Variations of soil properties in succession process of Phragmites community in estuarine wetland of Panjin

The estuarine wetland ofPanjin, Liaoning, China is an alluvial-marine plain of 5, 200 km2 in area, which was originated from a series of rivers, including Liaohe River, Shuangtaizi River, Dalinghe River, Xiaolinghe River and Daqinghe River. With the warming up of the climate and the decreasing of runoff from the upper reaches, degeneration plagues gradually arose in the Phragmites community. From the edge zone of Phragmites population, there successively arose four stripped plant populations, namely, Phragmites-Typha population, Limonium population, Suaeda population and mudflat nudation. In the community succession process, coevolution occurred in soil nutrients. Studies were carried out on variations of soil nutrients at different succession stages and different levels of the same succession stage. Results show that contents of organic matter, total nitrogen, total phosphorus and soluble salts in surface soil were all higher than those in bottom stratum; Soluble salt content in surface soil increased from Phragmites population to mudflat nudation.