Deficit Irrigation Management of Winter Canola in the Southern High Plains.

Canola can be an important alternate crop in the Southern High Plains with a wide range of potential benefits that include source of high quality oil for human consumption, potential feedstock for biodiesel industry, protein rich meal source for dairy animals, and good rotational crop to control weed problems in predominantly winter cereal rotation. Field trials were conducted at Agricultural Science Center at Clovis, NM in 2008-2009 and 2009-2010 seasons to compare growth and water use patterns of winter canola with winter wheat and also to develop water use and yield relationships for winter canola. Six levels of irrigation ranging from rainfed (only irrigated to establish the crop) to about 25% higher than the estimated evapotranspiration of winter wheat were used in the study. Each plot was irrigated with surface drip system with water meters to measure the exact amount of water applied. Winter canola exhibited excellent recovery from late spring frost that killed most of the regrowth early in the spring. Seasonal pattern of biomass accumulation was observed on three of the irrigation treatments. Biomass production responded to irrigation levels. Early in the season, when winter crops are used for grazing, biomass production by winter canola was comparable to winter wheat. Results from first year indicated that two canola cultivars used in the study, Rally and DKW-41-10 differed in their response to irrigation management. Seed yield of Rally was higher under the High Plains conditions (2.04Mg ha^-1). Harvest index, which is an indicator of biomass partitioning into seed yield, was more stable in canola over the range of irrigation levels. Seed oil content ranged from 39 to 42 per cent, lower numbers reported from the drier treatments. Response of oil content to irrigation management was much smaller compared to seed yield. Results from both years along with soil moisture data will be presented in the meeting.