Characteristics of Physicochemical Properties and Salt Ion Evolution of Surface Saline Soils in Coastal Reclamation Areas
Coastal of Jiangsu has vast reclaimed regions.Exploring evolution dynamics of saline soil properties following reclamation can benefit to understanding characteristics of soil quality variations in coastal reclamation zones.In this study,32 surface soil samples were collected from different reclamation zones in Yancheng City,Jiangsu Province to analyze the main soil quality indicators,including physicochemical properties,salt ion content,sodium adsorption ratio(SAR),and electrical conductivity(EC),etc.The results showed that:1)In the hundred-year scale,indicators of coastal soil C/N and pH initially increased then declined,with a turning point of around the 20th year after reclamation.C/N ratio was significantly lower than the mean of traditional cultivated lands of China.Soil organic carbon(SOC)and total nitrogen(TN)contents generally increased over the reclamation time;2)Both EC and SAR were in a rapid decreasing trend.Soil quality overall reached soil quality level of traditional cultivated lands of China in the 40th year after reclamation and soil salt content generally decreased to about 1 g/kg.Soil NO3-and NO2-were the two main nitrogen forms in all soils.Soil NO3-content kept stable initially and then decreased significantly when it was reclaimed for over 100 years.However,soil NO2-content increased within 20 years after reclamation and then declined significantly in 40 years reclamation.Notably,coastal saline soils transformed from chlorinated salt soils to a combination of chlorides and sulfates ones over hundred-years of reclamation;3)Complex relationships were found among salt ions evolution,soil physicochemical properties variations and reclamation time following reclamation.The combined contributions of reclamation time,pH-EC factor and total SOC-TN factor was greatest to the evolution of salt ions in the reclaimed soils.
万方数据
维普
