Field Pennycress Seeding Dates in Corn and the Subsequent Effects on Soybean Yield.

Field pennycress (Thlaspi arvense L.) has the potential to serve as a cover crop and an oilseed crop for biofuel production. Field research was conducted from 2014 to 2016 near Novelty, Missouri to 1) determine the effect of seeding date on corn (Zea mays L.) yield; 2) evaluate the effect of corn herbicide management systems on pennycress establishment and yield; and 3) evaluate the effect of pennycress on soybean [Glycine max (L.) Merr.] yield.  The experiment was arranged as a split-plot design with field pennycress seeding date as the main plot and corn weed management systems as the sub-plot.  Field pennycress was broadcast overseeded into corn at the V6 and VT growth stages and drill seeded after corn harvest. Corn yields in 2014 and 2015 were high (14 to 17 Mg/ha).  There was no effect of field pennycress overseeding date on corn yields in 2014, and slight differences in corn yields (484 kg/ha) among pennycress seeding dates in 2015. Field pennycress yields were up to 380 kg/ha in 2015 and 250 kg/ha in 2016 when overseeded into corn or drill-seeded following harvest.  Field pennycress did not affect soybean yield in 2015 although overall yields were low (700 to 1300 kg/ha) due to extremely wet conditions throughout the region. Continued field research is needed to integrate field pennycress into cropping systems in the Midwestern United States.