ADSORPTION OF METSULFURON-METHYL ON SOILS UNDER OIL PALM PLANTATION: A CASE STUDY

The adsorption of metsulfuron-methyl herbicide in four types of soil series taken from an oil palm estate has been investigated using a batch technique with the herbicide detected using a reversed phase C18HPLC technique. Selected soil physicochemical properties were also analysed. The adsorption behaviour of the herbicide in the soils was evaluated using Freundlich and linear adsorption isotherms. Results indicated that soil from Bernam series exhibited strongest adsorption affinity for the herbicide followed by Jawa, Selangor and Tongkang soil series with distribution coefficient value of ca. 29.0, 19.2, 18.3 and 18.0, respectively. Comparison of the soils physicochemical properties revealed that whilst Tongkang and Selangor soil series have similar pH values, their organic matter content differed significantly from one another. Bernam soil on the other hand exhibited the lowest pH values compared to the other three soils but its organic matter content is similar to that of Selangor soil and is significantly higher than Tongkang and Jawa soil series. Thus it could be concluded that differences in soil properties contributed to the varying adsorption coefficient values observed in the present study. In agreement with previously reported studies, this observation supports the contention that soil properties play an important role in controlling the adsorption behaviour of metsulfuron-methyl herbicide in soils.