干旱和半干旱区油蒿对土壤空间异质性的响应

空间异质性影响种群的分布和波动。在对数据进行归一化处理的基础上,应用地统计学方法研究干旱和半干旱区两个气候带内油蒿对土壤空间异质性的响应。结果表明：在中等尺度（500 m样线,间隔10 m取样）上,腾格里沙漠沙坡头固定沙地土壤水分的空间异质性大于毛乌素沙地芹河半固定沙地,相应地,沙坡头地段油蒿密度、有机质、全氮和有效磷含量的空间异质性大于芹河地段,因而认为,土壤水分的空间异质性决定油蒿密度的空间异质性,进而又反作用于土壤养分的空间异质性。结合油蒿生物量的空间异质性分析认为,土壤水分的空间异质性并不总是能够影响植物生物量的空间异质性。进一步分析表明,对于沙坡头地区,适当进行放牧或者其他干扰,将有助于增大土壤属性的空间异质性,以促进油蒿植被的持续存在。

Response of Artemisia ordosica Population to Spatial Heterogeneity of Soil in Arid and Semi-arid Regions

Spatial heterogeneity affects the distribution and fluctuation of plant population.In this paper the geostatistics method was used to study the spatial heterogeneity of A.ordosica population and soil moisture on the basis of data normalization in Shapotou area of Ningxia Hui autonomous region and Qinhe area of Shanxi province.The results showed: on the middling scale of sampling,the heterogeneity of soil moisture in Shapotou area was greater than that of Qinhe area,correspondingly,the heterogeneity of the plant density and contents of the organic matter,total nitrogen and available phosphorus in Shapotou area were greater than those of Qinhe area.It is concluded that the heterogeneity of soil moisture affects the heterogeneity of A.ordosica population,in return affects the heterogeneity of soil nutrients;the heterogeneity of soil moisture could not always influence the heterogeneity of biomasses of the plant.Further analysis showed that A.ordosica vegetation in Shapotou area should be properly interfered,for example by grazing,to increasing the spatial heterogeneity of soil attributes,thus the plant community could exist for a long time.