An angle correction method based on the influence of angle and travel speed on deposition in the air-assisted spray

Abstract

Angle of spray direction and travel speed are important factors affecting deposition in a long-range air-assisted spray. However, former studies mostly compared tests to explore the appropriate angle and travel speed for uniform distribution. The present study investigated the effects of angle and travel speed on deposition uniformity using a two-dimensional air-assisted sprayer. The results showed that the coverage difference between the left and right sides of the canopy (Er) decreased with the increase in angle but increased with the increase in horizontal travel speed. The study proposed an angle correction method to evaluate the appropriate angle based on the principle of balanced cumulative of angle on duration (b-CAD). The validation tests performed after angle correction to 1.2° and 1.7° at the horizontal speeds of 0.30 m s−1 and 0.35 m s−1 showed that the Er decreased significantly from 8.6% and 10.4% to −2.3% and 2.9%, respectively. The coefficient of variation (CV) of overall samples (CVO) also decreased from 63.5% and 71.14% to 59.7% and 55.8%, respectively. Field tests on tomato crops in the greenhouse showed that Er significantly reduced from 11.7% to 4.0%, and CVO decreased from 83.7% to 62.0% after angle correction to 2.3°. Thus, the present study proposes an angle prediction model based on the b-CAD principle for applying the air-assisted spray on stereoscopic crops, which can effectively improve the uniformity of spray deposition on the left and right sides of the crop canopy and the coverage and uniformity among the samples.