APPLICATION OF ORGANIC AMENDMENTS TO REDUCE VOLATILE PESTICIDE EMISSIONS FROM SOIL

Atmospheric emission of volatile pesticides such as soil fumigants con tributes to air pollution, and feasible strategies to reduce their emi ssion are urgently needed. In this study, we investigated the potentia l of applying organic wastes to reduce the emission of two important f umigants, methyl bromide (MeBr) and methyl isothiocyanate (MITC), by e nhancing their degradation in surface soil. The degradation of both co mpounds was significantly accelerated in composted manure or biosolid- manure amended soils, and the enhancement was greater for MITC than fo r MeBr. The difference in degradation kinetics between sterile and non sterile amended soils indicates that degradation of MeBr in amended so ils was chemically mediated, while that of MITC was mainly a result of stimulated microbial degradation. Applying 5% of composted manure to the 5 cm surface soil in packed columns reduced MeBr emission by 12%, and almost completely eliminated the volatilization of MITC. As certai n organic amendments can suppress soil pathogens on their own, integra ting fumigation with organic waste application may potentially provide complementary pest control activity. The applicability and benefits o f such integrations should be further evaluated under field conditions .