Adsorption and movement of carbofuran in selected soils of Sri Lanka
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Date
1997-11-22
Authors
Kumaragamage, D.
Gamage, D. A. S.
Samatha, M. M. S. S.
Rathnayake, J. I. L. B.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
Carbofuran is an insecticide, which is readily adsorbed to soil particles. Adsorption of carbofuran is a key parameter controlling the extent to which it "ill leach through the soil to ground water. The main objective of this study was to investigate the adsorption and movement of carbofuran in major soil types of Sri Lanka. Carbofuran adsorption was studied in soil samples collected from 20 locations by equilibrating with a carbofuran solution. After equilibration. the supernatant was analyzed for carbofuran and the amount adsorbed was calculated. Movement of surface-applied carbofuran was studied in disturbed (packed) and in undisturbed soil columns.Carbofuran was applied to the surface, after which columns were leached with water and leachate samples were analyzed for carbofuran. 'The relationship between the amount of carbofuran leached and soil properties _was analyzed.
Carbofuran adsorption did not show a significant relationship with cation exchange capacity, pH and clay content. A significant quadratic relationship was observed between carbofuran adsorption and organic matter, but the linear relationship was not significant. When regression analysis was conducted separately for soils with pH less than 5.5, the relationship between organic matter and carbofuran adsorption improved. In soils with pH greater than 5.5, such a relationship was not observed. The percentage of carbofuran leached showed a significant negative relationship with soil organic matter content and a significant positive relationship with soil pH.
The results indicate that the adsorption of carbofuran is greater and leaching is less in strongly acidic soils with high organic matter contents. Thus, application of carbofuran to such soils. will reduce its effectiveness as a pesticide, but with less ground water pollution and therefore with less adverse effects on the environment
Description
Keywords
Soil Science , Sri Lanka , Carbofuran
Citation
Proceedings and Abstract of the Annual Research Sessions, November 22, 1997, University of Peradeniya, Sri Lanka pp 1-12