Decision Support Software for Soybean Growers: Analyzing Maturity Group and Planting Date Tradeoffs for the US Midsouth

Core Ideas: Modifying maturity group and planting date in soybean affects yield potential, yield risk, phenology, soybean price, and irrigation needs. Choosing among a set of 14 planting dates and 8 relative maturity groups is complex. Decision support software can help compare between relative maturity groups. Among other choices, soybean [Glycine max (L.) Merr.] producers in the Midsouthern United States face decisions regarding the optimum maturity group (MG) to select for a given planting date and location. From a profitability perspective, weather-driven irrigation water needs and harvest date implications on seasonal sale price complicate planting choices. Using a large set of experimental trials conducted across 10 locations in the Midsouth, the DSSAT-CROPGRO-Soybean crop simulation model was validated. Thereafter, the model was used to create a database of simulated 30-year yield and irrigation water needs based on past weather data for 13 locations. With that data, a spreadsheet-based tool was developed to compare soybean planting strategies by selecting from 2 soil textures, 14 different planting weeks, and 8 relative maturity group (rMG) choices ranging from rMG 3.0 to 3.4 to rMG 6.5 to 6.9 in 0.5-rMG intervals at each location. User-specific comparisons allow insights on yield potential, yield risk, phenology, irrigation needs, soybean price, and irrigation cost sensitivity analysis as well as profitability assessment across MGs and planting dates.