一维马尔可夫链模拟黑河中游流域土壤质地垂向变异  

One-dimensional Markov chain simulation of vertical change of soil texture in middle reaches of Heihe river,northwest China

作　　者：李丹凤[1,2] 邵明安[3] 

机构地区：[1]中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,杨凌712100 [2]中国科学院大学,北京100049 [3]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101

出　　处：《农业工程学报》2013年第5期71-80,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(基金编号:91025018)

摘　　要：黑河中游地区土壤剖面砂、黏层次相间排列的特点及部分区域剖面中出现的不透水层对土壤中的水分运动和溶质迁移具有重要影响。该研究调查了黑河中游100km2区域内土壤剖面的质地分层情况,运用一维嵌入马尔可夫链模型模拟该地区的土壤质地剖面。研究表明,研究区土壤剖面共出现砂土、壤质砂土、砂质壤土、壤土、黏质壤土、粉黏壤土和粉黏土7种质地类型,层次厚度呈对数正态分布。粉黏土未在表层土壤出现,而砂土在表层出现的概率明显高于其余质地类型,剖面某一质地层之下多出现细粒含量比其高的下一质地类型。剖面上相邻两质地层之间的转移具有明显的马尔可夫链特征(简称马氏性),且马氏链是平稳的。一维嵌入马尔可夫链模型能够较好地描述研究区土壤质地层次的垂向变化,剖面主要的质地层次组合为:砂—壤、壤—砂、壤—黏、黏—壤。对土壤质地剖面的定量模拟,可以为开展该区域土壤水循环、转化和溶质迁移等相关研究提供参考。In the Linze County, located in the middle reaches of the Heihe River, northwest China, the geomorphic types include alluvial-proluvial plain, plain of denudation, and desert grassland in the fringe of an oasis. The main landscapes of this region are composed of desert, oasis farmland and wetland, all of which distribute irregularly and patchily. The differentiation of soil textures was observed both horizontally and vertically. In a vertical direction, sand and clay layers in soil usually sandwich each other, even when there are some impermeable layers in some profiles. The heterogeneity of soil profile textures with depth significantly influences water movement and solute transport. In this study, all 2,000 soil samples were collected with a 5-cm diameter auger to a depth of 300 cm at 100 points in an area of 100 km2. After being taken into a laboratory and having been wind-dried, the soil mechanical composition was measured using a Malvern Laser particle size analyzer. Then the vertical change of soil textural layers was analyzed, and a MC-LN （Markov chain- lognormal distribution） model was constructed to simulate the soil textural profiles. Results showed that there were seven soil textural types occurring in the study area, namely, sand, loamy sand, sandy loam, loam, clay loam, silty clay loam and silt clay, respectively. Compared with the non-occurrence of silty clay layers in the surface soil, another six types of textural layers all occurred in the surface soil of the study area, while sand layers occurred with a much higher probability than the others. The layer thickness of each textural type in the study area was characterized as a lognormal distribution, with relatively thick sand and silty clay loam layers, and relatively thin sandy loam, loam and clay layers. For a certain textural type, layers occurred beneath it were mainly the two types which adjoined it, especially the one which contained more fine particles. The uncertainty analysis of soil textural layer transitions indicated that the form

关 键 词：土壤 质地 模型 马尔可夫链 转移概率矩阵 随机模拟 质地剖面 

分 类 号：S152.3[农业科学—土壤学]