Field gullies appear like a scar upon the landscape. You know the spots—you use tillage to fill in these cuts and gouges in the field, only to see heavy rains carve them out again. Now it appears no-till may be the answer for keeping those
The technical name for small, reoccurring drainage ditches is ephemeral gullies. These are often places where grass waterways can control the problem, but producers prefer to mechanically fill in the areas each year. Now new research is finding ephemeral gullies may lead to soil losses that exceed those from sheet or rill erosion.
Hydraulic engineer Carlos V. Alonso and agricultural engineer Ronald L. Bingner work at the Agricultural Research Service (ARS) National Sedimentation Laboratory in Oxford, Miss. They're teaming up with University of Buffalo scientists Lee Gordon and Sean Bennett and Natural Resources Conservation Service agricultural engineer Fred Theurer to evaluate the effects of ephemeral gullies on erosion.
Tillage practices remove or hide gullies until the rains come and cut new channels in the same location. Not only do these new channels easily erode, but they start another cycle of gully development and topsoil reduction.
The team has developed a model to evaluate how tillage practices can affect the formation and evolution of ephemeral gullies and subsequent soil erosion rates.
During a five-month growing season, tillage activities were simulated using once-a- year conventional tillage and no-till management. Mathematical models were applied to replicate a 10-year production span.
Findings suggest that on average, tillage in areas prone to ephemeral gully erosion can produce significantly higher soil erosion rates compared to those same regions under no-till management. Simulated cumulative ephemeral gully soil erosion rates for the tilled fields ranged from 240% to 460% higher than soil erosion rates in untilled fields.
The scientists say the negative effects of tillage simulated in these watershed models reinforce the advantages of soil conservation technologies such as no-till planting and other reduced tillage management practices.
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