Influence of Harvest Date on Winter Camelina Phenology, Seed Yield, and Quality.

Winter camelina (Camelina sativa [L.] Crantz) as an oilseed crop has gained considerable attention in recent years due to its adaptability to marginal soils, short growth cycle, and low agricultural inputs. There is a great need to assess the importance of oilseeds as winter cover crops in corn-soybean rotations. The present study was conducted to determine optimum harvest time of winter camelina to maximize seed yield and quality, while allowing establishment of soybean in a double-cropping scenario. Winter camelina was harvested at eight different dates ranging from early June through early July. Winter camelina phenology, seed yield and quality, and canopy reflectance indices (NDVI and LAI) associated with harvest time were evaluated. Seed moisture, LAI, and NDVI all decreased significantly (P < 0.05) as harvesting date progressed. However, no significant differences were observed in plant height and aboveground biomass. Seed moisture content was lowest (11.5 %) at the final harvest date. In contrast, a significant increase in oilseed yield and oil contents were observed as the harvesting date advanced. The highest (1373 kg ha^-1) and lowest seed yield (197 kg ha^-1) were observed at the last and first harvesting dates, respectively. Highest oilseed content (39%) was observed during the last two harvests dates. However, seed yield and oil content were statistically similar from about mid-June (fifth harvest date) through early July (eighth harvest date). Initial results indicate that seed yield and oil content of winter camelina may be maximized by harvesting around mid- to late June, thus allowing soybean to be planted as early as possible in a double cropping system in the Upper Midwest.