Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: June 7, 2006
Publication Date: July 11, 2006
Citation: Feyereisen, G.W., Strickland, T.C., Lowrance, R.R., Bosch, D.D., Sheridan, J.M., Sullivan, D.G. 2006. Long-term nitrogen load from the Little River Experimental Watershed on the Coastal Plain of Southwest Georgia. In: Proceedings of the American Society of Agricultural and Biological Engineers Annual International Meeting (ASABE). 7/11/2006, Portland, OR. Paper No. 062201. Interpretive Summary: Nitrogen is one of the major elements of concern regarding surface water quality because at high enough levels it can be unhealthy for people and it contributes to degradation of the aquatic environment for fish and animal life. The levels of nitrogen in the Little River, north and west of Tifton, Georgia, have been monitored since 1974. Over this period of time, the land use in the study area known as the Little River Experimental Watershed has roughly averaged 50% forest and 40% crop with the remainder representing pasture, urban/rural residential, and water. Cropping systems have changed from corn dominated in the 1970’s to a mixture of corn-soybean-peanut in the early 1980’s to a cotton dominated cotton-peanut rotation beginning in the mid 1990’s. It is important to understand the influence that the management of these cropping systems, with their particular tillage and fertilization and chemical applications, have had on the nitrogen levels in the Little River. This paper looks at trends in the nitrogen levels monitored in the Little River in Southwest Georgia and in the relationships of the land use changes over the past three decades to stream water quality.
Technical Abstract: The USDA-Agricultural Research Service, Southeast Watershed Research Laboratory initiated flow measurement of the Little River in a 334 km2 area near Tifton, Georgia in the late 1960’s. Monitoring of stream nitrogen concentrations began in 1974 for seven of the eight nested subwatersheds in the area, known as the Little River Experimental Watershed. This paper summarizes the first 30 years of the stream nitrogen record, from 1974-2003. The calculated nitrogen loading data provides insight into the effects of changing land use and agricultural practices, stream-side riparian zones, and climate cycles on nitrogen cycling over the long term in the Southeast Coastal Plain.