Harvesting systems (with and without residue burning) on the sorption and desorption of herbicides in sugar cane

Abstract

The agricultural potential of Brazil is pointed out as a stimulating factor for the development of manufacturing agrochemicals, especially herbicides. Sugarcane is an important crop in the country occupying more than 8 millions of hectares. Recently, its harvest system is changing in order to not burn the crop straw, which generates 80-20 Mg ha-1 of surface residues. The maintenance of the straw results in increased levels of soil organic carbon. This may affect the dynamic of herbicides behavior in soils once the sorption potential of these molecules usually tends to increase with soil organic carbon. However, studies evaluating the influence of organic matter addition by burning or not sugarcane are scarce, making difficult to predict humans and environment risks and to recommend safer field rates. Therefore, the objective of this work is to evaluate the effect of different crop management systems of sugarcane harvesting (with and without burning) in the sorption and desorption processes of pre-emergent herbicides diuron, hexazinone and tebuthiuron. (AU)