Yield, Oil Content and Water Use of Summer-Planted Winter Canola in Semiarid Oregon.

Winter canola has customarily been planted in early September in dryland fields in eastern Oregon.  Stand establishment is very difficult at this time because of low seedzone water content and high surface soil temperature.  To avoid these severe limitation, winter canola was planted in June and July when seedzone water content and soil temperatures are more favorable.    Four winter canola cultivars were sown in a 4 replication split plot experiment at 3 planting date in 2010, 2011, and 2012.  Planting date was the main plot treatment and cultivar the subplot variable.   Stand establishment and yield were best when winter canola were planted in June or July and poorest when planted in September in 2010 and 2011.  In 2012, stand establishment was equal for all planting dates, and yield greatest in the September planting.   Soil water content in June and July plantings were 50 to 75 mm lower in March just prior to bolting than September plantings.  After harvest, soil water content was equal for all planting dates.   Planting date influenced when soil water was utilized but didn’t influence the total water used.   Oil content was not affected by planting date.   Summer planting of winter canola in dryland Oregon is a practice that increases stand establishment and lowers risk.  Soil water is depleted earlier in the crop year, so yields can be expect to be lower in years of early spring drought.