REDUCING METHYL-BROMIDE EMISSION WITH A HIGH BARRIER PLASTIC FILM ANDREDUCED DOSAGE

A field experiment was conducted to study the effectiveness of a high- barrier plastic film (Hytibar) and reduced methyl bromide (MeBr) appli cation dosages in decreasing MeBr emission from soil fumigation. Compa rison was made with a conventional polyethylene film (PE) and a regula r application rate. MeBr emission from nine small field plots was cont inuously measured with two replicated active chambers. Replicated soil cores were taken to a depth of 3 m to determine MeBr degradation and to obtain a mass balance. Results indicated that about 64% of applied MeBr was lost to atmospheric emission when covered with the PE tarp fo r at least 5 days. The emission was reduced to 37.5% when covered with the Hytibar tarp for 5 days. MeBr emission was virtually eliminated w hen covering with the Hytibar tarp for more than 10 days (only 1.1-3.2 % loss). The low emission rate was verified from the degradation measu rements which, along with the flux measurements, produced nearly 100% mass balance. Combined use of a high-barrier plastic film such as the Hytibar with reduced application rates can significantly reduce MeBr a tmospheric emission while maintaining effective pest control efficacy.