Stover removal has minimal impact on pennycress seeded into standing corn

Authors: CUBINS, JULIJA - University Of Minnesota; WELLS, SAMANTHA - University Of Minnesota; JOHNSON, GREGG - University Of Minnesota; BLACK, KATIE - University Of Minnesota; PEREZ, JAYLEEN - University Of Minnesota; GONCH, ARIANNA - University Of Minnesota; FORCELLA, FRANK - Retired ARS Employee; Gesch, Russell - Russ

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2024
Publication Date: 4/8/2024
Citation: Cubins, J.A., Wells, S.S., Johnson, G.A., Black, K.L., Perez, J., Gonch, A., Forcella, F., Gesch, R.W. 2024. Stover removal has minimal impact on pennycress seeded into standing corn. Crop Science. 64(3):1085-1969. https://doi.org/10.1002/csc2.21242.
DOI: https://doi.org/10.1002/csc2.21242

Interpretive Summary: The two-year summer annual crop rotation of corn and soybean dominates the Midwest agricultural landscape. Because of this, the soil between late fall and spring remains bare and exposed to erosion and loss of critical nutrients like nitrogen. Pennycress is a winter annual oilseed crop that can potentially be grown between corn and soybean thus protecting the soil during the fall to spring fallow period. However, best management practices are needed to optimally establish pennycress in a corn-soybean rotation. This study, conducted at three locations in Minnesota over two growing seasons, evaluated the effects of corn stover removal on fall and spring establishment and seed yield of pennycress that was interseeded into corn at its R4 growth stage. Corn stover was removed up to 100% at 25% increments at the time of harvest. Pennycress germination and growth after interseeding was relatively low due to lack of light under the corn canopy. Stover removal did not impact pennycress fall canopy cover during the first season. However, the 100% stover removal rate during the second season resulted in much greater fall pennycress canopy cover than in the 0% removal treatment. Across all three sites and both years, pennycress seed yield was relatively high, averaging 1115 lbs./acre, and was not affected by corn stover removal. More research on optimizing interseeding pennycress into standing corn may be warranted based on these results.

Technical Abstract: In the Upper Midwest, corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) are the most prominent agricultural crops, but they only occupy land for half the year. Moreover, their fallow periods are associated with externalities such as nutrient leaching and soil erosion. These fallow periods are opportunities to establish winter-hardy oilseed crops, like pennycress (Thlaspi arvense L.), that can reduce the negative environmental impact while contributing to farm profitability. However, a lack of agronomic best management practices remains a barrier to introducing pennycress to the Upper Midwestern landscape. The objectives of this study were to evaluate the impact of corn stover removal on pennycress germination and establishment in the autumn and the following spring and to quantify pennycress seed yield. This study was conducted over the 2014-2015 and 2015-2016 growing seasons with ‘MN106’ pennycress at three locations in Minnesota, USA. Pennycress was seeded into R4 corn and stover was removed following corn harvest; stover removal ranged between 0 and 100% in 25% increments. Pennycress germination suffered due to a lack of light resources under the corn canopy and, overall, pennycress had less than 5 and 10% canopy cover in the autumn following stover removal in 2014 and 2015, respectively. Stover removal rate had no impact on pennycress canopy cover in autumn 2014, but the 100% removal treatment had greater canopy cover than 0% in autumn 2015. Stover removal did not affect pennycress seed yield, but the average yield, 1250 kg ha-1, was high relative to other studies using ‘MN106,’ indicating that this cropping method should remain the focus of future experimentation.