Performance of Low Permeable Tarps on Reducing 1,3-Dichloropropene and Chloropicrin Emissions in a Strawberry Field Trial.

Low permeable tarps have great potential to reduce fumigant emissions in strawberry fields with raised beds. A field study was conducted in Fall 2007 near Oxnard, CA to compare the emission reductions efficiency of two low permeable tarps [virtually impermeable film (VIF) and semi-impermeable film (SIF)] with standard polyethylene film with and without water applications to furrows (PE/water and PE, respectively). Fumigant, Inline [60.8% of 1,3-dichloropropene (1,3-D) and 33.3% of chloropicrin (CP)] was drip-applied 3 cm under the soil surface at 336 kg ha^-1. Following the application, 1,3-D and CP flux from top of the beds and furrows which was measured using dynamic flux chambers and gas-phase concentrations under the tarps were monitored for 8 d. Emission flux was highest immediately following the fumigant application. The highest emission flux occurred in PE tarped fields compared to the low permeable tarped fields. Differences in total emission losses were small between the VIF and SIF tarped fields. Total emission loss from the VIF and the SIF tarped fields were 62% of 1,3-D and 57% of CP loss from the PE. The field results confirmed the effectiveness of VIF and SIF films on fumigant emission reduction. Water application to furrow following fumigation did not affect fumigant emissions, which could be due to the very low emission from furrows (< 1% of total emission loss). The results indicate that low permeable tarps significantly reduce fumigant emissions when the fumigant is drip-applied to raised beds, and thus could minimize the negative impacts of soil fumigation on the environment.