Agronomy Blog

Crop Residue Effects and Management

by Leonard Luebker | Oct 20, 2017

One can find many articles and research projects that address crop residue breakdown, effects of crop residue on soil fertility, and overall crop residue management.

In general, we have observed minimum and no till practices increasing substantially the past several years.  Not only have there been government rules and regulations to follow, but growers can see big “savings” by less fuel, time, and equipment used, when field passes are cut back.  Not only have growers seen the economic impact from those, but also the “soil-saving” value of reduced tillage.

With these changes, the value of crop residue has gained a lot of attention from researchers and university personnel. Crop residue is material left in the field from the previous crop or two.  This would include the following: stalks, stems, leaves, pods, and weed fragments.  Crop residue, and the managing of crop residue, can be very beneficial to the overall production of a given field, or farm.

Benefits from Crop Residue

  • Crop residue from the previous crop provides cover during the critical time between growing crops.  This cover prevents additional erosion that would normally occur without cover.
  • Allows for more rain/moisture infiltration verses an unprotected soil.  This may cut evaporation and runoff up to 70%. 
  • Conserves moisture for crop usage.  Conserving an additional 2-5 inches of moisture under the surface may carry the crop through a dry spell, paying big dividends in yield.
  • Provides protection from wind erosion caused by a strong wind on dry soil.
  • Aids in prevention of soil surface compaction from a hard pounding rain.  A raindrop during a hard rain, may splash soil particles up to 3 feet away on a bare soil.  Once the surface is compacted, and/or sealed, it allows more runoff in the future.
  • Aids in less weeds by preventing sunlight reaching the soil.  The sunlight initiates weed seed germination.
  • Builds soil organic matter.  “Residue is a building block of soil organic matter.” Paul Jasa, University of Nebraska Extension engineer

Leonard Residue Chart - citedThe last few years we have obtained some very high yields in areas.  With the high yields, we have observed two things.  One, higher amounts of nutrients have been used from the soil.  Two, more residue has been produced, increasing the need for more focused crop residue management.  Breaking the crop residue down, leads to quicker availability and usage of the nutrients contained in it.  This chart shows the nutrient values found in residue.

Leonard Fig.1 A picture of heavy residue in a standing corn field preventing rain runoff. cited Leonard Fig.2 Earthworms aiding in the residue breakdown cited


Crop Residue Management:

  • Set a plan for decomposing the crop residue.This will release nutrients captured in the residue, making them available faster, for future crops.
  • Too much residue? This is a sign there might not be enough biological activity in the soil.
  • If needed, do a soil test for the soil pH.Is your soil pH in line for good microbial activity for the residue breakdown?
  • Should some lime be applied if the pH is too low?Low pH = acidified soil.If the pH is low, select Nitrogen sources that have a less lowering effect on pH.Ammonium based nitrogen has the highest risk of acidification, and lowering the pH.Nitrate nitrogen sources have the least acidifying effect.
  • Strive to be in the proper pH range for the crop you are growing.Range for corn is 5.8-7.0.Range for soybeans is 6.0-7.0. (For soybeans, 6.3-6.5 is optimal for nutrient availability, and biological nitrogen fixation.)And for forage legumes the range is 6.8-7.0.
  • Furrow Management at planting:Clear the residue in the furrow when planting to stabilize the soil temperature for uniform emergence.This will also provide a more uniform planting depth.
  • If earthworms are present, use practices to maintain their viability, because of their beneficial effects.They improve the soil structure, increase the number of soil microbes, and release nutrients in available forms to the crop.

 

In summary, having a residue cover, and your soil in line for optimal microbial activity, provides a host of beneficial effects, in the short and long term.

Sources and Additional Information:

  1. http://www.ctic.purdue.edu/resourcedisplay/298/
  2. https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/energy/conservation/?cid=nrcs143_023637
  3. https://cropwatch.unl.edu/2017/estimating-value-crop-residue
  4. http://www.agriculture.com/crops/tillage/crop-residue-as-a-soil-saving-strategy_187-ar51056
  5. http://www.ipni.net/publication/bettercrops.nsf/0/4D48284E4562FFD185257D3200574F66/$FILE/%20BC-1993-1%20p8.pdf
  6. http://www.nrcresearchpress.com/doi/pdf/10.4141/cjps96-111
  7. http://soilquality.org/indicators/soil_ph.html
  8. https://aglabs.com/pdfs/residue-decomposition.pdf
  9. https://www.wardlab.com/download/wardupdates/Nutrient.html
  10. http://www.cropnutrition.com/fertilizers-and-soil-acidity

Download a copy of this technical Bulletin: Tech_353 - Crop Residue Effects and Management

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