Assessment of Soil Quality of Tidal Marshes in Shanghai City

We take three types of tidal marshes in Shanghai City as the study object: tidal marshes in mainland, tidal marshes in the rim of islands, and shoal in Yangtze estuary. On the basis of assessing nutrient quality and environmental quality, respectively, we use soil quality index (SQI) to assess the soil quality of tidal flats, meanwhile formulate the quality grading standards, and analyze the current situation and characteristics of it. The results show that except the north of Hangzhou Bay, Nanhui and Jiuduansha with low soil nutrient quality, there are not obvious differences in soil nutrient quality between other regions; the heavy metal pollution of tidal marshes in mainland is more serious than that of tidal marshes in the rim of islands; in terms of the comprehensive soil quality index, the regions are sequenced as follows: Jiuduansha wetland＞Chongming Dongtan wetland＞Nanhui tidal flat＞tidal flat on the periphery of Chongming Island＞tidal flat on the periphery of Hengsha Island＞Pudong tidal flat＞Baoshan tidal flat＞tidal flat on the periphery of Changxing Island＞tidal flat in the north of Hangzhou Bay. Among them, Jiuduansha wetland and Chongming Dongtan wetland have the best soil quality, belonging to class III, followed by Nanhui tidal flat, tidal flat on the periphery of Chongming Island and tidal flat on the periphery of Hengsha Island, belonging to class IV; tidal flat on the periphery of Changxing Island, Pudong tidal flat, Baoshan tidal flat and tidal flat in the north of Hangzhou Bay belong to class V.