ASABE Technical Library - Abstract

Abstract. The overuse of fertilizers in supporting increased agricultural production to feed a growing population can contribute to a significant release of nutrients to groundwater via percolation, and adjacent waterbodies via surface and irrigation runoff. This excess of nutrients could be detrimental to aquatic ecosystems by altering the nutrients’ natural cycle. This environmental issue is of special interest in the Mississippi River Basin, as the downstream movement of nutrients from croplands stimulates the development of the hypoxia zone in the northern Gulf of Mexico. To address this regional concern, several types of Best Management Practices (BMPs) have been implemented with the fundamental aim of reducing nutrient loading from agricultural lands in the Mississippi Delta Region. In recent years, On-Farm Water Storage (OFWS) systems have been attracting much attention because of their potential benefits to the environment, farmers, and landowners. However, little is known about the watershed-scale impacts of these systems, as well as their effectiveness in reducing nutrient loading downstream. This study describes the seasonal variability of nitrate nitrogen and total phosphorus concentrations measured in the OFWS system at a farm in Porter Bayou watershed, Mississippi. We collected water samples from February 2012 to December 2014 and used boxplots along with the Wilcoxon rank-sum test to analyze water quality changes in the system. Our initial assessment of nutrient changes through the system showed a reduction of 67% in nitrate nitrogen concentration during winter, 50% during spring, and 32% during fall. Total phosphorus was reduced by 22% during the fall season. Preliminary results of this study will help improve the understanding of OFWS systems for water quality pollution control and water conservation.