INFLUENCE OF SOIL PROPERTIES ON ETHOFUMESATE MOBILITY

We studied the mobility of ethofumesate (2-ethoxy-2,3-dihydro-3,3-dime thylbenzofuran-5-yl methanesulphonate) in 23 soil samples by using soi l thin layer chromatography (soil TLC) and soil-packed columns. Eighte en of the samples assayed were from agricultural soils of the Marismas del Guadalquivir (a marshy region at the mouth of River Guadalquivir, SW Spain) and the other five were from natural, uncultured soils with organic matter contents above 3 The R(f) values obtained by soil TLC ranged between 0. 13 and 0.75 (R(f)BAR = 0.43). There was a scarcely s ignificant (p < 0.10) negative correlation between R(f) and the organi c matter content of the soils, organic matter + clay content (p < 0.10 ) and silt + clay content (p < 0.05). If only the Marismas soils are c onsidered, then the significance of the previous correlations is highe r, except for that between R(f) and the organic matter content; also, R(f) is further significantly correlated with the clay content (p < 0. 01) and the smectite content (p < 0.05). The herbicide mobility values obtained by using columns packed with soil samples from the Marismas under unsaturated-flow conditions confirmed the soil TLC results.