Self Maintaining Cover Crops Using Winter Annual Oilseeds.

Cover crops in the upper Midwest have shown to provide ecosystem services. However, the implementation of such practices is minimal as it presents many challenges: difficultly establishing and an added expensive to incorporate into current agricultural systems. Recently, two winter annual oilseeds, winter camelina (Camelina sativa L.) and field pennycress (Thalspi arvensi), have shown potential as winter annual cash cover crops in the northern corn belt. Winter annual oilseeds are winter hardy and have short life cycles which facilitate relay cropping with soybean in the upper Midwest.  Relay cropping provides growers with both the added benefit of a longer growing season and the opportunity to be harvested for profit. However, these species show weedy characteristics, such as contributing to the seed bank through seed shatter. The present study is being conducted to determine the ability of each winter annual oilseed to reseed itself through seed shatter at two different harvest dates, based on physiological maturities. The effects of different harvest dates are being investigated at Morris, MN (Barnes loam) and Lamberton, MN (Webster clay loam) in 2016 and 2017. Oilseeds were relay planted with soybean prior to oilseed harvest. Treatments will be evaluated for oilseed seed shatter at harvest, oilseed yield, subsequent soybean yield and emergence of oilseed until the first fall frost. This study aims at providing economic and efficient options to cover crop adoption in the upper Midwest by minimizing seed input.