中国南方土壤中白色土层的特征及其成因分析  

Characteristics and formation causes of white horizons in southern China

作　　者：章明奎[1] 麻万诸[2] 姚玉才[1] ZHANG Mingkui;MA Wanzhu;YAO Yucai(College of Environmental and Resource Sciences,Zhejiang University,Hangzhou 310058,China;Institute of Digital Agriculture,Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China)

机构地区：[1]浙江大学环境与资源学院,浙江杭州310058 [2]浙江省农业科学院数字农业研究所,浙江杭州310021

出　　处：《浙江农业学报》2019年第2期279-290,共12页Acta Agriculturae Zhejiangensis

基　　金：国家自然科学基金(41571207)

摘　　要：为了解具有"漂白层"土壤的分布规律、准确识别"漂白层",为土壤调查制图提供依据,从中国南方地区的浙江、福建和贵州等省采集了25个含白色土层的土壤剖面,分析这一地区土壤中白色土层的特征及其与地形、成土母质等的关系。结果表明,中国南方地区白色土层在质地、游离氧化铁和有机质含量等性状上有较大的变化。根据土壤颜色与游离氧化铁的剖面分布特征,可把研究的25个剖面中白色土层分为受母质影响的白色土层、受复合成土过程作用的白色土层和离铁作用形成的白色土层等3类。受母质影响的白色土层并非离铁作用的结果,其成因与母质中游离氧化铁含量较低或叠加母质有关;受复合成土过程作用的白色土层,其颜色与游离氧化铁存在不一致现象,白色土层是前期离铁作用的结果,而后期氧化铁在结构面上的淀积掩盖了漂白层的离铁特征;离铁作用形成的白色土层是真正用于土壤类别鉴定的"漂白层",其游离氧化铁含量明显低于其上覆或下伏土壤,以河谷平原、丘陵山地缓坡及山丘凹垅中的分布最为集中,其微地形表现为地表倾斜、低凹,易接受附近高处的水流,但地表一般不会积水,具有土内侧向排水的特点。为了区别于受母质影响的白色土层,建议在"漂白层"的鉴定标准中增加游离氧化铁含量与其上覆或下伏土壤的比较,建议标准为"漂白层的游离氧化铁含量为其上覆或下伏土壤的75%以下"。To understand the geographical distribution of soils with “albic horizon”,identify accurately the “albic horizon”in the fields and provide the scientific basis for soil investigation and mapping,twenty-five soil profiles with white color horizon were collected from Zhejiang,Fujian,and Guizhou provinces in the southern China.The characteristics of the white color horizon in the region and their relationships with landform and parent materials were analyzed.The results showed that great variations in texture,free iron oxide and organic matter were found in the soils with white color horizon in the southern China.According to the soil color and vertical distribution characteristics of soil free iron oxide,the twenty-five soil profiles were divided into 3 types,i.e.,white color horizons affected by parent materials,affected by composite soil processes,and formed by iron removal.The white color horizons affected by the parent materials were not the result of the iron removal,but were related to the low free iron oxide in their parent materials or superimposed parent materials of soil profile.Color for the white color horizons affected by the composite soil processes were not consistent with their free iron oxide profile distribution,as the white color was the result of iron removal in the former soil formation stage,and the iron oxide deposition on the soil structure in the later formation stage covered the iron removal characteristics of the bleach horizon.The white color horizon formed by the action of iron removal was an “albic horizon”,which could be really used for soil classification.The free iron oxide content in the horizon was obviously lower than that of the overlying or the underlying soil.The distribution of the soils with “albic horizon” was most concentrated in the valley plain,gentle slope of hilly mountain and hill ridge,and its micro topography was characterized by the slope and low concave surface,and it was easy to accept the water flow from the height.But their surface generally did

关 键 词：白色土层 漂白层 成土母质 地形 游离氧化铁 离铁作用 

分 类 号：S151[农业科学—土壤学] S55[农业科学—农业基础科学]