Concentration‐time relationships for methyl isothiocyanate in soil after injection of metham‐sodium

Abstract

Abstract Soil fumigation with metham‐sodium in the field was studied in detail by characterising soil and climatic conditions, and by measuring concentrations of methyl isothiocyanate. The effectiveness of two dosages in two contrasting soil profiles was compared on the basis of computed concentration‐time products for methyl isothiocyanate in the water phase. Under wet conditions, the vapour diffusion of methyl isothiocyanate was very slow and resulted in an irregular distribution in the soil. Showers further decreased effectiveness in the upper part of the soil. A dried top layer was unfavourable for the concentration‐time product near to the surface. Diffusion of methyl isothiocyanate to depths greater than about 30 cm was very slow.