The oil from canola (Brassica napus L.), a variant of rapeseed, has superior nutritional qualities. It is low in erucic acid and glucosinolates. In addition, canola oil is very low in saturated fat making it a preferred oil for human consumption. In 2004, United States growers produced 218 million kilograms of refined canola oil while American consumers consumed 387 million kilograms of canola oil (Anonymous, 2005a).
The National Winter Canola Variety Trial has been in existence at Belleville and Carbondale, Illinois since 1995. Of the 20 trials planted between 1995-2004, fifteen were harvested. Two trials were lost to poor stand establishment due to planting into dry soil conditions in late October. A third trial was also lost to dry conditions at planting causing poor stand establishment although it was planted in a timely manner. The fourth trial was lost due to winter kill from ice covering the plots for several days. The fifth trial was lost due to spring flooding. Across harvested trials, winter survival among cultivars ranged from 36-100% with an overall mean of 83.5%. Cultivar yields ranged from 0-4836 kg/ha with an overall mean of 2439 kg/ha.
Research was conducted in the 2003-2004 growing season to find the best management practices to increase winter survival and yield of winter canola. Planting date, seeding rate, and nitrogen rate were studied in separate experiments. Planting on September 10 or September 17 significantly increased yield as compared to later plantings of September 24 and 30. No advantage was found among the four seeding rates (6.7, 9.0, 12.0, and 13.4 kg/ha) tested. Higher nitrogen rates of 135 and 180 kg N/ha resulted in significant yield increases over the lower rates of 0, 45, and 90 kg/ha.
Based on these results, a factorial study was conducted in the 2004-2005 season testing three planting dates (9/9, 9/16, and 10/6), two seeding rates (9.0 and 11.2 kg/ha), and three nitrogen rates (90, 135, and 180 kg N/ha). The earlier planting dates of September 9 and 16 were found to significantly improve fall stand, winter survival, and yield. Again, no difference was found between the two seeding rates. A linear relationship existed between the nitrogen rates and yield with the highest nitrogen rate providing the highest yield. A thicker fall stand resulted in higher winter survival and both correlated to higher yield.