How Much Do Adjuvant and Nozzles Models Reduce the Spraying Drift? Drift in Agricultural Spraying

Abstract

The spraying of herbicides in crops has become the main form of weed con-trol. Although it means unexpected effects on non-target plants resulted by spraying drift. Thus, improvements in application techniques, as the best se-lection of spray nozzles and adjuvant, are essential to avoid environmental contamination and economic losses. On this work, we evaluate how much adjuvant associated with nozzles can reduce the spray drift. The nozzles used at experiment were air induction flat tip, hollow cone and twinjet and the spray liquids, which were composed of herbicide glyphosate and phosphati-dylcholine + propionic acid adjuvant. Measurements were made at wind tun-nel and droplet sizer, at laser diffraction method. The models of nozzles in-fluence in droplet size characteristics and in occurrence of spray drift. The use of adjuvants reduces the spray drift only combined with the twinjet nozzle, while for the other models the adjuvant did not reduce the global spray drift at significant levels. The adjuvant reduced the spray drift until 39%, while the nozzles model reduced until 74%. Both techniques when combined were able to reduce until 80%. The model of nozzle has the biggest result on drift miti-gation and the use of adjuvants can increase the drift mitigation specially with nozzles that produces smallest droplets.