Managing Irrigation with the SOYGRO Crop Growth Model in the Coastal Plain of Georgia

Abstract

Computer simulation of crop growth and management can improve management decisions for profitable production of soybean. This study was undertaken to adapt a crop model to evaluate irrigation management options and to simplify its use for farmers and extension agents. The yield prediction of the SOYGRO soybean crop growth model was validated for three soils and one cultivar using three years of data from controlled irrigation tests. The SOYGRO model was then used with 12 years of historical weather data to assess irrigation strategies. An economically preferred strategy was determined consisting of a threshold at 50% available soil water and 1.5 cm of water per irrigation. A PC version of the model was modified to allow real-time crop simulation to facilitate its use by growers and extension personnel. This modification allowed the user to run SOYGRO with current weather data then change to one of three hypothetical weather scenarios to predict the yield and profitability of an irrigation strategy.