Effect of nozzle pressure, air speed, leaf area density and forward speed on spray deposition in simulated crop canopy

The effectiveness of pesticide spray on crops is greatly influenced by target canopy characteristics, properties of chemical and application equipment & techniques. Lack of suitable designed sprayers results in poor deposition of chemical onto the target canopy and in considerable off-target losses of the chemical to cause environmental pollution and economic losses. To increase the efficacy of pesticides spraying, effect of air velocity, leaf area density (LAD), nozzle pressure and forward speed on deposition characteristics of an air assisted spraying system was studied on a simulated crop canopy constructed to represent vegetable and field crops. Results of the study showed that droplet size and droplet density on under side of the canopy were less than that on the upper side. Droplet density on the crop canopy increased with increase in nozzle pressure and speed of air used for assistance. But, leaf area density and forward speed of spraying system had negative effect on the droplet density. Higher speeds of air stream and nozzle pressure decreased the spray droplet size, while the forward speed and leaf area density did not influence it.