Evaluating soil salinization risk in typical coastal reclaimed regions in North Jiangsu Province

Salinization is a major obstacle for effective exploitation and utilization of soil resources in coastal regions of especially North Jiangsu Province. To that end, the gray relation theory was used to assess the risk of soil salinization in the farmlands of Jinhai Farm, Dafeng County. This is a typical region in North Jiangsu Province with extensive coastal land reclamation. A practical mathematical formula was designed to determine and classify risk evaluation index in the region. Results show that soil salinity, surface soil bulk density and groundwater mineralization are the most important drivers of salinization. For the farmlands of Jinhai, the range of ecological risk value (F) is 0.12~0.60 with an average of 0.30. This indicates that the risk of soil salinization is generally high and varies significantly with location in the study area. The spatial distribution of risk of salinization is similar to the distributions of soil salinity and groundwater mineralization. Due to differences in cropping and cultivation practices, the risk of salinization in rice fields is higher than that in cotton fields. While, there hardly exists low-risk regions, high-risk and medium-risk regions pervade across the study area. Areas of high-risk, medium-risk and severe-risk respectively account for 50.11%, 49.41% and 0.48% of total study area. Areas of high-risk and medium-risk need urgent amelioration measures. The findings in this study provide the basis for quality improvements in moderate-to-low-yield farmlands. It also lays the basis for scientific amelioration and management of saline soils in coastal regions of North Jiangsu Province.