Efeito da associação de métodos de controle de plantas daninhas sobre microrganismos do solo numa lavoura cafeeira(Coffea arabica L.)

Abstract

Combinations of methods for weed management may be useful for effective and economical control. The use of association of methods is what the farmers have of more modern in the use of this practice. However, the inadequate use of some of these methods may transform a weed species in a problem. The continuous use of a chemical may contaminate soils and interfere on the microbial community. This work had the objectives of evaluating the association of some methods for Bidens pilosa, Eleusine indica and Portulaca oleracea control in a 5 year-old coffee plantation and the effectiveness of these associations on soil microorganisms through determination of carbon microbial biomass and microbial respiration of the soil. The association of post-emergence (paraquat + diuron) and of pre-emergence (ametrine + simazine) herbicides were more efficient for weed control. Mower used in the rainy period had low efficacy, due to weed sprouting at 30 days after treatment. Paraquat + diuron did not showed good Eleusine indica control in the first year of application. The sequential application of post-emergence herbicide provided the highest carbon content of the biomass and soil respiration. Mower following two glyphosate applications, did not alter carbon level of the microbial biomass over time. The use of associations of methods, aided by the microbial analysis of the soil, allows a more precise evaluation of the behavior of these associations on the environment.