Lori Hoagland

Associate Professor and Soil Microbial Ecologist

Department of Horticulture and Landscape Architecture

Purdue University

History in ag. Different types Factors affecting

efficacy Research trial Considerations

for use

Humus theory: need regular additions of organic matter to the soil to maintain fertility and crop yield

Focus shifted in the 1800’s - Carl Sprengel (1787-1859), Sir Humphrey Davy (1778-1829), and Justus von Liebig (1803-1873) refuted humus theory and shifted focus to individual chemical elements

Haber-Bosch process (early 1900’s) -inorganic nitrogen fertilizer

Aristotle (384-322 BCE)

Sir Albert Howard (1873 – 1947) “the father of organic farming”- learned about importance of organic

matter studying composting in India- “the health of the soil, plant, animal

and man is one and indivisible”

Rudolf Steiner (1861-1925)

Lord Northbourne (1896-1982)

Lady Eve Balfour (1898-1990)

Jerome Irving Rodale (1898-1971)

Masanobu Fukuoka (1913-2008)

(Brady and Weil, 2002)

Loss of soil organic matter over time

Substance containing living microorganisms which, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant (Vessey, 2003)

No legal definitions for the term ‘biofertiliser’ in US

Replace soil nutrients (i.e. by biological N2 fixation)

Make nutrients more available to plants (i.e. by solubilization of nutrients)

Increase plant access to nutrients (i.e. by increasing the volume of soil accessed by the root system)

(Vacheron et al., 2013)

Soil bacteria that fix atmostphere nitrogen once established inside plant roots or stems

Martinus Beijerinck58 million years ago

Discovered in 1888

Inoculants

Symbiotic association of the mycelium of a fungus, with roots of certain plants in which the hyphae form a closely woven mass around the rootlets or penetrate the cells of the root

Fungus root- >90% of all land plants- Wide host range and cosmopolitan

distribution worldwide 400 million years ago

Root-colonizing bacteria that form symbiotic relationships with many plants

Rhizobacteria with PGP-activity include strains belonging to genera Bacillus, Pseudomonas, Azospirillum, Azotobacter, Alcaligens, Arthobacter, Agrobacterium, Burkholderia, Comamonas, Pantoea, Rhizobium

(Farag et al., 2013)

Crop

EnvironmentMicrobial inoculum

CultivarGrowth stage

Climate conditionsSoil typeCultural practices

Microbial strain/sPropagule concentrationFormulation

• Azospirrilumbrasilience

• 20 historic and modern wheat varieties

• Field (2 locations) and greenhouse trials

• Treated & untreated controls

• Replicated and randomized trials

2006-2009

Initial results at field site A in year one were impressive -> (10-20% yield and protein gains)

Yield protein benefits varied by location

Benefits varied by yearUninoculatedInoculated

AverageRainfall

OrganicMatter

InorganicN

Location inches (%) (lbs/ac)A 9.8 2.37 18.6B 20.4 3.49 28.7

Benefits varied by wheat variety

In some cases, the inoculant had severe negative effects

UninoculatedInoculated(Hoagland et al., 2008)

02468

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Mads

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Xerph

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Masa

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Goldc

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Hood

Floren

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Hatto

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Baue

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Buch

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Finley

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Fultz

Thom

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Turke

y

Cultivar

Incr

ease

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ield

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**

* **

Chart2

Madsen

Xerpha

Eltan

Finch

Masami

Goldcoin

Alba

Hood

Florence

Alicel

Hatton

Bauermeister

Buchanan

Finley

WA7976

Fultz

Thome

GoldenCr

Delmar

Turkey

Cultivar

Increase in yield (bu/ac)

4.1646637947

2.4837200692

5.6243832417

6.4650532507

17.1419169719

6.0207030657

14.042345595

7.4965095533

2.1360155686

6.5780777871

5.3178723252

17.9019293723

3.3013145345

2.6650110679

16.4156337422

7.4609437867

7.2764309037

9.0407997335

14.340902716

4.9044148258

Sheet1

Varietydiff

Madsen4

Xerpha2

Eltan6

Finch6

Masami17

Goldcoin6

Alba14

Hood7

Florence2

Alicel7

Hatton5

Bauermeister18

Buchanan3

Finley3

WA797616

Fultz7

Thome7

GoldenCr9

Delmar14

Turkey5

Sheet1

Cultivar

Increase in yield (bu/ac)

Sheet2

Sheet3

Compared 10 commercially available AMF inoculants and lab grown AMF cultures on corn, sorghum, trident maple and sweetbay magnolia

Results:- most commercial inoculants failed to promote root

colonization- some inoculants increased plant growth, but more likelydue to non-mycorrhizal ingredients in the products (fertilizers, PGR’s)

My lab’s experience with commercial AMF inoculants

Null Synergism between arbuscular mycorrhizal fungi and nitrogen fixation bacteria

Mycoparassitism of arbuscular mycorrhizal fungi by the fungus Trichoderma harzianum(De Jaeger et al., 2010)

(Bonfante and Anca, 2009) Negative

Positive (Schütz et al., 2018)

Mycorrhiza “helper” bacteria

Potential opportunity to help supplement fertility needs, particularly in dry environments and soils with low organic matter and high total soil P (Schütz et al., 2018)

Potential opportunity in greenhouse and vegetable transplants

Purchase products from reputable companies with independent, replicated research trials

Purchase fresh inoculants and store them properly

Definitions Different types Potential

mechanisms of action

Research trials (tomato/pepper)

Considerations for use

First commercial seaweed extracts manufactured 60 years ago (Craigie et al., 2011)

Schematic representation of effect and mechanisms(s) of activity of seaweed extracts (Sangha et al., 2014)

“A material that, when applied to a plant, seed, soil or growing media - in conjunction with established fertilization plans, enhances the

plant's nutrient use efficiency, or provides other direct or indirect benefits to plant development or stress response.”

“Products derived from natural or biological sources..”

Definition in the European Union

Definition in the United States

Do not contain nutrients

Organic plant biostimulants- Humic substances

- Protein hydrolysates

- Seaweed and other plant extracts

Inorganic plant biostimulants- Silicon

A mixture of complex organic compounds having yellow to black color formed by transformations (humification) of organic residues of plants and animals by soil microorganisms

Humins: not soluble in water at any pH valueHumic acids: not soluble in water under acidic conditions (pH < 2)Fulvic acids: soluble in water under all pH conditions

A mixture of organic/inorganic compounds from seaweed biomass using different manufacturing systems such as alkaline or acid hydrolysis or cellular disruption under pressure or fermentation

Ascophyllum nodosum

Fucus sp.

Laminaria digitata

Ecklonia maxima

CarbohydratesMineralsPhenolicsAmino acidsVitaminsPhytohormones

Leather wastes

Fish wastes

Feather wastes

Plant biomass

Carbohydrates

Minerals

Phenolics

Mixtures of polypeptides, oligopeptides and amino acids that are manufactured from protein sources using partial chemical and/or enzymatic hydrolysis

• Increase germination

• Improve nutrient uptake

• Improve nutrient-use efficiency

• Increase tolerance to and recovery from abiotic stresses (salt, water, heat, heavy metals)

(Brown and Saa, 2015 FIPS)

Plant stresses• Cold• Waterlogging• Drought• Salt• Heavy metals• Heat• Pathogens• Insect pests

Nutrients, Water Sunlight

Yield and quality

Agricultural biologicals

Genetically determine biomass partitioning

Yield lossNutrients, Water Sunlight Yield and quality

Yield loss due to stress

Yield lossNutrients, Water

Sunlight Yield and quality

Yield loss due to stress

• Trichoderma species -> two product formulations and untreated control

• Two tomato varieties

• Field trial

• Replicated and randomized trials

2011

Increased tomato transplant size in the greenhouse

Increased transplant survival and RS+WP1 increased biomass

* * *

* indicates significant difference from the control

• Trichoderma virensand protein hydrolysate, alone and in combination

• Untreated control

• Infected soil

• Greenhouse trial

• Replicated and randomized trials

2017

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

control Seed Phdrencg Seet trt,

bb

Seed treatment

Seed trt.+ drenchPHdrenchControl

g r

oot

Pepper root biomass (P

Potential opportunity to help plants acquire nutrients in low-quality ordegraded soils Potential opportunity to help plants

tolerate abiotic and biotic stressPurchase products from reputable

companies with independent, replicated research trials

What are your experiences using biofertilizer and biostimulantproducts?

Questions?

Bonfante, P., Anca, I.A., 2009. Plants, mycorrhizal fungi, and bacteria: a network of interactions. Annual Reviews of Microbiology 63:363-83.

Craigie, J.S., 2010. Seaweed extract stimuli in plant science and agriculture. Journal of Applied Phycology 23(3): 371-393.

De Jaeger, N., Declerck, S., and de la Providencia I.E., 2010. Mycoparasitism of arbuscularmycorrhizal fungi: a pathway for the entry of saprotrophic fungi into roots. FEMS Microbial Ecology 73(2):312-22.

Hoagland, L., Murphy, K., Carpenter-Boggs, L., Jones, S., 2008. Improving nutrient uptake in wheat through cultivar specific interaction with Azospirillum. Second ScientificConference of the International Society for Organic Agricultural Research (ISOFAR), Modena, Italy. pp. 526-565

Schutz, L., Gatttinger, A., Meier, M., Muller, A., Bolter, T., Mader, P, Mathimaran, N., (2018). Improving crop yield and nutrient use efficiency via biofertilization – A global meta-analysis. Frontiers in Plant Science 2204

Vessey, 2003. Plant growth promoting rhizobacteria as fertilizers. Plant and Soil 255(2): 571-586.

Biofertilizers and biostimulantsBiofertilizersLong History in agricultureEfforts to recouple fertility and soil healthBiofertilzers todayMechanisms of action RhizobiaMycorrhizal fungirhizobacteriaFactors affecting biofertilizer efficacyN-fixing inoculant trials in wheatresultsResults & conclusionsPerformance of mycorrhizal products marketed for woody landscape plants (Wiseman et al., 2009)Microbial consortiumsConclusions and Important considerations for biofertilizersbiostimulantshistoryBiostimulants todayTypes of productsHumic substancesSeaweed extractsProtein hydrolysatesApplications & Mechanisms of actionSlide Number 25Managing transplant stress in tomatoesSlide Number 27Mitigating Phytophthora capsici stress in pepper ResultsConclusions and important considerations for biostimulantsquestionscitations