Irrigation response and water productivity of deficit to fully irrigated spring camelina

Camelina [Camelina sativa L. Crantz] is an oil seed crop that could be adapted to the northern High Plains of the USA as a biofuel crop. Decreased ground water allocations in Nebraska necessitated determining the impact of limited irrigation on camelina. The objective of this research was to determine the effects of a range of irrigation levels on camelina yield, oil content, soil water changes and water productivity. The study was conducted for four growing seasons at two locations in western Nebraska. One site had a sandy soil whereas the other was a silt loam. Camelina was planted in early to mid-April. Cumulative irrigation treatments were 0, 100, 200, and 300mm with the highest rate adjusted to be non-ET limiting. Camelina extracted soil water from 0.9 to 1m depths which was shallower than canola. It showed significant response to irrigation during dry years but no response in above-average precipitation years. A water use efficiency of 7.0kg mm-1 with 125mm ETc required to produce the first unit of seed yield was shown. Camelina seed yield ranged from 428 to 2867kg ha-1 with 187 and 536mm of cumulative ET. In 2007 and 2008 camelina exhibited peak values in water consumed at 9–10 weeks after planting. Deficit irrigation reduced ET and yield plus accelerated maturity in those years. Oil content was increased by irrigation during drier years with no effect with high growing season precipitation. Oil content ranged from 25 to 50% depending on year, irrigation level and disease. Downey mildew significantly reduced oil content during 2009. Deficit irrigated camelina could be an alternative biofuel crop for this region but further genetic improvement would enhance its competiveness with spring canola.