库布齐沙漠不同植被类型群落特征与土壤有机质、全氮、含水量关系研究

Relationships between Community Characteristics and Soil Organic Matter,Total Nitrogen,Soil Moisture Content under Different Vegetation Types in the Kubuqi Desert

以库布齐沙漠不同植被类型的固定沙地、半固定沙地和流动沙地为对象,研究了不同植被类型群落物种多样性、生物量与土壤有机质、全氮、含水量之间的相互关系。结果表明:1)不同沙地类型间物种丰富度、物种多样性呈半固定沙地>固定沙地>流动沙地。而不同植被类型固定沙地间,则表现为演替时间较长的天然油蒿灌木林群落物种丰富度、物种多样性高于演替时间较短的人工杨树乔木林和人工沙柳灌木林群落。单位面积生物量(地上、地下)表现为由固定沙地到流动沙地依次递减,杨树乔木林固定沙地显著高于油蒿和沙柳灌木林固定沙地。2)不同植被类型土壤有机质和全氮含量随土层深度增加而逐渐降低,且由固定沙地到流动沙地依次递减,固定沙地不同植被类型土壤有机质和全氮含量排序为:人工杨树固定沙地>天然油蒿固定沙地>人工沙柳固定沙地,有机质含量与全氮含量具有显著的正相关关系。3)该区域不同植被类型的生产力受林分特征和土壤养分共同制约,而土壤含水量的差异会导致群落物种多样性的变化。

Taking the fixed,semi-fixed and flow sandy lands under different vegetation types in the Kubuqi desert of Northwest China as the test objects,the relationships between community diversity,biomass and soil organic matter,total nitrogen,soil moisture content under different vegetation types in the Kubuqi desert were studied.The results showed that： 1 The species richness and biodiversity of semi-fixed sandy land was greater than those of fixed sandy land,while those of the flow sand was the minimum in the Kubuqi desert.On the same fixed sandy land under different vegetation types in the Kubuqi desert,the species richness and biodiversity of natural shrub were greater than those of the artificial arbor and shrub.Then the biomass per unit area（ aboveground and belowground） decreased from fixed sandy land to flow sandy land,and the biomass of the Populus simonii arbor fixed sandy land was significantly higher than that of the Artemisia ordosica and Salix psammophila shrub fixed sandy land.2 The average contents of organic matter and total nitrogen in all the tested vegetation types decreased with the increase of soil depth,and decreased from fixed sandy land to flow sandy land,and were ordered as artificial arbor Artemisia ordosica fixed sandy land〉natural shrub Artemisia ordosica fixed sandy landartificial shrub Salix psammophila fixed sandy land,at the same time the organic matter content had significant positive correlation with the total nitrogen content. 3 The productivity of different vegetation types is conditioned by stand characteristics and soil nutrient,while the difference in soil water content could lead to the change of community species diversity.