The Research On The Relationship Vegetation And Edaphic Conditions In Lower Watershed Of Guishui River

The relation is one of the hot issue on Lake Wetland research in recent years between Lake Wetland vegetation and edapHic conditions recently.Viewing the latest research on above-mentioned relation,we found it mainly hasthree problems.The first,method of sampling conventionally is unscientific.The second,the research that change of the plant community with the reducing of moisture is absent.The third,the research that the cause and effect relationship between the plant community and the soil character is singularly.On account of it,first of all,this study will put forward scientific method--grid method,by analyzing the disadvantage of conventional method namely belt transect method,and on this basis,the concept of"grid method"was measurablely defined.Secondly,this study analyzing the model of establishing plant communities in significant soil moisture changes with the one-way layout analysis of variance from the statistical point of view,and explore the changes of plant communities.The result showed that through the combined of no significant difference of soil moisture,it can be divided into six categories in may.,four in july,five in september.And on this basis,classify the soil moisture for after Abscissa,ordinate community to build the type of plant communities with significant changes in soil moisture model.Finally,soil moisture,pH,organic matter,available N,available P,and K,TN,P and K,all 10 aspects of salt,through path analysis, build a plant diversity and biomass of the impact of factors causal relationship model,and on this basis to explore the influence of soil factors on plant diversity and biomass of the relationship between direct and indirect.The results showed that the diversity of plant available phosphorus has a direct impact,and soil moisture,organic matter and nitrogen through the diversity of plant available phosphorus take the role of indirect effects.Their impact on species diversity of the smallest order is:available P>＞organic matter＞TN＞Soil Mositure.Organic matter have a direct impact in the aboveground biomass of plants,and soil moisture content,available P,total salt and TN take the role of indirect effects through the organic matter,the order of smallest of their impact on Species diversity is:organic matter＞TN＞soil mositure＞available P＞total salt.Soil moisture for the plant below-ground biomass has a direct impact,and available P,organic matter and TN take the role of indirect effects through the organic matter,they have the impact of below-ground biomass of the order of smallest:soil mositure＞available P＞organic matter＞total N.Available P for the total biomass of plants that have a direct impact,and soil moisture, organic matter,total N and salt through the available P take the role of indirect effects on the total biomass of plants,their impact of total biomass of the smallest the order is:available P＞organic matter＞total N＞soil mositure＞total salt.