Mathematical modelling and experimental assessment of agrochemical drift using a wind tunnel

With the aim to gain a better understanding of the phenomenon of drift occurring during spray application of agrochemicals to agricultural crops, a laboratory testing was carried out using a wind tunnel under controlled environmental conditions (wind, temperature and relative humidity RH). Spray drift was measured with wind velocity of 1, 3 and 5 m/s and RH of 30, 50 and 70%. Under medium to high wind velocities the effect of RH was negligible. These results suggested to work out a simplified mathematical modelling by assuming the absence of droplets evaporation by means of closed solutions of the equations of the droplets motion. The main result of the mathematical model is the removal of the droplets smaller than about 80 μm from the spray produced by the nozzles.