Runoff Nutrient Concentrations Following Manure Application as Affected by Crop Residue

Manure is applied to cropland areas managed under diverse conditions resulting in varying amounts of residue cover. The objective of this study was to measure the effects of crop residue on nutrient concentrations in runoff from areas where beef cattle or swine manure were recently applied but not incorporated. Plots 0.75 m wide by 2 m long were established at the study site. Existing residue materials were removed, and corn, soybean, or winter wheat residue was added at rates of 2, 4, or 8 Mg ha-1. Manure was applied at rates required to meet estimated annual nitrogen requirements for corn. Control plots with manure but no-residue, and plots with no-residue and no-manure were also established. Three 30-min simulated rainfall events, separated by 24-hr intervals, were conducted at an intensity of 70 mm hr-1. Dissolved phosphorus (DP), total phosphorus (TP), NO3-N, NH4-N, total nitrogen, runoff, and soil loss were measured for each rainfall event