Field Pennycress Seeding Date and Corn Herbicide Management Effects on Corn, Pennycress, and Soybean Production

Field pennycress (Thlaspi arvense L.) has the potential to serve as a cover crop and oilseed crop for biofuels. Field research was conducted from 2014 to 2017 in northern Missouri to evaluate the effect of (i) pennycress seeding date on corn (Zea mays L.) yield; (ii) corn herbicide treatments on pennycress yield; and (iii) pennycress on soybean [Glycine max (L.) Merr.] yield. The experiment was arranged as a split-plot design with pennycress seeding date as the main plot and residual corn herbicide was the subplot. Pennycress was broadcast overseeded into corn at V4 to V6 and R5 to R6 growth stages, drill seeded after corn harvest, and compared with a non-seeded control. There were no differences in pennycress test weight, grain moisture, or yield among corn herbicide treatments. Corn yields were high (13.1 to 16.1 Mg ha(-1)), but there was no effect of field pennycress overseeding date on corn yields within years. Field pennycress yields were greatest when seeded into R5 to R6 corn in 2015 (252 kg ha(-1)) and 2016 (229 kg ha(-1)), but no yield differences were observed among seeding dates in 2017. Drill-seeded pennycress increased soybean yield in 2015 compared with the non-seeded control, though overall soybean yields were low (705 to 1320 kg ha(-1)) due to wet conditions. Pennycress did not affect soybean yield in 2016 or 2017 when yields were high (3950 to 4540 kg ha(-1)). Pennycress could be integrated into a corn-soybean rotation with no detrimental effects on either crop in northern Missouri.