Adsorption and relative mobility of flumetsulam
1997
Shaw, D.R. | Murphy, G.P.
Laboratory studies were conducted to evaluate flumetsulam adsorption and mobility in seven Mississippi soils of different organic matter content, pH, and texture. Adsorption isotherms were determined for all soils using a 1:1 (soil:water) technique. In six of seven soils, Freundlich n constants were close to unity, suggesting a partitioning-like adsorption mechanism for flumetsulam. Mobility was examined using packed soil columns. 14C-flumetsulam recoveries in leachate ranged from 1 to 70% and were influenced by both organic matter content and soil pH. However, the effects of organic matter content and soil pH were not independent. Consequently, clear relationships between flumetsulam mobility and either organic matter content or soil pH were not established across all soils. However, among soils of similar pH (7.5 +/- 0.3), mobility decreased linearly (R(2) = 0.75) as organic matter content increased from 0.7 to 3.6%. Across soils with similar organic matter content (3.9 +/- 0.3%), mobility increased linearly (R(2) = 0.98) as soil pH increased from 5.3 to 7.2. Net adsorption constants (K(d)) provided a more accurate assessment of flumetsulam mobility across all soils than K(oc).
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