|Qin, Ruijun - UC DAVIS|
Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 2, 2006
Publication Date: November 6, 2006
Citation: Mcdonald, J.A., Qin, R., Gao, S., Trout, T.J. 2006. Reduction of Fumigant Emissions Using Chemical and Organic Amendments. In "Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emission Reductions", p. 125(1-4), held in Orlando, FL, Nov. 6-9, 2006. Available: www.mbao.org/2006/06Proceedings/mbrpro06.html Technical Abstract: Water seal (water application to soil surface) has been shown as a cost effective method to reduce fumigant emissions in comparison with standard high density polyethylene (HDPE) tarp. Application of excess amount of water, however, inhibits fumigant diffusion within the soil profile and may affect fumigation efficacy. This study determined the effectiveness of adding chemical and manure amendments to the soil surface on reducing 1,3-D emissions in combination with HDPE tarp and to compare these amendments to water seal. Soil surface treatments of pre-moistened soil, initial water seal and chemical seal applied at molar ratio of 1:1 ammonium thiosulfate (ATS):fumigant, 1:1 ATS:fumigant + HDPE tarp, and 2:1 ATS: fumigant, and manure amendment with and without HDPE tarp were used. The emissions and distribution of 1,3-D were sampled and determined over two weeks. The pre-moistened soil treatment resulted in a lower emission peak (7 'g m-2 s-1) and total emission loss (20% of applied) for the first 5-d observations compared to water seal (9.7 'g m-2 s-1, 29% total loss) and 1:1 ATS:fumigant (7.9 'g m-2 s-1, 27% total loss) treatments. Application of more ATS (2:1 ATS:fumigant) and the manure amendment to surface allowed for slightly more reduction of emissions (6.0-6.5 'g m-2 s-1, and 20% total emissions, respectively. Results from this study suggested that pre-moistened soil conditions may be equally effective as using ATS or organic amendments within surface soil. The lowest emissions resulted from HDPE tarp over the manure and 1:1 ATS amendment treatments. Although previous research has shown that HDPE alone does not effectively reduce 1,3-D emissions, there appears to be a synergistic effect of the tarp and chemical or manure amendments on emission reduction.