The same rain that helps farmers grow crops can also cause a few headaches as that water works its way from agricultural fields.
Researchers at Kansas State University say they're learning more about what causes ephemeral gullies – or tracts of land that are carved out when runoff pushes soil off of the farm field and into nearby waterways.
"We have a lot more to learn, but we have developed models that can monitor water movement in a field as well as the detachment of soil particles, which leads to soil erosion, said Aleksey Sheshukov, assistant professor of biological and agricultural engineering.
Left alone, gullies grow larger with each high intensity rain event. For farmers, it's not just a scar on the field, but also a sign of losing money on land that is not farm-able.
"Soil erosion is a big issue in Kansas, Sheshukov said. "A significant percentage of the sediment that goes into waterways is due to soil erosion from gullies of nearby fields, which can also cause destruction of streambanks and pollute water.
"We are trying to learn about what causes ephemeral gullies and how to prevent them, Sheshukov said. "We are beginning to assess those practices, but because of the differences in geography and soil and other factors, we haven't developed complete strategies yet.
Thus far, conservation practices on farm fields are designed to slow the push of water through the channel that is formed by the gully. Terraces, no-till farming and winter cover crops are some of the practices that farmers already are using. Sheshukov hopes to find more to help farmers in Kansas and beyond.
"Reducing flow within the channel would help to minimize the power of the runoff, so we're looking at creating obstacles and increasing vegetation in the gully to reduce the power of the flow, he said.
Other options may include making the sides of the gully less steep, double-cropping in the gully, or creating artificial swales. Regardless, Sheshukov said one practice won't fit all situations because conditions in any given field vary by soil type, management, temperature, rainfall pattern and other factors.
Researchers are certain, though, that fields with loose soils, a higher slope or larger drainage area are more susceptible to soil erosion.
"In computer models, we can implement practices and get an average percentage of sediment load reduction, Sheshukov said. "But the range of what will be the actual reduction all depends on individual fields and individual pasture.
"Overall, there has been a lot more exposure recently to this problem, so I think we are gaining a better understanding of the issue. I hope in a few years we will be able to predict with more certainty the reduction rates for a given practice.
The research project is funded by the U.S. Department of Agriculture; Natural Resources Conservation Service; Kansas Center for Agricultural Resources and the Environment; and Kansas Water Resources Institute. The project includes experts in agronomy, landscape architecture, agricultural economics and biological and agricultural engineering.