Location: Water Management ResearchTitle: Emissions from soil fumigation in two raised bed production systems tarped with low permeability films Author
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2013
Publication Date: 7/27/2013
Citation: Qin, R., Gao, S., Thomas, J.E., Dickson, D., Ajwa, H., Wang, D. 2013. Emissions from soil fumigation in two raised bed production systems tarped with low permeability films. Chemosphere. 93:1379-1385. Interpretive Summary: Fumigation is often used to control soil-borne pests in raised-beds for high-value annual crops such as strawberry in California (CA) and tomato in Florida (FL). Fumigant emissions must be minimized to reduce air pollution and exposure risk. By carrying out field trials in CA and FL, the effects of bed designs from two different production systems and associated factors including tarping raised-beds with low permeability tarps on fumigant emissions were evaluated. When InLine was drip-applied at 340 kg ha-1 near the surface of beds, high emissions (31% 1,3-D) from virtually impermeable film (VIF) tarped beds (30 cm high and 107 cm wide) were measured while minor emissions (<0.3%) were from furrows in the CA trial. On the contrary, when carbonated Telone C35 was shank applied at 151 kg ha-1 to 20 cm deep in the raised beds (22 cm high and 76 cm wide) which were covered with totally impermeability film (TIF) in the FL trial, much higher emissions were determined from the uncovered furrows (~27% 1,3-D) as compared to the ~0.1% 1,3-D from the beds. The field results indicate that raised-bed configuration, tarp permeability, fumigant application method, soil properties and soil water content can be important factors to consider for developing strategies using low permeability tarp in raised-bed systems.
Technical Abstract: Raised beds are used to produce some high-value annual fruit and vegetable crops such as strawberry in California (CA) and tomato in Florida (FL), USA. Fumigation is an important tool to control soil-borne pests in the raised beds before planting. However, fumigant emissions have detrimental environmental consequences. This paper evaluates fumigant emissions and associated factors in two different production systems with raised beds covered by low permeability tarp to help guide strategies for effective emission control. In a field trial in a sandy loam soil of CA, InLine was drip-applied at 340 kg ha-1 to 5 cm deep in the beds (30 cm high and 107 cm wide) tarped with polyethylene (PE) or virtually impermeable film (VIF). In another field trial in a sandy soil of FL, carbonated Telone C35 was shank-applied at 151 kg ha-1 to 20 cm deep in the beds (22 cm high and 76 cm wide) tarped with totally impermeable film (TIF). Emissions from tarped beds relative to furrows were contrary between the two trials. For the CA trial, the emission was 46.6% applied 1,3-D and 26.7% of applied CP from PE tarped beds and 30.7% of applied 1,3-D and 14.6% of applied CP from VIF tarped beds, while that from uncovered furrows was <0.3% for both chemicals in both fields. In the FL trial, only 0.1% 1,3-D was emitted from the TIF tarped beds, but 27.1% was measured from the uncovered furrows. Factors contributing to the differences in emissions were chiefly raised-bed configuration, tarp permeability, fumigant application method, soil properties and soil water content. The results indicate that strategies for emission reduction must consider the differences in agronomic production systems. Modifying raised bed configuration and fumigant application technique in coarse textured soils with TIF tarping can maximize fumigation efficiency and emission reduction.