Background of the MSEA‐RZWQM Modeling Project

Abstract

AbstractThe Management Systems Evaluation Areas (MSEA) project was established in 1990 as a part of the Midwest Water Quality Initiative to evaluate the effect of agricultural management practices and systems on the quality of water resources, to increase understanding of processes affecting water contamination, and to develop cost‐effective strategies to reduce water contamination from pesticides and plant nutrients. The Midwest was chosen because it produces so much of the country's corn (>80%) and soybean (≈70%) crops, and consumes >50% of the N fertilizer and almost 60% of the herbicides applied. The MSEA project collected a large volume of data across a wide region. Properly calibrated and validated, simulation models could use this database to estimate water quality impacts over much longer periods than the expected life of the MSEA field program and to simulate responses for other combinations of soils, management systems, and weather conditions. The Root Zone Water Quality Model (RZWQM) was chosen for model improvement, calibration, and validation, to be followed by multilocation simulation of several specific management systems used in Midwest corn and corn‐soybean production. Model improvement was an iterative process across multiple locations. The next seven papers in this issue provide an overview of RZWQM Version 3.2, an explanation of the calibration‐validation process, and documentation of that process and the modeling at MSEA locations in Iowa, Minnesota, Missouri, Nebraska, Ohio, and Colorado.