MON 37500 Soil Residues Affect Rotational Crops in the High Plains1

摘要

MON 37500 is a sulfonylurea herbicide that selectively controls Bromus spp. in winter wheat. Field studies were conducted near Sidney, NE, and Archer, WY, to determine the sensitivity of corn, foxtail millet, grain sorghum, proso millet, and sunflower to soil residues of MON 37500. MON 37500 was applied to winter wheat at 0, 35, 69, and 139 g/ha in the autumn of 1997. Rotational crops were no-till seeded into the standing residues of the previous year's crop from 1999 through 2001. Grain yields for corn, foxtail millet, and proso millet planted 18 to 20 mo after herbicide application were not affected by soil residues of MON 37500. In contrast, average grain yields of grain sorghum were reduced from 1,760 to 30 kg/ha at Archer and from 4,480 to 390 kg/ha at Sidney as MON 37500 rates increased from 0 to 139 g/ha. Thirty to 32 mo after herbicide application, average grain yields of grain sorghum were reduced from 2,360 to 620 kg/ha at Sidney and average aboveground biomass was reduced from 4,000 to 1,800 kg/ha at Archer as MON 37500 rates increased from 0 to 139 g/ha. Nineteen to 20 mo after herbicide application, average sunflower seed yields were reduced from 1,450 to 20 kg/ha at Archer and from 1,830 to 540 kg/ha at Sidney as MON 37500 rates increased from 0 to 139 g/ha. Visual injury was observed 31 to 32 mo after herbicide application, but drought in 2000 prevented collection of seed yield data. In the High Plains, foxtail millet, proso millet, and corn may be successfully grown 18 to 20 mo after the application of MON 37500 to winter wheat. Successful production of grain sorghum and sunflower may require a minimum recrop interval between treatment and planting of >36 mo.