Soil, It’s Alive!

Adam Hayes, Soil Management Specialist Jake Munroe, Soil Fertility Specialist

OMAFRA

Eastern Ontario Crop Conference February 18, 2016

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Outline

• Types of soil life • Abundance of soil life • Functions of soil life • Measuring soil life • Soil management • Principles of soil health

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Soil organisms

Soil life represents <0.5% of total soil volume

However, it drives the functions we ask of our soils

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Types of Soil Life

• Microflora – Bacteria, fungi, algae

• Microfauna – Protozoa, nematodes

• Mesofauna – Mites, springtails, etc.

• Macrofauna – Earthworms, beetles, etc.

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Macrofauna

Microfauna

Microflora

Mesofauna

The Really, Really Little Guys Microflora

• Microscopic • Includes bacteria, fungi, green algae • Gain energy from wide variety of material

– Residue/simple sugars, plants, chemical compounds

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The Really Little Guys Microfauna

• Less than 0.2 millimetre body width • Mainly nematodes and protozoa • Live in water-filled pore spaces

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The Little Guys Mesofauna

• 0.2-2 millimetre body width • Includes mites, springtails, and others • Live in air-filled pores and residue

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The Big Guys Macrofauna

• Greater than 2 millimetre body width • Includes earthworms, beetles, and termites • Able to dig through soil

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What About Numbers?

Type Abundance

Bacteria 100 million - 1 billion / teaspoon

Fungi 1,000 - 15,000 lbs/acre

Protozoa 1,000 – 1,000,000 / teaspoon

Springtails 40,000 / square meter

Earthworms 150,000 / acre or up to 1,000 lbs/acre

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What About Numbers?

Type Abundance

Bacteria 100 million - 1 billion / teaspoon

Fungi 1,000 - 15,000 lbs/acre

Protozoa 1,000 – 1,000,000 / teaspoon

Springtails 40,000 / square meter

Earthworms 150,000 / acre or up to 1,000 lbs/acre

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What About Numbers?

Type Abundance

Bacteria 100 million - 1 billion / teaspoon

Fungi 1,000 - 15,000 lbs/acre

Protozoa 1,000 – 1,000,000 / teaspoon

Springtails 40,000 / square meter

Earthworms 150,000 / acre or up to 1,000 lbs/acre

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What About Numbers?

There are more microorganisms in a single teaspoon of healthy soil than

there are people on earth.

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What About Numbers?

In just the top 6 inches, all the organisms in an average soil weigh somewhere between

2,500 and 5,000 lbs/acre

No wonder some experts refer to soil life as an “underground herd”

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Topsoil represents area of greatest abundance and

diversity of soil life

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And Diversity?

Soil is one of the most diverse ecosystem on the planet.

• 1 gram of soil: thousands of species of bacteria • Up to 3,000 species of fungi exist in soil • Multiple species of earthworms in every acre

Diversity redundancy resilience

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Functions of Soil

22 Slide courtesy of Odette Menard

Functions of Soil Life

• Soil organisms perform many key functions of healthy soil, including: 1) Nutrient cycling 2) Maintaining soil structure 3) Symbiotic nutrient exchange 4) Disease suppression

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Nutrient Cycling

• Transformation from organic to inorganic forms

• Larger organisms tear up residue, smaller organisms decompose it

• Protozoa and nematodes: – Mineralize N – excrete

hundreds of lbs of NH4

+/acre/day

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bacteria

protozoa

Nutrient Cycling

• Actinomycetes – Give soil earthy smell – Important for hard-to-

decompose materials

• Earthworms – Night-crawlers pull

surface litter into permanent burrow

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Nutrient Cycling

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Soil Structure

• Glomalin is a waxy coating created by mycorrhizal fungi

• It helps aggregates form (acts like chewing gum) and protects them

• Very tough – good protector of

soil aggregates

• Lots in the soil! – 6,000-15,000 lbs/acre in top 6 inches

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CT, SW-F NT, SW-WW-SF Moderately-grazed pasture

WSA = 14% Total glomalin = 2.4 mg/g

WSA = 47% Total glomalin = 3.2 mg/g

WSA = 93% Total glomalin = 7.9 mg/g

Soil Structure

Adapted from: “The Role of Soil Biology in Improving Soil Quality”, Dr. Kristine Nichols

Dry

Wet

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Symbiotic Nutrient Exchange

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Disease Suppression

• In a healthy soil, populations of organisms are balanced

• Disease reduced by competition with pathogens, release of toxic compounds, and predator-prey relationships

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Measuring Soil Life

• Researchers – DNA – Nematode populations – Decomposition rate – Particulate organic matter – Microbial respiration rate – Bait lamina

• Commercial labs – Solvita – Organic matter, nematodes,

other

Field Measurements

• Cornell Soil Health Assessment – Organic matter – Active carbon – Soil Respiration – Soil Protein – Potentially mineralizable nitrogen (PMN)

• Haney – Total N, inorganic N, phosphate, Solvita C02-C, water

extractable organic C, water extractable organic N

Ontario Research

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• Over the long-term, no-till and more complex rotations resulted in higher soil health scores

• Three factors showed the greatest differences between tillage systems and crop rotations: 1) Aggregate stability 2) Percent soil organic matter 3) Potentially mineralizable nitrogen

Trapping Beetles

• Beneficial insect • Feed on slugs • Measure by trapping

Ground Beetles

Management Impacts on Soil Life

• Slugs can take up seed treatment which can have a negative impact when ground beetles feed on them

• Slugs will feed on weeds or rye before corn or soybeans

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Counting Earthworm Middens

Want to see 10 to 15 middens per square metre

Dig up a shovelful of soil

Soil Life

01020304050607080

Earthworms/m2

ConvChiselNo-till

Organic Matter Level %

Biological Activity

% 1 60

2 70

3 85

4 100

Complex Crop Rotations Improve Soil Life

• In general, more diverse rotations result in more diverse soil life

• A greater proportion of time with live roots in the soil means enhanced soil life and activity: – Corn-soybean rotation: 38% (~9/24 months with

live roots) – Corn-soybean-wheat: 53% (~19/36 months) – Corn-soybean-wheat (red clover): 61% (~22/36

months)

Potentially Mineralizable Nitrogen

40

0

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Corn-Soy Corn-Soy-Wheat

PMN

(mg/

kg/d

ay)

0-15 cm soil depth, after 14 years on clay loam soil (Ridgetown)

Cover Crops Improve Soil Life

The Cotton Test

• Bury men's cotton briefs for 60 days (wash new ones first)

• Leave the waistband showing so they can be easily found

• Dig up to see how much has been eaten

Can You Determine the Rotation & Tillage?

Tillage • Conv. till • No-till

Rotation • Cont. corn (C) • Cont. soys (S) • Corn-soys • Soys-Wheat (W) • C-S-W (RC)

Can You Determine the Rotation & Tillage?

Tillage • Conv. till • No-till

Rotation • Cont. corn (C) • Cont. soys (S) • Corn-soys • Soys-Wheat (W) • C-S-W (RC)

Can You Determine the Rotation & Tillage?

A B C D Middens/m2 0 50 1 35 # of Worms/m2 41 317 55 161 Wt. in grams 8.6 77.9 13.6 40 % Mature 24.4 21.6 24.8 16.9 Solvita 2.6 3.4 2.9 3.0 PMN 17 53 38 31 Organic matter 47 64 77 56 Aggregate Stability

15 58 36 33

Soybean Yield 56 67 66.5 63

1. Cont. Corn, 2. Cont. Soys, 3. C-S, 4. S-Wheat, 5. C-S-W (R.Clover) 1. Conventional tillage, 2. No-till

Can You Determine the Rotation & Tillage?

Cont. Soys CT

C-S-W(RC ) NT

S-W CT C-S NT

Middens/m2 0 50 1 35 # of Worms/m2 41 317 55 161 Wt. in grams 8.6 77.9 13.6 40 % Mature 24.4 21.6 24.8 16.9 Solvita 2.6 3.4 2.9 3.0 PMN 17 53 38 31 Organic matter 47 64 77 56 Aggregate Stability

15 58 36 33

Soybean Yield 56 67 66.5 63

Putting It All Together

• Manage with the “underground herd” in mind • Diverse crop rotation + organic amendments =

diverse foods • Continuous cover = consistent food source • Stable aggregates = habitat

Soil life drives soil function. Put your soil life to work to increase productivity and resilience of your soils.

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Questions?

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