Physical and chemical characteristics of a typical Mollisol in China

Mollisols (called Black soils) in China are distributed primarily in the northeast region, which is one of the three largest Mollisol areas in the world. Black soils are of major agricultural importance in China. This study reports the physical and chemical properties of this soil with use of a typical Black soil profile selected in Heilongjiang Province, China, and standard soil analytical procedures. The soil is characterized with a thick (60 cm) mollic epipedon. The upper layer of the epipedon contains 5.8% organic carbon, and its CEC is 43.7 cmol(+)/kg. The macroaggregate (>0.25 mm) stability of the epipedon is high (between 63 and 68% of the soil sample weight), which provides favorable soil structure and conditions for plant growth. Soil texture is clay loam for all horizons except the upper layer of the mollic epipedon, which is sandy clay loam. Bulk density increases with depth, and total porosity declines with depth, due most likely to the profile distribution of organic carbon (decreasing with depth). Total nitrogen (N) and phosphorus (P) and available water are also larger in the upper epipedon than the lower horizons. Overall characteristics make this soil fertile and productive. The results of this study can be used as baseline data for examining any change in soil properties of the same soils resulting from agricultural management and practices and for comparisons of pedogenic and carbon cycling studies of Mollisols in China or worldwide.