【作者】 李宝富；

【导师】 熊黑钢；

【作者基本信息】 新疆大学 ， 人文地理学， 2010， 硕士

【摘要】 本文以新疆奇台县绿洲不同耕种时间、两种植被覆盖度以及冻融前后土壤含盐量为研究对象,运用地统计学、聚类分析以及相关分析等方法对其含盐量变化规律、盐分剖面类型、空间变异性及其影响因素进行了研究。结果如下:(1)仅受自然条件影响的未耕地,土壤含盐量高,是典型的盐渍土。并且表层聚集现象明显。含盐量在表层(0~20cm)占整个剖面的34.31%。耕种时间较长的5a、10a地则与之相反,多为底聚型盐分剖面。即荒地转化成人类熟作的农田(5a以上)这一过程中,土壤剖面盐分特征由前期的表聚型依次转化为均匀型、震荡型和底聚型。随着人类耕种时间的加长,土壤各层含盐量的活跃程度变化依次为活跃层、次活跃层和较稳定层。有人类耕作活动的土壤盐渍化发生了逆向演替,耕种10a地平均含盐量仅有未耕地的20.90%。脱盐速度随着时间的增加而减小,由早期(0~3a)的1.56 g kg-1 a-1,下降为后期(5~10a)的0.04 g kg-1 a-1。(2)裸地和植被地土壤水盐都服从正态分布,剖面平均含盐量均属中等变异性,具有较强的空间自相关性。裸地土壤含水量属弱变异性,呈中等强度的空间自相关性;植被地属中等(偏弱)变异性,表现出较强空间自相关性。裸地的相关距离仅是植被覆盖地的1/10左右。(3)冻融前,表层(0-20cm)土壤电导率(0.30ms.cm-1)和含盐量(0.11%)最低,并且基本随着土层深度的增加EC及含盐量逐渐增大。而土壤盐分及EC空间分布的复杂性基本随着深度的增加逐渐减小。冻融后,表层(0-20cm)EC(0.38ms.cm-1)及含盐量(0.14%)变为最高。说明春季积盐现象明显(主要发生在60cm深度以上),但尤以表层最为严重(积盐率达30.0%)。秋季灌溉洗盐效果明显,剖面平均(100cm深度以上)EC和含盐量平均减少率为8.15%。而且洗盐深度大于100cm。另外,各层EC及盐分的变异性(中等变异性)未变,但变异系数增大(除40-60cm深度外)。(4)科学管水、合理用水、保障防护林面积、控制耕地面积是研究区绿洲可持续发展的基本原则。更多还原

【Abstract】 Salt contents in soils different in cultivation age, two vegetation coverage and fore-and-aft Freezing in Qitai County of Xinjiang were investigated for analysis of rules of the variation of soil salt content, types of soil salinity content profiles, spatial variability and their affecting factors, using the cluster analysis method and some other related methods. Analysis results:(1) Along with the transformation of wasteland into farmland (at least 5 years in cultivation history), the characteristics of soil salt content distribution in the soil profiles varied and followed the order of surface accumulation profiles (SAP), even distribution profiles (EDP), oscillation profiles (OP) and bottom accumulation profiles (BAP). The non-farmland high in salt content is typical of salinized soil, with significant phenomenon of surface accumulation; and the salt in the surface layer (0~20cm) accounted for 34.31% of that in the soil profile. The farmlands, 5 or 10 years old, mostly belonged to the category of BAP. With the farming operation going on and on, soil salt content in various salt–containing layers varied to varying degree showing an order of active layer (AL), sub-active layer (SAL) and relatively stable layer (RSL), and an extremely positive correlation between soil salt content and soil organic matter content gradually turned in an extremely negative one, while the correlation between soil salt content and soil pH went the other round. Under farming activities, soil salinization developed reversely. The average salt content in farmland 10 years old was only 20.90 percent as much as in wasteland. The desalination rate was reducing with the farming operation going on from 0.156% a-1 in the first three years of farming down to 0.004% a-1 when the farming activity went beyond 5 years.(2) The soil water and salt content of bare land and vegetation area obey log-normal distribution; soil salinity belongs to moderate variability with a strong spatial autocorrelation. Soil moisture variability in the bare land belongs to weak variability with moderate intensity of the spatial autocorrelation; vegetation area belongs to medium (weaker) variability with strong spatial autocorrelation. Bare land autocorrelation distance is about 1 / 10 of vegetation area.(3) Before the freezing, the value of soil salt content (0.11%) and electrical conductivity (0.30ms.cm-1)in topsoi(l0-20cm) is minimum, the deeper of soil depth, he higher of the value. While the complexity of soil salt content and electrical conductivity trend to decrease by the addition of the depth. After the freezing, the value of soil salt(0.38ms.cm-1)content and electrical conductivity (0.14%) in topsoil is maximum, it indicated that soil salt accumulation rate (30.0%) at the surface soil layer was significant in spring; soil salt desalination rate was obviously in fall, the average value of sections is decrease by 8.15%, the soil salt desalination depth is beyond 100 cm. In addition, spatial variability of salt content and electrical conductivity of every soil layers remained invariability, but the variance quotient gone to high.(4) Water of scientific regulation and using and maintenance of shelter-forest and cultivated land area are the basic principle of sustainable development in the research zone of oasis.更多还原