof neutrality but the lack of difference in individual‐ and sample‐based rarefaction curves alsosuggestsrandomnessinthesystematthisparticularscaleofinvestigation.Atthescaleinvestigateditwould appear that Collembola are not spatially aggregated and community assembly is drivenprimarilybyneutralprocesses.Whetherthisfindingisduetosmallsamplesizeordisturbanceorbothcannotbedetermined.Variabilitybetweendatesandsitesillustratesthepotentialofdrawingincorrect conclusions if only a single site at a single point in timewas used, i.e. if temporal andspatialheterogeneityisnotaccountedfor.

Appendix l l

SOIL ECOLOGY SOCIETY BIENNIAL ORAL PRESENTATION ABSTRACTS

Wednesday June 7th

PARALLEL ORAL SESSION A Bal l room C

Soilnetprimaryproductionandcarbonemissionsinatropicalrainforest:EffectsofleafcutterantsthroughanENSOcycle*MichaelAllen1,AmandaSwanson1,EmmaAronson1,ThomasHarmon2,RobertJohnson1,DiegoDierick,3ZhanChen4

1UniversityofCaliforniaRiverside,UnitedStates2UniversityofCaliforniaMerced,UnitedStates3FloridaInternationalUniversity,UnitedStates4ChineseAcademyofForestry,ChinaTropicalRainforests areportrayed as the lungsof theearthbecauseof theCO2 absorbedandO2released.ButsoilCO2fluxesremainpoorlyunderstood.Westudiedsoilnetprimaryproductionandcarbon emissions of amature tropical rainforest at the La Selva Biological Station in Costa Ricathrough an ENSO climate cycle.We used a Soil EcosystemObservatorywith sensors for CO2,O2,H2O, and Temperature. Fluxes were modeled. Automated minirhizotrons took daily images.MonthlymeasurementsofCO2andCH4weretakenusingchambers.Standingcropofrootswas120g/m2.Rootlifespanaveraged60days(6generationsperyear)forafinerootNPPof720g/m2/y,equaltoleafNPPof750g/m2/y.Fungalhyphalstandingcropaveraged3.5g/m2,lifespanaveraged24.9days(14.7generations/y)forafungalNPPof52.9g/m2/y.Respirationwas 1720g/m2/y versus 1831g/m2/y in the canopy. During La Niña (wet) phase ofENSO)soilsemittedupto0.3mg/m2/dayofCH4‐C,butduringtheElNiñodryphase,soilsconsumedupto1.3mg/m2/day.Antsrolledsoilintoballsreducingtortuosityandincreasingair‐filledporosityincreasing gas diffusion.With standingwater, CO2 flux blocked, and CH4 is emitted from controlsoils. A CO2 diffusion gradient from soil‐to‐nest‐to‐vent‐to‐atmosphere develops. O2 flows in theoppositedirection.LeafCutterAntnestsformachimneyofCO2fromsoilthroughtheforestcanopy.Wearecurrentlyestimatingthestrengthofthesechimneys.

Soilfungiresponsetoseasonalandannualvarianceinthreeagroecosystems*RachaelUpton1,KirstenHofmockel21IowaStateUniversity,UnitedStates2PacificNorthwestNationalLaboratory,DepartmentofEnergy,UnitedStatesThe Comparison of Biofuel Systems (COBS) field‐site is comprised of traditional cornagroecosystemandtworestoredprairie,fertilizedandunfertilized,whichdiversifybiofuelsourcesand promote soil organicmatter (SOM) retention. During prairie restoration, plant communitiesvaryovergrowingseasonsandacrossyears.Fungiplayakeyroleindeterminingthefateofcarbonin soil and are influenced by plant communities. Utilizing the COBS field‐site, we wanted todeterminetheresponseofthefungalcommunitytoshiftsinthecroppingsystemsacrossyearstodeterminepotential changes in their role incarboncycling.Wehypothesized thatalthoughplantcommunities’shiftintheprairiesacrossyearsinresponsetoseasonalvariationandfertilization,amicrobial“seedbank”forsoilfungiexistsduetotheabundanceofdormantfungalspecies.Wealsohypothesizedthatactive,moreselectivefungalcommunityrespondstoseasonalfluctuationsintheplantcommunityacrossthetwoprairies.Using an amplicon sequencing approach (ITS) we elucidated the fungal community structureresponseduetoseasonalchangesandshiftingplantcommunitiesacrossyears.Ourresultsshowedthat the two prairie fungal communities were significantly different from the continuous corncommunity.Additionally,wedidnotseeasignificantchangeinthefungalcommunityacrossyearsin each agroecosystem.We did see a significant seasonal impact on amore select and dynamicgroupoffungiacrossagroecosystems.Ourresultsshowanearlyresponseofthefungalcommunitytotheprairierestorationandthelastingimpactonthesoilcommunityforyearstofollow.

Mycorrhizalallocationdeterminestheirfunctionacrossvaryingenvironmentalcontexts*MichaelRemke1,MatthewBowker3,NancyC.Johnson4,MatthewWilliamson2,KarenHaubensak11NorthernArizonaUniversity,UnitedStates2UniversityCaliforniaDavis,UnitedStatesArbuscularmycorrhizal(AM)fungiareobligatesymbiontstoplants.Resourcelimitationmayfavorstronger mutualisms, where resource abundance may result in diminished mutualism or evenparasitism. Co‐adapted plants and mycorrhizal fungi have been documented to have greatermutualisticfunction.Themechanismsforthesedifferencesarenotwellunderstood,thoughithasbeenproposed that fungal allocation to different structuresmayhave a role.Within plant roots,thesefungiestablishsitesfornutrientexchange(arbuscules)andstorage(vesicles).Itislikelythatgreater investment instoragereduces theirability togatherand/orexchangenutrientsand thusmakes them less mutualistic and vice versa. We conducted a greenhouse study with Botelouagracilis to test mycorrhizal allocation and how it varies based on environmental context. WemanipulatedbothplantandAMfungioriginaswellascreatedtwolevelsofsimulateddrought.Wealsoconductedafieldtransplantexperimenttotestourfindingsinmoredynamicenvironments.Inthegreenhouse,wefoundthatplantsconsistentlygrewlargerandsurviveddroughtlongerwhentheywerepairedwithsympatricAMfungi.Additionally,after2yearsinthefield,sympatricplant‐AMfungipairingsyieldthegreatestplantgrowthregardlessofenvironment.Insympatricpairings,there was also more external AM fungal hyphae and a greater percentage of plant roots werecolonizedbyhyphaeandarbuscules.Inallopatricpairings,plantrootsweremoreheavilycolonizedby vesicles. These findings demonstrate potential mechanisms for how AM fungi can behave aseithermutualistsorparasitesdependingonenvironmentalcontext.

QuantifyingthecontrolsonSOMcharacteristicsbyMAT,disturbance,vegetation,depthandthesoilmatrix:AnOpusapproach

EldorPaulColoradoStateUmiversity,UnitedStatesAnalysisbyNMR,molecular‐biologicalmarkers,MiDIR,py‐MBMS,pyGCMS,physicalandchemicalfractionation,long‐termincubationand13C14Cshowedsimilaritiesovermanysoils.SitesincludedaMATgradientfromAlaskatoBrazil,cultivated‐virgin,US,mid‐continentsoilsandafforestedsoilsfromOntariotoMississippi.ThetundrasitehadlimitedpedogenesiswithgoodcorrelationbetweenMiDIRandpyMBMS.LongchainlipidsincreasedwithincreasingMAT.CultivationdecreasedSOC,labile C, cutin‐derived C and C:N ratios but increased the proportion ofmicrobial and suberin‐derivedC,andmeanresidencetimes(MRTs).Itdecreasedcarbohydrates,amineandcyclicNandlignin –phenol, derivatives. Lipids, sterols and high, molecular weight, unknown pyrolysisderivatives were increased. A subtropical, allophane soil with 20% SOC of which only 4%waslabileconsistedprimarilyofmatrix‐protected,microbial‐derivedcarbohydratesandNcompounds.A sandy soil, with negligible matrix protection, showed some chemical recalcitrance with 84%protectionofnativegrasslandSOCundercedarwithendomycorrhizaandCatranslocation. Pineson the native prairie had decreased SOC at depth with MiDIR spectra and biomarker analysisshowinghigheracid toaldehyde ratios indicatingmoreadvancedstagesof lignindecomposition.Depth,withsimilarqualitativebutmuchgreaterquantitativecompoundchangesthancultivation,increasedMRTs by thousands of yearswith decreased C:N ratios but often similar, labile SOCindicatingspatialcontrols. FractionationssuchasLF,POM‐sand,microbialbiomass, siltandclayproduced significantly different pool sizes‐turnover times. Chemical fractionations, whiledelineatingturnovertimes,werenotespeciallyeffectiveindeterminingpoolsizes.

CroprotationimpactsonAMF,PacquisitionandCsequestrationinsemi‐aridagroecosystems*StevenRosenzweig,MeaganSchipanski,StevenFonte,MaryStrombergerColoradoStateUniversity,UnitedStatesArbuscularmycorrhizal fungi (AMF)have thepotential to increaseplantnutrientacquisitionandenhance soil aggregation, both key processes influencing the sustainability of drylandagroecosystems. In conjunction with no‐till, cropping system intensification (reducing thefrequencyoffallowincroprotations)mayenhancenativepopulationsofAMFandothersoilfungithrough greater belowground inputs of C. We assessed soil organic carbon (SOC), water‐stableaggregation, andmicrobial phosholipid fatty acid (PLFA) abundance on 72 dryland no‐till fields.Three levels of cropping system intensity from wheat‐fallow to continuous rotations wererepresentedalongapotentialevapotranspiration(PET)gradientthatincreasesfromnorthwesternNebraska to southeastern Colorado. On a subset of 53 fields, we assessed AMF colonization ofwinter wheat roots and whole‐plant P concentrations at wheat heading. Intensified croppingsystemswere associatedwith increased SOC (p=0.03), AMF colonization ofwheat roots (<0.01),fungalPLFAabundance(<0.01),andaggregatemeanweightdiameter(MWD)(p=0.02)comparedtowheat‐fallowsystemswhenclaycontent,PET,andnumberofyears inno‐tillwere includedascovariates. Plant P concentrations increased with % AMF colonization of wheat roots (p=0.01)when PET and applied P fertilizer were included as covariates. Additionally, aggregate MWDsignificantly increased with total fungal PLFA abundance (<0.001), independent of climate, soiltype,ormanagement.TheseresultssuggestthatrobustandpositiveeffectsofcroprotationonSOCand P availability are mediated by enhanced AMF symbioses and fungal abundance. Overall, insemi‐arid environments, cropping system intensification fosters growth of native fungalcommunitiesthatenhancesoilfunction.

Isrootcarbonbetterstabilizedthanshootcarbon?Testingfeaturesoftheabove‐versusbelow‐groundpathway*NoahSokol,MarkBradfordYaleSchoolofForestry&EnvironmentalStudies,UnitedStatesConsiderable debate exists around the relative roles of aboveground versus belowground plantinputsinsupplyingcarbontothestablesoilorganiccarbon(SOC)pool.Yet,fewempiricalstudieshave testedactualmechanisticdifferencesunderpinning these twopathways, independentof thequantityandqualityofCflowingthroughthem.Weexaminedthreehypothesizedfeaturesthatmayaffect theproportionofabove‐vs.below‐groundplantC inputsstabilized inthemineralhorizon:1) physical distance travelled, 2) proximity to the dense rhizosphere microbial community, 3)deliverytothesoilaspulsedversuscontinuousinputs.Weinsertedafixedquantityofthecommonplantcompoundglucose(99atom%13C labelled) intosoilmicrocosms, throughabovegroundandbelowground entry points, proximately and distally from an artificial root, and as pulsed versuscontinuousinput.Werecovered62.1%moreCstabilizedinmicrocosmswhereCwasenteringbelowgroundversusaboveground, largelydue to thephysicalbarrierof theorganichorizon.We found52.5%moreCstabilized from high‐volume pulses (indicative of leaf litter leachate) than from low‐volumecontinuousinputs(simulatingrootexudates),duetogreateroverallspread/coverageoftheinput.Werecovered57.6%moretotalstableSOCininputsthatentereddistallyfromtheroot(i.e. ‘bulksoil inputs) than proximately to the root (‘rhizosphere inputs’), though a much higherconcentration of SOC and ofmicrobial biomass C in rhizosphere soil. Overall, these results helpdefine specific attributes that may permit the above‐ or below‐ground pathway to dominate Csupplytothesoilwithindifferentcontexts.

PlantcommunitycompositionandvariationinsoilorganiccarboninCaliforniarangelands

*ElizabethPorzig,ChelseaCarey,NathanielSeavyPointBlueConservationScience,UnitedStatesRangelandmanagersareincreasinglyprioritizingecologicalfunctionsofsoil.Soilorganiccarboniscentral to these efforts because it plays a fundamental role in soil fertility, soil stabilization, andwater holding capacity. On grazing lands, influencing soil organic carbon via vegetationmanagementisonestrategythroughwhichmanagersmaybeabletoaffectchange. Forexample,promoting deep‐rooted perennial grasses is hypothesized to increase soil carbon. However,dynamicsbetweensoilorganiccarbonandthevegetationcommunityarecomplex,andthere isaneed to understand broad patterns in soil organic carbon concentrations in relation to plantcommunity composition. In2016,wesurveyed theherbaceousplantcommunityandsoilorganiccarbon (0‐10 cm) at 220 locations in 15 counties in California. Using multiple regression ondistancematrices,wefoundasignificantrelationshipbetweenvegetationcommunitycompositionand percent soil organic carbon while controlling for geographic location, average annualprecipitation, and soil texture. Using indicator species analysis, we found that plant speciesassociatedwith high soil carbon included several functional groups, including perennial grasses,andplantspeciesassociatedwithlowsoilcarbonwereprimarilyannualforbs.Thissurveyofplantcommunity composition and soil organic carbon provides context for setting managementobjectivesandgeneratingmechanistichypothesesaboutplant‐soilinteractions.

Doesclimatewarmingalterplantdiversity‐soilcarbonrelationshipsandassociatedsoilmicrobialcommunities?*SarahCastle1,ZeweiSong3,StuartGrandy2,LindaKinkel11UniversityofMinnesota,UnitedStates2UniversityofNewHampshire,UnitedStatesPlant community richness can significantly influence the quantity, molecular diversity, andchemical identity of soil C and associated soil microbial communities and may have significantimplications for how soils respond to elevated temperatures under global warming. Here wehypothesizedthat: i)soilcarbonattributesvarywithplantdiversity; ii)differencesinsoilcarbonprofileswillbegreaterwithvaryingplantdiversityinwarmedvs.non‐warmedplantcommunities;andiii)microbialcommunitydiversitywillbepositivelycorrelatedwithsoilcarbondiversity.Wesampledsoilsfromaplantbiodiversityclimateexperimentestablishedin2008attheCedarCreekLTER,Minnesota,USA.SoilswerecollectedfromwithintherhizosphereofAndropogongerardiiandLespedeza capitata growing in monoculture or in 16‐species polycultures, under ambient orwarmed(~3‐5°C)conditions.Weusedampliconsequencingofbacterial16SandfungalITS2andpyrolysis‐GCMS analyses of molecular soil C chemistry to test our hypotheses. Molecular soil Cdiversitywassignificantlygreaterinpolyculturethanmonocultureplantcommunities(P<0.0001).Lignin and phenolic compounds, major C classes in soil from polycultures, were present in lowabundances orwere absent from soils ofmonocultures. Finally, fungal and bacterial communityassemblages varied betweenmono‐ and polyculture plant communities. Our results suggest thatplant diversity controls soil C pool size and molecular chemistry as well as the associated soilmicrobial community. We anticipate that plant diversity will moderate warming effects onmicrobial composition, which will be reflected in differences of metabolic potential amongmicrobialcommunities.

CompetitionreducesmicrobialcarbonuseefficiencyDanielMaynard,ThomasCrowther,*MarkBradford

YaleSchoolofForestry&EnvironmentalStudies,UnitedStatesTheefficiencybywhichmicrobesdecomposeorganicmattergovernstheamountofcarbonthatisretained in microbial biomass versus lost to the atmosphere as respiration. This carbon useefficiency (CUE) is affected by various abiotic conditions, such as temperature and nutrientavailability.Theoretically,thephysiologicalcostsofcompetitionshouldlikewisealterCUE,yetthedirectionandmagnitudeofthesecostsareuntested.Hereweconductamicrocosmexperimenttoquantify how competitive interactions among saprotrophic fungi alter growth, respiration, andCUE. By comparing individual performance to community‐level outcomes, we show that speciesinteractionsinduceconsistentdeclinesinCUE,regardlessofabioticconditions.CompetitionlowersCUEbyasmuchas25%,withthemagnitudeofthesecostsequaltoorgreaterthantheobservedvariationacrossabioticconditions.Ourresultssuggestthattheextenttowhichmicrobial‐mediatedcarbon fluxes respond to environmental change may be influenced strongly by competitiveinteractions.

Howdoplantseasonaldynamicsdriverootcarboninputstothesoilandtheirdistribution?CameronMcMillan,MichaelWeintraubUniversityofToledoDept.ofEnvironmentalSciences,UnitedStatesAprimaryconstituentofstabilizedsoilorganiccarbon(C)ismicrobialnecromass,muchofwhichisderivedfromplantinputsoflabilesolubleC,suchassacchariderichrootexudates,whichstimulatemicrobialproduction.Thequestionthisstudyaddressesis:howdotheseasonalityanddistributionofsoilsaccharidesvaryinassociationwithplantswithdifferentphenology?We hypothesized that variations in plants’ leaf expansion/senescence times are reflected inpatternsofrootexudation,basedonthetimingofCfixation.Weconductedanobservationalfieldstudyofsoilsaccharidedynamicsinatemperatedeciduousforestsandyclayloamsoilassociatedwith Acer rubrum (red maple) and Lonicera maackii (honeysuckle), chosen because of theircontrastingphenology, inNorthwestOhio,USA, fromApril‐December2015.Reducingsugarsandnutrients were measured in soil solution, and water and K2 SO4 extracts, along with microbialbiomass, respiration, and extracellular enzyme activities. Contrary to our predictions, reducingsugarconcentrationsandaccessibility,andmicrobialbiomasswerenotsignificantlydifferentinthesoils of these twoplants. This suggests that soil saccharide concentrationsmaynot be as tightlycorrelatedwith leaf presence as had been believed.We also found that the adsorbed saccharidepoolwasbelowdetection,andestimate that10 timesmoresaccharidesarespatially inaccessiblethanaccessibleinthesoilsolution.Thus,weconcludethataspatiallyinaccessibleCpoolshouldbeaddedtoourconceptualmodelofthesoilCcycle.

Appendix l l

SOIL ECOLOGY SOCIETY BIENNIAL ORAL PRESENTATION ABSTRACTS

Wednesday June 7th

PARALLEL ORAL SESSION BBal l room D

Land‐useimpactsonsoilbiodiversityandecosystemservicesinanAndeanfarmingcommunity*StevenFonte1,StevenVanek1,KatherinMeza2,AnneDeValenca3,RaulCarlosCcantoRetamozo2,EdgarOlivera,2MariaScurrah21ColoradoStateUniversity,UnitedStates2GrupoYanapai,Peru3WageningenUniversity,NetherlandsGrowing food demand, agricultural modernization, and climate change in the Andean highlandshave ledto intensificationofagriculture,with important implications forecosystemservices(ES)andbiodiversity.Basedonthischallenge,wesoughttounderstandtheimpactofcurrentland‐useandfuturetrendsonasuiteofsoil‐basedESinanagricultural landscapeofcentralPeru,soastoinformcommunity‐based land‐useplanning.Samplingpointswerestratifiedacross tendominantland‐uses(production fields, forests,pasturesanddegraded lands)andeachwasevaluatedusingcomposite indicators of soil fertility/nutrient provision, erosion control, C storage, economicproductionandsoilbiodiversity(groundvegetationandmacrofauna). Overall, land‐usesdifferedsubstantially in theES andbiodiversity supported. At lower elevations, forests (especially alderandmixed forest) supported the highest C storage, soil fertility, andmacrofauna abundance anddiversity.Higherelevation>3800m)land‐usesalsosupportedhighlevelsofsoilfertility,Cstorage,anddiversityofgroundvegetation. Erosioncontrol (assessedvia infiltration,soilcoverandbulkdensity)waslowestindegradedlandsandhighestinforestsandhighelevationpasture.Economicproductivitywasrelativelyhighinthelow‐midelevationcroppingsystemsandeucalyptusforests,andespeciallyinirrigatedcrop‐foragerotations.Whiletheireconomicproductivitywaslow,alderforests supportedhigh levelsof soil biodiversity andES, and showpotential to restoredegradedlands. Our landscape assessment identified important tradeoffs and synergies in ES and soilbiodiversity across the landscape that will inform future community landscape planning andconservationeffortsthroughouttheregion.

Firereducessoilbiotabiomassanddiversity:Across‐biomemeta‐analysis*YaminaPressler,JohnMoore,FrancescaCotrufoColoradoStateUniversity,UnitedStatesSoilbiotaplayacriticalroleincarbon(C)cycling.Fireimpactssoilbiotadirectlythroughinducingmortality and indirectly by changing above‐ and belowground environments,with consequencesforecosystemCcycling.Givenexpectedshiftsinfireregimeswithclimatechange,weconductedaglobal meta‐analysis of studies to investigate patterns in how fires affect soil biota. Wesystematicallyreviewedrelevant literature fromWebofScience(1988‐2016)andusedImageJtoextractdatadirectly fromfiguresandtables.Wecalculatedstandardizedmeandifferencesofsoilbiotabiomass,abundance,richness,evenness,anddiversityindicesbetweenburnedandunburnedsites.Wecomparedmeandifferencesbetweensoilbiotataxa,acrossbiomes,alongatimesincefiregradient, between wildfire and prescribed burns, and across laboratory methods. Overall, firenegatively impacted belowground communities. Fungal biomass ismore susceptible to fire thanbacterialbiomass.Fungal,bacterial,arthropodandnematodeabundancealldecreasedsignificantlyafter fire. Fire significantly decreased fungal and arthropod richness, evenness, and diversity.Responsesvariedconsiderablybybiome,firetype,andtimesincefire.Evaluatingtheeffectoffireon diversity of bacteria, nematodes, and protozoa was not possible due to lack of studies. Weintegrate our findings into a conceptual framework that highlights important controls andknowledgegapsoftheresponseofbelowgroundcommunitybiomass,abundanceanddiversitytofire.Understandingtheresponseofsoilbiotatofiremayhelppredicthowsoilcommunitiesandtheprocessestheyregulatewillfunctioninfireregimesofthefuture.

Soilmicrobialdispersalbywayofterrestrialslugs*EmmaAronson,DeniseJacksonUniversityofCaliforniaRiverside,UnitedStatesSoil microbial communities are highly variable and can change over time and with shiftingconditions.Newlytransportedbacteriamaybeabletoinvadeexistingbacterialcommunities,whichcan alter community structure and ecosystem functioning in terrestrial environments. However,thereare limitationsontheabilityof theseoften‐non‐motileorganismstodisperseontheirown.Onepossiblemechanismforbacterialdispersal isco‐invasionwithabove‐groundconsumers thatfeeduponbacteriathathavekeyecologicalroles.Onesuchconsumeristheterrestrialslug.Therearethousandsofspeciesofterrestrialslugslivinginavarietyofhabitatsfromtemperatetotropicalregions.Slugshavetheability to thrive inarangeofconditionsandtheirsuccess isattributedtomucusproductionthatdeterspredators,highreproductionratesandhavinganadaptableappetite.Slugs frequently ingest soil and plant bacteria from dead and living plant material, while alsopickingupbacteriaontheirbodiesandintheirmucus;thesebacteriacanthenbedispersedastheytravel.Introductionofinvasivespecies,suchasslugsandtheirassociatedbacteria,intonewregionsendangers regional and native biodiversityworldwide and is one of the leading causes of globalecologicalchange.Weproposearangeofexperimentstoevaluatethepotentialforterrestrialslugstotransportsoilbacteriawithinandacrossecosystems.

Characterizingtemperaturesensitivityasamicrobialtrait:Ameta‐analysisusingmacromolecularratetheory*CharlotteAlster,JosephvonFischerColoradoStateUniversity,UnitedStatesReactionratesinbiologicalsystemsarestronglycontrolledbytemperature,yetthedegreetowhichtemperature sensitivity varies for different enzymes and microorganisms is being largelyreformulated.TheArrheniusequationisthemostcommonlyusedmodeloverthelastcenturythatpredicts reaction rate response with temperature. However, the Arrhenius equation does notaccount for large heat capacities associated with enzymes in biological reactions, thus creatingsignificantdeviationsfrompredictedreactionrates.Arelativelynewmodel,MacromolecularRateTheory(MMRT),modifiestheArrheniusequationbyaccountingforthetemperaturedependenceofthese large heat capacities found in biological reactions.Using theMMRTmodelwedeveloped anovelframework(Alsteretal.,2016)toassesstemperaturesensitivityasabiologicaltraitinsoilsthroughaseriesofexperiments,providingevidencethatmicrobesandenzymescanhavedistincttemperaturesensitivitiesindependentoftheirexternalenvironment.Here,weperformedameta‐analysison102studiestoanalyzethedistributionofthesetemperaturesensitivitytraitsacrossavariety of biological systems (e.g., soils, the food industry, wastewater treatment) in order toidentify commonalities in temperature responses across these diverse organisms and reactionrates.Ourresultsrevealsignificantdifferencesbetweenmanytemperaturesensitivitytraitsbasedon categories such as the diversity of the microbes measured and the source of the microbialcommunity.Theseresultshaveimportantimplicationsforbasicunderstandingofthetemperaturesensitivityofbiologicalreactionsandforecologicalunderstandingofspecies’traitdistributions,aswellasforimprovedparameterizationoftemperaturesensitivityinmodels.

Improvinggrasslandrestorationefforts:thepowerofsoilamendments*EricDuell,AnnaO'Hare,GailWilsonOklahomaStateUniversity,UnitedStatesRestoration of native biodiversity has beenmetwith little success following eradication of non‐nativeplants.Whilemuchattentionhasbeenplacedonabovegroundprocesses,considerablylessresearch has focused on assessing the role of belowground microbial processes in restorationsuccess. Our researchwas conducted at Konza Prairie Biological Station inManhattan, KS, USA,whereseveralareashavebecomehighly invadedbyanon‐nativeC4grass (Bothriochloabladhii).Theseareasreceivedregularapplicationsofglyphosateforeightyears.However,revegetationwithnativespecieshasbeenunsuccessful.Toassessmechanismsthatpreventsurvivalofnativespeciesand to improve native species establishment, we established six replicate plots of each of thefollowing four treatments: (a) freshly collectedprairie soil (intactnativemicrobial communities)with native prairie seeds; (b) autoclaved prairie soil (absence of nativemicrobial communities)withnativeprairieseeds;(c)non‐inoculated(nosoilamendments)withnativeprairieseeds;and(d) non‐inoculated/non‐seeded control. Although inoculation with native or sterile soil did notinfluencepercentgermination,thepresenceofsoilmicrobessignificantlyimprovednativespeciesseedlingsurvival (41%),compared tosterilesoilornosoilamendments (10‐12%).At theendofthegrowing seasonplots receivingnative soilhadsignificantly lower re‐invasionby the invasivegrass(33%coverbyB.bladhii),comparedto52%coverfollowinginoculationwithsterilesoil,and70%coverinplotsreceivingnosoilinoculum.Ourstudyindicatesrestorationsuccessofdegradedgrasslands can be improved by additions of native plant seeds in combination with native soilmicrobialcommunities.

Rotationhistoryeffectsonsoybeanplantsandrhizospheremicrobiome*MariaSoledadBenitez,ShannonL.Osborne,MichaelLehmanUSDA‐ARSNorthCentralAgriculturalResearchLaboratory,UnitedStatesBenefits of diversified cropping systems stem from the interactions between soil characteristics,cropgrowthpatternsandphysiology,andotherorganisms.Inordertoassistintheunderstandingandimplementationofdiversifiedrotationsequences,a long‐termexperimentwasestablishedtoevaluatetheeffectsof4‐yearrotationsequencescontainingsoybeancomparedtoa2‐yearcornandsoybeanrotation.Withinthisexperiment,soybeanplantestablishmentandvigorwasmeasuredattheseedlingand floweringstage,after four4‐yearrotationcycles.Wholeplantsweresampled inthe field for shoot biomass and nutrient content measurements, and rhizosphere microbiomecharacterizationatbothtimepoints.Rotationsequencesignificantlyaffectedestablishment,rateofdevelopment and shoot biomass, where rotations with corn preceding soybean exhibited onaverage 25% lower vigor, regardless of length of rotation (2‐year vs. 4‐year). Rotationsincorporating pea resulted in up to 28% greater biomass when compared with counterpartrotationsdifferinginonlyonecropinthesequence(e.g.corn,pea,winterwheat,soybeanvs.corn,oat,winterwheat, soybean).Community‐levelanalysisof rhizosphere‐associatedbacteriadidnotreveal differentiation in response to rotation or crop sequence. Rhizosphere‐associated fungalcommunities,however,respondedtopreviouscropattheseedlingstage,whererotationsequenceswithwinterwheatprecedingsoybeandifferentiatedfromrotationsequenceswithcornprecedingsoybean. Further analysis will focus on the interactions between rotation sequence length, cropspecies and order within each rotation sequence, and specific responses of rhizospherecommunities.Thesedataprovideinsightonthemechanismspromotingsoybeanestablishmentandvigorindiversifiedcroppingsystems.

SoilbioticandabioticpropertiesfollowingBothriochloaischaemuminvasionintonativetallgrassprairie*ParkerCoppick,GailWilson

OklahomaStateUniversity,UnitedStatesBothriochloaischaemumisanon‐native,perennial,C4grassthathasbeenseededthroughouttheUSSouthern Great Plains for erosion control and increased forage production. This plant speciesfrequently invades beyond planted areas, dominating native prairies as a monoculture. Theinvasionintonativeprairiesmaybefacilitatedbypositiveplant‐soilfeedbacks,whereB.ischaemumalterssoilbioticandabioticpropertiestobenefititself,withnegativeeffectsonnativeplantspecies.Ourresearch,conductedinOklahomaandKansas,USA,assessesplantcommunitycompositionandsoilbiotic(e.g.soilmicrobialcommunities)andabiotic(e.g.soilaggregatestability,soilmoisture)propertiesinsitesinvadedbyB.ischaemum,andinadjacentnon‐invadedprairiesites.Ourresultsindicatesignificantly lowerplantspeciesrichness inB. ischaemum invadedsitescomparedto thenon‐invadedprairieatbothOKandKSlocations.BothOKandKSinvadedsiteswerecharacterizedby lower soilmoisture and loweroverall soilmicrobial biomass, compared tonon‐invaded sites.Significantly more macro‐aggregates >2mm) were present in soils from the OK invaded site,compared to adjacent non‐invaded soils.However, thiswas not consistent between locations, asrelativeabundanceofsoilmacro‐aggregatesoftheinvadedsiteinKSwaslowerthanadjacentnon‐invaded soil. Our results indicateB. ischaemum may facilitate loss of soil water availability andreducesoilmicrobialbiomass.AtbothKSandOKsites,B.ischaemuminvasionresultedinnegativeabove‐andbelowgroundeffects,potentiallyleadingtolossesinotherecosystemservices.

Leymusarenariusinvasionaltersbelowgroundinteractionswithmycorrhizaeandnematodeswithoutalteringnematodecommunitystructure*MatthewReid,SarahEmery

UniversityofLouisville,UnitedStatesBelowgroundinteractionscanbeimportantdriversofplantcommunitysuccession.Plant‐parasiticnematodes (PPN) and arbuscular mycorrhizal fungi (AMF) play particularly important roles inregulating primary succession in sand dunes. PPN contribute to the dieback of early colonizingnative grasses, allowing later‐successional species to establish, while AMF facilitate plantestablishment in low‐nutrient soils, as well as contribute to soil formation. Invasive plants maycause shifts in these belowground communities, potentially altering successional trajectories. InGreat Lakes sand dunes, the dominant native dune‐building grass is Ammophila breviligulata.Leymusarenarius, a dune‐building grass native toEurope, has recently invaded this system. In afieldsurvey,weassessednematodecommunitycompositionandAMFrootcolonizationassociatedwith each plant species.We found no differences betweenAmmophila and Leymus in AMF rootcolonization,whilenematodecommunitycompositionvariedonlyminimally.However,Ammophilaand Leymus differed in their dependence on and susceptibility to these soil organisms in acompaniongreenhouseexperiment.AMFprovidedmoreprotectionagainstnematodedamageforLeymuscomparedtoAmmophila, indicatingthatnegativesoilfeedbacksduetobuildupsofPPNinAmmophila dominated systems may not apply when Leymus invades. These results provideevidencethatchangestobelowgroundcommunityinteractionsmayfacilitateLeymusinvasion,withpotentialconsequencesforsuccessionaldynamics.

Tallgrassprairierestoration:Doesfunctionalgroupmatter?*GailWilson1,TimTodd2

1OklahomaStateUniveristy,UnitedStates2KansasStateUniversity,UnitedStatesWhiletheoverallgoalofrestorationecologyfocusesonassistingtherecoveryofecosystemsthathave been degraded, damaged, or destroyed, the most successful path to recovery is uncertain.Conversion of tallgrass prairie to row‐crop agriculture can result in state changes and biotic orabiotic ecological legacies that inhibit return to grassland state and require human intervention(restoration).Ourstudyassessedecosystemprocesses,suchassoilaggregatestability,soilorganiccarbon,relativeabundanceofsoilmicrobialfunctionalgroups,andnematodecommunitystructurefollowingseedingofanagriculturalfieldwithdiversemixturesofeithernativecool‐season(CSG)orwarm‐season grasses (WSG). These replicate restoration plots were compared with adjacentundisturbedprairie.Eightyears following seeding, arbuscularmycorrhizal fungal (AMF)biomassassociated with WSG was greater than CSG, yet remained significantly lower than undisturbedprairiesoils.SoilaggregatestabilityandSOCwerealsogreaterinWSGsoilscomparedtoCSG,butlikewise continued to reflect degradation relative to undisturbed prairie soil. No divergences innematodecommunitystructure,includingtrophiccompositionandmaturityindex,wereobservedbetweenCSGandWSGmixes.Communitiesunderbothmixes,however, remained fundamentallydifferent from that associated with undisturbed prairie, with restored prairie exhibiting lowerrelative abundances of herbivores andgreater relative abundancesof bacterivores.Our researchindicates ecosystem processes are highly complex andmay require extensive time for recovery.Nonetheless,restorationpracticesthatincludenativewarm‐seasongrassesdifferentiallypromoteAMFbiomass,whichhaswell‐documenteddownstreaminfluencesonsoilstructure,SOC,andsoilfoodwebs.

Soilecologicalresponsestopestmanagementpracticesinturfgrassvarywithpesticideuseintensity,identity,andapplicationprogram*KyleWickings,HuijieGanCornellUniversity,UnitedStatesPesticides play an important role in maintaining plant health in agricultural and horticulturalecosystems. However, improper use of pesticides can lead to negative impacts on non‐targetbeneficialorganismsandultimatelytheerosionofecologicalservices.Thereisincreasinginterestin understanding the effects of pesticides on soil biota in agricultural systems, however theirimpactsonsoil foodwebs inurbanecosystemsremainpoorlycharacterized.Wecarriedout twofieldexperimentsingolfturfecosystemstoinvestigatetheimpactsofpesticideusepracticesonthecompositionandfunctioningofsoilbiologicalcommunities.Specifically,wequantifiedtheeffectsofpesticide input intensity, identity, application rate, and frequency on soil microarthropodcommunities,rootsymbiontcolonization,belowgroundbiologicalcontrol,andextracellularenzymeactivitiesingolfcoursesoils.Ourresultsindicatethatincreasingpesticideinputintensityleadstoreductionsindecomposerarthropoddensities,mycorrhizalcolonization,andtheactivitiesofsomehydrolyticenzymes,buthaslittleeffectonbiologicalcontrolandpredatoryarthropods.Ourworkalso reveals that belowground communities are sensitive to differences in pesticide identity,applicationrate,andfrequency.Overall,ourfindingsidentifypesticideusepracticesthatarelikelytocompromisesoilecologicalfunction,butalsohighlightuniqueopportunitiesforachievingplanthealthstandardswithoutcompromisingbelowgroundecologicalservices.

Appendix l l

SOIL ECOLOGY SOCIETY BIENNIAL ORAL PRESENTATION ABSTRACTS

Thursday June 8th

PARALLEL ORAL SESSION C Bal l room C

Industriousleafcutterantsandtheirbigfootprintsintropicalsoils*TamaraZelikova1,DiegoDierick2,LuitgardSchwendenmann3,ThomasHarmon4,NicoleTrahan1,MichaelAllen51UniversityofWyoming,UnitedStates2FloridaInternationalUniversity,UnitedStates3UniversityofAuckland,NewZealand4UniversityofCaliforniaMerced,UnitedStates5UniversityofCaliforniaRiverside,UnitedStatesLeaf cutter ants are themost important herbivore in lowland tropical forest systems. They cutfreshleavesandbringlargeamountsofplantbiomassintotheirneststogrowtheirfungusgardens.The excavation and continual maintenance of their large nests modifies soil characteristics andbiogeochemistrywith direct and indirect impacts on soil carbon dynamics. But a big question ishowtoquantifytheecosystemfootprintofAttacephalotesants.Wesetupandinstrumentedasoilobservatory and over 3 years, measured soil carbon dynamics. Because half of the nests weinstrumentedwereabandonedduringthecourseofourstudy,wewereabletomeasurethelegacyeffectsofnests.AndbecauseourstudyfellduringanElNinoyear,wewerealsoabletomeasuretheimpactsofextremeclimatevariation.Thisprojecthasbeenalessoninperseverancebutourresultsshow that heterogeneity reins supreme and that the impacts of leaf cutter ants are first andforemoststructural.Theytrulyengineertheirnests,withlargeimpactsforcarbondynamicsinnestsoils.

InvasiveYellowBluestemandEuropeanearthworms:Conspiracyforecosystemdomination?

*RobertoCarrera‐Martínez1,MitchellJGreer2,BruceASnyder31DepartmentofBiology,UniversityofPuertoRico,MayagüezCampus,Mayagüez,PR;WarnellSchoolofForestry,TheUniversityofGeorgia,Athens,GA,UnitedStates2DepartmentofBiologicalSciences,FortHaysStateUniversity,Hays,KS,UnitedStates3DivisionofBiology,KansasStateUniversity,Manhattan,KS;DepartmentofBiologicalandEnvironmentalSciences,GeorgiaCollege&StateUniversity,Milledgeville,GA,UnitedStatesInvasional meltdown has been suggested between invasive plants and exotic earthworms, butmostly based on indirect observations. Invasive earthworms and the invasive grass YellowBluestem (YB) have both the potential to shift ecosystem function and structure. This researchaimedtodetermine if there isan invasionalmeltdownbetweenEuropeanearthwormsandYB.AmesocosmexperimentwasdesignedtoobservetheearthwormeffectsonthegerminationofYB.AsecondmesocosmexperimentaimedtoobservetheeffectofnativeandinvasiveearthwormsonthedevelopmentoftheseedlingsofYBandthenativegrassLittleBluestem(LB).Octolasiontyrtaeumwasusedastheinvasiveearthworm,Diplocardiasmithiiasnative,andnoearthwormascontrols.AfieldsurveywasperformedtoobservethedistributionofinvasiveearthwormswithrelationtoYBand native grasses. Germination rates of YB did not differ between treatments. Nonetheless, O.tyrtaeum gained a higher proportion ofmass thanD. smithii, suggesting a positive effect on theinvasiveearthworm that couldbe the result of seedpredation. LB seedlingmortalitywashigherwhen O. tyrtaeumwas present than when LB was alone, and died substantially faster than YBseedlingsinalltreatments,whichsuggestsanindirectpositivefeedbackofO.tyrtaeumonYBratherthan a direct interaction. In the field survey, only the invasive Aporrectodea was collected andexclusivelyinYBplots.Thissuggestedanotherindirectpositiveeffectontheinvasiveearthwormsandrevealsthatthissystemismorecomplexthatinitiallythought.

MicrobialCuseinpeatdepthprofilesunderwarming,asrevealedwithisotopicprofiling

*JessicaGutknecht,CameronBlakeUniversityofMinnesota,TwinCities,UnitedStatesManyoftheworld’speatlandsarelocatedinnorthernecosystemswheretheclimateischangingata rapid pace, creating concern over the fate of these carbon rich ecosystems. The microbialcommunityisacrucialaspectofbiogeochemicalfunctioningofthesepeatlandecosystems13CPLFAanalysiswasusedtocharacterizethemicrobialcommunityandprovideisotopicinformationaboutmicrobialcarbonuse throughpeatdepthprofiles taken fromtheSpruceandPeatlandResponsesUnderClimaticandEnvironmentalChange(SPRUCE)Project;anextensivestudyoftheresponseofpeatlandstoclimaticmanipulationinnorthernMinnesota.SPRUCEwarmingtreatmentsrangefrom5temperaturesfrom0to+9°C.Samplesforthisanalysisweretakenjustbefore,andduringdirectpeatwarmingdownto2mdepthonJune2014,September2015,andJune2015,respectively.Wefound both strong vertical stratification and variation over time, both in bioindicator abundanceandinisotopiccarbonuseprofiles.Inaddition,themicrobialcommunityinthesurfaceofthepeatprofile ismoreresponsivetoexternalconditionsthandeeperpeat.Deeppeatwarmingenhancedthe existing sensitivity of surface peat communities. Warming was related to increased fungalrelative abundance, and decreased anaerobic bacterial and actinobacterial relative abundance.Fungialsousednewercarbonunderwarming.Insummary,fungalcommunitiescouldbethemaindrivers of change in peatlands underwarming, and their use of new carbon either suggests thatpeat profiles may remain undecomposed under warming, or that fungal communities willeventuallyprimedecompositionofolderpeat.

UntanglingtheeffectsofindividualcovercropspeciescomparedtomixesonsoilecologyFelicityCrotty,ChrisStoateAllertonProject‐GameandWildlifeConservationTrust,UnitedKingdomAll plant species create legacy effects within the soil to some extent; changing the environmenteitherphysicallyorthroughtheremainingplantresidues.Cropchoice,rotation,andmanagement,aswell as establishmentpractice andmaintenance can all greatly affect soil organisms’ diversityand abundance. Cover crops can be grown over the autumn and winter ensuring green coverthroughout theyear.Theyhavebeendescribedas improving soil structure, reducing soil erosionandevenaformofweedcontrol.Thesecropsretainnutrientswithintheplant,potentiallymakingthem available for future crops, aswell as increasing organicmatter in the soil profile. Differentplantspeciescanbeusedascovercrops,includingoilandtillageradish,oats,phacelia,buckwheat,vetch,crimsonandberseemclover,aswellasmustard,ryeandlupins.Eachplantspeciesgrowsatdifferent rates, cycling nutrients in different ways; understanding which crop is doing whatindividually and in a mixture, is still poorly understood. Focusing on two years of cover cropexperiments, we show the effect of cover crops as mixtures and their effects on earthwormabundance,soilstructureandweedsuppressionaswellasfollowingcropyields.Wealsoconsiderthe impact of individual cover crop species on soil biology (nematodes, mesofauna andearthworms),decomposition,soilstructure,soilchemistryandweedsuppression.Overall, resultsare beginning to show the effect of agricultural practices and their consequencesonbiodiversitydynamicsandfunctionwhichcouldhaveanimportantimpactonfuturearableproduction.

UsingNEONdatatoexplorecontinental‐scalepatternsinsoilcommunitiesandprocesses*SamanthaWeintraub,LeeStanish

NationalEcologicalObservatoryNetwork,UnitedStatesThe National Ecological Observatory Network (NEON) is measuring surface soil biogeochemicalpoolsandfluxesalongwithdiversity,abundance,andfunctionalpotentialofsoilmicrobiotaat47sitesdistributedacrosstheUnitedStates.Thisincludesco‐locatedmeasurementsofsoilcarbonandnitrogenconcentrationsandstableisotopes,netnitrogenmineralizationandnitrificationrates,soilmoistureandpH,microbialbiomass,andcommunitycompositionvia16SandITSrRNAsequencingand shotgunmetagenomic analyses. Taken together, this suite of soil data have the potential torevealnewinsightsintothestructureandfunctionofsoilmicrobialcommunitiesandhowthismayvary over time, across biomes, andwith changes in climate and land use. Here,we describe thespatial and temporal components of theNEON soil samplingdesign, aswell as theworkflow fordiscovering and accessing NEON soil biogeochemical and microbial data. We will also presentpreliminary findings highlighting the types of ecological questions that can be addressed usingNEON’s soil data products. For example, early NEON data demonstrate edaphic controls onmicrobial community structure, gradients in soil stable isotopes within and across biomes, andrelationships between community functional potential, soil organic matter, and climate.

Fromwhereandhowdoplantsandmicrobesgettheirnitrogen?*StuartGrandy,AndreaJillingUniversityofNewHampshire,UnitedStatesNtransformationsandbioavailabilitylimitproductivityandalsoregulateenvironmentalNlossesinmostsoils.However,inmineralsoils,thepoolsandprocessesthatproducebioavailableNremaincontentious, leading to inaccurate predictions of key ecosystemprocesses and services.Herewearguethat tobetterunderstandNavailabilityweneedtoreconsider twobasicassumptions: firstthatNmineralizationisacoupled,predictableprocessthatcanbepredictedwithoutunderstandingmicrobial community dynamics; second, that N mineralization, per se, regulates N availabilityrathermineral‐Ninteractions.First,Nmineralization isregulatedbymicrobialprocessesthatareinherentlyuncoupled.Decomposercommunityenzymeinductiondrivesproteolysis,theexocellularfirst step in N mineralization. Yet, cellular carbon use efficiency and stoichiometry are internalprocessesdrivingammonification. Second,while soil aminoacidsand inorganicNoriginate fromlitterandsoilorganicmattermineralization,weargueinrhizospheresmineral‐associatedorganicmatter (MAOM) is the largestproximal sourceofN forplants andmicrobes. Severalbiochemicalstrategiesenableplantsandmicrobestocompetewithmineral‐organicinteractionsandeffectivelyaccessMAOM.WeshowthatthecompetitivebalancebetweenthepotentialfatesofNmonomers—bound to mineral surfaces or dissolved and available for assimilation—depends on the specificinteraction between clay mineral properties, soil solution, mineral‐bound organic matter, andmicrobial community. The strategies to mobilize and acquire MAOM N create unique plant andmicrobialcommunitydynamicsthatpromotenichedifferentiationandspeciescoexistenceinplantandmicrobialcommunities.

Thefutureofprotein*PhillipTaylor1,PeteNewton2,AlanTownsend21MadAgriculture,UnitedStates2UniversityofColorado,UnitedStatesThe global rise inmeat consumption is a megatrend of modern civilization, and is projected toincreasefrom200to450milliontonsby2050.Livestockproductionhasincreasedtheallocationofland and resources to produce animals, which has driven climate change, deforestation,biodiversitylossanddamagestoglobalecosystems.Sustainableanimalfeedisurgentlyneeded,butfewoptionsexist.Whatisthefutureofanimalfeed,andparticularlyprotein?Wediscoverarapidemergence of novel, sustainable proteins in research, development and market sectors. Newproteins include algae, fungi, bacteria and insects.Nearly all these innovations includemajor co‐benefits of economic competitiveness and solving agricultural sustainability challenges. Thesetrends are paralleling with increasing cost of fishmeal, which is fueling investments in cost‐competitive alternatives. The growth in novel, sustainable proteins is also driven by shifts inconsumer consciousness and growing concerns over the impacts of the modern food system.Sustainableanimalfeedisalreadya$4billionmarketintheUS,anddemandhasgrown400%overthe past decade. We also find a rising proportion of consumers are willing to pay more forsustainable livestock; the growth in grass‐fed beef and free‐range chickens markets are telltaletrends. There are number of barriers slowing the commercialization of novel proteins (e.g. feedregulations).Finally,weexaminepolicymechanismsthatcouldacceleratethedevelopmentanduseof sustainable proteins, which is urgently needed to avoid further deterioration of globalecosystemsusedtoprocureanimalfeed.

Biocarbonasaneffectivemicrobialinoculumcarrierinanagriculturalmaizefieldtrial*ErikaFoster,MatthewWallenstein,FrancescaCotrufoColoradoStateUniversity,UnitedStatesAs technologies develop in sustainable agriculture, we must ensure maximization of treatmenteffects.Researchindicatesthatreducedirrigationandfertilizerinputsarepossiblewithpropersoilmanagement. Two innovative strategies include use of microbial inoculum to promote plantnutrient availability and use of biochar‐charcoal amendments to improve soil structure and addorganic carbon. Since only low application rates of biochar are economically feasible, we testedratesof0.78Mgh‐1and0.39Mgha‐1ofCoolTerra®biocarbon(treatedbiochar)inafullyfactorialmaizefieldtrial.Webandedthebiocarbonnexttotheseedtomaximizeeffects.Incombinationwiththis treatment, we inoculated the biocarbon with phosphorus‐cycling plant growth promotingmicrobes fromGrowcentia® (MAMMOTHP) and tested this versus the recommended three‐timesurfaceapplication.Weusedthesetreatmentsundertworeducedinputstrategies:a20%temporalreduction in irrigation and a 20% reduction in fertilizer application. We hypothesized that thecombination treatment of biocarbon and microbial inoculum would maintain the highest maizeyieldunderreducedirrigationandfertilizer.Afteroneyear,thelowandhighbiocarbonapplicationrates increased yield by 8.9% and 11.1%, respectively. The yield from plots with the microbialinoculum appliedwith a biocarbon carrier was equal to the repeated surface application of theinoculumalone.Thismaysuggestthatthebiocarboncarrier increasedtheeffectof the inoculum.Further microbial DNA analysis is in progress to analyze if the crop response correlates withchangesinthesoilmicrobialcommunitystructure.

Theroleofthebelowgroundplantmicrobiomeinclimatechangeinducedrangeshifts*KellyRamirez,WimVanDerPutten,BastenSnoek

NetherlandsInstituteofEcology,NetherlandsWith climate change, plants have been able to shift their ranges into novel environments wereconditions have been made suitable due to warming temperature and changes in precipitation.Muchbelowgroundrangeexpansionresearchhasfocusedoneitherpositiveplant‐soilinteractions,such asAMF symbiosis, or on negative plant‐soil interactions, such as pathogens. Less focus hasbeengiventothecoremicrobiomeofplanthosts.Usinghigh‐throughputIlluminasequencingweassessedsoilandrootmicrobialcommunitiesundernative and range expanding plant species spanning a north‐south latitudinal transect in centralEurope. As expected, the soil and root microbiomes are both strongly influenced by the plantspeciesunderwhichtheygrow.Specifically,about10%ofthemicrobiomecouldberelatedtothehostplantspecies.Interestingly,wefoundthatmicrobiomesassociatedwithrangeshiftingspeciesarelessvariablethanthoseassociatedwithnativespecies.Further,theenrichmentofmicrobesinroots(fromthesoil) isstrongerwithrangeexpandingspeciesthanwithnativeplantspecies.Ourresearchindicatesthatthesoilandrootmicrobiomescanprovideinsightintoplantrangeshiftsandmaybeimportantforplantestablishment.

Thetransformationofleaflitterintofecesbymillipedesreshufflesthecontroloflittertraitsondecomposition*François‐XavierJoly1,SylvainCoq2,MathieuCoulis3,StephanHättenschwiler2,JohanneNahmani21SchoolofEarthandSpaceExploration‐ArizonaStateUniversity,UnitedStates2CenterofEvolutionaryandFunctionalEcology,CNRS,France3CIRAD,UPRGECO,FranceCompared to the role ofmicroorganisms, the role of soil fauna on litter decomposition remainspoorly understood. Litter‐transformers for instance are thought to fasten decomposition byreducing litterparticle size and increasing itsmoisture.However, the few studies that compareddecomposition of feces with that of litter reported contrasting results, ranging from negative topositive effects.We hypothesized that these discrepancies result from the use of different litterspecieswithdistinctquality.Totestthishypothesis,wefedleaflitterfromtendifferentEuropeantree species to a commondetritivore species,Glomerismarginata, and compared (i) thephysicalandchemicalqualityand (ii)decompositionratesof feces to thatof thecorresponding litter.WefoundthatlittertransformationintofecesdecreasedtheC/Nratioandtheparticlesizeforalllitterspecies, and increased thewater‐holding capacity for eight out of ten litter species.Additionally,decompositionrates increased in feces foreightofout ten litterspecies,withrelativedifferencesrangingfrom0%to+150%.Differences in leaf litterdecompositionratesweremostlyrelatedtodifferences in litter C/N ratio andwater‐holding capacity,while feces decomposition rateswerelargely related todifferences in fecesparticle size.Ashypothesized,our results indicate that thiseffect clearly depended on the type of litter ingested by the litter‐transformers. Collectively, ourresultssupportthecommonviewthatlitter‐transformersenhancedecomposition,andsuggestthatthiseffectisrelatedtoareductioninparticlesizewhichlikelyincreasesthesurfaceareaavailableformicroorganisms.

Appendix l l

SOIL ECOLOGY SOCIETY BIENNIAL ORAL PRESENTATION ABSTRACTS

Thursday June 8th

PARALLEL ORAL SESSION DBal l room D

Advancingtheunderstandingoforgano‐mineralinteractions:Insightsfromnano‐scalesecondaryionmassspectrometry*MeganMachmuller1,CarstenMueller2,JenniferSoong3,CarmenHoeschen2,ClaudiaBoot1,FrancescaCotrufo11ColoradoStateUniversity,UnitedStates2TUMunich,Germany3UniversityofAntwerp,BelgiumTraditional analyses limit our understanding of submicron scale interactions that control thepersistenceoforganicmatter(OM).Bycombiningnano‐scalesecondaryionmassspectroscopyandisotopic tracing,we followed thedecompositionofplant litter and its associationwith clay sizedmineralparticlesurfacesoverthreeyearsinagrasslandsoil.Wefoundgreatestspatialcorrelationof litter C and N at intermediate (18 months) stages of decomposition, where 70% of mineralassociatedOMhadboth13Cand15Nenrichment.CandNassociationswerespatiallydecoupledatearly(7months)andlate(36months)stages.7monthsfollowinglitterincubation,72%ofmineralassociatedOMoriginatedfromlitterCand14%fromlitterN,and10%ofCandNwereco‐located.Early‐stage,highefficiencyCsorptioncorrespondedtothelossofnon‐structuralcompoundsfromlitter and high microbial C incorporation. As decomposition proceeded, litter biochemicalproperties becamemore important thanmicrobial pathways to the persistence of OM. This latestageofdecompositionhadmineralassociatedOMwiththelowest(62%)amountoflitterderivedCand thehighestamountof litterderivedN(84%),and54%of theCandNwereco‐located.AslitterNmovedintotheclayfraction,itattachedtoexistingorgano‐mineralsurfacesandeventuallysorbedwithout the presence of litter derivedC. Through the use of nanoSIMS,we revealednewinsights into the spatial heterogeneity of organo‐mineral interactions, anddemonstrate how thisvaries throughout decomposition as biological and biochemical mechanisms control OMpersistence.

Wetlandplantrangeshiftsmayaltersoilmicrobialcommunitiesandcarbonstorage*SamanthaChapman1,ChelseaBarreto2,EmberMorrissey2

1VillanovaUniversity,UnitedStates2UniversityofWestVirginia,UnitedStatesCoastalecosystemssuchasmangroveforestsandsaltmarshesstorelargeamountsofcarbonduetohighratesofplantproductivityandlowsoilorganicmatterdecompositionratesinanoxicsoils.Aswoodymangroves continue to encroach into herbaceous saltmarshes around theworld, it isimportant to understand how this range shift will alter soil microbial communities and carbonprocessing.Mangroveshavelarger,morearenchymousrootsthansaltmarshrootsandtheserootscould createadifferent environment for soilmicrobes thatprocess soilorganicmatterand thus,alter carbon cycling. In an ecotonal ecosystem in Florida, we compared wetland soil bacterialcommunity composition and function in mangrove‐dominated vs. salt marsh‐dominated plots.Bacterial community structure and soilmicrobial function differed betweenmangrove‐dominantandmarsh‐dominantplots.Specifically,wesawhigherabundancesofputativelyaerobicbacteriainmangrove‐dominant (e.g. Acidobacteria) than in marsh‐dominant soils and conversely, moreputatively anaerobicbacteria (Chloroflexi) inmarsh‐dominant soils. Further,mangrove‐dominantsoil organisms were more efficient at utilizing a labile C substrate than marsh‐dominant soilorganisms.Inordertoinvestigatehowrootchangesinrhizosphereoxygenavailabilitymaychangesoil organic matter processing, we manipulated headspace oxygen availability in lab‐based soilincubations.Wefoundthatcarbondioxiderespirationwas40‐50%higherinoxicconditions.Ourresults suggest thatwetland plants strongly influence sedimentmicrobial communities and thatmangroveencroachmentintosaltmarshesmayhaveimplicationsforwetlandsoilcarbonstorage.

Effectofrestorationtreatmentsandforesttypeonsoilmesofauna,fungi,andphysicochemistryinVallesCalderaNationalPreserve*KaraGibson1,ChanningLaturno1,AndreaRaya2,AnitaAntoninka1,NancyC.Johnson11NorthernArizonaUniversity,UnitedStates2UniversidadNacionalAutónomadeMéxico,MexicoThe structureof southwest forestshasbeendramatically alteredover thepast 140yearsdue toland use change and fire exclusion. Land managers are increasingly implementing restorationtreatments (thinning, prescribed fire) to improve forest health and fire‐resilience. The effects ofthese treatments aboveground have been studied extensively, but less is known about theirinfluence on soil communities and ecological function. We are studying the responses ofcommunitiesof soilmesofauna, fungi, andbacteria, aswell as soil physicochemicalproperties torestoration treatments at Valles Caldera National Preserve to compare the resilience of soilcommunitiesindifferentforesttypes.Wechosemicroarthropodsandnematodesasourfocalfaunasincethesetaxaarefunctionallyimportantandhavedemonstratedutilityasindicatorsofsoilfoodweb status. We collected soil samples from four forest types (xeric mixed conifer, mesic mixedconifer, old‐growth ponderosa, overgrown ponderosa) and three ponderosa pine restorationtreatmentsites(thinonly,thin/burn,control).Litterdepth,canopycover,andgroundcoverwerealsomeasured.Wewillbereportingondifferencesindensitiesofmicroarthropods,nematodes,andfungalhyphaebetweenponderosarestorationtreatmentsandamongforesttypes,whileobservingpatterns related to soil abiotic and aboveground variables. Our preliminary results show thatmicroarthropoddensitiesvaryamong forest types,butaresimilaramongrestoration treatments.Also,microarthropodabundanceispositivelyrelatedtocanopycoverandtotalorganiccarbon,butnegativelyrelatedtobulkdensity.Alterationoftheabundanceandcompositionofsoilmesofaunacanhaveimportantimplicationsfordecompositionandnutrientcycling.

Effectsofantibioticresiduesonextracellularenzymeactivityinsoils*MatthewHedin,JohnBarrettVirginiaTech,UnitedStatesAntibioticuse inagriculturalecosystemshas thepotential to increaseresistance insoilmicrobialcommunitiessince40‐95%ofanantibioticdoseadministeredto livestockisexcretedintactorasmetabolites into soil. Exposure to antibiotics is also known to alter microbial communitycomposition, biomass, and physiology. These changes in microbial communities have potentialconsequencesonelementalcyclinginagriculturalecosystems.Weexamined theeffectofdairycattlemanureonsoilmicrobialcommunitiesbymeasuring theirextracellular enzyme activity (4 carbon and 2 nutrient acquisition enzymes) along with severalmicrobial and environmental variables including antibiotic resistance gene (ARG) abundance.Sampleswerecollected fromdairy farmsinanationwidestudy,andincludedsiteswithhighandlow levels of manure input and antibiotic exposure associated with stocking rates. Responsesvariedamong individualenzymes,butwe foundanoverallsignificant increase in totalhydrolyticenzyme activity in high input sites indicating a change in the functioning of the microbialcommunity. Principle components analysis suggest that while some of the variation in enzymeactivitiesareassociatedwithARGabundance,soilorganicmatterwasthemostsignificantvariableaccountingfordifferencesinenzymeactivities.Thisreflectsaninheritchallengeinfieldstudiesofantibiotic exposure: the difficulty of distinguishing direct effects of antibiotic residues from theorganicmatterandnutrientsubsidyassociatedwithmanureapplications.Inongoingworkweareexperimentally manipulating soils to isolate the influences of antibiotics, manure resourcesubsidies,andbovinemicrobiomeinoculantsintosoils.

SpiesandBloggers:Newsyntheticbiologytoolstounderstandsoilmicrobialprocesses*CarolineMasiello,JonathanJ.Silberg,Hsiao‐YingCheng,IlenneDelValle,EmmFulk,GeorgeBennett

RiceUniversity,UnitedStatesSoil microbes can be programmed via synthetic biology to report on their behavior, informingresearcherswhentheyhaveparticipated inkeybiogeochemicalprocesses(e.g.denitrification)orwhen their immediate environment has passed a particular physical threshold (e.g. amicrobial‐scalechangeinsoilwaterconditions).Thisuseofsyntheticbiologyhasthepotentialtosignificantlyimprove our understanding of microbes’ roles in N, C, and water cycling; however, syntheticmicrobes have not yet seen wide laboratory use in soils because synthetic organisms typicallyreport by fluorescing, making their signals difficult to detect outside the petri dish. We aredeveloping a new suite of biosensors that report instead by releasing easily‐detected gases,allowing the real‐time, noninvasivemonitoring ofmicrobial behavior in soils. Biosensors can, intheory,beprogrammedtodetectprocessessuchasbiofilmproduction,variousstepsintheNcycle,methanogenesis,andcoordinatedsecretionofsomeformsofextracellularenzymes.StepsintheScyclemayalsobedetectable.Wewillprovideanoverviewof thepotentialusesofgas‐reportingbiosensors insoilecologyandwill report the development of the systematics of these sensors. Successful development of gasbiosensorsforsoilapplicationswillrequireaddressingissuesincluding:engineeringtheintensityofmicrobial gas production tomaximize the signal‐to‐noise using the tools of synthetic biology;normalizing the gas reporter signal to cell population size, managing gas diffusion effects ondetectedsignalresponse;anddevelopingmultiplegasesthatcanbeusedinparallel.

Influenceofwet‐drycyclesandorganicmanagementongrossnitrogendepolymerizationinagriculturalsoils*AmandaDaly1,AndreasRichter2,StuartGrandy11UniversityofNewHampshire,UnitedStates2UniversityofVienna,AustriaIn thewater‐insecure futurepredicted formany agricultural regions,cropproducerswill need toadoptpracticesthatmaintainbothyieldsandsoilqualitydespitedryconditions.Theseyieldswilldepend on sufficient soil nitrogen (N) provisioning, a process that more frequent drying andrewetting cycleswill likely disrupt.Water limitation could alter the rate at which soilmicrobesdepolymerizeorganicNintoplant‐accessiblemineralforms,butperhapsagriculturalmanagementregimescouldestablishfavorablesoilconditionsthatattenuateanynegativeeffectsofdroughtonNdepolymerizationandmineralization.Totesttheseideas,weexposedsoilsfrompairedorganicandconventionalplotsattheBeltsvilleandKBSlong‐termagriculturalexperimentsitestoeithermesicconditionsorfourdry‐rewetcyclesduringaneight‐weeklaboratoryincubation.Wet‐drycyclesincreasedDOCandaminoacidpools,anddecreasedMBCandN‐acquiringenzymeactivities. We found site‐specific and management‐specific effects within site: At KBS, wet‐drycycles decreased LAP activity and increased ammoniumpoolsmore inorganic soils compared toconventionalsoils.AtBeltsville,wet‐drycyclesincreasedammoniumanddissolvedNpoolsinbothmanagementtreatmentsand,inconventionalsoils,alsoincreasedaminoacidpools.Theinfluenceofwet‐dry cycles and agriculturalmanagement on grossN depolymerization andmineralizationrates measured using 15N isotope pool dilution will also be presented. Drying‐rewetting cyclesappeartoreducemicrobialbiomassandactivitybutalsoreleasepotentiallyplant‐availableNandimprovemicrobes’Nstatus;theseeffectsappeartobeamplifiedatsome—butnotall—sitesinsoilsunderorganicmanagement.

Temperature,moistureandmineralinteractionsalterthevulnerabilityoforganicmatterturnover

*A.PeytonSmith1,MalakTfaily2,KentRod1,VanessaBailey1,RyanRenslow11PacificNorthwestNationalLaboratory,DepartmentofEnergy,UnitedStates2EMSL,PacificNorthwestNationalLaboratory,UnitedStatesSorptionoforganicmatter(OM)tomineralsurfacesisaprimaryprocessgoverningitspersistence.How climate change‐induced shifts in temperature andmoisture influence the bioavailability ofpreviously‐bound OM remains highly uncertain. We coupled Fourier transform ion cyclotronresonance mass spectrometry (FT‐ICR‐MS) with CO2 respiration rates and 16s sequencing in ashort‐term laboratory incubation to test the combined effects of temperature (4˚ vs 20˚C) andmoisture(50vs100%water‐filledporespace,WFPS)onOMchemistry,microbialrespirationandcommunity composition in capillary fringe‐sediments maintained under different mineralogicalconditions(illiteamendedvsnon‐amended).WehypothesizedthatOMinillite‐amendedsedimentswouldbelessvulnerabletochangesinmoistureandtemperaturethanOMinnon‐amended,naturalsediments.Wealsohypothesizedthatincreasedtemperaturewouldaltermineral‐OMinteractionswithmoretransformationsofOMat20˚Cthanat4˚C.OurresultsshowthattransformationsofOMprimarilyoccurredin illite‐amendedsedimentsmaintainedat50%WFPSat20˚Ccomparedtoallsamples.However,more cumulativeCO2‐Cwas respired innon‐amended sediments at 20˚C.ThenominaloxidationstateofCandthearomaticity indexof theOMwerepositivelycorrelatedwithcumulativeCO2‐Crespired,suggestingthatcomplexformsofOMarethermodynamicallyavailablefor microbial degradation. Using ordination analysis, moisture at illite‐amendments alteredbacterial community structureat20˚C.Bacterialdiversitydecreased in illite‐amendedsediments.Our results, contrary to ourhypotheses, show thatOM transformationsweremost vulnerable inillite‐amendedcomparedtonon‐amended,naturalsedimentsandthatmoisturecontentinteractedwithtemperaturetoalterOMturnover.

Nitrogenlimitationofdecompositionanddecay:Howcanitoccur?

*ColinAverill1,BonieWaring21BostonUniversity,UnitedStates2UtahStateUniversity,UnitedStatesNitrogen(N)limitationofterrestrialproductivityiscommon,andsoilNavailabilityisassumedtocontrol terrestrial productivity in many theories of ecosystem ecology. Yet there are conflictingconceptualmodelstoexplainhowNavailabilityinfluencesdecompositionoforganicmatterbysoilmicrobial communities. Experiments findN can both stimulate and inhibit decomposition. InitiallitterNcontentisstronglyrelatedtotherateoflitterdecay.EctomycorrhizalfungicanexacerbateN‐limitation ofmicrobial decomposers and increase soil carbon (C) storage. Indirect contrast tothese findings, experimental additions of inorganic N to soils broadly show a suppression ofmicrobialactivity, inconsistentwithN‐limitationofdecomposition.Additionally,N‐richsubstratesmayincreasecarbonuseefficiency(CUE)ofmicrobialgrowth,therebyincreasingretentionofCinthemicrobialbiomassandultimately,enhancingsoilCstoragebyincreasingthemineralsorptionrate.We use a mathematical model to resolve contrasting interpretations of the role of N indecompositionandsoilCstorage.Webelievesomediscrepancybetweenpatternsobservedacrossgradientsoforganicmatterstoichiometryvs.Nfertilizationexperimentsmaybelinkedtofertilizedinducedosmoticstressandacidification,ratherthannutrienteffectsperse.Second,N‐limitationofdecompositioncanincreaseCstoredinparticulateorganicmatter,butmaydecreasetransferratesofCtomineralsurfacesduetoanegativeeffectonmicrobialCUE.Hence,Navailabilitymayalwayslimittherateofdecomposition,buttheultimateeffectonsoilCstoragewilldependoninteractionsbetweenphysiology,mineralogy.

Aninteractivelearningmoduleforteachingecologystudents(andprofessors)aboutdatabasesformanagingandqueryinglargedatasets*BeckyBall1,SuzanneDietrich1,DonGoelman2

1ArizonaStateUniversity,UnitedStates2VillanovaUniversity,UnitedStatesData and databases are ubiquitous: they are relevant across all disciplines to solve real‐worldproblems.Inthemoderneraof“bigdata”ecology,futuregenerationsofecologystudentsneedtobeproblemsolverswhocanappropriatelyhandlelargeamountsofdatausingappliedcomputingapproaches, despitemajoring in STEM fields that are typically light in appliedmathematical andcomputingcoursework.Throughaninterdisciplinarycollaborationwithappliedcomputingfaculty,wehavedevelopedanecology‐specific interactivevisualizationmodule that teachesstudents thebasic principles of databases. The goal of themodule is to provide a foundation for students tounderstand how databases can be used as an effective tool in their future field of study. Thelearningmoduleusesaspecificecologicalexampleexaminingdatafromacollectionofhypotheticalstudies simulating multiple factors of climate change across multiple sites in the Long‐TermEcological Research Network (LTER). In the interactive visualization, students learn: (1)conceptually,what is adatabase is andhowdoes itdiffer froma spreadsheet? (2)How toquerydatabasestoanswertheirresearchquestions.Themoduleisavailableopen‐accessonline,utilizingnotonlytheecologicalcustomizationdescribedabove,butalsoexamplesinGISandotherfieldsofstudypotentiallyrelevanttoecology.

Integratingsoilbiodiversityandsoilecologyintonon‐soil‐focusedundergraduatecoursesLorenByrne

RogerWilliamsUniversity,UnitedStatesBecause soils underpin human well‐being, societies need citizens who are environmentally soilliterate—thatis,whounderstandbasiccharacteristicsofsoilecosystems,anduseknowledgeaboutsustainablesoilmanagementto informdecisions.Cultivatingsuchliteracydependsonrobustsoilecologyeducationeffortsthatshouldbeledbysoilecologists.Attheundergraduatelevel,offeringspecializedsoilecologycoursesisakeystrategy,thoughithaslimitations.Analternativeapproachthat will reachmore students, andmay bemore practical in many contexts, is to integrate soilbiodiversity andecology intonon‐soil‐focused courses, including introductorybiology formajorsandnon‐majors,andsustainabilitystudiescourses.Theobjectiveofthistalkistosharereflectionsaboutandstrategies forhowtoachievethisgoalbasedontheauthor’s teachingexperiencesatasmall undergraduate university. For example, as part of revisions in an introductory biologylaboratory,twosessionsaboutphylogeneticsandecologicalinteractionsweredevelopedusingsoilorganisms. Inothercourses,soilecosystemprocesseshavebeenusedto framediscussionsaboutecosystem services and sustainability. These brief introductions have been observed to increasestudents’appreciationforsoilbiodiversityandecosystems.Thus,soilecologistsshouldidentifyandembracemoreopportunitiestousesoilbiodiversityinsupportofmoregeneralteachingaims(e.g.,evolution education). In addition, soil ecologists should help non‐soil scientist colleagues do thesamebyformallydevelopingandsharingrelevantteachingmaterials.Havingmoresoilecologistsengagedinsucheffortsisessentialforhelpingsociety’sfutureleadersdeveloptheirenvironmentalsoilliteracy.

Appendix l l

SOIL ECOLOGY SOCIETY BIENNIAL ORAL PRESENTATION ABSTRACTS

Thursday June 8th

PARALLEL ORAL SESSION E Bal l room C

SESEarlyCareerResearchAwardeePresentation–TomCrowtherQuantifyingglobalsoilcarbonlossesinresponsetowarmingMarieCurieFellowattheNetherlandsInstituteforEcologyThemajorityoftheEarth’sterrestrialcarbonisstoredinthesoil.Predictingthebalanceofcarbonbetween the soil and the atmosphere is critical if we are going to understand climate change.Ifanthropogenicwarming stimulates the loss of this carbon to the atmosphere, it could accelerateplanetarywarming.Despiteevidencethatwarmingenhancescarbonfluxestoandfromthesoil,thenet global balance between these responses has remaineduncertain.Ipresent a comprehensiveanalysis of warming‐induced changes in soil carbon stocks by assembling data from 49 fieldexperimentslocatedacrossNorthAmerica,EuropeandAsia.Ishowthattheeffectsofwarmingarecontingenton thesizeof the initial soil carbonstock,withconsiderable lossesoccurring inhigh‐latitudeareas.Byextrapolatingthisempiricalrelationshiptotheglobalscale,weprovideestimatesof soil carbon sensitivity to warming that may help to constrain Earth system modelprojections.Undertheconservativeassumptionthattheresponseofsoilcarbontowarmingoccurswithinayear,Ishowhowabusiness‐as‐usualclimatescenariowoulddrivethenetlossof~1.5PgCfromthesoileachyear.Thisvalueisapproximately12–17percentoftheexpectedanthropogenicemissions over this time.This provides strong empirical support for the idea that risingtemperatureswill stimulate thenet lossof soil carbon to theatmosphere,drivingapositive landcarbon–climatefeedbackthatcouldaccelerateclimatechange.

Partialsupportforthe‘environmentalheterogeneityhypothesis’intallgrassprairierestorations*DrewA.Scott,SaraG.Baer

SouthernIllinoisUniversity,UnitedStatesThe 'environmental heterogeneity hypothesis' proposed a mechanism to allow resourcepartitioning and species coexistence. In accordance with this hypothesis, plant diversity ispredicted to increase with variability in resources, but there has been weak support fromexperimental studies. The objective of this research was to characterize the amount andheterogeneity (coefficientof variation)of soil nitrate andproportionofphotosynthetically activeradiation reaching soil surface as related to plant community structure during plant communitydevelopment. This was accomplished using a geostatistically‐informed sampling design and co‐located plant, soil, and light measurements across a chronosequence of restored prairies. Meannitrate decreased exponentially with restoration age (P < 0.001), but there was no directionalpattern in nitrate heterogeneity. Mean amount and heterogeneity of light availability decreasedexponentiallywith restoration age (P <0.001). Light availability heterogeneity (P = 0.005),meansoil nitrate (P = 0.001), and mean light availability (P = 0.002) were correlated with plantcomposition(Bray‐Curtisdissimilarities).MeannitratewasinverselyrelatedtoShannon'sdiversity(P=0.002)andrichness(P<0.001).Thisstudyindicatesthatamountofnitrateismorestronglyrelated to plant diversity than heterogeneity inmeasured resources. This study further suggeststhat competition for resources, rather than resource partitioning through environmentalheterogeneity,likelyhasagreaterinfluenceonplantdiversity.

Fungalresponsestoaninvasiveplantinawarmer,fertilizedforest*MarkAnthony1,SeritaFrey1,KristinaStinson21UniversityofNewHampshire,UnitedStates2UniversityofMassachusetts,UnitedStatesGlobal change is altering the availability of soil resources that can promote successful plantinvasions.Theeffectsofinvasiononsensitivesoilmicroorganismsmightthereforebeamplifiedinaglobal change context, feeding back to further alter soil resource availability. In this study, wemeasured the impacts of Alliaria petiolata (garlic mustard) invasion on fungal functional guilds(saprotrophs, ectomycorrhizae, arbuscular mycorrhizae, and pathotrophs) in the context ofsimulatedNdeposition(5gNm2yr‐1),soilwarming(+5°C),andtheirinteraction. Todothis,weinitiated an experimental invasion within warmed and N amended plots at the Soil Warming ×Nitrogen Addition Study at the Harvard Forest Long‐term Ecological Research (LTER) site inPetersham, MA. Two year after invasion, soil was collected and analyzed for fungal communitystructureandsoilresourceavailability(water,organicCandN,inorganicN,finerootcontents).WefoundcleareffectsofsimulatedNdeposition,soilwarming,andtheirinteractiononlabileorganicCpools, inorganic N availability, and the quantity and spatial distribution of fine roots. Fungalcommunities were most significantly reassembled in invaded × fertilized × warmed plots, aresponseaccompaniedbygreaterCmineralizationandtheredistributionoffinerootsfrommineralsoil into the organic horizon. Conversely, the effect of invasion on the arbuscular mycorrhizalcommunity was buffered in plots with fertilizer and heat. Our results suggest that impacts ofinvasionon fungi canbeboth enhanced (general fungal response) and ameliorated (mycorrhizalresponse)inthecontextofglobalchange.

Investigatingdeficitirrigationimpactsonbelowgroundprocessesandclimatechangemitigationpotential*NoraFlynn1,LouiseComas2,CatherineStewart2,StevenFonte11ColoradoStateUniversity,UnitedStates2USDA‐AgriculturalReasearchService,UnitedStatesThepressureofrisingglobalfooddemandincombinationwithincreasinglylimitedwaterandlandresources requires the development of farm management practices that improve plant‐waterproductivity and contribute to farmers’ capacity to adapt to a changing climate.Deficit irrigation(DI) is a strategy to reducecropwaterusagewithminimal impactsoncropyield, andmayhaveimportant implications for climate change mitigation. Deeper root growth and reduced surfacemoistureunderDIare likelyto impactsoilbiologicalactivity,whichinturnregulatesgreenhousegasemissions,organicmatterturnoverandnutrientdynamics,yettheimpactsofDIremainpoorlyunderstood.TobetterunderstandDI impactsonmicrobialprocessesanditspotential tomitigateglobalwarming,weevaluatedgreenhousegasemissionsandmultiplesoilphysical,biologicalandchemical properties under different DI intensities in a replicated corn field trial near Greeley,Colorado.Treatmentsdifferedbasedontargetpercentofmaximumcropevapotranspiration(ET).The lowestETtreatment(40%ofETin latevegetativeandmaturationstages)exhibitedreducedN2O emissions in comparison to well‐watered treatments. Additionally, the 40% ET treatmentresulted in significantly greater root proliferation at depth (below 40 cm) than the full ETtreatment, and significantly greatermicrobial abundance at depth. These results suggest that DImayhelptomitigateclimatechangeviareducedN2Oemissionandalteredsoilmicrobialactivity.

Usingextracellularpolymericsubstances(EPS)frombacteriatomakesoilsmoredrought‐adapted*JosephBlankinship1,KennethMarchus2,JoshuaSchimel21UniversityofArizona,UnitedStates2UniversityofCaliforniaSantaBarbara,UnitedStatesCrops—andplantsinallecosystems—dependonhealthysoilsthatcansupplywaterandnutrientsevenwhen it isnot raining (or irrigating).Onepossible strategy forhelping agricultureadapt todrought is to learn from soil bacteria. When soils dry out, bacteria are known to releaseextracellularpolymeric substances (EPS) into the soilenvironment thatactas superbsponges toincrease water retention and as pipes to increase availability of soluble resources. However,nothingisknownaboutthelinkbetweensoilEPSandplanthealth.WhatifwecouldaugmentEPSinsoilduringdroughtasawayofhelpingcropsadapt?ThisquestionwasstudiedusingsoilsfromSeaSmokeVineyardnearLompoc,California.Pinotnoirgrapevinesweregrown inagreenhousewithsoilsofvaryingamountsofxanthangum.XanthangumisabacterialEPSpolysaccharidethatisorganically certified and commercially produced. We captured close‐up images showing howstrandsofxanthangumconnectdrysoilparticlesthatwereotherwisehydrologicallydisconnected.Laboratorytestsshowedthataxanthangumconcentrationofatleast0.5%(bymass)wasneededtoincreasesoilwater‐holdingcapacityandaggregatestability.Andgreenhousetrialswithxanthanguminvineyardsoilsshoweda40%increaseinwater‐useefficiencywithoutsacrificingnitrogensupplyorplanthealth.Ifxanthangumcansuccessfullysustainnutrientavailabilitywhilereducingirrigationdemand, thenbacterialEPS(whetheramendedornaturallysecreted)couldbeaviablestrategyfordealingwithwaterscarcityinaridlandagriculture.

TheinfluenceofJapanesestiltgrassonsoilmicrobes,edaphicproperties,andtreeregenerationinanitrogensaturatedenvironment*TylerRippel,PasqualeSucci,SamanthaChapmanVillanovaUniversity,UnitedStatesManynortheasterndeciduous forests suffer frompoor seedling regenerationdue to soil impactsfrom invasive understory plants and nitrogen deposition. Specifically, Japanese stiltgrass(Microstegium vimineum), a non‐native invasive grass that is widely spread throughout easternAmerica,caninhibitnativetreesuccessionthroughavarietyofsoilinfluencessuchasalteringpH.InahighlyinvadedPennsylvaniaforestwhichhasNsaturatedsoils,weinvestigatedthefollowingtwonovelquestions:(1)DoesJapanesestiltgrass influencenitrogencycling innitrogensaturatedenvironments? (2) Does Japanese stiltgrass invasion have a stronger influence on soil dynamicsimportant for treeregeneration thanoverstory treecommunitycomposition?WeexaminedplotswithandwithoutJapanesestiltgrassinwetlands,grasslandsandsuccessionalforests.Weassessedmultipleplanttraits,soilpH,soilnutrientpoolsandavailability,andamoAgeneabundanceinfivereplicatesofeachcommunitytype.InplotswithJapanesestiltgrass,wefoundaubiquitousincreasein bulk pH and rhizosphere pH. Soil NO3‐was 36% higher in plots that had Japanese stiltgrass,indicating thatnitrificationmaybe increasedeven in thesenitrogensaturatedsoils.Our findingssuggest that Japanese stiltgrass controls N cyclingwithinwetlands, grasslands, and successionalforestspossiblybyraisingpH to induce increasednitrificationrates.Theseresults implicate thatforestmanagementmay have to account for alteredN cycling and the legacy effect of increasednitrateinsoils.OurresultssuggestthatforestmanagersmayneedtoaccountforalteredNcyclingandthelegacyeffectofincreasednitrateininvadedforestsoils.

Consequencesofchangingrainfallpatternsonnitrousoxidefluxesincroppingsystems*KateGlanville,G.PhilipRobertsonMichiganStateUniversity,UnitedStatesIntheUSMidwest,thedryintervalsbetweenprecipitationeventsandtheamountofprecipitationfalling in single events are increasing and predicted to increase furtherwith all greenhouse gasemissions scenarios. N2O fluxes are closely linked with soil moisture, causing changing rainfallpatternstoverylikelyinfluenceN2Ofluxes.SincethemajorityofanthropogenicN2Oproductionisfrom agricultural soils, in which fluxes are largely controlled by oxygen, nitrate, and carbonavailability, it is important tounderstand the effects of changing rainfall patternsonproduction.Ourobjective is to test thehypothesis that changingrainfallpatternsstronglyalterN2O fluxes inagriculturalsoilsasmodulatedbycroppingsystemandlandscapeposition.Weusedainfallmanipulationshelterstocreatesoilsexposedtosameamountsofrainfalldeliveredat different intervals (3‐day, 2‐week, and 4‐week). The initial phase of this experiment wasconducted for 10‐weeks in a no‐till continuous‐corn system in place from 2008 at the KelloggBiological Station Long‐Term Ecological Research site. Results from the first field season showcumulativeN2O fluxeswere four times higherwhen rainfall occurred in 4‐week rather than subweeklyor2‐weekintervals.Resultswillalsobereportedfromthe2016fieldseasonandrelatedtochanges in denitrifier enzyme activity and nitrate availability. Understanding patterns andmechanisms for N2O fluxes from the soil is important for developing mitigation practices andparameterizingbiogeochemicalmodels.

Prescriptionsideeffects:ControlledburningaltersresourcestoichiometryinaMidwesternforestsoil*MeghanMidgley1,QuinnTaylor2

1TheMortonArboretum,UnitedStates2UniversityofSanDiego,UnitedStatesIneasterndeciduous forests,burning isa common forestmanagement techniqueused tocontrolinvasiveunderstoryplants,suchasbuckthornandthistle,andpromoteoakregeneration.However,little is known about how controlled burns impact soil properties. As alterations to soilbiogeochemistryaffectplantgrowthandcompetition,changesinthesoilmayenhanceordampenthe desired impacts of controlled burning. In this study, we assessed the impacts of controlledburningonsoilbiogeochemistrybycomparingadjacentannuallyburnedandhistoricallyunburnedforestsinTheMortonArboretum’sEastWoods.We found that high‐frequency controlled burning fundamentally altered the carbon : nitrogen :phosphorus(C:N:P)stoichiometryofextracellularenzymeactivities,microbialbiomass,andsolubleCandnutrients. Inparticular,burningdecreasedmicrobialbiomassC:P(P=0.049)andincreasedthe abundance of C‐ and N‐degrading enzymes relative to P‐degrading enzymes (P = 0.044 and<0.01,respectively),indicatingthatburningincreasedPincorporationintomicrobialbiomasswhilesimultaneouslydecreasingmicrobialPdemandrelativetoCandNdemand.AsfirevolatilizesCandN at lower temperatures than P and increased soil pH (P < 0.01), these changes in microbialbiomassandenzymestoichiometryarelikelydrivenbyincreasedPavailabilityrelativetoCandNavailability.Thus,importantsideeffectsofburningarechangesinresourcestoichiometry–ashifttowardsC‐andN‐limitationandawayfromP‐limitation.Theconsequencesoftheseshiftsforplantcommunity composition remain a critical unknown for predicting the restoration outcomes ofcontrolledburning.

LinkingsoilCandNcyclingandtracegasfluxeswithsoilbacterialcommunitiesalongagradientofsimpletocomplexcroprotations*BrendanO'Neill1,ThomasSchmidt2,G.PhilipRobertson1,SashaKravchenko1,StuartGrandy31MichiganStateUniversity,UnitedStates2UniversityofMichigan,UnitedStates3UniversityofNewHampshire,UnitedStatesIncreasing rotational complexity in agroecosystems can have multiple belowground effects butlinkages between nutrient cycling pathways and themicrobial communities that carry out theseprocessesremainpoorlyunderstood.Wetrackedsoilcarbon(C)andnitrogen(N),tracegasfluxesand soilmicrobial communities along a gradient of increasing cropping system complexity fromcontinuous grainmonocultures to up to five plant species in 3‐year rotations – includingwintercover crops – in treatments that have not received external inputs. Rotationswith a history ofcovercropsrespiredatleast20%moreCO2,hadgreaterpotentialCandNmineralizationrates,andshifted patterns in microbial enzyme potentials, compared to all other rotations without covercrops.Denitrificationwasalsodifferentundercovercropswithgreaternitrousoxideemissions,areduction in denitrificationpotential, and a shift in the phylogeny of genes for nitrite reductase(nirK).Finally,croprotationalcompositionhadnoeffectonsoilbacterialrichnessordiversity,butbacterialcommunitycompositionsignificantlydivergedinrotationswithcovercropscomparedtothose without. Differences in community composition were strongest between taxa of theProteobacteriaintherotationswithcovercropsandAcidobacteriainrotationswithoutcover.Ourresults show that even amid a range of the quality and quantity of plant inputs from differentrotation,covercropsexertedanoverridingeffectonsoilCandNdynamics,tracegasfluxes,andthephysiologyoforganismscarryingoutnutrientcycling.

Edaphicmanipulationofthesoilcommunityofbiofuelswitchgrass(Panicumvirgatum)inthreesoils*JoniBaumgarten,JohnDighton

RutgersUniversity,UnitedStatesPanicum virgatum is a potential biofuel crop that is tolerant of many different soils. Previousexperimentsby theauthorshave shown that the soil community andP.virgatum are resilient tonitrogen fertilizer additions in good agricultural soil. However, in less nutrient‐rich soils wherebiofuel crops should be grown to prevent competitionwith food crops,P. virgatummay show agreaterresponsetochangesinthesoilconditions.Weask:doesP.virgatumgrowthrespondtosoilmanipulations (adding nitrogen fertilizer and commercial mycorrhizal inoculum) differently inthree different soils—good agricultural soil, marginal agricultural soil, and sand from the NewJerseyPineBarrens,whereswitchgrassgrows indisturbedsites.Weconducteda3x2x2 factorialdesigngreenhouseexperimenttotestthehypothesisthatswitchgrassbiomassyieldswillrespondtomanipulationsofthesoilcommunityinonegrowingseason.Results differed by soil type, but not by fertilizer ormycorrhizal inoculum treatments. PrincipleComponentsAnalysisofwellcolordevelopmentintheBiologMicroPlatesshowsdifferencesduetosoiltypebutnotbyothertreatments.Soilarthropodmorphospeciesdifferedbysoiltypebutnotbyother treatments.Nematodenumbersdifferedsignificantly (p=0.000006)bysoil type,butnotbyother factors. Mycorrhizal colonization did not differ by soil type or treatment. There weredifferences in rootmass by soil type (p=0.0044 level), and by fertilizer (p=0.09). Above‐groundbiomassdifferedsignificantlybysoiltypebutnotbytheothertreatments.Theseresultsshowtheresilienceofthesoilcommunitytoperturbationacrossallsoiltypes.

Environmentalcontrolsonfree‐livingnitrogenfixationandnitrogenmineralization*DarianSmercina,LisaTiemann,SarahEvans,MarenFriesenMichiganStateUniversity,UnitedStatesPlantaccessiblenitrogen(N) iscontrolledbyNfixation(N‐fix)andNmineralization(N‐min),yetthereisnoconsensusonthelinkbetweenN‐fixandN‐minratesinsoils.TobetterunderstandthedynamicsofN‐fixversusN‐min,weusedsixmarginalland(lowsoilN)sites,acrossMichiganandWisconsin, planted with switchgrass (Panicum virgatum) monocultures. Split plots receivedfertilizerNatallsites.Duringthe2016growingseason,wemeasuredpotentialN‐fixandnetN‐minrates, and assessed several plant characteristics and soil biological and chemical propertiesincludingplanttissuecarbon(C)andN,rootmass,photosyntheticefficiency(qL,qP,ΦII,LEF),soilmicrobial biomass C and N, extracellular enzyme activities, plant available N (PA‐N), and soilmoisture.Atpeakgrowingseason,N‐fixpositivelycorrelatedwithplantavailableammonium(PA‐NH₄) across all sites.N‐fix rates did not differ between sites or between sub‐plots, regardless offertilization.TwoMichigansites,LuxArbor(LUX)andLakeCity(LC),weresampledmonthlyduringthegrowingseason.Averagedacross6months,LCN‐fixratesweresignificantlygreaterthanLUXN‐fix rates. At LC, N‐fix positively correlatedwith soilmoisture and PA‐NH₄, while N‐fix at LUXnegatively correlated with urease activity. Across all sites and sample dates, net N‐min wasnegative, indicatingN immobilization, andpositively correlatedwith soilmoistureandpeptidaseenzymeactivities.ThesedatademonstratehighvariabilityinthemostdominantpathwaysforplantaccessibleN.Ongoinganalyseswillelucidatewhetherplantcharacteristicsorothersoilvariablesaredrivingthisvariability.

SESServiceAwardee–DeborahNeherSoilhealth–whatprogresshavewemadeinthepast25years?UniversityofVermontMycareer in soil healthbegan in1990as amemberof theAgricultural Lands componentof theEnvironmentalMonitoringandAssessmentProgram.Idedicatedthepast25yearsofmycareertoevaluating soil invertebrates (nematodes,protozoaandmicroarthropods)asbiological indicatorsofsoilhealth.Duringthat time,myresearchwent throughphasesofevaluatingsamplingdesignsand statistical reliability of indices, calibration steps, andecological interpretation. This researchprovided the necessary empirical support for choosing nematode communities as one of 16indicators to monitor the condition of farmlands in the US by the H. John Heinz III Center forScience,EconomicsandEnvironment,StateoftheNation’sEcosystemreportlastpublishedin2008.Political and economic environments were not conducive to bringing the Heinz proposal to fullimplementation. In the meantime, scientists at Cornell University developed a ComprehensiveAssessmentofSoilHealthtestandtheUSDANaturalResourceConservationServiceestablishedaSoilHealthAssessmentprogram.Consequently,soilhealthisnowawidelyusedtermbutseemstorepresent a selectivememory of the science performed. Rather than repeat history, it is time torefreshmemoriesandtellthestoryofsoilhealthresearchandachievements.

Appendix l l

SOIL ECOLOGY SOCIETY BIENNIAL ORAL PRESENTATION ABSTRACTS

Thursday June 8th

PARALLEL ORAL SESSION FBal l room D

Pathwaysandpatternsofplantlitterchemistrythroughoutdecomposition*BeckyBall1,KyleWickings2,LynnChristenson31ArizonaStateUniversity,UnitedStates2CornellUniversity,UnitedStates3VassarCollege,UnitedStatesDecomposition of plant litter is a fundamental ecological process, integral to energy flow infoodwebs,biogeochemistryandsoilformation.Moststudiesofplantlitterdecompositiontypicallymeasure only initial litter chemistry and assume that initial chemical differences determinedecompositiondynamicsinlaterstagesofdecay.However,initialdifferencesinmacronutrientsdonotalwayspredicthowlitterwillbehavethroughoutdecomposition.Theless‐frequentlymeasuredparameters, including micronutrients, phenolics and structural compounds can alter thedecomposition process, and changes in their relative abundance may be important. Litterdecomposition is a key regulator of C and nutrient cycling; thus, a more comprehensiveunderstanding of this process is imperative.We tested the hypothesis that initial differences inlitter chemistry among species will not persist in later stages of decomposition, with chemicalcontenteitherdivergingorconvergingthroughoutdecompositionasdeterminedbythelocalbioticandabioticenvironments.Todoso,wehavecompiledarchivedlittersamplesfromacrosstheU.S.from a broad range of plant species and ecosystems to identify patterns of changes in litterchemistryduringdecomposition.On theseexisting samples,weanalyzeda comprehensive setoflitterchemistrymeasurementsacrossstudiesincludingmacro‐andmicronutrients,fiberandotherlabileandrecalcitrantplantcompoundsknowntoimpactdecomposition(polysaccharides,protein‐andnon‐protein‐derivedN‐bearingcompounds,lignin,lipids,andphenols)acrossaconsistentsetof decay stages. Results support our hypothesis, with both divergence and convergence of litterchemistryoccurringovertime,andtherelationshipwithplantfunctionalgroupandecosystemwillbeexplored.

Augmentationofbasalresourcesinasoilfoodwebchangespatternsofintraguildpredationanddecompositionrate*MonicaFarfan,DavidWise

UniversityofIllinoisatChicago,UnitedStatesPredation between generalist predators that consume shared prey on a lower trophic level istermed intraguild predation (IGP).We investigated how augmentation of the resource base of aforest‐soil food web alters the dynamics of an IGP module consisting of two size classes ofpredaceous mites and shared fungivorous prey (fungivorous mites and Collembola). Becausechanges in this IGPmodule could alter decomposition rates by affecting fungal grazing,we alsoexamined effects of resource enhancement on the rate of decomposition of a standardizedsubstrate.Inthetwo‐yearexperiment,basalresourceswereaugmentedbyaddingartificialdetritusto increasesaprophytic fungi.Duringeachfieldseason,150 fenced1‐m2plotsreceivedbi‐weeklydetritalenhancementsatoneofthreerates:High(4x),Low(1x),orNone(0x);50unfenced,non‐enhanced plots served as a Reference treatment. Detrital enhancement increased densities offungivorous prey and Parasitidae, a family of predaceous mites. The High rate changed thedominant fungivorous taxon fromTydeidae to Tarsonemidae, amite family specializing on thin‐walledfungalhyphae,whichwerelikelymoreabundantinthattreatment.Pathanalysesrevealedacomplex pattern of changes in the IGP module in response to detrital addition. One emergentpatternwasthetendency forresourceenhancement to increasethedegreetowhich increases inthesmallerIG‐PreypositivelyaffecteddensitiesofthelargerIG‐Predators.Decompositionratewashighest in theHigh treatment,probablybecause saprophytic fungiweremoreabundant in thoseplots, and because fungivores had a negative impact on decomposition in the Low treatment.

Microarthropodsinbeddedpack:Asourceforbiocontrolofbitingflypestsondairyfarms?MichaelLeDuc,TuckerAndrews,ThomasWeicht,*DeborahNeher

UniversityofVermont/PlantandSoilScience,UnitedStatesBedded pack dairy systems use straw orwood chips to bed cows throughout the cold Vermontwinter.Layersofbeddingandmanureaccumulateforupto8months,begintocompost,generatingheat that comforts the cowshoused indoors.Microarthropodswere extracted frombeddedpacksamples using Tullgren funnels. Summer bedded pack contained communities of mite(mesostigmata,astigmataandoribatida)andpseudoscorpions.Twogeneraofmesostigmataareinthe family Uropodidae. The limited literature on published ecology indicates these mites cansurvive on a variety of fungi, but likely feed on preferentially on fly larvae. Likewise, thepseudoscorpionsarealsolikelypredatorsonflylarvaeinthesystem.Oneachoffivefarmssites,wehaveidentifiedtwomites,MacrochelidaeGlyptholaspissp.andParasitidaeEugamasussp.,thathavepotentialtoactasflypredators.Preferentialfeedingtrials,currentlyunderway,haveconfirmedthepredation of Glyptholaspis‐ sp. on Musca larva. Other important mite taxa include AcaridaeRhizoglyphus.Futureresearchwilltestthehypothesisthattheseflypredatorsmaybeabiocontrolmechanismformanagingfliesthatvectorthebacteriathatcausemastitis.

Soilmicrobialcommunitiesandgasdynamicscontributetoarbuscularmycorrhizalnitrogenuptakeandtransfertoplants*RachelHestrin1,MariaHarrison2,JohannesLehmann11CornellUniversity,UnitedStates2BoyceThompsonInstitute;CornellUniversity,UnitedStatesArbuscularmycorrhizalfungi(AMF)associatewithmostterrestrialplantsandinfluenceecosystemecologyandbiogeochemistry.ThereisevidencethatAMFplayaroleinsoilnitrogencycling,inpartby taking up nitrogen and transferring it to plants. However, many aspects of this process arepoorlyunderstood,includingthefactorsthatcontrolplantandfungalaccesstonitrogenstoredinsoil organic matter. Soil microbial communities sampled from different cropping systems wereadded tomicrocosms and incubations to assessmicrobial contributions to nitrogenuptake fromorganicmatter. Stable isotopeswere used to track nitrogenmovement fromorganicmatter intoAMFandhostplants.ResultsshowthatAMFcanincreasetotalplantbiomassandnitrogencontentfourfold,butthatbothAMFandfree‐livingmicrobescompetewithplantsfornitrogenfromorganicmatter. Surprisingly, gaseous nitrogen species also contribute significantly to plant nitrogencontent. This research links interactions between plants, mycorrhizal symbionts, and free‐livingmicrobeswithterrestrialcarbonandnitrogendynamics.

Invasiverootherbivoresacceleratesoilcarboninputsandsoilorganicmatterdecomposition

*HuijieGan1,ChaoLiang2,KyleWickings11CornellUniversity,UnitedStates2InstituteofAppliedEcology,ChineseAcademyofSciences,ChinaIncreasingevidencerevealsthatCinputsoriginatedfromrootsaremorelikelytobepreservedinsoils compared to plant litter from aboveground. Despite awareness of the importance of rootinputs forsoilbiogeochemicalprocesses,ourunderstandingofhowbioticplantstressorssuchasroot herbivores alter the input and cycling of root‐derived carbon remains limited. To test thehypothesis that root herbivory alters soil microbial activity and C cycling, we carried out threeseparate experiments; a lab incubation, amanipulative field study, anda large‐scale field survey.Collectively,ourstudies indicatethatathighdensities,rootherbivoresreducedtotalorganicC insoilsandsuchreductionsareassociatedwithincreasesinmicrobialbiomassandhydrolyticenzymeactivities.Incontrast,rootfeedingappearstohavelittleimpactonmicrobialnecromassinsoils.Wefurtherproposeaconceptual framework illustratingtheroleofbelowgroundherbivores insoilCcycling,anddiscussimplicationsoflargechangeinpopulationdynamicsofrootherbivores,duetoclimate change or invasive species, for soil organic matter dynamics and soil C sequestration.

Oribatidmitesasatooltoassesssoilrecoveryafteroilsandsmining*BrittanyMcAdams1,SylvieQuideau1,MathewSwallow2,LisaLumley31UniversityofAlberta,Canada2Mt.RoyalUniversity,Canada3RoyalAlbertaMuseum,CanadaBitumen extraction via surfacemining has disrupted nearly 1000 km2 of boreal forest habitat inAlberta, Canada, requiring forest ecosystems to be reconstructed from the ground up. Previouswork has investigated the influence of vegetation and reclamation materials on soil microbialcommunities,soilorganicmatterquality,andnutrientcycling.Littleattentionhasbeenpaidtothereestablishmentofsoilmesofaunatomeasuresoildevelopment.Oribatidmitesplayakeyrole inthe boreal forest floor where they dominate the detritivore community and participate in thecomminutionoflitter.Insightintothestageofdevelopmentandqualityofforestfloorsundergoingreclamation may be found through using oribatid mites as bioindicators. The objectives of thisstudywereto(1)assessoribatidmitecommunitycompositionwithtimesincereclamation(8‐31yrs) and (2) investigate the application of community analyses (≥ 0.3mm) as a bioindicator offorest floor development. We used a chronosequence of aspen and spruce stands undergoingreclamation and compared them to the undisturbed forest matrix. Species‐level identificationrevealedthepresenceofanovelforestflooratsitesundergoingreclamationhadthebiggestimpactonoribatidmitereestablishment.Reclaimedstandswithanovelforestfloorthickness≥2cmhadsimilaroribatidmitespeciesrichnessanddiversitytothatofundisturbedstands.Assemblagesinstandsundergoingreclamationremaineddifferentfromassemblagesfoundinundisturbedstands.Evidenceofbioindicatorpotentialwasseenintheshiftinrelativeabundancefromcommontorarespecieswiththedevelopmentofanovelforestfloor.

IssoilporewateranexchangedepotfornutrientsinArctictussocktundrasoils?*AnthonyDarrouzet‐Nardi1,MichaelWeintraub2,JaneMartinez1,DanielaAguirre1

1UniversityofTexasatElPaso,UnitedStates2UniversityofToledoDept.ofEnvironmentalSciences,UnitedStatesMoistacidic tussock tundrasoils inArcticecosystemsmaintainhighmoisturecontent (~80%bymass) throughout the roughly three‐month‐long summer growing season (May‐July). In thiswetenvironment, soil pore water may serve as a well‐mixed medium, or exchange depot, in whichenzymaticdecompositionofsoilorganicmattertakesplaceandnutrientsareexchangedbetweenplantsandmicrobes.Alternatively,biogeochemicalactivitiesmaybemore localized inmicrositeswithin the soil separated by the complex physical structure of the soilmatrix.Herewe evaluatethese alternative hypotheses using comparisons of both seasonal nutrient dynamics and soilecoenzymeactivitiesinsoilporewaterandsoilextractions.Differencesinconcentrationsbetweenporewater and extractions show thatnutrients in the soil porewater are typically lowwith theexception of a flush of nutrients at the beginning of the season, suggesting that nutrients areexchangedviasoilporewaterduringsoilthawbutthatcyclingismorelocalizedduringthegrowingseason. In contrast, analyses of sugar concentrations in soil pore water show that they followseasonal trends associatedwith plant production. The finding ofmore localized nutrient cyclingactivity is corroboratedby lowecoenzymeactivities in soilporewatercomparedwith the largersolidparticles inthesoil.Takentogether, thesedatasuggestthatsomebiogeochemicalprocessessuchasrootexudationandnutrientturnoveratthawarefacilitatedbyawell‐mixedsoilporewaterpool while others such as microbial uptake of decomposition products are more localized.

ASerengetiwithoutarbuscularmycorrhizas:Quantifyinginteractionsbetweenmigratorymammalsandfungalsymbionts*BoStevens1,JeffreyPropster1,GailWilson2,AndrewAbraham1,ChaseRidenour1,ChrisDoughty1,NancyJohnson1

1NorthernArizonaUniversity,UnitedStates2OklahomaStateUniveristy,UnitedStatesBoth mycorrhizas and grazing mammals influence phosphorus (P) availability and primaryproductivityofgrasslandecosystems.Grassesareestimated toobtainasmuchas90%of theirPfromarbuscularmycorrhizas,andthesesymbiosesareparticularlyimportantinacquiringPfromthehighlyweatheredsoilswhichtypicallyoccurintropicalgrasslands,suchastheSerengeti.Large,migratoryungulateshavebeenshowntotranslocatenutrientsandincreasetheavailabilityofPforgrassland vegetation. The P content of vegetation and the abundance of arbuscularmycorrhizal(AM)fungiarehighestinregionswiththehighestsoilP.TheconcentrationofPinplanttissuesmayinfluence themigratorypatternsofungulates in theSerengeti;during thegestationperiod,whennutritionalrequirementsareincreased,grazingmammalsseekareascontainingplantswithhigherP concentrations.Thepurposeof this studywas toanalyze the interactive rolesofAM fungiandmammalian grazers on the P cycle and primary production in the Serengeti. Bayesian linearregressions were used to infer the primary factors that influence AM fungal abundance in theexperimental plots. Thebestmodel indicated that total soil Pwas the strongest predictor ofAMfungalbiomass,itwassignificantlyandpositivelycorrelatedwiththeAMfungalbiomassingrazedplots,butnotinungrazedplots.BiomassmeasurementsofAMfungiwerecombinedwithpublisheddata on the abundance and physiology of large ungulates in a customized Madingley model tosimulatePdynamicsandnetprimaryproductionoftheSerengetiecosystem.

Pulsesize,frequencyandsoil‐littermixingalterthecontrolofcumulativeprecipitationoverlitterdecompositionindrylands*François‐XavierJoly,HeatherThroop

SchoolofEarthandSpaceExploration‐ArizonaStateUniversity,UnitedStatesIt has traditionally been considered that macroclimate is the predominant driver of litterdecomposition rates. However, in drylands, cumulativemonthly or yearly precipitation typicallyfails topredict theserates. Inthesesystems, thewindowsofopportunity fordecomposeractivitymay rather depend on the precipitation size and frequency and local factors affecting litterdesiccation,suchassoil‐littermixing.Weusedafull‐factorialmicrocosmexperimenttodisentangletherelativeimportanceofcumulativeprecipitation,pulsefrequency,andsoil‐littermixingonlitterdecomposition. Decomposition saturated with increasing cumulative precipitation when pulseswere large and infrequent, suggesting that littermoisture no longer increased and/ormicrobialactivitywasnolongerlimitedbywateravailabilityaboveacertainpulsesize.Greaterprecipitationpulsefrequencythusincreaseddecomposition,suggestingthatperiodsofmicrobialactivitydependmore on precipitation frequency than quantity. Soil‐litter mixing consistently increaseddecomposition,withgreatestrelativeincrease(+194%)underthedriestconditions.Inafollow‐upexperiment, we investigated how pulse size altered the dynamic of litter moisture and littermicrobialrespiration.Wefoundthatbothlittermoistureandmicrobialrespirationsaturatedwithincreasingpulsesize,confirmingtheexistenceofapulsesizethresholdabovewhichlittermoistureand consequent microbial activity are no longer limited by water availability. Collectively, ourresults highlight the need to incorporate soil‐litter mixing as key driver of decomposition indrylands,andtoconsiderprecipitationatfinertemporalscale,particularlyinthecontextofclimatechangethataffectsthesizeandfrequencyofprecipitationevents.

Peatlandmicrobialcommunityresponsetoalteredclimatetemperedbyplant–soilinteractions

*AshleyKeiser1,MontanaSmith2,SherylBell2,KirstenHofmockel21IowaStateUniversity,UnitedStates2PacificNorthwestNationalLaboratory,DepartmentofEnergy,UnitedStatesUnder future climate change scenarios, boreal peatlands can expect warmer, longer growingseasons and alterations to the already fluctuating water tables. With combined increases inatmospheric CO2 concentrations and temperature, we can further expect increased sphagnumgrowth in these peatlands, and thus, the potential for increased, labile root exudates during thegrowingseason.Increasedavailabilityoflabilerootexudatesmayfurtherstimulateanincreaseinmicrobialbiomassand,indirectly,microbialcellturnover,whichprovidesbio‐availablecarbon(C)and nitrogen (N) compounds for microbial degradation and assimilation. Using experimentalmicrocosms, we explored how the interaction between belowground labile carbon compoundinputsandalteredclimateimpactpeatlandCcycling.Therewasasignificant interactionbetweenmoistureandtemperature,withthegreatestcumulativeCmineralizedathightemperaturebutlowmoisture. However, the magnitude of the response to climate varied by substrate addition. Forexample, glycine‐amended communities had the greatest cumulative carbon mineralized at lowtemperatures,butthelowestathightemperatures.Glycinetreatmentsalsosustainedhighlevelsofrespirationacrossthedurationofthestudyresultinginthemostnarrowdifferencesincumulativemineralization among climate treatments, and thus, appear least sensitive to temperatureincreases.Collectively,ourresultsindicatethatmoisturealone,throughpotentialfuturealterationsin thewater table,doesnotalterdecomposition.An interactionbetween increased temperaturesandmoisture fluctuationsmay cause future increases in decomposition, and thus, increased CO2respiration frompeatlandecosystems,but thismaybe temperedbybelowground carbon inputs.

TheeffectofCdecompositionenvironmentonplantdetritusCinsoilorganicmatter

*AnnaCates,TheaWhitman,RandallJacksonUniversityofWisconsin‐Madison,UnitedStatesWhile it is established that increasing temperature and moisture increases the rate of soil Cmineralization, we do not know whether these factors alter the chemical quality or physicalprotectionoftheremainingsoilC.Byincubating13C‐depletedplantbiomassandsoilundervaryingtemperatureandmoisture,wearetrackingthefateoftheplant13Cinsoilpools,aswellasmicrobialactivityoverthecourseofdecomposition.Atdestructivesamplingearly, intermediate,andlateindecomposition,wearefractionatingsoilsintosize‐basedaggregates,estimatingmicrobialbiomassCandefficiency,assayingextracellularenzymeactivity(EEA),andexaminingmicrobialcommunitycompositionvia16ssequencing.When25%ofbiomasswasdecomposed,weobservedthreetimestheCO2effluxrateandtwicethesumofEEAat30°Cthan22°C.CO2effluxrateisgreaterat65%water‐filledporespace(WFPS)than45%WFPSat30°C,buttheoppositeistrueat22°C.Microbialbiomass and C use efficiency were over 80% higher at 22 °C and 45% WFPS than all othertreatments. Preliminary data suggests more macroaggregates were formed at 22°C, butmicroaggregateswerenotaffected.CurrenttheoreticalandcomputationalmodelsassumethatifCismineralizedrapidly,totalsoilCstockswilldeclineovertime.However,ifphysicalprotectionofCremainingisalteredbytemperatureandmoistureduringdecomposition,meanresidencetimesofsoilCpoolsshouldbeadjustedaccordinglytobetterpredicthowchangingenvironmental factorsaffectthelong‐termstabilizationofsoilC.

OrganicNcyclinginagroecosystems*KirstenHofmockel1,AlisonKing21PacificNorthwestNationalLaboratory,DepartmentofEnergy,UnitedStates2IowaStateUniversity,UnitedStatesDiversifying cropping systems often entails altering othermanagement practices, such as tillageregime or nitrogen (N) source that together can influence plant‐microbe‐soil interactions. Wehypothesized that compared to conventional systems, the integrated effects of crop rotation, Nsource,andtillageindiversifiedcroppingsystemswillpromotemicrobially‐mediatedsoilCandNcyclingwhileattenuatinginorganicNpools.Totestthishypothesis,westudiedacroppingsystemstrialinits10thyearinIowa,USA,whichtesteda2‐yrcroppingsystemofcorn/soybeanmanagedwithconventionalfertilizerNinputsandconservationtillage,to3‐yrand4‐yrdiversifiedcroppingsystemsmanaged with compostedmanure, reduced N fertilizer inputs, and periodic moldboardploughing. We assayed soil microbial biomass, soil extractable NH4 and NO3, gross proteolyticactivity, and potential enzyme activity of six hydrolytic enzymes eight times during the growingseason.Atthe0–20cmdepth,nativeproteaseactivityinthe4‐yrcroppingsystemwasgreaterthaninthe2‐yrcroppingsystembya factorof7.9,whereasdissolved inorganicNpoolsdidnotdifferbetween cropping systems (P = 0.292). At the 0–20 cm depth,MBC andMBN the 4‐yr croppingsystemexceededthoseinthe2‐yrcroppingsystembyfactorsof1.51and1.57.Ourfindingssuggestthat diversified crop cropping systems, even when periodically moldboard ploughed, supporthigherlevelsofmicrobialbiomass,whichcoincideswithgreaterproductionofbioavailableNfromSOM, and a deeper microbially active layer than conventional corn/soy systems that comprisemuchoftheMidwesternUSlandscape.