Soil Health &

Sustainable Agriculture

Eric BoettgerResource Conservationist

NRCS – Rhode Island

Sustainable Agriculture

The goal of sustainable agriculture is to meet society’s food and textile needs in the present without compromising the ability of future generations to meet their own needs.

Soil Health: How does soil health fit into sustainable

agriculture?

The continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals, and humans

Soil Function to Support Agriculture

• Nutrient cycling

• Water (infiltration & availability)

• Filtering and Buffering

• Physical Stability and Support

• Habitat for BiodiversitySoil Health Management Systems need to contain practices and activities that address ALL of these soil functions

Helping People Help the Land

Properties of Soil Health:

Dynamic Properties:Management dependant properties that we do have the ability to change relatively easily

• Organic matter content• Biological activity• Aggregate stability• Infiltration• Soil fertility• Soil reaction (pH)

Inherent Properties:Physical properties that usually cannot be changed without much difficulty

• Soil texture • Type of clay• Depth to bedrock• Drainage class

Poll Question 1

Providing habitat for soil micro-organisms is one of the primary functions of agricultural soils?

TRUE

FALSE

Poll Question 1

Providing habitat for soil micro-organisms is one of the primary functions of agricultural soils.

TRUEOther functions include:

• Nutrient cycling• Water (infiltration & availability)• Filtering and Buffering• Physical Stability and Support

Soil Health Planning Principles

• Manage more by Disturbing Soil Less

• Use Plant Diversity to Increase Diversity in the Soil

• Grow Living Roots Throughout the year

• Keep the Soil Covered as Much as Possible

Manage More by Disturbing the Soil Less

• Agricultural Disturbance reduces– Soil Organic Matter

– Reduces Habitat for Soil Organisms

• Types of Disturbance

–Physical (tillage)

–Chemical (over application)

–Biological (over grazing)

Manage More by Disturbing the Soil Less

Loss of SOM as CO2

Physical Disturbance

Forest SOM = 4.3 %

CT 17 yr- Soybean monoculture SOM = 1.6 %

20

cm

laye

rSame Soils: Dynamic Soil Properties

Changed!

62.8% loss of SOM after

17 yr intensive

tillage

1. Disturbance stimulates weed 2. Increases weed population 3. Diminishes Fungal biomass and spores4. Reduces infiltration5. Increases soil temperature

6. Diminishes the habitat of the soil microbes

7. Increases the necessity for synthetic inputs

Biological Disturbance Impacts of Overgrazing

Chemical disturbances: Over-Applicationof pesticides, fertilizers and manures

Cover Crop

No Till

Practices that address soil disturbance

• Cover Crop• No Till • Nutrient Management• Pest Management• Prescribed Grazing

Four R’s of Nutrient Management

Right Source

Right Rate

Right Place

Right Time

Proper Nutrient Management

Poll Question 2

Soils can be disturbed by physical, chemical or biological activities?

TRUE

FALSE

Poll Question 2Soils can be disturbed by :Physical - tillageChemical – Over applyingBiological activities – Over grazing

TRUE

Increasing Diversity in a Crop Rotation

• Growing more plants in the same rotation period

– Increase soil organic matter

– Breaks pest cycles

– Improves nutrient availability

Use Plant Diversity to IncreaseDiversity in the Soil Microbes

• Plants interact with microbes– Trade sugar, carbohydrates & proteins from roots for

nutrients (Exudates)– Each plant has a unique “exudate” that attract a

specific group of soil microbes– Microbes convert plant material to OM

• Soil requires a diversity of plant carbohydrates to support the variety of microbes

• Lack of plant diversity will drive system to favor some microbes more than others– Disturb soils are dominated by bacteria– Created the habitat for them to flourish

Biodiversity Key to Success

• Lack of biodiversity severely limits any cropping system

• A diverse and fully functioning system provides nutrients, energy and water

• Diversity above ground equals diversity below ground

Practices that address Diversity

Conservation Crop Rotation

Cover Crop

Buffer Practices to Improve Diversity

Contour Buffer Strip

Cross Wind Trap Strips

Riparian Herbaceous Buffer

Field BorderFilter Strip

Hedgerow

Field Border

Poll Question 3

Diversity in the plant community above ground leads to diversity in the soil microbes below ground?

TRUE

FALSE

Poll Question 3

Diversity in the plant community above ground leads to diversity in the soil microbes below ground.

TRUE

Grow Living RootsThroughout the Year

• Increases microbial activity influences the N mineralization and immobilization

• Increases plant nutrient/vitamin uptake/ associations with mychorrhizal and bacteria

• Increases biodiversity and biomass of soil organisms

• Improves physical, chemical and biological properties of soils

• Sequesters and redeposit nutrients

• Increases OM, Increases OM, Increases OM !!!

Soil Organic Matter &Available Water Capacity

1 inch of Soil Organic Matter has the capacity to hold

29,000 gallons of water per acre

Grow Living RootsThroughout the Year

• 1.0% OM = – 10,000 lbs Carbon– 1,000 lbs Nitrogen– 100 lbs Phosphorous– 100 lbs of Sulfur.

• Mineralization Rate = 2-3% from Organic N to Inorganic N.

• Resulting in 20 to 30 lbs of useable N per acre.

Soil Organic Matter Nutrient Bank Account.

How to Keep a Living Root All Year Long?

• Keep soil covered

• Interseed into Growing Crops

– Planting cover crop before harvesting of cash crop

Poll Question 4

There is no advantage to getting a cover crop seeded four weeks earlier in the fall?

TRUE

FALSE

Poll Question 4

A cover crop seeded four weeks earlier in the fall will provide cover, roots and diversity!

FALSE

Keep it Covered as Much as Possible

• Control Erosion

• Protect Soil Aggregates

• Suppresses Weeds

• Conserves Moisture

• Cools the Soil

• Provides Habitat for Soil Organisms

Soil Temperatures

Soil temp w/Cover Crop Soil temp w/ Bare Soil

When soil temperature reaches

J.J. McEntire, WUC, USDA SCS, Kernville TX, 3-58 4-R-12198. 1956

140 F Soil bacteria die

130 F 100% moisture is lost throughevaporation and transpiration

113 FSome bacteria species startdying

100 F 15% moisture is used for growth85% moisture lost through

95 F evaporation and transpiration

70 F 100% moisture is used for growth

Practices that address Keep it Covered

Conservation Crop Rotation

Cover Crop

Mulching

Poll Question 5

Some bacteria can start to die when soil temperatures exceed 100 degrees?

TRUE

FALSE

Poll Question 5

Some bacteria can start to die when soil temperatures exceed 100 degrees?

TRUE

Soil Health Planning Principles

• Manage more by Disturbing Soil Less

• Diversify with Crop Diversity

• Grow Living Roots Throughout the year

• Keep the Soil Covered as Much as Possible

Soil Health Technology

Wouldn’t it be great if we had a test for Soil Health?

Soil Health Technology

Cornell Soil Health Testing Services

More information and up-to-date soil health testing at:

http://soilhealth.cals.cornell.edu/

• Sample submission

• Manual • Blog • New manual

in progress

Cornell Soil Health Team soilhealth.cals.cornell.edu

Soil Health Technology

Physical Indicators

• Available Water Capacity

• Surface Hardness and Subsurface Hardness

• Aggregate Stability

Soil Health Technology

Biological Indicators

• Organic Matter Content

• Protein Content

• Root Pathogen Pressure

• Respiration

• Active Carbon

Soil Health Technology

Chemical Indicators

• Standard soil fertility test

• pH

• P - phosphorus

• K - potassium

• Minor elements • Deficiency or

toxicity

Soil Health Technology

Cornell Soil Health Testhttp://soilhealth.cals.cornell.edu/extension/test.htm

Interpret results and work with farmers to implement practiceshttp://soilhealth.cals.cornell.edu/extension/manual.htm

Managing Cover Crops Profitably - SAREhttp://www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition/Text-Version

Crop Rotations - SAREhttp://www.sare.org/content/download/60067/808447/Crop_Rotations.pdf

Soil Health