Evaluation of atrazine, simazine, and isoxaflutole applied early preplant in glyphosate-resistant soybean

摘要

This study was designed to evaluate soybean response to soil applied herbicides in weed-free conditions. The study was conducted on a Weir silt loam with 1.5 percent organic matter and pH 6.4 at the Belleville Research Center. Fertilizer applied was50 and 150 lb/A P_2O_5 and K_2O, respectively, to an area that had been cropped to corn in 2001. Bergmann-Taylor brand 'B-T 369CR' glyphosate-resistant soybean was planted 1.0 inch deep at 75 lb/A into a no-till seedbed on May 30. Plots consisted of four rows with 30 inch row spacing, 28 ft long arranged in a randomized complete block design with 3 replications. The herbicides were broadcast applied with a CO_2 pressurized sprayer using 8002 flat fan tips at 40 PSI in 20 GPA water. Application timingswere early preplant 30 days prior to planned planting date (EPP30), preemergence (PRE) and soybean stage V4 (V4). Monthly rainfall in inches was 2.7, 3.9, 3.5, 3.5, 2.0, 1.2, 3.9, 4.9, 6.6, 1.7, 3.7 and 3.6 in September, October, November, December, January, February, March, April, May, June, July and August, respectively. The study was weed-free.