Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Proceedings
Publication Acceptance Date: September 11, 2005
Publication Date: October 31, 2005
Citation: Gao, S., Trout, T.J. 2005. Potential of using surface water applications to reduce fumigation emissions. Proceedings of International Research Conference on Methyl Bromide Alternatives. Annual International Research Conference on MeBr Alternatives and Emissions Reduction, p. 109-1 and 109-4. Interpretive Summary: Reducing emissions of fumigants is critical to minimizing detrimental impact to the environment, and to ensure practicable use of alternative fumigants for agricultural production. Cost-effective practices in reducing fumigant emissions are mostly needed. This study tested if surface water applications can effectively reduce emissions of 1,3-dichloropropene (1,3-D) in comparison with plastic tarp treatments in soil column experiments . Results show that surface water applications were as effective or even more effective than using standard plastic tarp to reduce 1,3-D emissions. As using water is less expensive than plastic tarp, surface water application practices may be developed to control fumigant emissions.
Technical Abstract: High emission rates of fumigants from soil increase the risk of detrimental impact on workers, bystanders and the environment, and jeopardize future availability of fumigants. Efficient and cost-effective approaches to minimize fumigant use are needed. This study evaluated the potential of surface water application (or water seal) to reduce 1,3-dichloropropene (1,3-D) emission from soil (Hanford sandy loam) columns. Treatments included dry soil (control), initial water application (8 mm water just before fumigant application), initial plus a second water application (2.6 mm) at 12 h after fumigation, initial plus two water applications (2.6 mm each time) at 12 h and 24 h after application, standard high density polyethylene (HDPE) tarp, initial water application plus HDPE, and virtually impermeable film (VIF) tarp. Emissions from the soil surface and distribution of 1,3-D in the soil-gas phase were monitored for two weeks. Each water application abruptly reduced 1,3-D emission flux, which rebounded, however, over a few hours. Peak emission rates were substantially reduced, but total emission reduction was small. Total fumigant emission was 51% of applied for the control, 46% for initial water application only, and 41% for the three intermittent water applications with the remaining water treatment intermediate. HDPE tarp alone resulted in 45% emission, while initial water application plus HDPE tarp resulted in 38% emission. The most effective soil surface treatment was VIF tarp (10% emission). Surface water applications can be more effective and less expensive than standard HDPE tarp. High frequency of water applications is required to substantially reduce emissions.