Objective  Dam silty soils were developed from the sediments of the artificial dam construction or flood storing in the gully of the Loess plateau, which was considered as not only an important soil erosion control measure but also an effective way to increase arable land. In order to understand the attribution of the dam silty soils in the Chinese Soil Taxonomy (CST) classification system, totally 5 soil profiles were selected in the loess plateau.

  Method  In each selected soil profile, soil forming conditions, profile morphological characteristics, parent materials and land uses were recorded referring to Manual of Field Soil Description and Sampling in situ. The soil samples were collected and taken to the laboratory for soil physical and chemical measurement with referring to Soil Survey Laboratory Methods. On this basis, the diagnostic horizons and diagnostic characteristics of the soil profiles were determined, and the classification of dam silty soils was attributed in CST at the higher and basic category levels.

  Result  All the selected dam silty soil profiles had a depth higher than 120 cm with the anthro-silting parent material, the color for most of the soil layers were dominated by the turbid-yellow orange, the soil texture were composed by silty loam, loam and sandy loam. The soil organic carbon content was ranged from 1.33 to 8.29 g kg⁻¹, pH ranged from 8.40 to 9.80, as well as the content of CaCO₃ ranged from 19.4 to 173.5 g kg⁻¹. The selected soil profiles included two diagnostic surface horizons (ochric epipedon and cambic horizon), one diagnostic evidence (salic evidence), and six diagnostic characteristics (anthro-siliting materials, mesic soil temperature regimes, ustic soil moisture regimes, udic moisture regime, redoxic features and calcaric property). The 5 profiles were attributed into 2 soil orders (cambosols, primosols), 2 suborders (ustic cambosols, authric primosols). One subgroup (Typic Hapli-Ustic Cambosols) was attributed for the group of Hapli-Ustic Cambosols, while four subgroups (Silti-Parasalic Anthric Primosols, Silti-Mottlic Anthric Primosols, Silti-Calcaric Anthric Primosols, Silti-Calcaric Anthric Primosols) were attributed for the group of Silti-Anthric Primosols. According to the classification standards of soil families and soil series in CST, they were attributed for 4 soil families (clay loamy mixed calcaric type mesic temperature-Typic Hapli-Ustic Cambosols, loamy mixed calcaric type mesic temperature-Silti Parasalic-Anthric Primosols, etc.) and 5 soil series (Liujiayuan series, Sanchuankou series, etc.). The established 5 soil series were referenced to the same soil species (Dam silty spongy soil) in the Chinese Soil Genetic Classification (CSGC), which indicated that the CST classification system had higher discrimination than the CSGC system for the dam silty soil.

  Conclusion  Even the dam silty soil only had a short soil forming time, the intensive agricultural production activities such as ploughing, fertilization and irrigation could accelerate soil development and probably prompted soil attribution from primosols to cambosols. The diverse soil genesis of dam silty soil determined diverse properties of the established soil series, which indicated that specific soil use measures should be proposed to each soil series to promote the ecological environmental health and achieve high quality development of agricultural production in the Yellow River basin.