Master of Science, The Ohio State University, 2023, Horticulture and Crop Science

When attempting to maximize soybean yield it is vital to analyze the interactions that occur between planting date and cover crop presence. Research has consistently shown that planting date has the greatest influence on soybean grain yield. However, studies testing for how early soybean can realistically be planted and impacts that may result from such a planting are non-existent. Therefore, the objectives of this study were to 1) determine the yield impact when growing soybean with or without a rye cover crop for three different planting dates and 2) to measure the survivability of soybean seedlings at each planting. A field experiment was conducted at two locations within Ohio in South Charleston and Wooster for the 2021 and 2022 growing seasons. A randomized complete block design was utilized consisting of four replications with nine treatments. The two factors examined were planting date and cover crop presence along with termination timing. Herbicide burndown of the cover crop was coordinated with the planting date of each soybean group. Plant population over time, soil temperature along with percent moisture over time, soybean yield, and rye biomass dry weight were evaluated. Plant populations were between 25% and 42% greater as planting was delayed into May and the best stands were achieved by forgoing a cover crop. However, the treatments with the greatest plant populations planted in May did not result in a yield advantage compared to the plantings in early or late April. When planting ultra-early prior to 15 April, a cover crop proved unnecessary and should be avoided. Planting ultra-early with a cover crop resulted in significant yield declines across both locations of between 24% and 59% compared to planting ultra-early without a cover crop.

Committee: Laura Lindsey (Advisor); Alex Lindsey (Committee Member); Marilia Chiavegato (Committee Member) Subjects: Agriculture; Agronomy