Methyl Bromide Emission Reduction with Field Management Practices

Abstract

Current methods of soil fumigation may allow up to 65% of the applied methyl bromide (MeBr) to escape to the atmosphere. To protect stratospheric ozone and prevent economic losses from MeBr phaseout, there is an urgent need to find alternative fumigation techniques that can reduce MeBr emission. A field experiment was conducted to study and compare the effect of different management methods on MeBr emission reduction. Tested parameters included injection depth (0.25 and 0.6 m), use of polyethylene or a high-barrier plastic, bare soil, and irrigation. MeBr emission was estimated by sampling for the increase in soil bromide ion. Deep injection increased MeBr degradation and reduced total emission. Compared to bare soil, covering with plastic tarp significantly reduced MeBr emission. MeBr emission was reduced to <15% with the high barrier plastic. Irrigation and tarping enhanced MeBr containment and degradation. Effective treatment of citrus nematodes, fungi, and yellow nutsedge seeds was achieved for shallow injection with tarp or deep injection with the high-barrier plastic. The optimal method for pest control and MeBr emission reduction appears to be a combined use of the high-barriertarp, irrigation, and deep injection.