Using EM38 to assess the progress and mechanism of salt leaching from tsunami affected soil in Aceh, Indonesia

摘要

A portable electromagnetic induction instrument (EM38) was used in both the horizontal (EMh) and the vertical (EMv) dipole orientations, to monitor changes in soil salinity in the tsunami affected areas of Aceh. The relative changes EMh and EMv over time were used to assess leaching progress and mechanism in both lowland irrigated and rainfed rice fields, and rainfed palawija (dry season crops) fields. Time series data from EM38 surveys indicated that leaching of salts from the tsunami affected soiloccurred slowly by both vertical displacement and horizontal movement in flood waters. However, the vertical leaching was more restricted due to the presence of a claypan layer in the lowland rice fields. Faster removal of salts should be facilitated byproviding adequate surface drainage and irrigation channels to allow good water circulation.