Soil Fate of Agricultural Fumigants in Raised-Bed, Plasticulture Systems in the Southeastern United States
- Dan O. Chellemi *a,
- Husein A. Ajwab,
- David A. Sullivanc,
- Rocco Alessandroa,
- James P. Gilreathd and
- Scott R. Yatese
- a USDA–ARS, US Horticultural Research Lab., 2001 S. Rock Road, Fort Pierce, FL 34945
b Dep. of Vegetable Crops, Univ. of California, 1636 East Alisal St., Salinas, CA 93905
c Sullivan Environmental Consulting, Inc. 1900 Elkin St., Suite 200, Alexandria, VA 22308
d PhytoServices, 16 W. Hillcrest Dr., Greenville, SC 29609
e USDA–ARS, U.S. Salinity Lab., 450 W. Big Springs Rd., Riverside, CA 92507. Assigned to Associate Editor Robert Dungan
Soil concentrations and degradation rates of methyl isothio-cyanate (MITC), chloropicrin (CP), 1,3-dichloropropene (1,3-D), and dimethyl disulfide (DMDS) were determined under fumigant application scenarios representative of commercial raised bed, plastic mulched vegetable production systems. Five days after application, 1,3-D, MITC, and CP were detected at concentrations up to 3.52, 0.72, and 2.45 μg cm−3, respectively, in the soil atmosphere when applications were made in uniformly compacted soils with a water content >200% of field capacity and covered by a virtually impermeable or metalized film. By contrast, DMDS, MITC, and CP concentrations in the soil atmosphere were 0.81, 0.02, and 0.05 μg cm−3, respectively, 5 d after application in soil containing undecomposed plant residue, numerous large (>3 mm) clods, and water content below field capacity and covered by low-density polyethylene. Ranked in order of impact on the persistence of fumigants in soil were soil water content (moisture), soil tilth (the physical condition of soil as related to its fitness as a planting bed), the type of plastic film used to cover fumigated beds, and soil texture. Fumigants were readily detected 13 d after application when applied in uniformly compacted soils with water contents >200% of capacity and covered by a virtually impermeable or metalized film. By contrast, 1,3-D and MITC had dissipated 5 d after application in soils with numerous large (>3 mm) clods and water contents below field capacity that were covered by low-density polyethylene. Soil degradation of CP, DMDS, and MITC were primarily attributed to biological mechanisms, whereas degradation of 1,3-D was attributed principally to abiotic factors. This study demonstrates improved soil retention of agricultural fumigants in application scenarios representative of good agricultural practices.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2011. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.