Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2004
Publication Date: 6/1/2005
Citation: Sullivan, D.G., Wood, C.W., Owsley, W.F., Norfleet, M.L., Wood, B.H., Shaw, J.N., Adams, J.F. 2005. Denitrification from a swine waste amended bermudagrass system. Comm. Soil Plant Anal. 36 (9/10): in press.
Interpretive Summary: Land-application of animal waste is a less-costly alternative to commercially available nitrogen (N) sources. Yet, atmospheric N losses following animal waste amendments are not well understood. This study was designed to measure denitrification rates from swine waste and commercially fertilized bermudagrass (Cynedon dactylon [L.] pers) pastures over three consecutive growing seasons. Each year plots received three split applications of swine waste or commercial fertilizer. Swine waste treatments were applied based on plant phosphorus requirements (9 kg ha-1) and supplemented with ammonium nitrate to meet plant N requirements (112 kg N ha-1). Results showed that denitrification losses were significantly greater from swine waste amended plots only during periods of peak denitrification. Losses were generally less than 1.0% of total applied N, suggesting that denitrification is not a critical N loss pathway in swine waste amended bermudagrass systems.
Technical Abstract: Nitrogen losses following land-applied animal wastes present an environmental and economical dilemma for producers. Gaseous N losses from pastureland contribute to global warming, ozone depletion, acid rain and inefficient plant N uptake. This study was designed to monitor nitrous oxide emissions following swine waste and commercial fertilizer treatments to bermudagrass (Cynedon dactylon [L.] pers) pastures. Denitrification rates were monitored on a biweekly basis for six 0.12 ha bermudagrass pastures for three consecutive growing seasons (1998 - 2000). Treatments consisted of three split applications of either swine effluent supplemented with ammonium nitrate (SW) or commercial fertilizer (CF). Swine effluent was applied based on plant phosphorus (P) requirements of 9 kg ha-1 application-1. Denitrification measurements began two weeks following initial applications and continued on a biweekly basis throughout the duration of the study. Peak denitrification rates were greatest in 1998, ranging from 0.6 to 1.7 ug N20-N m-2 h-1 for effluent treated plots, and 0.3 to 1.5 ug N20-N m-2 h1 for commercially fertilized plots. Total N20-N losses following land applied swine effluent were significantly greater than commercially treated plots only during peak periods of denitrification. Results from this study suggest denitrification is not a significant N loss pathway in swine waste amended bermudagress systems.