P996: Investigating the fate of agrochemicals in the Mississippi delta: Place-based soil chemistry with dual enrollment students

Author: Lacey S. Fitts, Delta State University, USA

Co-Author: Paxton W. Fitts, Mississippi State University, USA; S. Ryan Fulgham, Delta State University, USA

Date: 8/7/14

Time: 11:30 AM11:50 AM

Room: MAK A1117

Related Symposium: S70

The Mississippi Delta is a rural agricultural region with over 80% of land use dedicated to row crop farming. Agricultural overuse of urea fertilizer negatively impacts the environment and production costs. When applied under non-ideal conditions, up to one third of topical urea may be converted to ammonia and lost to the atmosphere via volatilization. Although this process is known, the extent of volatilization varies greatly depending on soil type and interplay of environmental conditions. Soil samples collected from fields adjacent to school property were characterized, and volatilized ammonia was trapped in boric acid containing methyl red indicator. The samples were back titrated at 7 and 14 days with sulfuric acid to determine the percent nitrogen lost. Oven-dried soils were used as controls and exhibited near zero losses. Both acidic and alkaline soils exhibited lower losses than neutral soils, and all soils at field capacity moisture exhibited nitrogen losses. The highest losses were observed in a Brittain silt loam soil with over 30% of applied nitrogen lost to the atmosphere. Student-designed follow up projects investigated the effects of temperature, polymer coatings, and soil pH on ammonia volatilization losses. The results were disseminated through science fair projects and communications with local farmers, and students reported high levels of engagement with this place-based project.