Abstract:

To understand the evolution pattern of soil quality of the marine soils with land use process, the fertility characteristics of the soils with different periods of reclamation from Xiasha Bridge to Jiashao Bridge in Hangzhou Bay were sampled and analyzed. The changes in quality indicators of the soils with reclamation time were explored subsequently. The results showed that the desalination and decalcification of sandy soil were relatively rapid. After 15 to 30 years of reclamation, the soil salt content decreased to less than 1 g/kg, reaching the safe range for crops. After 100 years of cultivation, the surface soil had been decalcified, and the decalcification rate of the subsoil was higher than 50%. After the reclamation of sand marine, soil organic matter, nitrogen and phosphorus gradually accumulated, while potassium gradually decreased. After 15 to 30 years of reclamation, the organic matter, total nitrogen and total phosphorus in the topsoil were 111%, 39% and 33% higher than that before reclamation, respectively. After 100 years of reclamation, the total potassium in the topsoil decreased by 12% as compared with before reclamation. With the increase of reclamation and utilization time, the content of available calcium, available magnesium, available boron and available molybdenum in the topsoil gradually decreased, while the content of heavy metals showed a slight increase trend. The content of water-stable aggregates in the soils was very low, but it could also increase with reclamation time. Overall, the soil quality of reclaimed sandy marine soils develops in a clear trend that is conducive to crop growth with the increase of utilization time.

Key words: sand marine soils, Hangzhou bay, reclamation, soil fertility quality, fertility characters, salt content, organic matter, evolution