Submitted to: International Congress on the Chemistry of Crop Protection
Publication Type: Abstract Only
Publication Acceptance Date: 8/9/2002
Publication Date: 8/9/2002
Citation: Papiernik, S.K., Yates, S.R. 2002. Emissions of fumigant compounds through agricultural films. International Congress on the Chemistry of Crop Protection. 2:118.
Technical Abstract: Controlling atmospheric emissions of soil-applied fumigants is important for protecting air quality, and containment of fumigants in the soil increases efficacy. High-density polyethylene (HDPE) films are commonly used in soil fumigation with methyl bromide (MeBr), but these films are permeable to MeBr, and a large fraction of the applied mass may be lost through volatilization. Less-permeable films are being developed for use in soil fumigation. In these experiments, we used sealed permeability cells to determine the mass transfer coefficient (h, a measure of the resistance to diffusion) of fumigant compounds across agricultural films. Results indicated that the HDPE films tested were less permeable to MeBr than to other fumigant compounds, indicating the limited utility of HDPE for containment of MeBr alternatives. Investigation of the effect of environmental conditions on the permeability of HDPE indicated that temperature and HDPE film type had the largest impact on the h of all fumigant compounds across HDPE. Other factors investigated, including fumigant mixtures, exposure to field conditions, and condensed water on the film, had a much smaller or insignificant impact on the apparent permeability. Preliminary results for virtually impermeable films (VIFs) indicate hs several hundred to several thousand times lower than those for HDPE. Studies using packed soil columns indicated the potential for emissions reduction with the use of low-permeability agricultural films. Cumulative emissions of all fumigants through a continuous tarp of representative VIF were ~10 percent of those through 1-mil HDPE, with a corresponding increase in the soil fumigant concentrations in VIF-tarped columns.