Laboratory‐Scale Measurements and Simulations of Effect of Application Methods on Soil Methyl Bromide Emission

Abstract

Methyl bromide (bromomethane, MeBr), which originates from the oceans, fumigation, and a few other sources, is reportedly contributing to the ozone depletion in the stratosphere. Due to the heavy reliance on this fumigant in the production of many crops, it is of particular importance to accurately quantify the atmospheric input of MeBr arising from agricultural uses, and develop feasible measures to minimize these emissions. In this study, we determined the effect of two important application variables, surface tarp and injection depth, on MeBr transport and transformation in the soil and its emission from the soil surface under controlled conditions. Following 20-and 30-cm injections, covering the soil surface with 1-mil (0.025 mm) high-density polyethylene film resulted in an average of 48% reduction in MeBr emission. Increasing the injection depth from 20 to 60 cm caused a decrease in MeBr emission of 54% under untarped conditions and 40% under tarped conditions. The influence of application methods on MeBr atmospheric emissions should be considered when estimating the contribution of agricultural fumigation to the overall atmospheric MeBr burden on a global scale. The results also indicate that MeBr emission after soil fumigation may be substantially minimized by using surface tarpaulins and deep injections.

Strain IMB-1, a Novel Bacterium for the Removal of Methyl Bromide in Fumigated Agricultural Soils

“…Physical manipulations (e.g., soil compaction and deeper injection of MeBr) have been proposed to increase the retention time of MeBr within the soil matrix, thereby allowing for its more extensive degradation and subsequent decrease in its outward flux to the atmosphere (13). In addition, use of thicker, impermeable covering tarps has been proposed to reduce losses (14,37), as has the substitution of methyl iodide for MeBr (11,25). However, enhancement of microbial degradation of MeBr while it is present in the soil matrix may also be a means to eliminate emissions.…”

Gas‐Phase Distribution and Emission of Chloropicrin Applied in Gelatin Capsules to Soil Columns

“…All samples were analyzed within 72 h after collection. The gas sampling and storage methods were quantitative and reproducible (Gan et al, 1997).…”

Evaluation of permeation rates of soil fumigants through plastic films by the cup method

“…Such films typically remain intact in the field for 1-2 weeks, after which the film is removed for planting or punctured for placement of seedlings. Polyethylene (PE) films are most commonly used in soil fumigation, but these films are reportedly permeable by MeBr [7][8][9][10][11][12] and other soil fumigants. 12,13) To reduce emissions and to develop fumigation management practices that protect the environment while providing adequate pest control, they must also maintain their impermeability to fumigant vapors under field conditions.…”