为了解宁夏中部地区地带性土壤——灰钙土的发育特性及其在中国土壤系统分类中的归属,在研究区内挖掘8个代表性的土壤剖面,进行剖面形态观察,采集分层土壤样品,测试理化性状.结果发现:(1)灰钙土中发生的主要成土过程有:弱腐殖质积累、弱淋溶淀积过程.(2)8个供试剖面中检索出的诊断依据有淡薄表层、干旱表层、雏形层、钙磐等诊断层,黄土和黄土状沉积物岩性特征、半干润/干旱土壤水分状况、温性土壤温度状况、钠质特性、石灰性等诊断特性和钙积诊断现象等.(3)依据《中国土壤系统分类检索(第三版)》,可将8个供试剖面初步归属为雏形土、干旱土2个土纲,干润雏形土、正常干旱土2个亚纲,简育干润雏形土和简育正常干旱土2个土类,普通简育干润雏形土、钠质简育正常干旱土2个亚类.依据《中国土壤系统分类土族与土系划分标准》将供试剖面初步划分为5个土族,5个土系.(4)参比研究表明,灰钙土在土壤发生分类和系统分类中的分类类别不是简单一对一的关系,发生分类中相同的类别可对应系统分类中不同类别,系统分类定量化的分类指标使土壤分类更加量化,减少了同名异土情况的发生,提高了分类的准确性.%[Objective]In order to explore genetic characteristics and ascription in the Chinese Soil Taxonomy of sierozem,a zonal soil typical of Central Ningxia,8 representative soil profiles were dug for examination and analysis in the study area.[Method]Firstly,sites for the eight soil profiles were defined with the aid of Arcgis 9.3 and GPS;profiles dug out for examination,description and characterization;and then soil samples collected from each soil layer of the profiles for analysis of physicochemical properties.[Result]From morphological characterization of the soil profiles and analyses of the soil samples,it was learnt that the main soil forming processes of the typical sierozem involved weak humus accumulation process,and weak eluviation-illuviation processes. By referring to and identification in line with"the Keys to the Chinese Soil Taxonomy(third Edition)",it was found that the eight profiles had the following diagnostic horizons and characteristics,ochric epipedon,aridic epipedon,calcipan,loess and loess-like deposits,ustic/aridicsoil moisture regime,mesic temperature regime,sodic feature and calcaric property,and calcic accumulation. In the Chinese Soil Taxonomy,the 8 soil profiles could tentatively be sorted into the soil order of Cambosols and Aridosols,the soil group of Hapli-Ustic Cambosols and Hapli-Orthic Aridosolss,and the subgroup of Typic Hapli-Ustic Cambosols and Sodic Hapli- Orthic Aridosols. According to the standard for classification of soil families and soil series in the Chinese Soil Taxonomy,the 8 soil profiles could tentatively be sorted into five soil families,i.e. Sandysilica mixture calcareous mesic-TypicHapli-Ustic Cambosols,Loamysilica mixture calcareous mesic-Typic Hapli-Ustic Cambosols,Loamy feldspar mixture calcareous mesic- Sodic Hapli- Orthic Aridosols,Loamysilica mixture calcareous mesic-Sodic Hapli-OrthicAridosols and Loamy feldspar mixture calcareous mesic-Typic Hapli-Ustic Cambosols,and five soil series,i.e. Qingshan series,Majiatan series,Dazhanchang series,Haochuan series and Xiamaguan series.[Conclusion]The reference studies of the eight soil profiles in different soil classification systems show that between the two soil classification systems,the Chinese Soil Genetic Classification and the Chinese Soil Taxonomy,does not exist any simple one to one relationship. While the same types of soil in the Genetic Classification System may correspond with several type in the Chinese Soil Taxonmy. The quantitative norms in the Chinese Soil Taxonomy make soil classification more quantified,thus improving the accuracy of soil classification and eliminating the phenomena of different soils having the same soil name.
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