Canola Response to N Fertilizer Rates in Irrigated Cropping Systems.

In considering producing canola (Brassica campestris L.) for oil production for biofuels, optimizing N fertilizer rates is an important consideration to determine the feasibility of energy generation. Additionally, irrigated row crop producers in the irrigated areas of the inland Pacific Northwest need alternative crops in potato (Solanum tuberosum L.) production systems since disease pressure precludes planting potatoes more frequently than every 3 – 5 years in a given field.  Canola cultivars Athena and Rapier were fall planted in 2006, 2007, and 2008 for summer production in 2007, 2008, and 2009.  Plots (4.8m x 9.1m) were arranged in a randomized block design with four replicates of five different N rates (applied as urea), ranging from very low to high.  Soils samples were collected post harvest to a depth of 30 cm and analyzed for NO₃-N.  Yield was determined by harvesting the center one-third of each plot with a Wintersteiger plot combine, the seed collected, weighed to determine yield, and a sub sample saved for oil analysis.  In both 2007 and 2008 yield differed by variety but not N rate.  Seed oil analysis is ongoing and will be evaluated to determine if there is any relationship between seed oil and N rates.  However, the lack of yield response to N suggests that canola could be produced with low N rates, increasing the energy efficiency of this potential biofuel crop.