Tolerância de cultivares de soja aos herbicidas imazaquin, diclosulam e sulfentrazone, aplicados em solo de textura arenosa

Abstract

With the objective to evaluate the genotypes of soybeans when using the herbicides Imazaquim, diclosulam and sulfentrazone, this research was conducted at “ Fazenda Tres Irmãos “ pertaining to Jatai county, Goias, during the growing season 2000/2001. After planting the genotypes of soybeans in arenaceous soil, containing 17,19% clay, 44 g/kg of organic material and CTC of 12,49 cmol/dm³, the herbicides, imazaquin, diclosulan, and sulfentrazone, were sprayed pre-emergence in the following doses – 140 and 280g. /ha, 35 and 70g/ha, 600 and 1200g/ha, respectively. After 15 and 30 days, after the spraying (DAT) of the herbicides, the plant intoxication of the herbicides was evaluated in the genotypes of soybeans. By random of harvest, the height of the plants and insertion of the first string bean, number of plants and yield were evaluated. The conclusions were: a) The herbicides imazaquin, diclosulam and sulfentrazone caused plant intoxication in the genotypes of soybeans planted in arenaceous texture. Especially when the double, of the recommended dose was used. b) In the doses tested, the herbicides didn’t significantly affect the plant density, nor the height of the insertion of the first string bean in the genotypes of soybeans. c) Sulfentrazone in dose equivalent to 1200g/ha, reduced significantly the height in the genotypes-GOBR 93-1283, EMGOPA-316 and CRIXÁS, compared with the untreated area. Diclosulan, in dose equivalent to 35g/ha caused reduction in height in the genotypes – GOIÂNIA, GOBR 93-122243 RNC and LUZIÂNIA. GOBR 93-122243 RCN, GOIÂNIA, LUZIÂNIA, EMGOPA 316, SANTA CRUZ and CRIXÁS already had their heights affected compared with the untreated area, in a dose equivalent to 70g/ha of diclosulan. Imazaquin, in a dose equivalent to 280g/ha, affected significantly the height in the plants of the sort, CRIXAS. d) Diclosulan in dose equivalent to 70g/ha caused significantly reductions in yield in the genotypes – GOBR93-1283, GOBR93-12243 RCN, EMGOPA-302, SANTA CRUZ and EMGOPA-313. Sulfentrazone, used in a dose equivalent to 1200g/ha, caused a reduction in the productivity in the genotypes – GOBR 93-1283, GOBR 93-122243 RNC, GOIATUBA, LUZIÂNIA, EMGOPA-316, EMGOPA-314, SAMBAÍBA, EMGOPA-302, EMGOPA-313 and CRIXÁS. The genotypes – GOIATUBA, EMGOPA-316 and SANTA CRUZ had already showed reductions in productivity, when using imazaquin in a dose equivalent to 280g/ha; e) The genotypes of soybeans showed different tolerance with the herbicides sulfentrazone, diclosulan and imazaquin, specially when there was used a doublet dose.