Controle químico de plantas daninhas no sorgo sacarino

Abstract

Sorghum [Sorghum bicolor (L.) Moench] is a plant native to Africa and Asia, and this crop is well adapted to hot and dry environments. It is considered a source of energy and presents high potential for the production of fuel alcohol in the off-season of sugarcane. The objective of this work was to evaluate the growth of three cultivars of sweet sorghum (SF15, BRS506, BRS511) submitted to the application of two herbicides used in weed control. The experiment was installed at the Experimental Vale do Curu Farm (FEVC-UFC), in the municipality of Pentecoste-CE from March to July 2016. The treatments used were the three genotypes of sweet sorghum, submitted to weed control, with the following formulations: T1 - atrazine (2,500 g ha-1), T2 - atrazine + nicosulfuron (2,500 + 50 g ha-1), T3 - atrazine + nicosulfuron (2,500 + 40 g ha-1), T4 - atrazine + nicosulfuron (2,500 + 30 g ha-1), T5 - atrazine + nicosulfuron (2.500 + 20 g ha-1) and T6 - atrazine + nicosulfuron (2.500 + 10 g ha-1). Growth data were collected at 20, 40, 60 and 80 days after herbicide application. Growth parameters were evaluated: plant height, leaf number, stalk diameter and leaf insertion angle 3. The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability and regression analysis. The results showed that the cultivar that presented the best growth characteristics was the cultivar SF 15, obtaining a greater number of leaves, a larger diameter of the stem, desirable characteristics for a good ethanol productivity, however, this genotype has a spongy stem, with little broth, resulting in low ethanol production. The doses of nicosulfuron in mixture with atrazine caused interference only in the stem diameter variable. The time factor was significant for all growth variables.