Crop growth and productivity of winter camelina in response to sowing date in the northwestern Corn Belt of the USA

Camelina [Camelina sativa (L.) Crantz] is a member of the Brassicaceae family, consisting of both winter and spring biotypes. In the northern Great Plains, USA, winter camelina has the potential to serve as a low-input oilseed crop for cover and/or as a source of oil used for advanced biofuels as well as human and animal consumption. Winter annual biotypes of camelina are well suited for double- or relay- cropping systems. The objective of this study was to determine optimum sowing dates for achieving the highest winter camelina seed yield as well as the delivery of several ecosystem services. The experiments were conducted in Fargo, ND in 2017-2018 and in Fargo and Prosper in 2018-2019 seasons. Six sowing dates from the end of June to midOctober were evaluated. The experimental design was a randomized complete block with four replicates at each location. A total of 700 pure live seeds m(-2) were sown in each date. Fall stand counts ranged from 17 to 279 plants m(-2) with greater stands at later fall sowing dates. Spring stand counts ranged from 7 to 84 plants m(-2), with higher stand counts for sowing dates from the beginning to mid-September. Across plants in several sowing dates that survived the winter, seed yield ranged from 99 to 1317 kg ha(-1). Results indicate that winter camelina sown before September usually does not survive the winter in this region. When winter camelina is used as a cover crop, sowing prior to mid-September was critical for biomass production and reducing soil residual nitrate. However, when winter camelina is harvested as a cash crop, the highest harvestable seed yield occurred with fall sowing in September and even as late as early October.