Strategies to Reduce Irrigation Requirement of Winter Canola.

Depleting Ogallala aquifer and low rainfall in the southern High Plains (SHP) limits agricultural production in the region. Current cereal dominated cropping systems use lot of water and have further exacerbated the water shortage problem. Water efficient crops should be adopted to sustain the aquifer and agriculture in SHP. Winter Canola is a broad leaf, multi-purpose crop that can be grown for oil, forage, biofuel; also offering several rotational benefits. The goal of this research is to identify a stage where irrigation can be withheld without substantial yield loss. A split-split block design; with or without irrigation during dormant periods to refill soil profile as the main plot treatments. Four stage-based irrigation treatments; fully irrigated (Irr), no irrigation at vegetation stage (Vstss), no irrigation at reproductive stage (Rstss), and Rainfed, as the sub-plots. Three varieties; Hekip, Riley, and DKW-46-15 as sub-sub-plot factors, with four replications per treatment. Dormant season irrigation significantly improved seed yield, oil yield, and biomass (at α = 0.10). Fully irrigated treatments produced the highest seed and oil yield. Although, dormant irrigation increased seed and oil yield, and biomass for each staged-based irrigation treatment, the interaction was only significant for oil yield (at α = 0.05). With irrigation during dormant period, Vstss and Rstss treatment showed a 4% and 32% yield loss and with no dormant irrigation yield losses were 42% and 47% respectively. Among yield components, pods per plant influenced seed yield more than thousand seed weight, and seeds per pod. Dormant season irrigated Irr canola significantly increased pods per plant by 25%. Overall, Hekip performed better than the other two cultivars. Dormant season irrigated Vstss proved to be the best irrigation strategy for canola. Irrigation can be withheld during vegetative stage without much yield loss, provided soil profile was re-filled during dormant period.