荒漠绿洲过渡带林地开垦对土壤有效态微量元素的影响

摘要

选择荒漠绿洲过渡带的林地开垦区为研究对象，运用地统计学和ArcGis空间分析工具相结合的方法，研究了林地开垦后土壤中有效态Fe、Cu、Zn和Mn含量的空间变异特征和丰缺状况。结果表明：林地开垦后有效态Mn显著缺乏（ P＜0．05），平均值为4．24 mg·kg－1，低于临界值的土壤占土壤总数的32．25％，有效态Fe和Ze次之，分别有21．82％和29．36％的样品低于临界值，4种微量元素空间变异强度均＞25％，呈较明显的空间变异性；半方差函数分析中，有效态Fe块金值最大，有效态Mn变程最小，4种有效态微量元素块金值与基台值的比值均＜25％，表明4种有效态微量元素空间依赖性均较强；在空间结构中，4种有效态微量元素呈明显的片状和斑块状分布，有效态Cu主要分布于研究区西南和西北部，有效态Zn和Fe主要分布于中部，有效态Mn呈东西方向对称分布且东部含量大于西部；在有效性评价中，单项指数（Ei）以有效态Mn最高，达2．83，综合指数（Ec）以有效态Fe最高，达1．27，有效态Cu的 Ei值和Ec值均较低。%Selection of desert oasis ecotone of forest land reclamation area as the research object ,using the method of statistical tools and ArcGis spatial analysis of combining research ,spatial variability of woodland effective state in soil after reclamation of Fe ,Cu ,Zn and Mn content and the condition of abundance or deficiency .The results showed that :After the land reclamation ,the available Mn was obviously insufficient ( P<0 .05 ) .The average content was 4 .24 mg· kg-1 .Soil with the Mn content which was lower than the critical value occupied 32 .25% of all the soil .Insufficiency degrees of available Fe and available Ze ranked the second place .Fe contents in 21 .82% of samples and Ze contents in 29 .36% of samples were lower than critical values .The spatial variation intensities of 4 microelements exceeded 25% , while these microelements showed obvious spatial variability ;Analysis of semi variance function ,nugget value maximum available Fe ,available Mn variable range minimum ,4 kinds of available trace elements nugget value base table value <25% ,showed that 4 kinds of available trace elements spatial dependence are strong ;In the space structure ,sheet and patchy distribution obviously 4 available trace elements are ,available Cu mainly distributed in the study area in southwest and northwest ,available Zn and Fe were mainly distributed in the middle available Mn in east-west direction ,symmetri-cally distributed and Eastern content greater than western ;According to availability evaluation results ,available Mn had the highest single index ( Ei ) ,which reached up to 2 .83;available Fe had the highest comprehensive index ( Ec ) which reached up to 1 .27;and Ei and Ec values of available Cu were relatively low .