Impact of changes in the relationship between salinity and soil moisture on remote sensing data usage in northeast Thailand

Abstract

Although rice is a major agricultural product in northeast Thailand, its productivity is low and unstable because rice is cultivated under rainfed conditions and there are issues with soil salinization. In this region, some of the paddy fields have been abandoned because of severe soil salinization. Therefore, effective agricultural management strategies are needed to manage soil salinization for achieving stable agricultural production. To realize effective management strategies, it is necessary to understand the spatiotemporal distribution of soil salinization. To evaluate and update the spatiotemporal soil salinization using remote sensing data, we first evaluate the relationship between soil electrical conductivity (ECe) and soil moisture content (SMC) during dry seasons. Subsequently, the effect of changes in this relationship on the normalized difference salinity index (NDSI) derived from remote sensing data for estimating soil ECe is evaluated. The relationship between ECe and NDSI, depending on the soil moisture conditions in the study area, is clarified. The findings of this study indicate that for estimating ECe using the NDSI, it is necessary to consider not only soil moisture conditions but also its quality at the time of satellite observation.