The implementation of cover crops in crop rotation is a suggested soil health practice. As cover crops are not harvested and sold, they do not directly provide monetary gain to producers. Therefore, it is imperative that planting cover crops does not negatively affect the subsequent cash crop. However, there is no overall consensus in the literature regarding the effects of cover crops on cash crop yield. To better understand the effects of cover crops on soybean growth and yield in Oklahoma soybean systems, trials were conducted in Bixby, OK, in 2019 and Perkins, OK, in 2019, 2020, and 2021. The objectives of these trials were to (1) determine how different cover crop mixes affect soybean growth parameters and (2) determine if cover crops significantly influence soybean seed yield. Treatments within the trials included six cover crops and a fallow treatment. Soybeans were planted after the termination of the cover crops. Yield and growth parameter data were collected after harvest. No significant differences or consistent trends were detected in the yield among treatments. While cover crops had a significant impact on the number of three- and four-bean pods, no other differences in the growth parameters existed, and they never translated into significant yield differences. Based on our data, cover crops would not benefit the overall cash crop production in the continuous cover crop soybean system in Oklahoma. However, the fact that cover crops did not consistently or significantly reduce soybean yield allows growers to explore other benefits, such as weed management or soil health improvement.
Plant mapping was introduced in soybean, but its illustrative capabilities in stress response are yet to be implemented. Methods to track the soybean physiological response are explained in this note by mapping pods in a coordinate system. A growth chamber study was conducted to measure the specific impact of simulated moisture stress on crop yield and pod development across three stages of crop growth. The treatment growth stages were R2, R3, and R5 (Full Bloom, Beginning Pod, and Beginning Seed, respectively), with two moisture stress durations of 7 and 14 days. A coordinate system was developed to understand soybean pod setting and yield by plotting each unique point on the plant using a set of numerical coordinates. This method summarizes soybean morphology during its vegetative and reproductive growth. Utilizing this method, we found that the growth stages during which moisture stress is experienced and the duration of the stress determined and influenced the location of pods on the soybean plant. The stress level factors impact the yield on the mainstem and branches by pod capacity at different magnitudes. This encoding procedure assists in tracking the location of aborted pods. It protects the yield by retaining pods, thereby leading to a better understanding of the stress experienced by these plants.