EFEITOS DE PALHADAS DE PLANTAS DE COBERTURA E DE HERBICIDAS NA CULTURA DO FEIJÃO-CAUPI

Abstract

The objective of this research was to evaluate the yield of the cowpea bean crop, when cultivated on straw of cover crops, whether or not handled with herbicides applied after emergence. The experiment was conducted in the field, in a randomized complete block design with three replicates. In a 5x2 factorial scheme, five types of straw were tested: sorghum, ruziziensis grass, tanzania grass, marandu grass and fallow. The second factor was characterized by the absence and the application of the ready mix of bentazone + imazamoxi at the dose 600 + 28 g ha-1 at 13 days after emergence and the herbicide haloxyfop-p-methyl at the dose of 62.35 g ha- 1 at 18 DAE. The density and dry mass of weeds were evaluated at 20 and 85 DAE of the crop, plant height (AP), stem diameter, chlorophyll content, stem dry mass, flowers, pods, leaves and shoot and leaf area in flowering (46 DAE). At harvest, the production components were evaluated: number of grains per pods, number of grains per plant, weight 100 grains, population of cowpea plants and yield of grains. Grassgrass weeds, tanzania grass and marandu grass on the soil surface reduce the dry mass of weeds, constituting a necessary management where chemical control was not performed. In these treatments there was no AP reduction. Regardless of the use of straw, herbicide application is essential to ensure crop productivity. Cowpea cultivation on sorghum straw, ruziziensis grass, tanzania grass and marandu grass results in higher yields of grains.