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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Publications at this Location » Publication #288145
Title: A micro spot injection system for studing the effects of carbonation on fumigant dispersion in soil

Author
item QIN, RUIJIN - University Of California
item PFLAUM, TOM - University Of California
item Gao, Suduan
item HANSON, BRAD - University Of California

Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2012
Publication Date: 11/6/2012
Citation: Qin, R., Pflaum, T., Gao, S., Hanson, B. 2012. A micro spot injection system for studing the effects of carbonation on fumigant dispersion in soil. Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions, November 6-8, 2012, Maitland, Florida. p. 61:1-4.

Interpretive Summary: Using carbon dioxide (CO2)-pressurized injection systems to apply carbonated fumigants was found to lead to more effective dispersion of chemicals for better pest control efficacy as compared to conventional fumigation systems pressurized with nitrogen (N2). However, determination of how carbonation can be effectively used to increase fumigation efficiency especially for perennial crops is limited with current commercial fumigation equipment. Therefore, we constructed a micro spot fumigant injection system (MSFIS) that is used for carbonating fumigant and injecting fumigants at a target pressure. Laboratory tests showed that much higher amounts of CO2 can be dissolved in Telone C35 than N2 at the same pressure, which may be one of the reasons for improving fumigant dispersion. Injection of carbonated or nitrogen pressurized water using the system can achieve injection accuracy >99%. These results indicate that the system is ready to be used to evaluate how carbonation can be effectively utilized to improve fumigant diffusion and pest control in perennial tree systems. The information developed using this system will ultimately assist the adoption of this technology by the industry for the efficient use of fumigants.

Technical Abstract: Fumigant transport to deep soils is needed to control plant parasitic nematodes and soil borne pathogens for perennial crops. Using carbonated fumigants and carbon dioxide (CO2)-pressurized fumigant injection systems may achieve this target when compared to conventional fumigation systems pressurized with nitrogen (N2). However, information on how carbonation enhances the fumigant dispersion and subsequent pest control in California is lacking because of the safety concerns over transportation of carbonated fumigants and the limitations of using existing commercial application apparatus. A micro spot fumigant injection system (MSFIS) was constructed with the aim of accurately applying carbonated- or N2-pressurized fumigants into soil to evaluate the fumigant dispersion and pest control efficacy. The MSFIS does not only carbonate fumigants, but also injects the fumigants at the desired target pressure. Laboratory tests showed that at controlled room temperature, the amount of CO2 dissolved in Telone C35 increased steadily with the headspace pressure and much less N2 dissolved into the fumigant at the same pressure. At 50 psi, the dissolved N2 in Telone C35 was ~0.24% N2 (w/w) compared to 1.72% CO2 (w/w). Laboratory injection tests with N2-pressurized or carbonated water at 50 psi showed high injection accuracy (99.5-100% of the target value). These results suggest that the MSFIS can be used for applying N2 pressurized or carbonated fumigant in field. The practicality and validity of the system needs to be confirmed in further field evaluations.