毛乌素沙地南缘沙漠化临界区域土壤养分的空间异质性  

Spatial heterogeneity of soil nutrients in the critical area of desertification in Southern Mu Us Sandy Land

作　　者：邱开阳[1] 谢应忠[1,2] 许冬梅[1,2] 时项锋[1,2] 刘丽丹[1,2] 齐拓野[1,2] 马涛[1] 

机构地区：[1]宁夏大学西北土地退化与生态恢复国家重点实验室培育基地,银川750021 [2]宁夏大学草业科学研究所,银川750021

出　　处：《生态学报》2010年第22期6052-6062,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30860200);国家自然科学基金资助项目(30960268);国家973计划前期研究资助项目(2010CB434805)

摘　　要：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 Southern edge of Mu Us Sandy Land is the frontier of land desertification. Conservation and sustainable use of the vegetation in this sandy land-grassland transition area is crucial for preventing vegetation deterioration in the sandy land and its bordering areas. Investigating spatial heterogeneity of soil nutrients and relevant ecological processes in this critical area is useful to understand the processes and mechanisms of land desertification, and helpful for sustainable land use planning. Based on the field survey along a sandy land-grassland transect, we analyzed the heterogeneity of soil nutrients using the geostatistical techniques such as semivariogram, Kriging interpolation, and spatial distribution maps. Results showed that （ 1 ） The semivariogram of soil available potassium （K） was best described by the spherical model and that of soil total nitrogen （N） and soil available phosphorus （P） were best described by the exponential model. Soil available K showed a characteristic of strong spatial autocorrelation, and 88.2% of the variation was found within the distance of 511 m. Soil total N and available P showed a modest degree of autocorrelation; and 50.1% and 51.4% of the variation were found within the distance of 511m and 143 m respectively. Geostatistical analysis indicated that spatial variation in soil available P occurred in a small scale; whereas ecological processes determining soil total N and available K contents exerted their effects in a larger scale. （2） Regular spatial patterns of all the 3 soil nutrients were identified. The content of soil available K and P decreased at first and then increased along the transect from Lespedeza potaninii community to Artemisia ordosica community; and this trend was approximately consistent with the changing process of the ecological boundary in the study area. While the change of soil total N along the transect was quite different, decreasing gradually from Lespedeza potaninii community to Artemisia ordosica community, which corr

关 键 词：沙漠化临界区域 土壤养分 空间异质性 景观界面 毛乌素沙地 

分 类 号：S158[农业科学—土壤学]