While heavy and intense spring rainstorms falling on already wet soils did a number on many row crop fields across the Midwest this year, they also provided a great opportunity for farmers to examine erosion concerns to improve soil conservation.
“Even fields with structural conservation practices (i.e. terraces, grassed waterways, water and sediment control basins) or conservation management practices (i.e., minimum tillage, cover crops, etc.) experienced soil erosion this spring,” said Kristina TeBockhorst, Iowa State University (ISU) agricultural engineering field specialist.
“These weather conditions were challenging, but also provided a great opportunity for farmers to examine erosion concerns to improve soil conservation,” she added. “Farmers should inspect their structural conservation practices and perform any required maintenance to keep them functioning as soon as it is practical.”
TeBockhorst said farmers should remove any sediment (silt) that has built up within the waterway channel to maintain full water conveyance capacity.
“If needed, reshape the waterway channel to remove rills or gullies and seed bare spots back down with a waterway grass mix,” she said. “Along waterway edges, look for sediment build-up and gully formation.
“Level off the edges to allow water to enter the grassed waterway rather than running downslope alongside of the waterway,” she added. “Farming direction should be perpendicular to the waterway to prevent gully formation along its edges.”
Promoting water flow
Moreover, she advised regular mowing and vegetation removal should be done to keep excessive grass growth from impeding water flow. “During wet periods, keep off grazing livestock and heavy equipment to prevent compaction and tire tracks,” she added. “Farmers should pay special attention to waterway outlets, as gully erosion can often start there and cut its way upslope into the field.”
She said terrace or basin embankments with severe overtopping should also be repaired to prevent further erosion.
“Reshape the ridge by adding soil to any low areas and reestablish any grass cover that has been lost,” she said. “Control trees on the embankment and avoid removing sediment from the ridge with tillage operations.”
“Broken, crushed or punctured tile segments should be replaced and wide joints should be covered to keep sediment from washing in,” she said. “Inspection of unprotected tile outlets is also important, as gullies often form here. If a surface and subsurface water outlet is in a common area, farmers should consider installing a drop structure to protect the outlet from erosion.”
Repairing damaged structures
State Conservationist Kurt Simon said sediment alone could simply be a maintenance issue that is not eligible for cost share. However, he said the USDA could provide farmers technical assistance to help ensure the conservation practice is restored (by the farmer) to its original design.
“If there was structural damage to the practices, like holes in terraces or waterways washed out, the Emergency Conservation Program (ECP) might help if there is no maintenance agreement on the practice,” he said.
“Or, the Environmental Quality Incentives Assistance Program (EQIP) could help if the damaged practice was built using EQIP funds. However, it’s important to note fixing damaged practices without addressing soil health may be a short-term fix until the next big rain.”