Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 15, 2010
Publication Date: November 12, 2010
Citation: Gao, S., Hanson, B.D., Qin, R., Wang, D., Yates, S.R. 2010. Comparisons of surface sealing methods in emission reduction from soil fumigation using field plot tests. Journal of Environmental Quality. Available on line: Nov 2010, doi:10.2134/jeq2009.0422. Interpretive Summary: Over several years, a great effort has been made by researchers to develop field effective methods to reduce emissions from soil fumigation. A field trial using field plot tests was conducted to determine the effectiveness of several commonly proposed field methods to reduce emissions from shank injection of Telone II. Emission reduction of 1,3-dichloropropene by standard polyethylene tarp, post-fumigation water treatments and organic amendment were limited depending on soil and environmental conditions as well as how the treatment was applied. The most promising emission reduction technique was tarping fumigated field with low permeable film so called virtually impermeable film (VIF). The VIF significantly reduced emissions and retained higher fumigant concentration under the tarp compared to any other treatment. The results show the potential of VIF tarp to improve uniform distribution of fumigant in the soil profile. This may further lead to use lower application rates than currently used for satisfactory pest control. The information is valuable for various commodities and regulatory agencies to identify practices that minimize emissions while achieving good efficacy from pre-plant soil fumigation.
Technical Abstract: Effective agricultural management to reduce emissions from pre-plant soil fumigation is needed in developing policies and regulations towards fumigant use. Field plot tests provide an important tool for determining the effectiveness of surface sealing or other mitigation techniques on emission reduction. These methods also provide insight on how environmental conditions and standard field operations affect emissions for typical grower fields. Several commonly proposed emission reduction methods were simultaneously tested in a trial involving shank injection of Telone® II (97.5% 1,3-dichloropropnene and 2.5% inert ingredient) in a sandy loam soil. The experiment was conducted late September 2008 in the San Joaquin Valley of California. Emissions were measured using dynamic flux chambers and provided short-term flux and cumulative loss values. The results showed that a virtually impermeable film (VIF) reduced emissions by more than 95% and the glue joints did not significantly affect the tarp performance in the field. The VIF also retained higher or more uniform distribution of gaseous fumigant in soil profile and would benefit efficacy. Standard high density polyethylene (HDPE) tarp reduced total 1,3-D emissions about ~50% in this trial, which is higher than most reported values. Post-fumigation intermittent water treatments (seals) reduced cumulative emission losses only about ~20%, which was likely affected by water amount and application times. Amendment of composted dairy manure to surface soil at 49.4 Mg ha-1 (~20 tons per acre) was not found to be effective in emission reduction during this experiment. Use of VIF was found to be the most promising technique in reducing emissions, allowing lower application rates while providing satisfactory pest control.