Residual quantities of methyl salicylate, sprayed on sand, red loam, and heavy loam soils, were estimated by measuring evaporation rates in a laboratory simulation setup.Methods for homogeneous dissemination of liquid on the surface and for controlling and measuring droplet size and surface concentration were developed. A flow system was built for measuring the time dependence of the vapor concentration in a wind tunnel, at various flow rates.Our experiments have demonstrated that the efficiency of soil spraying is affected by droplet size—the highest residuals were obtained with the biggest droplet diameter.It is clear, however, that the final determination of the optimal droplet size is a function of soil type and agricultural requirements.