Spatio-temporal variability of soil salinity and sodicity in agricultural reclaimed coastal wetlands, Eastern China

Abstract

ABSTRACT The spatio-temporal distribution of soil salinity and sodicity is the key to understand the law of water and salt transport in porous media and put forward the amendment measures of saline soil. A total of 56 soil sample sites were selected from four agricultural reclamation regions and an adjoining coastal wetland. Descriptive statistical and geostatistical analyses were performed to describe the spatio-temporal variability of soluble salt ions, soil salinity and sodicity indicators. The results showed that the average concentration of soil soluble salt (SSC), pH, sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) decreased by 97.1%, 2.9%, 95.1% and 94.9% during the whole reclamation period. Meanwhile, soil salinity and sodicity indicators showed a significant positive correlation with soluble salt ions and declined significantly with increasing years of reclamation except HCO3 −. The spatial distribution of concentration of SSC, pH, SAR and ESP was similar to that of soluble salt ions except HCO3 −, which showed a higher concentration in areas reclaimed for 5 and 30 years, and lower concentration in areas reclaimed for 38 and 61 years. Additionally, the area of saline and alkaline soils above moderate levels accounted for 54.5% and 62.7% of the total area.