Findings from this project will be shared with producers in form of new and improved management recommendation guides that include the outcomes listed below (i.e. see Salmeron et al. in reference list). In addition, the data generated can be used to develop an interactive user-friendly decision tool for farmers (i.e. see SOYMAP and SOYRISK in reference list).
• Provide site-specific management adaptation choices (planting date x MG combination) that increases yield and economic returns under rainfed and under no water stress. These recommendations will be based on results that include planting dates from March to July, MG 2 to 5, and 7 locations across KY.
• Provide planting date and cultivar MG management adaptation strategies that consider different common soils in KY as well as soil depths.
• Identify site-specific diversification strategies (i.e. planting 20% of acreage in early April with MG 3 cultivars, and planting the rest in May with MG 4) that reduce risk and increase overall net economic returns.

Note to the KY Soybean Board: These 7 sites are the locations where the Soybean Performance Tests are conducted . Please communicate with the PI. Montse Salmeron (msalmeron@uky.edu) if you would like to see any additional location included to better characterize the range of environmental conditions in the state.

A planting date field trial was carried out successfully in 2020 under irrigated and rainfed
conditions, and with MG 2 to 5 soybeans. Data from planting date trials conducted in Lexington
during 2017 to 2020 were compiled and summarized in a draft manuscript by the graduate
student hired for this project. This draft manuscript identifies optimum cultivar MG choices for
planting dates in May and June under either irrigated and rainfed conditions, as well as the
yield decline with delay in planting date. In brief, under conditions of no water stress, soybean
yield would decrease by 2.8 bu ac-1 per week of delay in planting date (for MG 4 cultivars). The
yield response to planting date under rainfed conditions was more variable. Yield reductions
due to water limitation ranged anywhere from 0 to 37 bu ac-1 during the 2017 to 2020 growing
seasons. Yield losses due to water stress were greater for May planting dates compared to
June. These results suggest that while early planting dates may increase soybean yield
potential, the expected yield gain from advancing planting date may be limited in years of
insufficient precipitation. Similarly, we would expect deep soils with a high water retention
capacity to benefit more from planting in April, and require a full-season cultivar maturity to
achieve maximum yield potential. The graduate student expanded on this research by utilizing
the data to calibrate the DSSAT-CROPGRO model and explore a wider range of planting dates,
genotypes, locations, soil types, and irrigation management scenarios. This research is followed
up by a newly funded project to develop a management decision tool.