MINIMIZING METHYL-BROMIDE EMISSIONS FROM SOIL FUMIGATION

There is great controversy concerning the need to phase out methyl bro mide (MeBr) to protect stratospheric ozone. Unlike chlorinated hydroca rbons, MeBr occurs naturally in the atmosphere making it difficult to differentiate the threat to stratospheric ozone depletion from anthrop ogenic use of MeBr compared to natural sources. New technology has bee n developed which could nearly eliminate MeBr emissions from soil fumi gation, bringing into question the need for a phase out. A field exper iment demonstrated that virtually impermeable films (VIF) reduced MeBr emissions to near-zero levels. When compared to soil fumigation using conventional high-density polyethylene film (HDPE), the total global MeBr emission could be reduced from 32 Gg/yr to less than 1 Gg/yr, if VIF were required. In addition, reduced application rates are possible since using VIF reduces wasteful leakage and increases pest-control e fficiency. With such low emission rates, and considering the large unc ertainty in global estimates of MeBr, it seems that the phase-out of M eBr as a soil fumigant is unjustified.