|Allen, Leon - Hartwell|
Submitted to: Soil and Crop Science Society of Florida Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/15/2000
Publication Date: N/A
Interpretive Summary: The phase-out of methyl bromide by the year 2005 requires evaluation of potential alternative soil fumigant to ensure sustainable production of vegetables. One of the most promising chemicals is 1,3-dichloropropene (1,3-D). We need to determine the potential environmental risks of 1,3- D compounds as well as MeBr in raised-bed agriculture when conventional polyethylene film soil covers are employed. ARS and UF scientists at Gainesville, FL measured crop growth and yields, along with emissions of 1,3-D from the soil in raised bed polyethylene covered fields. We found that MeBr application rates could be reduced by half and still maintain excellent pest control and crop production. We found that bare soil or beds covered with conventional plastic film lost significantly more 1,3-D than high barrier films. This study forewarns us that alternative chemical fumigants may face the same fate as methyl bromide if new agricultural management practices are not adopted in States that administer soil fumigants under plasticulture. It also demonstrates the potential for decreased soil fumigant use while maintaining a high level of pest control and crop yield when barrier films are used.
Technical Abstract: The soil fumigants methyl bromide (MeBr) and 1,3-dichloropropene (1,3- D) face use restrictions due to their potential environmental hazards and health risks. One of the proposed solutions to reduce these concerns is the use of virtually impermeable films (VIF) to decrease gaseous emissions into the atmosphere. The majority of research investigating these films has focused primarily on quantifying chemical efflux through the film, with little attention to pest control efficacy. The results of a fall tomato study showed that the amount of MeBr currently used could be reduced by as much as half if VIF are employed. The VIF tarps reduced substantially the amount of 1,3-D volatilization, which in turn could lead to more chemical degradation in the soil. In plots where pesticide was applied with no film cover, fruit yields were reduced by half due to poor pest control, compared to film covered plots. Because of potential volatilization and plume drift, VIF use should be considered more often in research dealing with alternative chemical replacements for MeBr as decreased atmospheric release and lowered chemical use may prevent other agricultural chemicals from suffering the fate of that of MeBr.