Yield tradeoffs of early corn harvest to enhance pennycress establishment

Authors: Mohammed, Yesuf; Gesch, Russell - Russ; WELLS, SAMANTHA - University Of Minnesota; HELLER, NICHOLAS - Illinois State University; LINDSEY, ALEXANDER - The Ohio State University; HARD, ALEXANDER - University Of Minnesota; PHIPPEN, WINTHROP - Western Illinois University; BEDEKER, BETHANY - Illinois State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2023
Publication Date: 6/12/2023
Citation: Mohammed, Y.A., Gesch, R.W., Wells, S.S., Heller, N.J., Lindsey, A.J., Hard, A.W., Phippen, W.B., Bedeker, B. 2023. Yield tradeoffs of early corn harvest to enhance pennycress establishment. Agronomy Journal. https://doi.org/10.1002/agj2.21370.
DOI: https://doi.org/10.1002/agj2.21370

Interpretive Summary: In the upper Midwest, the soil is left bare between corn harvest and the next crop planting, leaving it vulnerable to soil erosion and nutrient losses. Pennycress is a winter oilseed crop that can be planted in fall following corn harvest to provide soil cover from fall until the next spring, while producing seeds that can be used for making biodiesel. This helps to diversify and intensify (i.e., adding a different crop than usual) cropping systems. But the time between corn harvest and winter is short thus making pennycress establishment challenging. Early maturing corn hybrids may be harvested early enough to allow more time for establishing pennycress, but also may not yield as much as full-season hybrids. In this study, we planted five corn hybrids varying in maturity, and after harvest, pennycress was immediately planted. Pennycress was harvested the following spring, and then planted to soybean as a double crop. The objectives of the study were to compare different corn hybrids on pennycress establishment, seed yield, oil content and corn grain yield tradeoff from using early hybrids. The study was conducted at four locations: Morris and Rosemount (MN), Custar (OH) and Lexington (IL) over two growing seasons. The corn hybrids used ranged from 76 to 95-day corn at Morris and Rosemount, and from 95 to 113-day corn at Custar and Lexington. Results showed that seeding pennycress following early maturing corn hybrids allow better pennycress establishment with increased soil cover particularly in early spring compared with seeding pennycress following late maturing corn. Average across growing seasons, pennycress seed yields ranged from 346 to 694 lb/ac at Custar, 572 to 744 lb/ac at Lexington, 323 to 699 lb/ac at Morris, and 744 to 1818 lb/ac at Rosemount. The use of 86-day corn hybrid for the two Minnesota sites, and 95-day corn hybrid for Custar and Lexington sites facilitated timely pennycress establishment with little or no corn grain yield loss compared with the longer-season hybrids. Results will inform growers that introducing pennycress as a new oilseed crop into their existing corn-soybean rotations can provide soil cover and new economic opportunity. Results also provide information for university extension specialists, agricultural consultants, and other scientists seeking ways to sustainably intensify and diversity crop production.

Technical Abstract: Oilseed pennycress (Thlaspi arvense L.) establishment following grain corn (Zea mays L.) harvest in northern latitudes is challenging because of short duration between corn harvest and soil freeze. The use of shorter-season corn hybrids than typical for the region may partly solve this challenge, but tradeoffs in reduced corn yield may be a concern. The objectives of this study were to evaluate corn relative maturity (CRM) hybrids on timely pennycress establishment, seed and oil yields, and evaluate yield tradeoffs of both corn and pennycress. The CRM hybrids ranged from 76 to 95-day for northern sites (Morris and Rosemount, Minnesota), and from 95 to 113-day for the southern sites (Custar, Ohio and Lexington, Illinois). Pennycress plant density, green cover, and yield were generally greater when pennycress was seeded following early corn hybrids. Average across years, pennycress seed yields ranged from 388 to 778 kg ha-1, 641 to 834 kg ha-1, 362 to 784 kg ha-1 and 834 to 2038 kg ha-1 at Custar, Lexington, Morris, and Rosemount, respectively. The use of 86- and 95-day corn hybrids for the northern and southern sites, respectively, facilitated timely pennycress establishment with little or no corn yield loss compared to longer-season hybrids. Late pennycress seeding led to less autumn emergence thus providing minimum soil cover, but emergence increased in spring. Developing pennycress varieties better suited for emergence under high corn residue or employing alternative residue management practices to increase autumn pennycress emergence is recommended. Additionally, economic analysis of the entire crop rotation (corn-pennycress-soybean) is needed.