Revista Brasileira De Herbicidas 2000; 1(3): 219-224
Selectivity of sulfentrazone on soybean cultivars and the residual effects on rotation crops, in Savanna soils
DOI: 10.7824/rbh.v1i3.338
Edaphic characteristics, in interaction with the clímate and the specific cultivar, may cause crop toxicity in an area treated with a residual herbicide. Two experíments were carried out on two Cerrado soils, in Campo Grande (MS), to evaluate the selectivity of sulfentrazone on 21 soybean cultivars, as well as the residual effects on successive soybean crops.The first experiment was on a sandy soil, with 8% clay, 2% lime, 90% total sand and 2.3% organic matter. The second experiment was carried out on a soil with 35% clay, 11% lime and 54% sand. Treatments in both cases were: sulfentrazone at 500 and 1000 g/ha, diclosulam at 35 and 70 g/ha, sulfentrazone+diclosulam at 250+25 and 500+50 g/ha, and a control where the weeds were mechanically cut. Results showed that higher phytotoxicity was found only in the experiment on sandy soil, with sulfentrazone at 1000 g/ha and diclosulam at 70 g/ha, in Conquista cultivar, and at a lower level in the Taquari and Paiguás cultivar. Millet, oat and sorghum sown in sucession to soybean, showed phytotoxicity symptoms to sulfentrazone (1000 g/ha) and diclosulam (70 glha). Chemical treatments, in both experiments, showed efficient control of Digitaria horizontalis, Amaranthus viridis, Ipomoea grandifolia, Portulaca oleraceae and Bidens pilosa. It was concluded that preemergence aplications of diclosulam can injure some soybean cultivars on sandy soil.
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