Using SWAT‐MEA to determine optimal placement of crop management systems under no‐till

Abstract

AbstractNo‐till is one of the common conservation practices implemented in the Fort Cobb Reservoir Watershed (FCREW) located in central Oklahoma to improve soil and water resources while ensuring sustainable crop production. In this study, we used the recently developed Multi‐Objective Evolutionary Algorithm for the Soil and Water Assessment Tool model (SWAT‐MEA) to determine the optimal spatial placement of crop management systems when converting from conventional tillage to no‐till in the FCREW. A previously calibrated and validated Soil Water and Assessment Tool (SWAT) model for the FCREW for conventionally tilled land under winter wheat (Triticum aestivum L.), sorghum (Sorghum bicolor L.), and peanuts (Arachis hypogaea L.) cropping system was used. The objective functions for this study were maximizing crop yield ranks while minimizing sediment, total P (TP), and total N (TN) yield loads. Four modifications made in the SWAT‐MEA in order to achieve the defined goal of this study include an automated process of conversion from conventional to no‐till, ability to use crop yield ranks in the optimization process and to sum up species of N and P to TN and TP, and creation of a public domain standalone executable. Results indicated that converting from a conventionally tilled to no‐till system under optimal placement of crop management systems reduced TN, TP, and sediment yield losses by 45, 32, and 65%, respectively, while crop yields were not significantly affected. Overall, this case study shows that the SWAT‐MEA was able to successfully identify the optimal placement of crop management systems under no‐till condition and can be used for decision making.