Evaluation of susceptibility of Amaranthus species to the herbicide trifloxysulfuron-sodium using nonlinear models

Abstract

Various elements have the potential to negatively impact crops in the agricultural sector, such as the presence of weeds that compete for essential resources, hindering growth and production and resulting in financial losses. There are several methods employed for weed control, among which herbicides stand out for requiring less labor and lower costs compared to others, especially in large-scale cultivation. The objective of this study was to use nonlinear models to assess the dose-response curve of the herbicide trifloxysulfuron-sodium applied to weeds of the genus Amaranthus. Data were collected at doses of 16D, 4D, D, 1/4D, 1/16D, 1/64D, and absence of products, where (D) represents doses of 7.5 and 17.5   The models were adjusted using the least squares method, employing the Gauss-Newton algorithm in the R software. Quality evaluation criteria included the coefficient of determination, residual standard deviation, Akaike information criterion, and the Bates and Watts curvatures. The fitted models met the assumptions of normality, independence of residuals, and homogeneous variance. Based on the results, the Michaelis Menten model was considered the most suitable for describing the data. It was observed that Amaranthus species exhibit variations in susceptibility to the herbicide, with A. hybridus and A. deflexus being the least and most susceptible, respectively, requiring doses of 6.02  and 306.90 to achieve 95% control.