Swine Lagoon Effluent Disposal by Overland Flow: Effects on Forage Production and Uptake of Nitrogen and Phosphorus

Abstract

AbstractSwine (Sus scrofa) production requires economical and environmentally safe waste management systems. The objective of this study was to determine the effect of swine lagoon effluent on dry matter yield and N and P uptake of a mixture of hybrid bermudagrass [Cynodon dactylon (L.) Pers. cv. Russell] and annual ryegrass (Lolium multiflorum Lam.) grown on a Marvyn loamy sand (fine‐loamy, kaolinitic, thermic Typic Kanhapludult). Treatments included a control with no nutrient additions, NH4NO3 at 560 kg N ha−1 yr−1, and swine lagoon effluent at 560, 1120, and 2240 kg N ha−1 yr−1. Effluent was applied using an overland flow technique. The highest lagoon effluent rate added N at 4 times and P at 11 times the normally recommended rates for these forage grasses. Total dry matter yield was significantly increased by NH4NO3 and swine lagoon effluent additions, compared with the control treatment. Dry matter yield for the lowest effluent rate was not significantly different from that for the NH4NO3 treatment, and dry matter yields were not significantly different among the three rates of lagoon effluent. Increasing the effluent rates generally increased total N and total P concentrations in the forage. Recoveries were about 32% for N and 20% for P at the lowest rate of lagoon effluent, and about 13% for N and 9% for P at the highest rate. The low recoveries of N and P with higher than recommended effluent rates could have environmental implications for the quality of soil, groundwater, and surface runoff.