The Effects Of Soil And Water Environment On The Growth Of Phragmites Australis In Ebnur Lake Wetland

In this study, taking Ebnur lake wetland as study area, field investigation and laboratoryexperiments were conducted to get the data of the characteristics of Phragmites australis growth, soiland water environment factors. Using the acquired data, quantitative study on features of soil andwater and Phragmites australis growth indicators in the Ebnur Lake typical Phragmites australisdistribution wetland were carried out by applying analytical methods such as correlation analysis,regression analysis and principal component analysis etc. to reveal laws of effects of soil and waterenvironment factors on growth and distribution of Phragmites australis and provide a theoreticalbasis to improve Ebnur wetland ecosystem. Study results as follow:(1) The study results of soil environment factors show that while the fluctuation ranges of soilsalinity big, spatial variability is not too strong and vertical distribution presents table cluste ringeffect; besides both fluctuation range and spatial variability of salt ions are big. Soil salinization anoverall characteristic of which is weak is characterized with chloride-sulfate and sulfate mixedtypes in each sampling site. Spatial variation and fluctuation of pH value vertical distribution ofwhich gradually decreased with soil depth is comparatively low, the soil type is subalkalic neutralsoil. The changing rate of soil organic matter vertical distribution of which decrease with soil dept his relatively huge while spatial variability is less strong. The average soil moisture increasesgradually with soil depth though spatial variability is weak.(2) Differences between the water environmental indicators are quite obvious, except for pH, K~+,Na~+, HCO3-, etc. spatial variability of other elements are quite strong. TDS ranged from0.4to33.5gL-1, the water depth range from-125to108.6cm, pH values ranged from6.7to7.9.(3) The changing ranges of all growth indicators of Phragmites australis are considerably huge.There is a very significant positive correlation between the Phragmites australis plant height andstem diameter, population density and relative growth rate (RGR (H)).Besides Stem diameter anddensity and relative growth rate (RGR (H)) was significantly positively related, population densityand relative growth rate (RGR (H)) are also positive correlated. (4) Phragmites australis average height, average stem diameter and relative growth rate (RGR(H)) showed a significant positive correlation to the average water depth to which relative growthrate (RGR (D)) is positively but slightly correlated. The negative correlation between all growthindicators and average TDS is less significant. Phragmites australis growth will be inhibited byneutral pH of the water. Soil salinity is the main limiting factor, acidic and subalkalic conditions areconducive, though less obvious, to the growth of Phragmites australis. Soil moisture and organicmatter will be considered as main stimulating soil factor due to its significant positive correlationswith each growth indicators of Phragmites australis.The results of principal component analysis as follow: The appropriate water depth in the studyarea is the major water elements which exhilarates growth of Phragmites australis to which TDS hastotally opposite effects. Soil moisture and soil organic matter content is predominant soilenvironment factors contribute to the growth of Phragmites australis while soil salinity and salt ionswill restrain the growth of Phragmites australis. Besides, promising effect of suitable acid andalkaline environment should not to be neglected.