Suitable weather condition frequency for fungicide soybean application in Tangará da Serra, Mato Grosso, Brazil

Abstract

ABSTRACT The aim of this study was to model the decendial and hourly variability of meteorological variables, namely air temperature, relative air humidity and wind speed, in the Tangará da Serra region, Mato Grosso, Brazil, to determine the best schedules for fungicide applications to soybean crops. Hourly weather data between 2004 and 2017 from the Tangará da Serra municipality’s automatic station were made available by Brazil’s National Meterological Institute (Instituto Nacional de Meteorologia, INMET). Decendial variability (ten days 01 to 36) and hourly variability were analyzed for ten days that concentrated fungicide soybean crop applications, namely ten days 34, 35, 36 and 01. The following parameters were adopted as suitable fungicide application climate: wind speed ≥ 0.83 ≤ 2.77 m s-1, relative air humidity ≥ 50% and air temperature ≤ 30 °C. Relative humidity was not a limiting factor for application on ten days 34, 35, 36 and 01. Due to hourly maximum temperatures, suitable application conditions are less than 10% at 1:00 PM. The most frequent suitable weather conditions schedules are concentrated between 5:00 AM and 7:00 AM, and at night, from 7:00 PM.