玛纳斯河流域绿洲土壤养分空间变异特征与格局

运用经典统计学及地统计学的半变异函数定量研究了玛纳斯河流域绿洲表层土壤(0～10cm)中有机质、全氮、全钾和全磷4种养分含量的空间变异特征。结果表明:4种养分含量数据均服从正态分布,有机质、全氮和全磷的理论模型属于指数模型,全钾的则符合球状模型。全氮和全钾的空间自相关范围为24.18km和35.78km,空间结构上具有中等空间相关性,随机性因素引起的全氮和全钾的变异分别占48.93%和48.23%,是结构性因素(气候、母质、地形、土壤类型等)和随机因素(施肥、耕作措施、种植制度等)共同作用的结果;有机质和全磷的空间自相关范围为79.10km和82.63km,空间结构上具有强相关性,块金值与基台值之比分别为25.06%和20.00%,其空间变异主要由结构性因素引起的。在地理信息系统(GIS)支持下,通过Kriging插值研究了玛纳斯河流域绿洲土壤养分的空间水平分布规律并对土壤养分要素含量等级进行了评价。有机质、全氮和全钾具有南北部高,中间低,由南北向中心递减的趋势;有机质、全氮、全钾含量为较丰富以上等级面积分别占研究区的0%、97.91%、99.69%;全磷含量从中心往南递增,北部分布较均匀;全磷含量为较丰富以上等级的面积占研究区的10.62%。

Spatial variability and pattern of soil nutrients in the oasis of Manas river watershed

Using classic statistics and geostatistics,the spatial variability of topsoil(0-10cm) soil organic matter,total nitrogen,total potassium and total phosphorusin the oasis of Manas river watershed were studied.Results showed that all soil nutrients measured were distributed normally.The semivariogram models of soil nutrients were best described by exponential model,except for the total potassium,which was best fitted by spherical model.The ranges of total nitrogen and total potassium were 24.18km and 35.78km,respectively and their spatial variation produced by random factors account for 48.93% and 48.23%,indicating that the spatial variability of total nitrogen and total potassium were commonly produced by structural factors such as climate,soil parent material,terrain and soil types and random factors such as fertilization,tillage measures,cropping systems.The ranges of organic matter and total phosphorus were 79.10km and 82.63km and the ratio of nugget to sill of them were 25.06% and 20.00%,having strong dependent spatial correlation,showing that the spatial variability of organic matter and total phosphorus were primarily caused by structural factors.Based on the GIS,the spatial distribution patterns in horizontal direction and grade distribution of soil nutrients content in oasis of Manas river watershed were evaluated using Kriging.The results showed that soil nutrients content except for total phosphorus showed an increasing trend from center of the studied area to the south and north and the area for them in rather rich and rich level accounted for 0%,97.91% and 99.69% of studied area,respectively.While total phosphorus content had a declined trend from south to center and distributed uniformly in the north area.The area for it in rather rich and rich level occupied 10.62% of the studied area.