Soil organic matter and pesticide fate. (5870)
Authors:
A. Farenhorst* - Univ. of Manitoba, MB, Canada
Abstract:
Pesticide fate and movement in soil is influenced by the molecular characteristics of the pesticide, as well as the physical, chemical and biological properties of the soil.
Pesticide sorption partitioning coefficients (e.g., Kd, Kf, which are measures of pesticide sorption by soil) are sensitive input parameters in pesticide fate and leaching models. There are numerous reports that confirm that soil organic carbon content (SOC) is the single most important parameter explaining the amount of sorption of pesticides by soil. It is also known that the strength of the relation between SOC and herbicide sorption varies spatially, from region to region and within agricultural fields. Although direct evidence is often lacking, it has been suggested that this variation is induced, in part, by differences in soil organic matter composition. The usefulness of studies that identify fractions of organic matter that are most reactive to pesticides is evident. This presentation reviews the progress that has been made since synthetic organic chemicals began to be used as pesticides in the 1940s. Most literature is focussed on micro-scale measurements using
pesticide sorption analyses to measure the interaction between soil organic matter fractions with specific pesticides. The importance of these micro-scale
measurements for advancing our understanding of pesticide fate and leaching at the soil-landscape scale will be evaluated.
Speaker Information: Annemieke Farenhorst, Univ. of Manitoba, MB, Canada, Department of Soil Science, Winnipeg, MB R3T 2N2; Phone: 204-474-6858; E-mail:
Session Information: Wednesday, November 3, 2004, 7:55 AM-12:00 PM Presentation Start: 11:40 AM
Keywords: pesticide; soil organic matter; sorption; review
