|Allen, Leon - Hartwell|
Submitted to: Journal of Environmental Science and Health
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/14/2011
Publication Date: 6/1/2011
Citation: Thomas, J.E., Ou, L., Allen Jr, L.H., Vu, J.C., Dickson, D.W. 2011. Improved soil fumigation by Telone C35 using carbonation. Journal of Environmental Science and Health. 46:1-7. Interpretive Summary: Soil fumigation to control pests is an important part of current agricultural practice. A reduction in fumigant emissions is required to insure worker safety and environmental health. A field trial was conducted in Citra, Florida by USDA-ARS-CMAVE scientists and University of Florida collaborators to investigate whether the use of carbon dioxide (CO2) to carbonate and pressurize Telone C35 would improve the delivery of the fumigant to such an extent that its application rate could be decreased without sacrificing efficacy. The results, in conjunction with the use of black virtually impermeable film, metallized polyethylene (PE) and blue PE as plastic covers, show that the carbonation of Telone C35, compared to the application by nitrogen gas (N2) pressurization, resulted in faster dispersion of the soil fumigant with greater vertical and lateral distribution. Besides, the reduced application rate (75%) of carbonated Telone C35 was as effective in weed and in nematode controls as the full application rate using N2 pressurization to force injection of the fumigant. In addition, the cumulative amount volatilized from the carbonated fumigant beds at 75% application rate was lower than that emitted by the full rate of Telone C35 using N2. This would result in less environmental risks.
Technical Abstract: Field trial was conducted to investigate whether carbonating Telone C35 (1,3-dichloropropene with 35% chloropicrin) would improve the delivery of the fumigant to such an extent that the application rate could be decreased without sacrificing efficacy. The plastic films used were black virtually impermeable film, metallized polyethylene (PE), and blue PE. The use of carbon dioxide (CO2) to carbonate and pressurize Telone C35 provided quicker and deeper distribution, compared to the application by nitrogen gas (N2) pressurization. The deeper distribution of Telone C35 components with CO2 application might lower the initial concentration of Telone C35, but did not alter the disappearance rate of the active chemicals. Although the faster vertical distribution within the bedded soil of the Telone C35 by CO2 enhanced volatilization of the chemicals compared to volatilization of similar reduced rate applied by N2, the cumulative amount volatilized from the carbonated fumigant beds at 75% application rate was lower than the cumulative amount emitted by full rate of Telone C35 using N2. The efficacy of the carbonated Telone C35 at 75% application rate was as effective in control of weed and nematode as full application rate using N2 pressurized injection.