Effect of spray nozzle type and crop canopy on spray deposition

Abstract

A study was carried out to investigate if the interaction between nozzle type and crop canopy has an effect on spray deposition and come up with ways of improving spray deposition during chemical applications to crops. The overall goal of the study was to optimize chemical use in crop production and minimize chemical pollution of the environment resulting from off-target spray deposition. Three nozzle types; disc-core hollow cone, disc-core full cone and extended range flat spray, and five crop canopy types; maize, soybean, tomato, mung bean and carrot were investigated. Two tracer solution application rates of 150 and 600 litres/ha were used in the study at a pump delivery pressure of 3 bars. Manganese sulphate monohydrate was used as a deposition tracer. Spray deposition on crop canopies was quantified using the Periodate Oxidation method. Results from the study indicated that nozzle-canopy interaction significantly affected spray deposition at 5% level of significance. It was also found out that spray deposition could be improved by up to 189% and 355% at tracer solution application rates of 150 and 600 litres/ha, respectively, if nozzles are selected based on crop canopy type.