UTILIZAÇÃO DE HERBICIDAS NO CONSÓRCIO ENTRE MILHO E FORRAGEIRA Panicum maximum cv. BRS ZURI

Abstract

The introduction of forage species in intercropping systems with grain crops has been adopted by farmers and ranchers in different agricultural regions of Brazil since this system seeks synergism between the grains and/or silage production and the forag e production for animal grazing and stubble formation. However, it is of essential importance that forages are managed to avoid yield losses caused by interspecific competition. The use of subdoses of selective herbicides to maize is an efficient alternati ve with the objective of avoiding losses by competition. Thus, the objective of the present study was to evaluate the effect of the herbicide subdoses application in the suppression of forage Panicum maximum cv. BRS Zuri intercropped with hybrid maize B2360PW and how this interaction influences the weed population and the biometric and productive variables of both maize and forage. The experiments were conducted in the experimental area of IF Goiano, Rio Verd e Campus, under randomized block design, with four repetitions. The treatments consisted of six subdoses of glyphosate herbicides (0, 48; 96; 240; 480; 960 g a.e. ha 1 ), nicosulfuron (0; 2.5; 5; 12.5; 25; 50 g ha 1 ) and tembotrione (0; 3.78; 7.56; 18.9; 37 .8; 75.6 g a.i. ha 1 ), and maize in monoculture. The results show that in the three experiments there was a reduction in the dry mass and density of weeds in the plots with the forage presence. This was mainly due to the suppression imposed by the forage i n the plots. For the glyphosate herbicide treatments tested, the dose of 480 g a.e. ha 1 can be an alternative since there was adequate forage development and no maize yield losses. The 50 g ha 1 dose of the herbicide nicosulfuron caused phytotoxicity in t he maize hybrid, causing losses in the yield components of the crop. Furthermore, the tested subdoses were not enough to suppress the forage growth. Similarly, the subdoses of tembotrione did not suppress the forage BRS Zuri after application, however, the re were no yield losses for maize, showing that cultural practices such as intercropping can be used to enhance the agricultural production systems.