Chemical properties and fertility analysis of dredger-fill silt during soil formation: The tianjin dredge–fill project

Dredger-fill silt has been used in the port of Tianjin, China to reclaim land; however, the dredger-fill silt has no soil ecological function. Translating the silt into soil rapidly and accelerating the soil-forming process are key to solving the ecological problems of the Dredge–Fill project. This study measured 15 chemical properties of the dredger-fill silt for 8 years of the soil forming process to explore fertility changes and the critical factors affecting soil formation. The results showed that: (1) the salinity of silt changed from severe to mild with a reduction in Na + and Cl - concentration. Other ion concentrations changed slightly. (2) Effective nutrients significantly decreased during soil formation. Soil organic matter (SOM)，the nitrate-nitrogen, available phosphorus (A-P) and available potassium (A-K) decreased by 26.22%, 86.23%, 45.92%, 33.61% respectively, indicating severe nutrients loss. (3) Principal component analysis showed that silt fertility decreased significantly and the total soil fertility loss was severe. This study has significance for the artificial improvement of silt.