Spatial Optimization of Six Conservation Practices Using Swat in Tile‐Drained Agricultural Watersheds |
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Authors: | Margaret M. Kalcic Jane Frankenberger Indrajeet Chaubey |
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Affiliation: | 1. University of Michigan Water Center, Ann Arbor, Michigan;2. Agricultural and Biological Engineering, Purdue University, West Lafayette, Indiana;3. Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana |
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Abstract: | Targeting of agricultural conservation practices to the most effective locations in a watershed can promote wise use of conservation funds to protect surface waters from agricultural nonpoint source pollution. A spatial optimization procedure using the Soil and Water Assessment Tool was used to target six widely used conservation practices, namely no‐tillage, cereal rye cover crops (CC), filter strips (FS), grassed waterways (GW), created wetlands, and restored prairie habitats, in two west‐central Indiana watersheds. These watersheds were small, fairly flat, extensively agricultural, and heavily subsurface tile‐drained. The targeting approach was also used to evaluate the model's representation of conservation practices in cost and water quality improvement, defined as export of total nitrogen, total phosphorus, and sediment from cropped fields. FS, GW, and habitats were the most effective at improving water quality, while CC and wetlands made the greatest water quality improvement in lands with multiple existing conservation practices. Spatial optimization resulted in similar cost‐environmental benefit tradeoff curves for each watershed, with the greatest possible water quality improvement being a reduction in total pollutant loads by approximately 60%, with nitrogen reduced by 20‐30%, phosphorus by 70%, and sediment by 80‐90%. |
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Keywords: | optimization best management practices agricultural conservation practices nutrients Soil and Water Assessment Tool watershed management |
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