Monday, November 13, 2006 - 10:45 AM
123-1

Surface Seals Reduce 1,3-Dichloropropene and Chloropicrin Emissions.

Suduan Gao, USDA-ARS, SJVASC-Water Mgt Research, 9611 S Riverbend Ave., Parlier, CA 93648 and Thomas Trout, USDA-ARS, 2150 Centre Ave, Ft. Collins, CO 80526-8119.

Reducing emissions is essential for minimizing the detrimental impact of soil fumigation and for maintaining the availability of fumigants to agricultural uses.  This study determined the effectiveness of surface water applications to reduce emissions of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) by comparing with other surface seals under field conditions.  Telone C35 (61% 1,3-D and 35% CP) was shank-applied to a sandy loam soil in San Joaquin Valley, CA.  Soil surface seal treatments included standard high density polyethylene (HDPE) tarp over dry and pre-irrigated soil, virtually impermeable film (VIF) tarp, initial water application immediately following fumigation, and intermittent water applications after fumigation. Among the surface seals, VIF and HDPE tarp over dry soil resulted in the lowest and the highest total emission losses, respectively. Intermittent water applications reduced 1,3-D and CP emissions significantly more than HDPE tarp alone and the initial water application only following fumigation. The initial water application reduced emission peak, delayed emission time, and reduced total emissions as effectively as HDPE tarp. Pre-irrigated soil + HDPE tarp reduced fumigant emissions similarly as the intermittent water applications and also yielded the highest surface soil temperature which may benefit overall soil pest control.