SORPTION OF HERBICIDES IN RELATION TO SOIL VARIABILITY AND LANDSCAPE POSITION

Abstract

Using the soil-water sorption partitioning coefficient (Kd), this study quantified the spatial variation of 2,4-D sorption by soil in an undulating-to-hummocky terrain landscape near Minnedosa, MB, Canada. Herbicide sorptionwas most strongly related to soil organic matter content and slope position, with greatest sorption occurring in lower landscape positions with greater soil organic matter content. The relation between sorption and slope position was more pronounced under conventional tillage (CT) than under long-term zerotillage (ZT). Using multivariate regression and three independent variables (soil organic matter content, soil clay content and soil pH), the prediction of herbicide sorption by soil was very good for CT (R² = 0.89) and adequately for ZT (R² = 0.53).

Keywords:

• Herbicide
• Sorption
• Partitioning coefficient
• Landscape position
• Zero-tillage
• Conventional-tillage

ACKNOWLEDGMENTS

We gratefully acknowledge the financial support by the Natural Sciences and Engineering Research Council of Canada, the Scientific and Environmental Affairs Division of the North Atlantic Treatment Organization, and the University of Manitoba.