Effect of Atrazine on Soybean Tolerance to Metribuzin

Abstract

Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] at 0.14 kg/ha and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)one] at 0.56 kg/ha applied under field conditions interacted synergistically to reduce soybean [Glycine max(L.) Merr. ‘Harsoy-63′] growth. In the greenhouse, a number of combinations with atrazine at 0.07 kg/ha or greater and metribuzin at 0.56 kg/ha and greater interacted synergistically to reduce soybean fresh and dry weights 30 days after planting. Over a soil pH range of 4.6, 5.6, and 6.7, atrazine–metribuzin interactions were more apparent as the soil pH values increased. Atrazine at 10-5and 10-6M concentration in the sand culture nutrient solution during the early growth of ‘Swift’ soybean seedlings decreased14C-metribuzin uptake and movement into the 12-day-old soybean shoots during the 12-hr treatment period. However, 10-7M atrazine increased14C-metribuzin in the shoot by increasing stomatal aperture and subsequent transpiration. Conditions favoring the synergistic interaction were low atrazine residue levels which increase soybean transpiration, high metribuzin rates, and high soil pH levels.

Atrazine Persistence in a Corn‐Soybean Doublecropping System1

“…of Florida, Gainesville, FL 32611, respectively. metri buzin [ 4-amino-6-ter t-bu ty 1-3-(meth y lthio )-as-triazine-5(4H)-one], an herbicide widely used for soybean weed control, has been observed (7). This synergism resulted in much greater soybean :phytotoxicity than would be expected from the additive effect of the atrazine and metribuzin.…”

Metribuzin and trifluralin residues in faba bean following preplant incorporated application

“…Although Ladlie et al (1977) reported that tank mixing trifluralin with metribuzin significantly reduced root uptake of metribuzin by soybean seedlings, tank mixing with trifluralin at the Saskatoon site did not significantly affect the magnitude of metribuzin residues in the green foliage of faba bean. Consequently, residue data for metribuzin, whether applied singly or as a tank mixture, were combined for the 0.28 and 0.42 kg ha -1 application rates at this site.…”

Electrochemical Reduction of Metribuzin

“…Spectrophotometrically obtained values were reported to be 0.99 [45], 1.1 [46] and 1.0 [47]. The latter authors [47] dissolved metribuzin in methanol where the alcohol adds to the azomethine bond even more strongly than water, and forms an j-adduct.…”