Manejo das plantas daninhas no milho através da densidade de plantio e do consórcio com girassol

Abstract

The sunflower has been studied in the control of weeds through some methods, such as that of the intercropping. The objective of the present work was to evaluate the yield of AG 1051 maize cultivated at four planting densities (30, 50, 70 and 90 thousand plants per hectare), with weed control via sunflower intercropping. The experiment was carried out at the Experimental Farm Rafael Fernandes, Federal University of the Semi-Arid - UFERSA, from May to September, 2015. A randomized complete block design was used with splitplot and with five replications. The planting densities were applied to the plots and weed control was assigned to the subplots. The weed control methods were: without weeding; two hoeings (at 20 and 40 days after sowing), and sunflower intercropping. In the intercropping, the sunflower was sown at the sowing stage of corn, between the rows of the grass, at the density of 25 viable seeds m-2. Yields of cottonseed, green maize and grain maize were obtained and the respective economic analyzes were carried out. Hoeings and intercropping provided the highest values of fresh mass of baby corn (at the density of 90,000 plants per hectare), fresh mass of commercial husked (at the densities of 42,114 and 67,753 plants per hectare, respectively) and grain yield (at densities of 68,769 and 71,719 plants per hectare, respectively). There was a reduction of fresh weed mass and grain yield sunflower as corn planting density increased. For baby corn production the highest net income and profitability were obtained at 90,000 plants per hectare, with and without hoeings, and 70,000 plants per hectare with intercropping. For green cor production, the highest net income (but with negative profitability index) was obtained with 30,000 plants per hectare. The highest yields of green maize were obtained with two hoeings and with the intercropping in the densities of 50 thousand and 70 thousand plants, per hectare, respectively. Net income, rate of return and profitability index indicated non-viability of grain (dry corn) production.