Submitted to: Almond Industry Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: September 22, 2005
Publication Date: December 7, 2005
Citation: Gao, S., Trout, T.J. 2005. Developing methods to reduce emissions from soil fumigation.. Almond Industry Conference Proceedings, pp 235-241. Interpretive Summary: Minimizing emissions of fumigants is critical to protecting workers, bystanders, and the environment, and to ensure practicable use of alternative fumigants for production of high value crops. This project evaluated soil surface water application effect on emissions of 1,3-dichloropropene (1,3-D) and plastic tarps through both laboratory column experiments and a field trial with small plots. Results show that soil surface water applications, if managed well, were as effective or more effective than using standard plastic tarp. As using water is less expensive than plastic tarp, surface water application practices did show high potential to reduce fumigant emissions, especially in areas where irrigation water and sprinkler systems are available.
Technical Abstract: Regulations on uses of soil fumigants are primarily based on their toxicity and air emissions. In addition to maintaining practical use of alternative fumigants for production of high value crops, minimizing emissions is also critical to protecting workers, bystanders, and the environment. The objective of this study was to evaluate if water application to the soil surface can effectively reduce fumigant emissions. Laboratory column experiments and a field trial with small plots were conducted to compare various treatments including plastic tarps [standard HDPE and virtually impermeable film (VIF)], soil moisture condition (dry vs. wet), and surface water application amount and timing. Results have shown that surface water application can reduce 1,3-D emission as effectively or even better than using standard HDPE tarp. Each surface water application resulted in abrupt reduction of emission rates. Soil surface preparation and intermittent water application schedule are critical to maximizing the effect of water application on emission reduction. Initial water applications also delayed peak emission time thus reducing the risks to workers and by-standers during fumigation. Initial soil moisture below HDPE reduced emissions much more than HDPE over dry soil. Further research needs to investigate the optimum amount of water needed and its application schedule on reducing fumigant emissions. As using water is generally less expensive than using plastic tarp, practices with surface water applications using a sprinkler system can be developed to reduce fumigant emissions under field conditions.