Canola and Camelina Yield and Water Use Under Limited Irrigation.

As ground and surface water sources decline in the western US, irrigated crops that use less water but offer sustained income potential are needed. The objective of research conducted from 2006 through 2009 was to determine effects of limiting irrigation on plant growth, seed yield and crop water use of spring camelina and canola. Locations were Scottsbluff, Alliance and Sidney, NE. Four irrigation schemes (0, 100, 200, and 300 mm or sufficient irrigation to be non-ET limiting) were used with irrigation timing based on estimated crop water use or critical growth stages. Rain gauges recorded irrigation and rainfall. Soil water content from 0-15 cm was determined gravimetrically, while water contents at soil depths of 0.3, 0.6, 0.9 and 1.2 m were determined from neutron probe measurements. Cumulative water use (evapotranspiration) was calculated from the water balance equation, assuming negligible rainfall or irrigation water loss due to surface runoff or deep percolation. Camelina seed yields increased from 560 to 2800 kg ha^-1 over an irrigation water use range of 185 to 500 mm whereas canola seed yields increased from 600 to 3300 kg ha^-1 over an irrigation water use range of 165 to 575 mm. Yield-ET and production function data will be discussed. Irrigation and water use irrigation production functions will provide additional management tools for predicting camelina and canola yields under limited and full irrigation cropping systems in the High Plains.