Planting date and maturity groups effects on soybean yield in Wisconsin

Soybean [Glycine max (L.) Merr.] planting date (PD) and maturity group (MG) selection are critical decisions for optimizing crop development and enhancing yield potential. This study examines the interaction effects of PDs and MGs on soybean yield in southern Wisconsin, utilizing a fractional replication experimental design across two growing seasons (2022 and 2023). Five PDs in 2022 and six in 2023 were tested, with 50 soybean cultivars per PD, encompassing MGs ranging from 0.3 to 2.9. Results reveal that optimal soybean yield occurred with early planting, particularly before May 20, with MGs between 1.5 to 2.9 performing best. Delayed planting led to diminished significance in MG selection for yield, but overall yield declined consistently, roughly 20 bu/acre, every 20 days beyond the May 20 PD. Practical implications suggest early planting to maximize sunlight capture and extend the seed fill period, alongside the selection of cultivars within the appropriate MG range. While this study is limited to a single location and 2-year duration, future collaborative efforts across multiple sites could provide a more comprehensive understanding of PD and MG interactions, benefiting soybean cultivation practices in diverse environments. Overall, our findings offer valuable insights for southern Wisconsin soybean farmers seeking to optimize yield and profitability in their operations.