CONTROLE DE PLANTAS DANINHAS E SELETIVIDADE DE HERBICIDAS PRÉ-EMERGENTES NO SORGO

Abstract

Weeds represent a problem for the cultivation of sorghum, there are practically no herbicides recommended for grass control in Sorghum bicolor cultivation. The aim of this work was to evaluate the control effectiveness and selectivity of pre-emergent herbicides in sorghum culture. The experiment was carried out at the Instituto Federal Goiano Campus Urutaí, in the field under second crop conditions, with the sowing of the Semeali XB 6022 granifero sorghum. Soon after sowing, the herbicides Trifluralin, Metolachlor and Pendimethalin were applied in increasing doses. The experimental design was in randomized blocks in a 3x4+1 hierarchical factorial scheme, with three herbicides, four dosages and an additional control without application. The initial stand was evaluated at 14 days after application (DAA), visual phytotoxicity, dry matter, final stand, number of profiles, stem diameter, plant height, panicle insertion height, number of panicles per plant, number of Panicles per Meter, Panicle Length, Thousand Grain Weight and Productivity. The data were submitted to analysis of variance and compared by Fisher's LSD test at 5% significance. To verify the relationship between the variables analyzed, a correlation analysis between the characteristics was performed. The application of Trifluralin and Pendimethalin reduces the initial stand and presents greater visual phytotoxicity in sorghum. With the application of Pendimethalin and Trifluralina plants have a higher number of panicles per plant, but they do not differ from Metolachlor. Metolachlor contributes to the highest Panicle Insertion Height. The application of Metolachlor at a dose of 960 g ha-1 guarantees the highest yield of granifera sorghum with 6467.74 kg ha-1.