Abstract

Soil acidification is one of the top concerns of the coastal wetland areas. In recent decades, by reclamation of coastal potential acid sulfate soils for agricultural activities (rice field, shrimp farming,...), humans have caused soil acidification. pH and the presence of secondary iron minerals (hematite, goethite) and ferric iron minerals (jarosite, schwertmannite, copiapite) are considered as the indicators of acidic soil. This study is to rapidly detect acidic status of soil through identifying secondary iron minerals by characterized band ratios. Sentinel-2A data with B4/B2 and B11/B8 can determine iron oxides and ferric iron minerals. The identified spectral result of fallowed ponds on ratio images shows the correlation with measured pH and mineral composition data (XRD). This research promises applicability of used band rationing method as well as potential of Sentinel-2A data in monitoring soil acidification in coastal wetland areas.