“Black soils” recently proposed by the FAO Global Soil Partnership, include fertile soils, characterized by a thick, dark-colored soil horizon rich in organic matter. This study addressed the proposed concept of “black soils”, in terms of taxonomic relationship of their corresponding soil types of existing soil classifications. Similarity studies were based on the calculation of taxonomic distances between selected soil groups with organic matter–enriched horizons of the Russian Soil Classification System, the United States Soil Taxonomy and the World Reference Base for Soil Resources. In the process, we used the so called ”centroids”, which are the calculated mean values of several soil properties for each of the soil groups using legacy data derived from national and international databases. The results indicated that the Great Groups of the Mollisol Order in the US Soil Taxonomy had small taxonomic distances within the order, except some soils with shallow depth to the hardpan or permafrost. Dark-colored Vertisols and Andisols were found to differ from the Mollisols and similar soils found in similar environments mainly under grasslands. We recommend excluding Vertisols and Andisols from the “black soils” cluster due to the peculiarity in their properties, potential use and management. While the Vertisols and Mollisols of the Soil Taxonomy were completely dissimilar in properties, the WRB Vertisol Reference group and Russian dark-humus compact soils fitted well the Mollisols cluster, presumably due to the different concept of the Vertisols in the studied system. The soil types of the “black soils” of the Russian soil classification had a short distance to the corresponding Reference Groups of the World Reference Base. Also, the similarity was high with the Great Groups of the US Soil Taxonomy for all soil types except of Kastanozems, but the relationship in places was not well interpreted from a pedogeographic point of view. We ascribed the phenomenon to the geographical bias of the databases. Though “black soils” form a distinct cluster that roughly corresponds to the Mollisols Order of the US Soil Taxonomy, the taxonomic distance within the group may be significant, contributing to the pedodiversity of soilscapes of “black soils”.

粮农组织全球土壤伙伴关系最近提出的“黑土”包括肥沃的土壤，其特征是浓厚的深色土壤层层富含有机质。这项研究从现有土壤分类的相应土壤类型的分类关系出发，提出了“黑土”的概念。相似性研究基于俄罗斯土壤分类系统，美国土壤分类学和世界土壤资源参考库中富含有机物的某些土壤组之间分类距离的计算。在此过程中，我们使用了所谓的“质心”，它们是使用从国家和国际数据库中获得的遗留数据为每个土壤组计算的几种土壤特性的平均值。结果表明，美国土壤分类学中的大类莫利索尔阶在该阶内的分类学距离很小，除了一些浅层土壤到硬盘或永久冻土之外。发现深色的Vertisols和Andisols与Mollisols和在类似环境下（主要是在草原下）发现的类似土壤不同。我们建议将“ Vertisols”和“ Andisols”排除在“黑土”类中，因为它们的特性，潜在的使用和管理具有特殊性。虽然土壤分类学中的Vertisols和Mollisols在性质上完全不同，但是WRB Vertisol Reference组和俄罗斯的深色腐殖质致密土壤很好地适合了Mollisols团簇，这可能是由于所研究系统中Vertisols的概念不同。俄罗斯土壤分类的“黑土”的土壤类型与世界参考基准的相应参考组的距离较短。同样，除土壤病毒之外，所有土壤类型与美国土壤分类法大类的相似性都很高，但是从人文地理学的角度来看，地方之间的关系并没有得到很好的解释。我们将这种现象归因于数据库的地理偏向。尽管“黑土”形成了与美国土壤分类法的“ Mollisols Order”大致相对应的独特簇，但该组内的分类距离可能很长，这有助于“黑土”土壤景观的多样性。与美国土壤分类法大类在所有土壤类型上的相似性都很高，但卡斯坦诺西姆除外，但从人文地理学的角度来看，地方之间的关系并没有得到很好的解释。我们将这种现象归因于数据库的地理偏向。尽管“黑土”形成了与美国土壤分类法的“ Mollisols Order”大致相对应的独特簇，但该组内的分类距离可能很长，这有助于“黑土”土壤景观的多样性。与美国土壤分类法大类在所有土壤类型上的相似性都很高，但卡斯坦诺西姆除外，但从人文地理学的角度来看，地方之间的关系并没有得到很好的解释。我们将这种现象归因于数据库的地理偏向。尽管“黑土”形成了与美国土壤分类法的“ Mollisols Order”大致相对应的独特簇，但该组内的分类距离可能很长，从而导致“黑土”土壤景观的多样性。