Alternatives to MEBR for California Cropping Systems
Location: Water Management Research
Title: Methods evaluated to minimize emissions from preplant soil fumigation
Submitted to: California Agriculture
Publication Type: Review Article
Publication Acceptance Date: November 24, 2009
Publication Date: January 15, 2011
Citation: Gao, S., Hanson, B.D., Wang, D., Browne, G.T., Qin, R., Ajwa, H., Yates, S.R. 2011. Methods evaluated to minmize emissions from preplant soil fumigation. California Agriculture. 65(1):41-46.
Interpretive Summary: Fumigant emissions are detrimental to air quality and minimizing emissions is required by environmental regulations. This paper reviews updated research findings on methods to minimize emissions from soil fumigation. Among all surface sealing and treatment methods (plastic tarps, water seals, chemical treatment and organic amendments), low permeability tarp is the most effective technology to reduce emissions with improved efficacy and this type of tarps also demonstrates the potential in using reduced application rates because of its effectiveness to retain fumigants under the tarp. Problems in maintaining the tarp integrity in field applications need to be resolved. The information is useful to commodities relying on soil fumigation, regulatory agencies, and science community in searching effective methods to control fumigant emissions to minimize potential exposure risks to workers and bystanders and reduce VOC emissions that degrade air quality.
Reducing emissions from soil fumigation is required to comply with environmental regulations. Low emissions can be achieved through management of application methods such as deep injection and subsurface drip, physical barrier with plastic films, irrigation to form water seals or achieve relatively moist soil conditions, and reduce treatment areas to planting rows or sites. Soil chemical treatment (e.g., thiosulfate) can be extremely effective in lowering emissions and may prove an effective strategy for extreme cases such as spills. Although incorporation of composted dairy manure to surface soil at or below 25 tons/ha did not show effectiveness to reduce emissions in some field tests, higher rates or other effective materials have the potential in addition to the benefits to improve soil physiochemical properties. Low permeable plastic tarps (e.g, VIF) have shown the most promising in reducing emissions while improving efficacy. This type of films may also lead to lower application rates that can compensate with the high costs associated with the film. Research data on the performance of new films (e.g., TIF) are needed for field applications. Feasible techniques for different commodities should consider the vailability to their production system, effectiveness on emission reduction, potential impact on pest control, and the costs.