Weed control in soybean with preemergence application of metribuzin and sulfentrazone
(Research Report, Hettinger REC, December 2024)A trial was conducted to evaluate weed control resulting from the application of metribuzin and sulfentrazone (Spartan) in soybean. Soybean were planted on May 20, 2024 using a John Deere no-till planter at a depth of 1.5 inches and a seeding rate of 110,000 seeds/A. Plots were four rows of soybean planted in 30-inch rows. Rows 1 and 2 were planted using soybean variety “AG07XF4; Rows 3 and 4 were planted with soybean variety “AG07XF2”. Two soybean varieties were used to compare varietal tolerance to metribuzin and sulfentrazone. Plot size in this trial was 10 feet wide and 40 feet long. Four replications of treatments were randomized in a randomized complete block. Herbicide treatments were applied after soybean were planted, also on May 20. Soybean was evaluated for injury at 31 days after planting; no visual injury was observed for either soybean variety (Table 1). Soybean stand was measured from one meter in a random location within each row of each plot, no differences in soybean stand was observed. Kochia, common lambsquarters, and green foxtail were evaluated from control at 31 and 47 days after treatment (DAT). Control of all three weeds increased when metribuzin rate increased from 5.33 to 10.7 oz/A. There was no increase in weed control when the rate of sulfentrazone increased from 4 to 8 oz/A. Kochia control was increased when combinations of metribuzin and sulfentrazone were applied, with 100% kochia control at 47 DAT with the combination of metribuzin at 10.7 oz/A and sulfentrazone at 8 oz/A. Common lambsquarters control was 92 to 100% with sulfentrazone alone and was similar for the combination treatments. Green foxtail control was also best when sulfentrazone and metribuzin were tank-mixed. Weed biomass was measured at 35 and 57 DAT. All treatments reduced weed biomass compared to the untreated, but there were no statistical differences among treatments. Soybean yield was not collected in this trial due to the drought conditions that reduced yield in trial to near zero.