Soil Health Assessment and Agronomy-Driven Improvement Dennis 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 Photo: Lynn Betts, NRCS and resilience The productivity of agricultural systems is maintained or increased with technology, diesel, nutrients, pesticides, water, …
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., CO 2 , CH 4 , N 2 0) • 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
Carbon and soil organic matter CO 2 Organic C inputs Plants Of the organic carbon entering the soil: • 2-5% active Active ( days – years) • 3-10% slow • 10-30% passive Slow • The rest becomes ( decades) CO 2 Passive ( 100s – 1000s years)
Outline • Text
Summary Weil & Brady, The Nature and Properties of Soils, 15 th 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 SURFACE SUB-SURFACE Compaction Soil Cover Residue Breakdown Aggregate Stability Biological Activity Surface Crusting
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 Soil Cover Residue Breakdown Biological shredding, fragmenting, cycling or incorporating of previous crop residue. Rating Criteria Acceptable Unacceptable Large residue pieces Residue pieces are after planting; can small, mixed in be handled without surface or minimal crumbling; or crop residue residue from 2 or remaining from >1 more cropping cropping seasons 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 Today May 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 P 2 O 5 , 30 lbs less K 2 O, 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! Dir Direct comments an and questions to: o: den ennis is.chessman@ky.usd sda.gov 202 202-527 527-4000 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 Re-emergence of f Cover Crops
Cover crops influence on N availability and fate within common corn N management systems N Release N Uptake N Conservation Inorganic N sources that cover Cover crop residue N crops interact with: release depends on: • • Physiology Soil inorganic N from OM • Residual N • Species: Legume, • Applied N, if a portion of N is grass, cereal applied in the Fall (DAP or Manure) • C:N ratio Corn and Soybean N and Yield
Effect of f Cover Crops and Nit itrogen Application Tim iming on Nit itrogen Lo Loading Th Through Subsurface Drainage Shalamar Armstrong 1 , Catherine O’Reilly 2 , Richard Roth 3 , Mike Ruffatti 3 ,Travis Deppe 3 and Corey Lacey 4 1 Assistant Professor, Purdue University Department of Agronomy, 2 Associate Profess of Hydrogeology Department of Geography-Geology, Illinois State University 3 M.S. Candidate In Agriculture Sciences , Illinois State University Department of Agriculture, 4 Graduate Research Assistant, Purdue University Department of Agronomy
Nutrient Loss Reduction Strategies Evaluated 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
Treatments 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 *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
Research Design Field History • 10 years Strip-till before Corn and No-till before Soybeans • Current Nitrogen Management : 60 % Fall N and 40% Spring N A Tile Monitoring Station Rep. 1 Rep. 2 Rep. 3 15 Individually Tiled Fields: 1.6 Acres 72 rows
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