Objective The aim was to summarize and analyze the diagnostic layers and characteristics of Shajiang black soil in Hebei Province, to classify its soil system and fill the gap in the soil series puzzle of Hebei Province.

Method The Shajiang black soil distributed in the fan edge depression of the alluvial plain at the foot of Taihang Mountain and Yanshan Mountain was selected as the research object, and the soil system classification method was used to study the advanced and grassroots units of soil system classification.

Result The 10 tested profiles have characteristics such as dark humus surface layer, embryonic layer, sticky layer, calcium layer, and homogeneous humus, which can be classified into three soil classes: homogeneous humus soil, embryonic soil, and leached soil. According to the soil moisture status, they were further divided into five subclasses: moist homogeneous humus soil, moist embryonic soil, moist embryonic soil, dry moist embryonic soil, and dry moist leached soil. Based on their redox characteristics, calcium deposition phenomenon, salt deposition phenomenon, and lime content, they were further divided into seven soil classes and eight subclasses. On this basis, the grassroots units were divided into 10 Tu ethnic groups, and based on the differences in thickness, burial depth, and color of the black soil layer, burial depth of the sand ginger layer, and size and abundance of sand ginger nodules, 10 soil systems were established, including the Zhaojiakou system and the Xidiantou system.

Conclusion Through systematic investigation of Shajiang black soil in Hebei Province, it can fill the gap in the puzzle of soil series in Hebei Province.