Stover removal has minimal impact on pennycress seeded into standing corn

In the Upper Midwest, corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are the most prominent agricultural crops, occupying land for only half the year. Their fallow periods are associated with nutrient leaching and soil erosion, but they also represent an opportunity to establish winter-hardy crops, like pennycress (Thlaspi arvense L.), that can reduce negative environmental impacts while contributing to farm profitability. A lack of agronomic best management practices remains a barrier to pennycress adoption. The objectives of this study were to evaluate the impact of stover presence on pennycress stand establishment and seed yield after seeding pennycress into R4 corn. This study was conducted over the 2014-2015 and 2015-2016 growing seasons with MN106 pennycress at three locations in Minnesota. At maturity, corn plants were removed from plots in 25% increments between 0% and 100% to simulate stover removal scenarios. Pennycress seedlings were unable to compete with corn for available light resources and did not have enough time following corn harvest to establish a dense stand in the autumn with only 5% and 10% green cover in 2014 and 2015, respectively. Despite poor early season emergence, the average seed yield, 1223 kg ha-1, was high relative to other studies using MN106, indicating that challenges of growing pennycress under adverse conditions may not be a barrier to competitive seed yields. Experimentation on the corn-pennycress system should continue in the future to further explore and establish best management practices for this double crop. Rate of stover removal minimally impacted pennycress germination. Pennycress seedlings provided little autumn soil coverage. Stover removal rate did not affect pennycress seed yield.