Comparison of Desiccant Timing and Harvest Method in Canola.
Brian M. Jenks1, Denise M. Markle1, Gary P. Willoughby1, John R. Lukach1, Fabian D. Menalled2, and Edward S. Davis2. (1) North Dakota State Univ, 5400 Highway 83 South, Minot, ND 58701, (2) Montana State Univ, 719 Leon Johnson Hall, Bozeman, MT 59717-3120
A study evaluating the use of desiccants as a harvest aid in canola was conducted at three locations in 2005: 1) Minot, ND, 2) Langdon, ND, and 3) Bozeman, MT. The objectives were to: 1) determine the effect of paraquat and diquat applied preharvest at three timings on canola yield, seed moisture, and seed quality, 2) compare yield, seed moisture, and seed quality of swathed canola to paraquat and diquat-treated canola, and 3) determine the effect of harvest timing following a paraquat or diquat application on canola yield, seed moisture, and seed quality. Paraquat was applied at 7.8 oz ai and diquat was applied at 6 oz ai. One treatment was swathed with a plot swather on the same days the paraquat/diquat treatments were applied. The paraquat, diquat, and swath treatments were harvested 7 and 14 days after treatment (DAT). Yield loss due to shattering was minimal at any location. In Minot, paraquat- and diquat-treated plots produced similar canola yields compared to swathed treatments. Canola yields were also similar for the three timings and two harvest dates. There were no differences in test weight and oil content between desiccated or swathed canola. In Langdon, paraquat- and diquat-treated plots produced similar canola yields and seed weight compared to swathed treatments. However, the later desiccant/swath timing produced higher yield and seed weight than timing 2, which in turn, was higher than timing 1. In Bozeman, paraquat- and diquat-treated plots produced similar canola yield and test weight compared to swathed treatments. Canola yields were also similar for the 2 harvest dates averaged across desiccants and timings. However, canola swathed or desiccated at the third or latest timing did yield higher than canola treated at the other two timings. Additionally, canola desiccated or swathed at the earliest timing had a significantly lower test weight.