Modelling the Emission of the Fumigants 1,3-Dichloropropene and Methyl Isothiocyanate from Soil to Air

摘要

After their injection into the soil, a fraction of the fumigants 1,3-dichloropropene and methyl isothiocyanate (formed from metham-sodium) diffuses up to the soil surface and escapes into the air. The rates of emission of the fumigants into the air were computed with a model describing their behavior in soil. For both fumigants, it was computed that up to a few tens of percent of the dosage can be lost by volatilization. Deviations between the contents of methyl isothiocyanate measured in soil and those computed prompted further model development. A model for the behavior of non-volatile pesticides in soil was extended and modified to estimate the effect of rainfall and evaporation and that of diurnal changes in soil temperature on the rate of emission of fumigant into the air. (Copyright (c) 1992 SC-DLO.)