Landscape Structure and Nutrient Budgets in an Agricultural Watershed, Southwest, Ohio

Author Institution: Department of Geography, Miami UniversityManaging for uncultivated lands in agricultural watersheds may be a cost effective way to improve surface water quality. For this study, landscape structure and nutrient (N, P) budgets were compared in seven first-order basins of Marshall's Branch watershed, Preble County, OH. Row crops were the dominant land use in all basins. Three basins had greater than 25% of stream buffers forested and nitrate concentrations below average. Four basins had higher pasture and residential land use proportions and phosphorus concentrations higher than average. Growing season precipitation in 1994 was low, resulting in low nutrient transport. Although no basins had net export of nutrients, trends exist that point out relationships between landscape structure and nutrient storage. Of particular importance is the strong effect small changes in forested stream buffers had on nitrogen flows in the basins, suggesting small land use changes in targeted areas can affect positive changes in basin-wide nutrient dynamics