Influence of soil texture on selectivity of fomesafen applied in cotton pre-emergence

Abstract

The selectivity of pre-emergence herbicides depend of the soil characteristics. In this context, the aim of this works was evaluated the fomesafen selectivity to cotton crop in soil with contrasting textural class. The experiment was performed under greenhouse conditions in completely randomized design, with five replications. The treatments were organized in factorial arrangement 5 x 2, with the first level representing five doses of fomesafen (0, 175, 350, 525 e 700 g ha^-1) and the second factor two soils with contrasting texture: sandy loam texture (200 g kg^-1 of clay, 40 g kg^-1 of silt and 760g kg^-1 of sand, pH de 4,47 e 1,59% de O.M.) and clayey (760 g kg^-1 of clay, 110 g kg^-1 of silt and 130g kg^-1 of sand, pH 5,7 e 2,30% de O.M.). The evaluations performed were the number of emerged plants at 7 and 14 days after emergence (DAE), phytointoxication at 7, 14 and 21 DAE. At 35 DAE, it was collected the shoot and the roots of cotton plants to determined the shoot and roots dry mass. Fomesafen presented potential to be used for cotton, cultivar FM 993, however, the phytointoxication symptoms was very intense in plants treated with high doses in sandy loam soil. Thus, the fomesafen doses need to be adjusted according to the textural class, and the content of organic matter of the soil.