Studies on the usage of speed sprayer in a sloping orchard

On the range of deposits and adhesion of spray droplets

Abstract

This investigation was carried out to obtain useful and practical data on the application of orchard sprayers in a sloping apple orchard. In this paper authors reported mainly on the range of deposit and the adhesion of spray droplets.
1. The liquid droplets sprayed by an orchard sprayer are carried away with air stream. The calculated drifting distance of droplets (100 microns) was about 16 meters in the vertical direction and about 130 meters in the horizontal direction, but in practice the range of deposit of spray liquid was about 10 meters.
2. On a sloping land, the distance between the onchards prayer and the tree was longer than on a flat land, therefore, it was difficult to obtain good coverage of the gross tree with spray droplets.
3. If the tree was far from the orchard sprayer and had a large volume, few spray droplets got to and into the tree crown, and the degree of deposit on the gross tree crown was low.
4. The spraying direction and the condition of terrace affected the adhesion of chemicals and the result of pest control. On spraying upward, the spray droplets were intercepted by the frontal foliage and did not get into the crown thoroghly.
If terrace was high and steep, the degree of adhesion was higher on the upper part of the tree than on the lower part, because the spray droplets impinged on the terrace and drifted along the slope upward.
5. In order to achieve good penetration and adhesion of liquid droplets sprayed on a sloping orchard, it was neccesary that the terrace was low, and the tree form should be altered.