Cropland filter strip removal of cattle manure constituents in runoff

Authors: Gilley, John; Sindelar, Aaron; Woodbury, Bryan

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2016
Publication Date: 12/1/2016
Publication URL: https://handle.nal.usda.gov/10113/5763078
Citation: Gilley, J.E., Sindelar, A.J., Woodbury, B.L. 2016. Cropland filter strip removal of cattle manure constituents in runoff. Transactions of the ASABE. 59(6)/1681-1693.

Interpretive Summary: It is obvious that manure application should not occur immediately next to a water course. Setbacks are prescribed distances away from conduits to surface and ground water where manure application is not allowed. There is little scientifically-derived information available to help identify setback distances required to effectively reduce contaminants from incoming runoff on cropland areas. The objective of this study was to determine the effects of setback distance and runoff rate on concentrations and transport rates of selected constituents following land application of beef cattle manure. The twenty plots examined during the investigation were 3.7 m wide and 4.9, 7.9, 11.0, 17.1 or 23.2 m long. After an initial set of rainfall simulation tests were completed to determine the background concentrations and transport rates of selected constituents, manure was applied to the upper 4.9 m of each plot and additional tests were conducted. Runoff was analyzed for dissolved phosphorus (DP), total phosphorus (TP), NO3-N, NH4-N, total N, boron, calcium, chloride, magnesium, potassium, sodium, sulfate, EC, pH, and sediment content. A setback distance of 12.2 m effectively reduced the concentration of each of the constituents except NO3-N and transport rates of DP, TP, NH4-N, boron, and potassium to values similar to those obtained on the no-manure treatment. An equation was identified that provided reliable estimates of the effects of setback distance on the concentration and transport rates of selected constituents. Runoff rate significantly influenced transport rates for each of the measured constituents with values generally increasing as runoff rates increased. The experimental results indicate that setbacks can serve to effectively reduce the transport of pollutants in runoff from areas on which beef cattle manure is applied.

Technical Abstract: There is little scientifically-derived information available to help identify setback distances required to effectively reduce contaminants from incoming runoff on cropland areas. The objective of this study was to determine the effects of cropland filter strip (CFS) length and runoff rate on concentrations and transport rates of selected constituents following land application of beef cattle manure. The twenty plots examined during the investigation were 3.7 m wide and 4.9, 7.9, 11.0, 17.1 or 23.2 m long. After an initial set of rainfall simulation tests were completed to determine the background concentrations and transport rates of selected constituents, manure was applied to the upper 4.9 m of each plot and additional tests were conducted. Runoff was analyzed for dissolved phosphorus (DP), total phosphorus (TP), NO3-N, NH4-N, total N, boron, calcium, chloride, magnesium, potassium, sodium, sulfate, EC, pH, and sediment content. A CFS length of 12.2 m effectively reduced the concentration of each of the constituents except NO3-N and transport rates of DP, TP, NH4-N, boron, and potassium to values similar to those obtained on the no-manure treatment. A first-order exponential decay function provided reliable estimates of the effects of CFS length on the concentration and transport rates of selected constituents. Runoff rate significantly influenced transport rates for each of the measured constituents with values generally increasing as runoff rates increased. The experimental results indicate that CFS can serve to effectively reduce the transport of pollutants in runoff from areas on which beef cattle manure is applied.