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Environmental Benefits of Precision Farming - A Modeling Case Study

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In this study, we evaluated the environmental impacts of spatially variable versus uniform phosphorus fertilizer application rates on a 32-ha commercial corn field in Blue Earth County of southern Minnesota. In 1998, the phosphorus rates (0-39 kg/ha) were variably applied in accordance with measured surface soil pH and soil Bray P levels across 50 x 50 grid spacing. Surface runoff and tile drain leaching losses of sediment and phosphorus were measured using automated sampling systems. The Agricultural Drainage and Pesticide Transport (ADAPT) model was calibrated to measured water fluxes, and losses of sediment and phosphorus to surface waters. There was good agreement between measured and modeled water fluxes, sediment, and phosphorus losses. Using the calibrated model, a sensitivity analysis was conducted for both uniform and variable rate phosphorus application strategies using a 50-yr climatic record. Phosphorus losses for the variable strategy were significantly lower than losses for a uniform strategy.
Gowda, P.H. , Mulla, D.J. , Larson, W.E. , American Society of Agricultural Engineers.
Paper presented at the 2005 ASAE Annual International Meeting, held July 17-20, 2005, Tampa, Florida.
Paper 2005, no. 051042
Journal Articles, USDA Authors, Peer-Reviewed
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