Date of Award
Master of Science (MS)
Department of Agriculture
Cover crops are a key management strategy for mitigating the negative environmental impacts of agriculture. However, only 3% of Illinois crop acres report planting cover crops, largely due to a lack of direct financial incentive. Pennycress (Thlaspi arvense L.) is a cash cover crop that could provide a solution to this problem by providing environmental benefit as well as an economic return. Although it has achieved profitable yields in clean, well-managed breeding plots, pennycress faces establishment challenges when planted after corn in an agricultural setting. Therefore, the objective of this research project was to evaluate different agronomic management strategies to improve pennycress growth in the field conditions following corn harvest. Corn harvest leaves behind substantial residue on the field, which impedes the seed-to-soil contact necessary for pennycress germination. Pennycress was planted behind one management system where corn was harvested for silage and four systems where corn was harvested for grain with varying residue management and planting strategies. Pennycress growth was significantly better in the low-residue conditions following silage, and there was no difference among the four residue management strategies. Thus, the management of corn residue alone may not be a feasible option for improving pennycress growth after corn is harvested for grain. Full-season corn hybrids are typically harvested in October to November, but pennycress grows best when planted by late September. Corn hybrids with shorter relative maturity (RM) can be harvested in the fall and may offer an earlier planting date for pennycress. Treatment levels included pennycress planted behind five corn hybrids ranging from 95- to 113-day RM and one harvested for silage. Pennycress growth was best when planted behind silage. Although the 95- and 100-day RM treatments performed better than the longer-maturing hybrids, they still could not compete with the silage treatment. This shows that there may be some advantage to planting pennycress behind shorter maturing corn hybrids, but corn residue still inhibits ideal germination and crop growth. Results of both studies indicate that the residual corn stover remaining after grain harvest is a significant hinderance to optimal pennycress growth. Other low-residue crops that allow early planting need to be identified and evaluated to allow for the success of pennycress as a profitable cover crop in Illinois.
Wohrley, Bethany, "Pennycress Establishment in Response to Management of Corn Residue and Harvest Date" (2022). Theses and Dissertations. 1583.