Two devices for field sampling agricultural spray drift were evaluated in a wind tunnel to determine their performance: a battery powered rotary sampler which collects drops on a moving surface, and a passive sampler of synthetic wool yarn. Both samplers were tested under controlled conditions at wind speeds of 0.25, 0.5, 1.0 and 1.5 ms-1 using monodispersed spray of 10, 15, 20, and 25 µm diameter to characterise their performance; collection efficiencies varied from approximately 40 to 100% for the yarn, and from 1 to 70% for the rotary sampler. The two samplers are complementary; with the calibration data reported here the rotary sampler becomes a quantitative method for drift measurement. The passive yarn sampler provides more limited data, however, the lower cost of each sampler and subsequent analysis mean that a large number can be used in conjunction with a few rotary samplers to provide a good estimate of spray drift.
Cooper, J.F.; Dobson, H.M.; Smith, D.N. An evaluation of two field samplers for monitoring spray drift. Crop Protection (1996) 15 (3) 249-257. [DOI: 10.1016/0261-2194(95)00113-1]