Espectro de gotas e ângulos de abertura dos jatos de pontas de pulverização turbo Teejet Induction (TTI) em função de caldas e da pressão de trabalho

Abstract

In order to optimize the technique of applying the herbicide dicamba, this study aimed to determine the interference of different drift-reducing adjuvants and spray pressures on the droplet spectrum and spray angle generated by the Turbo TeeJet Induction (TTI) nozzle, across five different flow rates, in the spraying of solutions containing a mixture of dicamba and glyphosate. Two experiments were conducted using the Turbo TeeJet Induction (TTI) nozzle at flow rates ISO 015, 02, 03, 04, and 05, all at a 110° angle. The working pressures were 1, 1.5, 2, 4, and 7 bar. The application rate chosen for preparing the solutions was 110 L ha-1. The doses used in the treatments were 1.5 L commercial product p.c. ha-1 for the herbicide Dicamax (D) and 3.0 L p.c. ha-1 for Roundup Transorb R. In the case of the adjuvants, they were identified with numerical codes, at doses of 1.61 L ha-1 for adjuvant 32, 0.75% for adjuvant 21, 0.60% for adjuvant 02, and 0.10% for adjuvant 10. The adjuvant 31 was added at a fixed concentration of 0.5% v v-1 in the solutions prepared with drift-reducing adjuvants 02, 10, and 21. The experimental design was completely randomized with three replications. For the first experiment, the solutions were formulated with deionized water. The droplet spectrum was analyzed using a real-time particle analyzer positioned below the spray simulator. The analyzed variables were the median volumetric diameter (MVD), the percentage by volume composed of droplets smaller than 150 µm (V150), and the relative amplitude (RA). Samples were collected in the laboratory, with monitoring of environmental conditions (temperature and relative humidity). The data were subjected to regression analysis to fit the mathematical model that best explains the results (MVD, V150, and RA) as a function of the variations in the recommended concentrations of the adjuvants in the solutions. In the second experiment, the solutions were formulated with deionized water at room temperature and with Brilliant Blue FCF dye, Sensient Colors/USA brand. To measure the spray angle, the captured images were processed using the Image J software. The data were analyzed by variance to identify the interaction between the pressure and the solution composition factors. In the first experiment, the solutions of dicamba and glyphosate that contained adjuvants 21 or 02 experienced the greatest interference from pressure regarding the variations in MVD, RA, and V150. The herbicide solutions without adjuvants or with adjuvant 10 indicated that the MVD was less affected by pressure compared to the others. Adjuvant 32 stood out in generating coarse droplets and ensuring application safety. In the second experiment, the variance analysis indicated that all treatments had a statistically significant impact on the spray angle of the TTI nozzle. The interaction between the solution and pressure showed that the combination of these factors influenced the characteristics of the spray angle of the TTI nozzles. Therefore, it is concluded that the choice of adjuvant and spray pressure exert a significant influence on the droplet spectrum and the spray angle of the TTI nozzle. Adjuvant 32 stood out compared to the other treatments.