2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 5
Presentation Time: 8:00 AM-6:00 PM

Effects of Dissolved Organic Matter on Residues of Chlorpyrifos in Soil and on Plant Uptake

MA, Aijun, Dept. of Scenery Gardening, Jiangsu Polytechnic College of Agriculture and Forestry, Jiangsu, 212400, China, HE, Renhong, Dept. of Agronomy, Jiangsu Polytechnic College of Agriculture and Forestry, Jiangsu, 212400, China and LIN, Yusuo, Key Laboratory of Soil Management and Pollution Control, State Environmental Protection Administration, Jiangsu, 210042, China, maaijun2@163.com

Dissolved organic matter (DOM) is comprised of a myriad of macromolecules with specific physical and chemical properties that may influence the fate of hydrophobic pesticides in the soil-plant system. A pot experiment was conducted to evaluate the effect of dissolved organic materials derived from green manure (GM) and pig manure (PM) on Chlorpyrifos dissipation in Typic Ferri-Udic Argosols (Chinese Soil Taxonomy 2001) and Chlorpyrifos uptake by Chinese Cabbage (Brassica chinensis). Chlorpyrifos was added to soil with an initial concentration equivalent to 5 mg.kg-1. Following the pesticide application, DOM (100 mg.L-1) was applied to the plants by surface irrigation during growing season. The degradation of Chlorpyrifos in soil was calculated by fitting the data to a first-order equation Ct=C0e-kt. In the presence of GM and PM effluent, the dissipation of Chlorpyrifos is faster; the final Chlorpyrifos residue in soil is 5.8% and 37.3% less than that in DOM free soil. Furthermore, DOM application diminished Chlorpyrifos phytoavailability and bio-concentration significantly, total uptake of Chlorpyrifos by Chinese Cabbage in the absence of DOM was 61.4% and 20.8% more than those irrigated with GM and PM effluent, respectively. However, the extent to which the residue was influenced differs according to the DOM type; the GM exhibited higher reductions than PM. Our findings indicate the use of organic waste-derived effluents for irrigation may be applied to provide means to reduce Chlorpyrifos residue in soil-plant systems.