ILF

Conservation - Crops

cornfield


What is an appropriate level of residue cover?

Leaving crop residue on the soil surface can minimize surface runoff and soil erosion, improve water infiltration, and increase organic matter content. Most experts suggest that effective conservation tillage systems leave at least 30 percent residue cover after planting.  Additional residue is recommended on soils with steeper slopes where the potential for erosion is greater.

For further information about residue cover:
Resource Conservation Practices: Residue management and cultural practices PM1901a (Mahdi Al-Kaisi and Mark Hanna)
Residue removal and potential environmental consequences
How residue removal affects nutrient cycling

What are some considerations when making the decision to convert CRP acres into crop production?

The Conservation Reserve Program (CRP) was established to protect highly erodible land by taking it out of row crop production to reduce soil erosion.  Producers enter into 10 to 15 year contracts or longer depending on funding availability for the CRP.  Many of the original CRP contracts have or will expire in the next few years, leaving producers with the decision of what to do next.

If the choice is made to convert these acres into crop production, it is important to remember that the soils are highly erodible. Careful planning is needed in order to sustain the soil and environmental benefits that have been established over the years that the land was under CRP. Careful selection of tillage systems that are suitable for CRP such as no-till, or permanent conservation practices (terraces, grassed waterways, buffer strips, etc.) will be essential in reducing soil erosion.

The use of annual or perennial cover crops in the crop rotation is another practice that should be considered in the conversion of CRP to row crop production.  Cover crops sustain the gained benefits of soil organic matter build up, microbial biodiversity, soil structure, and other physical and biological improvements that are essential to soil and water quality.

For further information about CRP and crop production:
Tillage options after CRP - CRP Issues and Options
Planting corn or soybeans into CRP sod ground - CRP Issues and Options
Applying Fertilizer and Lime to CRP Land; ISU Extension

What are some benefits of using cover crops in my corn-soybean rotation?

Cover crops can provide significant benefits to soil and water quality improvement, especially during off-season row crop production (e.g. corn and soybean), where the soil is vulnerable to water erosion and the potential of nutrient leaching to groundwater is increased.  Living cover crops increase the potential of an active root system to intercept soluble chemicals such as nitrate, and provides a source of organic matter input through above- and below-ground biomass.

Some of the challenges that producers face are the selection of cover crop varieties and the short window of growing, particularly in the Midwest.  Winter hardy varieties of cover crops are typically planted after the row crops are harvested in the fall and provide cover for the soil until they are killed in the spring prior to planting of the next crop.

For further information about cover crops:
Cover Crop Selection and Management for Midwest Farming Systems ILF Winter 2006 newsletter
Small Grain Cover Crops for Corn and Soybeans PM1999
Legume Living Mulches in Corn and Soybeans
Intercropping Winter Cereal Grains with Red Clover

What are some benefits and concerns with strip-tillage?

Strip-tillage is well suited to poorly drained, wet, cold soils where seed germination is often delayed. Only a narrow portion of the row is tilled, which helps dry and warm soils in the spring, easing planter operation and promoting germination.  The system can enhance efficiency when manure injection or commercial fertilizer application is incorporated into the tillage operation, reducing passes over the field. Specialized equipment does not always have to be purchased; most farmers already have the strip tillage equipment accessible (such as in-row chisels and ammonia applicator knives). These benefits must be weighed against a variety of potential concerns. For instance, strip-tillage can induce erosion, particularly in highly erodible soils. Strip-tillage also can contribute to soil compaction between tilled zones when the field soil moisture conditions are at or above field capacity.

For further information about strip-tillage:
Resource Conservation Practices: Consider the strip-tillage alternative PM 1901c (Mahdi Al-Kaisi and Mark Hanna)
Evaluating Soil Moisture Before Field Preparation and Planting

Other resources:

 

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