Evaluation of soil quality in reclaimed coastal regions in North Jiangsu Province

Soil quality in reclaimed coastal regions in North Jiangsu Province was quantified using comprehensive indexing method and selected soil physico-chemical property and crop growth index. Weight values were accordingly determined by correlation and principal component analysis method from which soil quality maps were developed. Results indicate a generally poor state of soil quality across reclaimed lands, with a substantial level of soil salinity. Soil organic matter (SOM) and N content is relatively low, with severe deficiency in alkali-hydrolysis N. SOM is the most important enabling factor of soil quality while soil salinity and groundwater mineralization are the limiting factors of soil quality. Both correlation and principal component analyses of soil quality have a similar and consistent result (r²=0.933 9**). Soil quality in different areas of reclaimed lands differs significantly and soil quality in cotton fields is generally superior to that in rice fields. There exists significant spatial similarity between soil quality maps developed from different methods. The findings of the study are important references for precision fertilization in moderate-to-low yield farmlands and in scientific management of problematic soils in coastal regions.