Deposição da calda na cultura da soja em função de diferentes pressões de trabalho e pontas de pulverização

Abstract

The service pressure influences the characteristics of the hydraulic spraying of pesticides and can change the spray penetration in the soybean canopy. This study aimed to evaluate the effect of pressure on the spray deposition in soybean crop, promoted by different models of spray nozzles. The experiment was conducted in a randomized block design, in a factorial model 2 × 4 + 1, with two nozzles (hollow cone - ATR and air induction hollow cone - TVI) and four service pressures (689, 1034, 1379, and 1724 kPa), with an additional treatment (flat fan nozzle at 448 kPa-API). The spray deposition on soybean (top and bottom parts of Vila Rica Cultivar R6 Stage) was analyzed using the fluorescent tracer Rhodamine B detected by fluorimetry, considering the same spray volume (200 L ha-1). We also evaluated the droplet spectrum, using the analysis of water-sensitive papers. It was concluded that the ATR nozzle, with smaller and more uniform droplets, resulted in a higher deposition of the tracer than the TVI nozzle. The pressure increase reduced deposition on the lower leaves. The deposit obtained with the flat fan nozzle (API) did not differ from those obtained by other nozzles.