Soil Health Assessment and Agronomy-Driven

ImprovementDennis Chessman

USDA – Natural Resources Conservation Service,

Soil Health Division

June 27, 2018

The diverse underground world

Drawing Credit: SESL, Australia

Healthy soils have diversity and abundance of life

Medicinal Breakthroughs

Fights disease and pests

In general, soils converted to crop production demonstrate:

• decreased water infiltration & storage

• less biological activity• lower biological diversity• less efficient nutrient

cycling• less C sequestered• higher summer

temperatures• less contribution to plant

vigor• lower stress resistance

and resilience

The productivity of agricultural systems is maintained or increased with technology, diesel, nutrients, pesticides, water, …

Photo: Lynn Betts, NRCS

Benefits we would like to derive from soils• Produce food, feed, fiber, biofuel feedstocks, and

medicinal products• Capture, filter, and store water• Cycle and recycle nutrients• Resistance and resilience to drought, temperature

extremes, fire & floods• Protect plants from pathogens and stress• Detoxify pollutants• Store C and moderate release of gases (e.g., CO2, CH4,

N20)• Stable – resist the erosive forces of wind and water

Soil biology is foundational to productive, sustainable cropping systems• Biology drives production and ecosystem service

benefits

• Soil organic carbon supports biology (both food and habitat)

• Crop, management and location determine SOC levels

CO2

Plants Organic C inputs

Active (days – years)

Slow(decades)

Passive (100s – 1000s years)

Carbon and soil organic matter

Of the organic carbon entering the soil:• 2-5% active• 3-10% slow• 10-30% passive• The rest becomes

CO2

Outline

• Text

Summary

Weil & Brady, The Nature and Properties of Soils, 15th edition

What is an in-field soil health assessment?• An evaluation (typically qualitative) of selected soil

and/or plant characteristics (indicators) whereby relative soil function is inferred

Approaches to in-field SH assessment

Considerations for in-field soil health assessments• Useful – provides valuable, accurate, meaningful information

• Usable – easily employed and interpreted by advisors and farmers

• Works for your system(s)

• Minimizes subjective effects

• Quick

• No meters, chemicals, paper strips, etc. (essentially physical and biological)

• Human sensory-driven

• Representative but reasonable sampling

• Encourages a conversation between the advisor and the grower

• Provides invaluable information for implementing soil test recommendations

Helpful steps in soil health assessment

• Soil maps• Info on inherent soil

properties • Potential productivity• Some soil health

information

• Producer conversation• Current concerns• Field & management

history and observations

• Field visit• In-field soil health

assessment

Potential conversation questions • What are the short- and long-term system management goals and

objectives?

• Are cover crops grown during typical fallow periods or between perennial crop rows?

• If yes, for how many years has the field been continually cover cropped?

• How are the cover crops planted and terminated?

• What are types and frequency of ground disturbing operations?

• What is the crop rotation?

• What is the typical nutrient management program? What about other amendments such as lime or gypsum?

• Are organic amendments such as manures or compost used? If so, how frequently and what amount?

• Is soil water management a concern (i.e. field too wet or too dry at planting)?

• Does water pond or run off during or immediately after rainfall events?

In-field indicators to assess soil function

Soil Cover Compaction

Surface Crusting Biological Activity

Residue Breakdown Aggregate Stability

SURFACE SUB-SURFACE

Other indicators that may be useful• Water infiltration rate

• Respiration

• Roots & pores

• pH

• EC

• Soil smell

• Soil color

• Soil temperature

• Salt accumulation

Soil health field assessment –signs at the surface

Residue BreakdownSoil Cover

Biological shredding, fragmenting, cycling or incorporating of previous crop residue.

Rating Criteria

Acceptable Unacceptable

Residue pieces are small, mixed in

surface or minimal crop residue

remaining from >1 cropping seasons

Large residue pieces after planting; can

be handled without crumbling; or

residue from 2 or more cropping

seasons

An example of an assessment field sheet

Managing agricultural lands to improve soil health – copying a page from natural systems

• Minimize disturbance

• Keep the soil covered

• Increase system biodiversity

• Maintain roots in the soil

Challenges to changing management

• Costs associated with changing the system –equipment, seed, time, etc.

• Peer pressure

• The unknown

• Pest population changes

• Covers use water

• Management and operations become more complicated – learning curve

• Rented land

• Markets and buyer expectations

• Transition time to new “normal”

What is the cost of status quo?

Front page, USA TodayMay 22, 2018

Benefits from changing management: a farmer example

Rulon Enterprises, 6300 acres, corn and soybean, Arcadia, IN

• Can increase SOM 0.1%/yr, thereby increasing corn yield goal by 2.7 bu/ac

• Using 20 lbs less P2O5, 30 lbs less K2O, 35 lbs less N than conventional practices

• In 2017, planted 5200 acres to covers at a total cost of $22.70/ac, net return of $57.76/ac, 254% ROI

• Short-term benefits of almost $42/acre

• Drought of 2012-13, county average corn ↓ 60 bu/ac, Rulons ↓ 10 bu (long-term benefit)

• Essentially eliminated soil erosion (long-term benefit)

The Furrow, Summer 2018, Cash in on covers

THANK YOU!

Direct comments and questions to: dennis.chessman@ky.usda.gov202-527-4000

This information is provided as a public service and constitutes no endorsement by the United States Department of Agriculture or the Natural Resources Conservation Service of any service, supply, or equipment listed.

Cover Crops and Nitrogen Management Impact on

Water Quality

Shalamar Armstrong

Soil Conservation and Management

Assistant Professor of Agronomy

Purdue University Department of Agronomy

National News: The Gulf of Mexico's Dead Zone Is The Biggest Ever Seen

• Text

This week, NOAA announced that this year's dead zone is the biggest one ever measured. It covers 8,776 square miles — an area the size of New Jersey. And it's adding fuel to a debate over whether state and federal governments are doing enough to cut pollution that comes from farms.

Farmers use those nutrients on fields as fertilizer. Rain washes them into nearby streams and rivers. And when they reach the Gulf of Mexico, those nutrients unleash blooms of algae, which then die and decompose. That is what uses up the oxygen in a thick layer of water at the bottom of the Gulf, in a band that follows the coastline.

Scavia, however, recently published a blog post calling these voluntary measures inadequate.

Re-emergence of Cover Crops

Cover crops influence on N availability and fate within common corn N management

systems

N Conservation

• Soil inorganic N from OM

• Residual N

• Applied N, if a portion of N is applied in the Fall (DAP or Manure)

N Release

• Physiology

• Species: Legume, grass, cereal

• C:N ratio

Inorganic N sources that cover crops interact with:

Cover crop residue N release depends on:

N Uptake

Corn and Soybean N and Yield

Effect of Cover Crops and Nitrogen Application Timing on Nitrogen Loading Through Subsurface Drainage

Shalamar Armstrong1, Catherine O’Reilly2, Richard Roth3, Mike Ruffatti3,Travis Deppe3and Corey Lacey4

1 Assistant Professor, Purdue University Department of Agronomy, 2Associate Profess of Hydrogeology Department of Geography-Geology, Illinois State University

3M.S. Candidate In Agriculture Sciences , Illinois State University Department of Agriculture, 4Graduate Research Assistant, Purdue University Department of Agronomy

1. Change N application timing from fall to spring

2. Change N application timing from fall to spring + cover crop

3. Addition of cover crops to fall applied N----Strip-till application of N into a living cover crop

Nutrient Loss Reduction Strategies Evaluated

Treatments

*Fall Anhydrous Ammonia was strip tilled into a living stand of Cereal Rye and Radish Mix

Total N rate for all plots: 224 kg ha-1

1. Control-No Fertilizer and No Cover crop

2. Spring Split Application of Nitrogen (20% Fall -DAP and 80% Anhydrous Ammonium)

3. Spring Split Application of Nitrogen (20% Fall-DAP and 80% Anhydrous Ammonium) + Cover Crops

4. Fall Split Application of Nitrogen (70% Fall-DAP and Anhydrous Ammonium and 30% sidedress- Anhydrous Ammonium)

5. Fall Split Application of Nitrogen (70% Fall-DAP and Anhydrous Ammonium and 30% sidedress- Anhydrous Ammonium) + Cover Crops

Research Design

ARep. 1 Rep. 2 Rep. 3

Field History

• 10 years Strip-till before Corn and No-till before Soybeans

• Current Nitrogen Management : 60 % Fall N and 40% Spring N

15 Individually Tiled Fields: 1.6 Acres 72 rows

Tile Monitoring Station

Methodology – Cover Crop Planting

Cover Crop Mixture Daikon Radish (8%) Cereal Rye (92%)

Seeding Rate: 84 kg ha-1 (74 lb/ A)

Planting Date: Early to mid- Sept.

Cover Crop N Uptake

Fertilizer application timing did not significantly effect cover crop N uptake.

Average shoot N uptake was 66 kg ha-1

(59 lb/A)

On average the cover crop interacted with 30% of the N fertilizer applied.

*

*

Can Cover Crops Reduce N Loading in all N Management Systems?

Reduction in N loading

Cover Crops + Corn

Change N application from fall to spring

Change N application timing from fall to spring + CC

Fall N vs. Spring N + CC

Leave N application in the fall + CC

Fall N +CC vs. Spring N + CC

Cover Crop Impact on Water Quality

PrecipitationTotal = 63 inchesAnnual Average = 25 inchers

N Loading Treatment ComparisonFall N 52 kg ha-1 year-1 (46 lb/A)Fall N + CC 30 kg ha-1 year-1 (27 lb/A) 42%Spring N 60 kg ha-1 year-1 (53 lb/A)Spring N + CC 30 kg ha-1 year-1 (27 lb/A) 50%

N Loading TreandsFall N vs. Spring N = EqualFall N vs. Spring N + CC = 42% Spring N vs. Fall N + CC = 50% Spring N + CC vs. Fall N + CC = Equal

2:1 ratio between cover crop

biomass N and N prevented from leaving the tile.

Potential Cover Crop N Cycling(2:1 Ratio)

Cover Crops interacts with inorganic N within the soil solution that is less susceptible to loss via tile drainage.

Cover Crops interacts with inorganic N within the lower portions of the soil profile that is more susceptible to loss via tile drainage.

Environmental Economic Implications of the Study

Erosion Rdeuction…

Nitrogen Load Reduction

31%Cover Crop Biomass

Mineralizationand N Cycling

60%

Conservation Scenario Range of Cover Crop Adoption Cost

Recovery from Environmental BenefitsCash crop yield differences considered 26-86%

Assuming cash crop yield is equal 66-102%

Roth et. al., 2018 A cost analysis approach to valuing cover crop environmental

and nitrogen cycling benefits: A central Illinois on farm case study, Agricultural Systems.

Cover Crop Performance on a Watershed Scale: Potential Impacts on Water Quality

Shalamar Armstrong1 , Catherine O’Reilly2 , Ben Bruening2, Corey Lacey4, Richard Roth4, Michael Ruffatti5, and Min Xu4

,

1Assistant Professor Agronomy, Agronomy Department, Purdue University,

2Associate Profess of Hydrogeology Department of Geography-Geology, Illinois State University,, 4Graduate Student,

Agronomy Department, Purdue University, and 5Support Agronomist, Department of Agriculture, Illinois State University

Plot scale analysis of Cover Crops• Controlled

experiment• Limited to no

farmer influence

Watershed scale analysis of Cover Crops• Reduced experimental

control• Heavy farmer influence

Objective

Determine the impact of watershed scale mass cover crop adoption on water N loading.

Study Site:

• Lake Bloomington Watershed, Towanda, IL

• Land use: 93% row crop agriculture, >90% tile drained

• Dominant soils: poorly drained silty clay loam and somewhat poorly drained silt loam that lies within a 0-2% slope

• Number of farmers involved Treatment = 6 farmers

Control = 4 farmers

Tile Water Sampling Locations

ControlNo-Cover Crop

262 ha

TreatmentCover Crop

465 ha

Lake Bloomington Watershed Towanda, IL

Cropping Systems and N Management Uncontrolled

33%

67%Soybean (311 ha)

Corn ( 154 ha)

47%53%

Fall N (165 ha)

Spring N (144 ha)

36%

64%

Corn ( 93 ha)

Soybean (169 ha)

100%Fall N (169 ha)

Treatment Watershed(Even Year Soybean Dominant)

Control Watershed(Even Year Soybean Dominant)

35% of watershed land area

65% of watershed land area

Cover Crop Selection Uncontrolled

Note: Farmers used their knowledge of cover crops to drive their cover crop selection.

Cereal Rye/Radish before soybean

Radish/Oats or Annual Rye/Radish before corn

Cover Crop Biomass and N Uptake(Fall 2015 and Spring 2016)

Above ground biomass was collected on 8 ha grids across the watershed and analyzed for %N.

26 lb/A

44 lb/A

Cover Crop Biomass and N Uptake(Fall 2016 and Spring 2017)

26 lb/A

22 lb/A

47 lb/A

Cereal Rye N uptake and Spring Soil IN Concentrations

P<0.0001

Spring 2016

Cover Crop Impacts on Water Quality

cover crop cover crop

SummaryPlot Scale

• On average, cover crops interacted with 30% of the N fertilizer applied.

• 2:1 ratio between cover crop shoot biomass N and N prevented from leaving the tile.

• Cover crops reduced N loading via tile drainage by 42-50%, despite N application timing

• Cover crop benefits of N cycling and N scavenging has the potential to off-set a large percentage of the cover crop adoption cost.

Watershed Scale

• Mass cover crop adoption on a watershed scale is possible.

• There was a signal of cover crop impacts on water quality.

Thank You!