Double-Cropping Pennycress (Thlapsi arvense L.) with High-Value Short-Season Crops in the Upper Midwest.

Pennycress (Thlapsi arvense L.) is a recently developed winter annual oilseed that can mitigate nutrient runoff while providing an additional source of income. Planted as a winter annual cash cover crop, this species provides ecosystem services in both the fall and spring. Pennycress oil has potential use as an industrial feedstock for various products, such as biofuels and lubricants. However, pennycress does not reach maturity until mid- to late-June, after traditional full-season corn and soybeans are planted in the Upper Midwest. The objective of this study is to identify and evaluate short-season crops that could fit into a double-crop system with pennycress. Varieties of six crops with differing lengths of maturity were chosen for a total of fourteen treatments. These crop varieties were monitored for leaf area index (LAI), height, growth stage, weediness of pennycress, and yield. The study was carried out in 2016 at Rosemount Research Station (Rosemount, MN) and Swan Lake Research Station (Morris, MN). Germinating pennycress had no effect on crop yields compared to plots kept weed-free. At Rosemount, sweet corn and soybean varieties that were closest to full season maturity groups (0.7 and 1.4) had yields comparable to yields of full season corn and soybean in Minnesota, while the 0.3 and 0.2 MG soybean varieties resulted in a 25.8% and 14.5% yield loss, respectively. Eclipse black bean yield was equivalent to variety trials run by North Dakota State University, while Montcalm kidney bean had a 50.7% yield gain. Understanding the potential of different short-season high-value crops double-cropped with pennycress will help to develop new agricultural rotations that are both ecologically and economically sustainable.