Field Pennycress and Camelina Oilseed Yield in a Relay Cropping System with Soybean.

Field pennycress and camelina are proposed as potential oilseed cover crops that can fit into a soybean production system aimed at greater profitability while providing needed cover to address critical soil and water quality issues. Successful integration of soybeans with oilseed cover crops requires maintaining or increasing oilseed yield of both the cover crop and soybean. This can be especially challenging given the short growing season in Minnesota. Planting soybeans into standing field pennycress or camelina is being considered as a way of extending the growing season of soybean compared to a traditional double cropped system. Here we present results of an experiment to explore yield of soybean and oilseed covers when planted together in a relay system compared to a traditional double crop system across three locations in Minnesota. The experimental design was a randomized complete block in a split plot arrangement. Main plots consisted of field pennycress, camelina, and a no oilseed cover check. Subplots were oilseed cover harvest timing (early or late) in a relay cropping system and a conventional double cropping system in which soybeans are planted after oilseed cover harvest. Preliminary results indicate no soybean yield penalty when relay cropped with oilseed covers compared to a double crop system. Field pennycress and camelina oil yield was not influenced by early or late harvest. Furthermore, both oilseed cover crops reduced soil nitrate in the spring compared to no cover treatments.  These finding suggest that pennycress or camelina can be successfully integrated into a soybean production system. Furthermore, oilseed cover crops can provide ecosystem services by reducing soil nitrate availability early in the season.