Soil Physicochemical Properties And Its Effect On The Growth Of Phragmites Australis In Liaohe Degraded Wetland

The paper studied the vegetation characteristics and soil environment changes duringdegeneration of Liaohe estuary wetland in2009, and different degraded reed (Phragmitesaustralis) wetland(non-degraded areas, the middle of degradation and the edge ofdegradation)in2013, discussed soil properties and plant characteristics of reed degradedwetland, analyzed the main factors which effect the degradation. It provides the scientificbasis on restoration of degraded wetlands management and protection. The main work andconclusions are as follows:1、The analysis of vegetation and soil in Liaohe estuary wetland showed that thedegraded wetlands divided into reed community, reed-Artemisia abrotanum community,reed-Suaeda salsa community, Aeluropus littoralis-Suaeda heteroptera Kitag community, thebiomass and height of reed were decreasing during degeneration of wetland, and reed wasreplaced by Suaeda heteroptera Kitag, which was more salt-tolerant. Content of soil organicmatter, total nitrogen, total phosphorus in the process of degeneration were first increased andthen decreased, but soluble salt content increased; the contents of organic matter, totalnitrogen, total phosphorus, soluble salt decreased gradually with the increasing of soil depth,2、Reed biomass, leaf weight and height in non-degraded areas were higher than that indegraded areas; total nitrogen, total phosphorus, potassium ions, sodium ions and magnesiumions were mainly concentrated in leaves, while calcium ions was mainly concentrated instalks.3、Soil organic matter, total nitrogen, total phosphorus, available nitrogen, availablephosphorus and cation exchange capacity in non-degraded areas were higher than that ofdegraded areas. Soil salinity in the middle degraded areas was higher than in thenon-degraded areas. Correlation analysis showed that organic matter and total nitrogen,available nitrogen, total phosphorus, available phosphorus and cation exchange capacity were positively correlated, indicated that they have the same sources, soluble salts and totalnitrogen, total phosphorus, total potassium, available phosphorus, available potassium, andcation exchange capacity showed a negative correlation. Principal component analysisshowed that the first principal component consist of pH, organic matter, total nitrogen, totalphosphorus, available nitrogen, available phosphorus, K+,Na+,Mg2+and cation exchangecapacity, and the first principal component variance contribution rate was58.531%. Analysisshowed that the decreased supply of water, without exogenous fertilizer input and harvest ofreed all the year round were the main factors caused the degradation of Liaohe wetland.