By Sjoerd Duiker, Soil Scientist
Rill erosion in crop fields is still a common sight. In some cases these rills become gullies. The difference between rills and gullies is that rills can still be crossed easily with farm equipment, but gullies cannot. Rills can easily become gullies in no-till fields if the erosion continues unabated.
If you see rills forming in your field, it is important to diagnose the cause and change management so they do not become gullies. Once you have gullies in your field the only thing to do is to fill them back in and make sure they do not form again.
Four Ways to Reduce Rill Erosion:
- To avoid rill erosion you need to maximize infiltration. Rill erosion can only happen if there is surface runoff. So first of all, maximize infiltration by using soil health-improving practices. This includes improving surface tilth and organic matter using permanent no-till, vigorously growing cover crops, deep-rooted bio-drilling crops, close-cropped crops, planting on the contour, heavy mulch cover, perennial grass and forage crops, manure and compost, and avoiding compaction.
- The next line of defense is make sure soil is armored (covered) at all times with crop residue and living cover and live root systems to hold the soil in place.
- Another practice to reduce rill erosion is strip cropping and contour planting. To alternate strips of annual crops with perennial sod planted on the contour helps stop runoff from creating rills that might form in the annual crop. The strips don’t have to be as narrow with no-till as with tillage because of the improved soil health and increased infiltration in the no-till annual crop strips.
- Where water commonly collects in the landscape to form concentrated runoff, it is beneficial to have grassed waterways. The grassed waterways have perennial sod forming grasses that grow in the summer to create a dense mat and fibrous root mass underground to protect the soil in the winter. Annual cover crops planted after summer crops often don’t have enough time to develop to provide the same cover as a permanent sod on soils with seasonally high water tables where the cover crops drown out.
