Successful Mitigation of Agricultural Runoff
In a previous article posted on this website, information about US-EPA’s new herbicide strategy is presented. This strategy mainly involves the mandatory adoption of measures that will mitigate runoff from agricultural fields where herbicides have been applied. Of course, runoff from fields used for crop production will necessarily carry any pesticide and/or fertilizer nutrient that has been applied to or ends up on/in the soil.
The Missouri Edge of Field [EoF] Water Quality Study has measured the effect of conservation practices such as grass waterways, cover crops, and terraces on the quality of water that leaves a farmer’s crop field. The farmer-driven project was made possible by investment from the Missouri Soybean Merchandising Council [a QSSB] and The Missouri Corn Merchandising Council. Results from this project are presented in the report titled “Missouri Edge of Field Five-Year Water Quality Research Program, 2017-2022”. Major points presented in that report follow.
• Goals of the project were to 1) quantify the effectiveness of on-farm conservation practices, 2) demonstrate the benefits of voluntary adoption of agricultural conservation practices, and 3) support improved water quality efforts.
• A field approach was used in the study, and all fields were cropped to the commonly-used corn-soybean rotation.
• Conservation programs that were included and monitored were grass waterways with and without terracing and grass waterways with and without cover crops.
• As expected, most runoff and its load–e.g. nitrate, total N, total P, total suspended solids or sediment–leaving fields occurred in the spring when rainfall is usually greatest and soil is usually most exposed.
• Overall results showed that grassed waterways reduced runoff, decreased soil erosion, and improved the quality of water that left the field. Grassed waterways used in conjunction with cover crops was most effective at decreasing runoff.
• A reduction in the erosion rate resulted in a reduction in P leaving a field.
• The results from this EoF study demonstrate and confirm the effectiveness of conservation practices for reducing runoff, decreasing soil erosion, and improving water quality.
This research did not monitor herbicide load in the water runoff from study fields. However, it seems logical that a similar setup could be employed to monitor herbicide load in water leaving a field in order to meet the mitigation requirements that will be required by EPA’s new herbicide strategy that is mentioned in the above-linked article and that will be part of each herbicide’s label. This will likely require a commitment of funds from commodity groups as well as financial incentives provided by agencies such as USDA’s Natural Resources Conservation Service [NRCS]. Click here and here to access details about NRCS’s EoF monitoring program.
U.S. crop producers must face the strong likelihood that government regulations will make it increasingly difficult to continue to rely only on chemical pesticides to control weeds and other pests that plague soybeans. Thus, documentation of practices such as those highlighted above that protect non-agricultural parts of the ecosystem will become more important in coming years as producers seek proven economical methods to decrease agricultural’s perceived negative effect on the surrounding environment.
Composed by Larry G. Heatherly, Sept. 2024, larryh91746@gmail.com