Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pennycress is a new winter oilseed crop that can be grown between corn and soybean to provide live soil cover and can be harvested for profit. Thus, pennycress is considered a ‘cash’ cover crop which may attract increased grower adoption. However, the short window between grain corn harvest and soil freezing makes pennycress establishment difficult. Early maturing corn hybrids can be harvested early enough to allow more time to have decent establishment of pennycress in fall. This approach allows soybean double-cropping with seeding of soybean following pennycress harvest thus allowing growers to harvest two crops in one growing season. However, corn grain yield decreases due to the use of early corn hybrids compared with the full-season conventional hybrid is a concern. But we do not have this information. Therefore, the objective of this study was to assess the economic benefits of growing pennycress between grain corn and soybean using early corn hybrids. This study was conducted at Morris and Rosemount (Minnesota), Custar (Ohio) and Lexington (Illinois) over two growing seasons. The corn hybrids used ranged from 76-day to 95-day corn at Morris and Rosemount, and 95-day to 113-day corn at Custar and Lexington. The results showed that seeding pennycress following early maturing corn increased annual net benefits (ANB) to the extent of 40% compared with the full-season hybrid. The silage corn-pennycress-soybean rotation provided more net benefit than the system with grain corn because of higher pennycress yield. However, the 105-day corn at Custar and Lexington, 95-day corn at Morris, and 86-day corn at Rosemount resulted in minimal losses in ANB compared with the silage corn system. Results indicate that incorporating pennycress after silage corn or early maturing grain corn in a corn-soybean rotation may be economically feasible. Results will inform growers in selecting corn hybrids to follow with pennycress in a corn -soybean rotation to maximize economic return. Results also benefit extension specialists, agricultural consultants, and other scientists interested in how to integrate pennycress into corn-soybean rotations.

Technical Abstract: The narrow window to establish pennycress (Thlaspi arvense L.) following grain corn (Zea mays L.) harvest before soil freezing is challenging. The use of early corn relative maturity (CRM) hybrids may accelerate corn harvest for improving pennycress establishment, but corn yield reduction is a concern. We investigated the economic feasibility of integrating pennycress between corn-soybean [Glycine max (L.)] rotation using varying CRM hybrids. The CRM hybrids ranged from 76-d to 95-d (full season) at northern sites (Morris and Rosemount, Minnesota), and 95-d to 113-d (full season) at southern sites (Lexington, Illinois, and Custar, Ohio). Full-season corn harvested for silage was included as a treatment representing optimum conditions for sowing pennycress. Soybean was double-cropped following pennycress harvest. Partial budget procedure was used for economic analysis. The annualized net benefits (ANB) of the whole system (corn-pennycress-soybean) ranged from USD 315 ha-1 to 945 ha-1. The silage corn system produced greater ANB than the grain corn at all sites due to greater pennycress yield. But the 105-d corn in the south, 95-d corn at Morris, and 86-d corn at Rosemount resulted in minimal ANB losses compared with silage corn. Among grain corn treatments, some of the early CRM treatments resulted in greater ANB (up to 40%) than the full season hybrid. Results demonstrate economic potential to integrate pennycress into a corn-soybean system using early CRM hybrids. Valuing the diverse ecosystem benefits pennycress offers as a cash cover crop may help facilitate pennycress adoption to achieve system sustainability.