Herbicide absorption by sugar cane crop

Abstract

Several studies have been conducted in Brazil to evaluate the risk of soil and water contamination by herbicides used in sugar cane crop. In order to better understand the fate of those compounds in the environment, the objective of the proposed project is to develop and to validate a mathematical model that estimates and simulates herbicide concentration in sugarcane sap. Such model, known as Bioconcentration Factors Affecting Absortion of Herbicides in Sugarcane (BCFHS), relates: sugarcane evapotranspiration; water-plant partition coefficient; fresh weight; herbicide dilution; herbicide degradation rate in the soil solution, water content in the soil and soil properties such as clay, sand, organic matter, pH, density, and sugarcane lipid content (roots and leaves). BCFHS is based on herbicide absorption with water uptake. Tebuthiuron is the herbicide selected to validate the model. Sugarcane plants will be cultivated under two experimental conditions: 1-) soil, and 2) hydroponics. The proposed model for tebuthiuron absorption will be used to simulate the absorption and bio-concentration of other herbicides that are commonly used in sugarcane, such as acetochlor, ametryn, clomazone, diuron, hexazinone, metribuzin, picloram, simazine and sulfentrazone. The outcome of this proposed mathematical model will be a useful tool to estimate herbicides concentration in sugarcane to avoid environmental pollution and to predict safe herbicide testing rate during the registration process of new products. (AU)