Evaluation of spatial application accuracy of sensing-spraying system for variable rate application of oil palm trees

Abstract

Precious agricultural agents are lost during conventional spraying systems. The use of sensing and spraying system to spray according to the plant size reduces spray losses which reduces farming costs significantly and contributes to environmentally friendly crop farming. The continuous change in the size of the plant canopy requires an accurate adjustment of the quantity of liquid. The objectives of this study are examining, analyzing and improving the ability of the sensing and spraying system in detecting and spraying the plants under higher speed conditions. In this paper, two different ultrasonic sensors WRA1 and EZ0 were used to investigate the effect of sensor response time on detecting different distances and spatial application accuracy (SAA) of VR spraying system at different driving speeds. The results of the first assessment of an electronic control system for proportional spray application to the canopy length showed there was no significant effect of driving speed from 1.1 to 3.3m/s on ultrasonic detected distance measurements. Sensor EZ0 gave a shortest response time at driving speed range of 1.1- 3.3 m/s with error in range of 11-15 cm. The use of VR sprayer with the ultrasonic detection system was fast and accurate enough to spray at the correct positions above the plant with a maximum SAA of 97.7%.