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 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 appears to be more acres of farmland exposed to the effects of spring weather. Less crop residue was left on fields and fewer conservation practices seem to be in place to help slow down or eliminate the effects of heavy rain events. This combination creates soil erosion, the removal of layers of soil from the land surface by the action of rainfall and runoff. This can lead to significant topsoil loss over time if the erosion is not treated. Since this nutrient rich topsoil is needed to produce high quality crops, it is extremely important to keep it in place. This can be accomplished through conservation practices including crop residue management, adding cover crops to the crop rotation, and erosion control structures.
Residue management consists of leaving last year’s crop residue on the soil surface. This reduces soil erosion by reducing the impact of raindrops that dislodge and move soil particles. The amount of residue cover left on the field is greatly affected by the type of crop, operation, and implements used. Cover crops can be planted in the fall or spring to reduce soil erosion which also reduces the impact from raindrops that dislodge and move the soil particles. Cover crops are also utilized as a nitrogen source and can built soil organic matter.
With more frequent high rainfall events saturating the ground for longer periods of time, it is noticeable that erosion is occurring in areas where it hasn’t in the past. Shannon Carpenter (District Conservationist) and Bill Fitzgerald (Soil Conservation Technician) with the Natural Resources Conservation Service (NRCS) left their office on May 24th to inspect a sediment basin that was installed on May 22nd. The intent was to see how the structure was performing during the rain event. “The sediment basin held up well, but down the road we observed water flowing to a road culvert from two sources of runoff”, said Carpenter. “There was runoff coming from a very flat crop field and runoff flowing from a managed pasture. The water flowing from the crop field was very brown in color from the sediment in the water, but the water flowing from the managed pasture was clear with no sediment.” It was also observed that the flat field with very low amount of crop residue on it had sediment flowing quickly off the field. Crop fields with high residue levels with water standing had water moving more slowly off the field. When the soil becomes saturated all row-crop fields have the potential for soil to move off site.
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 sediment basins to name a few.
There are many conservation practices that can be used to keep soil in place. Establishing the right conservation practices such as leaving more crop residues on the field is a great place to start. If you would like more information on conservation practices or on how to measure residue on your fields please contact the NRCS or SWCD office at (320) 983-2154. Your local NRCS conservationist will work with you to develop a customized conservation plan to address potential resource concerns for your operation.