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毛乌素沙地南缘沙漠化临界区域是沙地-草地景观界面的关键部位,研究该区域土壤养分的空间格局和生态学过程,对于土地沙漠化的机理研究具有重要的意义。采用经典统计与地统计学相结合的方法,通过半变异函数及其模型、克里格局部插值估计、空间分布图等研究了毛乌素沙地南缘沙漠化临界区域土壤养分的空间异质性特征。结果表明:研究区土壤速效钾含量符合球状模型,全氮和速效磷含量符合指数模型;速效钾含量具有强空间自相关性,其结构方差比为0.882,而全氮和速效磷含量表现为中等程度的空间自相关性,其结构方差比分别为0.501和0.514;3种土壤养分空间自相关距离存在差异,其中全氮和速效钾的变程均为511m,而速效磷的变程为143m;3种土壤养分的分布格局呈现明显的空间规律性,从牛枝子群落到黑沙蒿群落,速效钾和速效磷含量先降低后升高,与研究区的界面变化过程一致,而全氮含量逐渐降低,与研究区的植被覆盖度变化一致;3种土壤养分的标准差都较小,Kriging插值结果比较可靠。
The critical desertification area on the southern margin of Mu Us desert is a key part of the sand-grassland landscape interface. Studying the spatial pattern and ecological process of soil nutrients in this area is of great significance for the study on the mechanism of land desertification. By using the combination of classical statistics and geo-statistics, the spatial heterogeneity of soil nutrients in the critical desertification area of the southern Mu Us Sandy Land was studied by means of semivariogram and its model, Kriging local interpolation estimation and spatial distribution map. The results showed that the content of available potassium in the study area accorded with the spherical model and the content of total nitrogen and available phosphorus was in accord with the exponential model. The content of available potassium was strongly spatial autocorrelation with the ratio of structural variance of 0.882, while the content of total nitrogen and available phosphorus was moderate Degree of spatial autocorrelation, the structural variance ratios were 0.501 and 0.514, respectively. There were differences in the spatial autocorrelation distances of the three kinds of soil nutrients. The range of total nitrogen and available potassium was 511m, while that of available phosphorus was 143m. The distribution pattern of soil nutrients in three kinds of soil showed obvious spatial regularity. The content of available potassium and available phosphorus decreased first and then increased from the branch of Acacia crassicarpa community to the community of Artemisia mandshurica, which was consistent with the change of interface in the study area, Which is consistent with the change of vegetation coverage in the study area. The standard deviations of three kinds of soil nutrients are small, Kriging interpolation result is more reliable.