Conservation Notes: Spring crop field conditions

Sheet and rill erosion after spring rain. Photo supplied

As farmers finish up spring planting and reflect back on the hectic last few months, there are a few things that can be reviewed.  First, how did my fields fare in some of the heavy rainfall events that occurred?  Second, where are there problem areas and what can be done to correct them?

This year there appeared to be more acres of farmland exposed to the effects of spring weather.  Less crop residue was left on fields and fewer conservation practices are in place to help slow down or eliminate the effects of rainfall events.  This combination creates more sheet and rill erosion, the removal of layers of soil from the land surface by the action of rainfall and runoff.

This is the first stage in water erosion and leads to significant topsoil loss over time if the erosion is not treated.  Since this nutrient rich topsoil is the valuable element needed to produce high quality crops, it is extremely important to keep this soil in place.

This can be accomplished through conservation practices including residue management and erosion control structures.

Residue management is leaving last year’s crop residue on the soil surface.  Residues help reduce surface erosion by reducing the impact of rain that dislodge and move soil particles.

This practice also conserves soil moisture, reduces wind erosion, and improves soil organic matter beneficial to the soil.  The amount of residue cover left on the field is greatly affected by the type of crop, operation, and implements used.  Different tillage operations bury different amounts of residue.

Ideally, leaving 30 percent or more of residue on a field is the goal to provide the most benefit to the soil.  Although soil type and slope also play a significant role, the following are rough estimates of residue cover remaining after typical machinery operations.

After Corn: Moldboard plow – 0 percent, Chisel – 60 percent, Disk – 30 percent, Field Cultivator – 35 percent, Anhydrous Application – 75 percent, Planter – 75 percent

After Soybeans: Moldboard plow – 0 percent, Chisel – 40 percent, Disk – 20 percent, Field Cultivator – 20 percent, Anhydrous Application – 45 percent, Planter – 70 percent

Multiple passes with equipment quickly reduces the amount of residue left on a field.

Different tillage operations bury varying amounts of residue, and multiple equipment passes will quickly reduce the amount of residue left in the field.  Machinery operations will typically leave anywhere from 0 percent – 80 percent residue on the field depending on the crop, soils, slope, and machinery used.  Talk to your local conservation office to see if your farming practices are leaving enough residue in the field.

Other ways to reduce erosion include establishing grassed waterways or buffers to stabilize more erosive areas, incorporating a perennial crop in the crop rotation, cover crops, and installing a sediment basin to name a few.

There are many conservation practices that can be used to keep soil in place.  Many things can be done to reduce the effects of sheet and rill erosion.  Establishing conservation practices and leaving more residue on the field are ways to address this resource concern.

If you would like more information on conservation practices or on how to measure residue on your fields please contact the SWCD or NRCS office at 674-651-7160 ext. 3 or visit www.chisagoswcd.org.

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