Effect of Soil Amendments on Leaching of Thiamethoxam in Alluvial and Calcareous Soil

Abstract

In this study, peat, compost and charcoal were added to reduce groundwater pollution with thiamethoxam by soil columns. Iodide has been used as a water tracer at a rate of 10 mL (0.1 M) for each soil column and that leached fast in all soil columns. The breakthrough curve of thiamethoxam was appeared from leachates of calcareous soil column and alluvial soil column with iodide. Accordingly it is considered thiamethoxam is highly mobile compound in tested soils. The addition of soil amendments reduced downward movement and significantly increased cumulative percentage of thiamethoxam from soil columns. After application; 85.21, 93.23, 98.12 and 97.84 % of applied thiamethoxam were recovered in leachates of alluvial soil, 5% peat-soil, 5% compost-soil and 5% charcoal-soil. While; 91.50, 99.30, 94.09 and 86.89 % from calcareous soil, 5% peat-soil, 5% compost-soil and 5% charcoal-soil columns. This is first study to assess, leaching of thiamethoxam and effect of soil amendments on leaching by soil columns. This information can be used to understand how alterations in agricultural practices and potential effects to groundwater.