Desiccation of corn allows earlier direct seeding of winter camelina in the northern Corn Belt

Abstract

AbstractIn the U.S. Upper Midwest where growing seasons are short, establishing winter annual cover crops following corn (Zea mays L.) is challenging. Winter camelina [Camelina sativa (L.) Crantz] shows promise as a winter annual cover crop that can be dual cropped with soybean [Glycine max (L.) Merr.] to help diversify the corn–soybean rotation. This 2‐yr field study in southern and western Minnesota evaluated desiccating corn with a preharvest aid to hasten its dry‐down and hence harvest so that camelina could be no‐till drilled in a timely manner. We hypothesized that direct drilling camelina following corn harvest would improve establishment and yields. Sodium chlorate was applied as a desiccant to corn at early (D1) and mid‐R5 (D2) and physiological maturity (D3) stages of development, including an untreated check. The D1 and D2 treatments hastened corn harvest by 1 to 3 wk compared with the check. Corn grain yields were unaffected by the D2 and D3 treatments, but significantly declined by 16% in D1. Camelina seed yield did not differ among desiccation treatments and averaged 815 kg ha−1 across both locations with an average oil content of 385 g ka−1. Desiccating corn hastened its harvest allowing more time to drill‐seed camelina, thus improving establishment. However, more work is needed to improve management and genetics of winter camelina for use as a cash cover crop in corn systems.