Swath Deposit and Drift Evaluations for Roadside Sprayers

摘要

Two highway right-of-way sprayers were evaluated for swath uniformity and spray drift. The conventional sprayer (OC80 and OC150 nozzles) produced coefficients of variation (CV) for a 36 ft. swath width which ranged from 28 to 123% for varying wind conditions. Similar CV values for the Cibolo sprayer ranged from 21 to 124%. CV values of < or = 15% are typically considered to be acceptable. Ground and air sampler drift deposits at 200 ft. downwind were < or = 0.005 and 0.001% of the amounts applied for both sprayers. A new right-of-way spray head was developed and evaluated w.r.t. the uniformity of swath deposits (32 ft.) for a simulated 1:3 sloped embankment while attempting to deliver 20 gpa. The field, swath test results indicated, as in 1985 with other spray machines, that wind velocity and direction had a major influence on the lateral location and uniformity of swath deposits. The effective swath width of the new spray head was found to be about 25 ft. for low wind velocity conditions. Drift deposits from air samplers or ground targets were < or = 0.002% of applied at distances > or = 50 and > or = 150 ft., respectively.