Soil erosion from both wind and water can happen nearly anytime in Colorado. When soil leaves a field due to wind or water, the field’s productivity is reduced. Topsoil that leaves a field is the best soil and is high in organic matter. Low organic matter soils experience reduced crop yields. In addition, blowing soil can have consequences on the field the soil is blowing into not to mention a dust storm’s effect on the environment with reduced visibility. Water erosion simply carries top soil off your field and into someone else’s or the topsoil is carried into streams and lakes as sediment. Some weather issues magnify soil erosion potential such as drought, which reduces the amount of crop residue raised and thus the amount of cover protecting a field. Summer flooding due to intense rain storms can create water runoff issues.
The most effective soil erosion control strategy is to leave crop residues in place after harvest. This strategy insures maximum cover during winter dormant periods. Crop residue management includes practices such as reduced till, no-till, stubble mulch, strip cropping and cover cropping. Each of these methods substitutes chemical or cover weed control for tillage. Each one of these practices have advantages and disadvantages but all will help reduce both wind and water erosion potentials in a field. The bottom line is; when soil remains covered from the previous crop’s residue, both wind and water erosion will be reduced, leaving topsoil in place. Tillage, drought and flooding increase soil erosion issues.
What can be done when wind erosion has overtaken a field? Emergency tillage is an option to suppress wind erosion. Emergency tillage strategies should include the following: use a combination of tractor speed, tillage depth, and implement shovel size to achieve the roughest soil surface with the most soil clods. Surface roughness is the number one wind erosion control strategy when wind erosion is the issue. The rougher the soil surface with more dirt clods, the more protected the field will be. This condition becomes more difficult with extremely dry soils. Try to start the emergency tillage on upward wind field locations. Till in a perpendicular direction to prevailing wind direction. Our prevailing winds mostly come from the south making an easterly-westerly tillage direction most effective, when possible. Variations of this tillage direction can still be effective. Try and skip passes (up to 50% of the field) from tillage which leaves some crop residue anchored. Tillage should not be solid. Shovel spacing of 24 to 40 inches can reduce wind erosion, depending on soil type and conditions. If a second tillage is needed later, increase the tillage depth.
The best wind and water soil erosion control strategy is leaving past crop residues in place. However, if soil erosion from wind becomes an issue due to drought, emergency tillage can be a short-term option.
Source: Kansas State University MF2206
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