The best philosophy for erosion control is that it is better to prevent erosion than to try to correct it. There is no best solution for erosion control that will work in all situations. Erosion prevention and control must be developed for each site using the resources that are available.
On cultivated land, the best methods to use are those activities that will reduce the effect of wind and water on the soil particles. For the prevention of water erosion it is important to provide as much protection as possible for the surface of the soil. This includes management of tillage practices to leave residue on the surface and the use of cover crops in nonproductive seasons. Additional protection is provided by reducing the length of the continuous slope by installing terraces. To illustrate the effect of these practices, rework the sample problem with the appropriate values for terraces and residue.
Problem: Estimate the annual erosion for a field that has a rainfall factor of 220, consists mainly of loamy sand with 2% organic matter, averages a 4% slope with a slope length of 200 ft, and has been in continuous small grain with heavy residue, normally planted in June, and farmed with terraces.
A = R x K x LS x CP = 220 x 0.10 x 0.50 x 0.21 = 2.31 or 2.3 T/ac/yr.
In the original problem the soil loss was 4.6 T/ac/yr. With the modifications the soil loss is 2.3 T/ac/yr, a reduction of 50%.
Residues on the surface also help prevent wind erosion, but reducing the length of the slope does not. The critical factors for preventing wind erosion, other than residue, are the roughness of the surface and the unobstructed distance that the wind can blow. Reducing the unobstructed distance is an effective control. This explains the prevalent use of shelterbelts in the Great Plains region. A shelterbelt will provide protection downwind for up to ten times its height.
Other methods are appropriate for the control of both water and wind on small areas for a short duration, such as construction sites. A common practice is to use commercial silt fences, bales of straw or nets to help prevent soil from leaving the site. Installing temporary wind barriers and keeping the ground covered can control wind erosion.
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