Tecnologia de aplicação eletrostática no controle químico de plantas daninhas avaliado visualmente e por imagem aérea

Abstract

Among the processes of the application technology that need optimization, emphasizes the application of glyphosate herbicide for weed control. In this sense, in order to reduce losses to the environment by drift and provide greater contact with the drops with their targets, with larger deposits of phytosanitary products and lower rates of application, developed the system of electrostatic spray. However, some factors influence their performance as the physico-chemical characteristics of the syrup, altered mainly by adjuvants, the droplet size, the system of electrificationof drops and the mass/ charge ratio. Another ally in the management of weeds is the precision agriculture, which allows monitoring of crops, indetification of pests, disease and weeds , and can be used for evaluation of efficacy of herbicides with software for processing images captured with aircraft carriers, remotely control valves piloted (ARP). Considering the above the objective of this work was to evaluate visually and by image carrier the effectiveness of weed control with herbicide using the electrostatic spray system, with addition of adjuvant in two application rates (50 and 90 L ha-1) ), compared to the rate of 150 L ha-1. The experimental design was randomized blocks with ten treatments and four replications. In duplicate, with two areas and diferente times, totaling 40 plots per experiment, in a 2 x 2 x 2 + 2, being the abscence and presence of electrostatic spray, presence and absence of adjuvant and two application rates (50 and 90 L ha-1), in addition to the conventional additional control and enforcement (150 L ha-1). We used the herbicide glyphosate, at a dose of 2 L ha-1, and the adjuvante soy lecithin + propionic acid, at a concentration of 0,5 L 100 L-1. We evaluated the physicochemical properties of the grout, load / mass relations, droplet spectrum, spray deposition on the weeds, losses to the soil, effectiveness of control and drift . Along the syrup of application was added also the Brilliant Blue dye tracer for the study of the deposition on the weeds and losses to the soil the method of spectrophotometric. The drift was evaluated by the method of fluorimetry, with the tracer Rodamina B®. The visual analysis of the effectiveness of weed control were performed throught the scale of notes, developed by the Latin American Weed Association - ALAM. Next to the visual evaluation were performed flights with ARP to capture images and later the same were processed with the Software ImageJ and SisCob . The electrostatic spray not influence in any of the evaluated variables. The adjuvant improved the effectiveness of weed control in several situations, altered the properties of the syrup and provided lower drift. The correlation between the visual analyzes and by image carrier were positive and demonstrated potential as an alternative for the evaluation on the effectiveness and weed control.