Objective The large-scale forest farm in the upper reaches of Baiyangdian Lake is a green barrier to improve the ecological environment of the Beijing-Tianjin-Hebei region and ensure the ecological security of Xiongan New Area and its surrounding areas. The soil physical and chemical properties of different stand types were studied to understand the soil fertility of different stands in order to provide scientific reference for the management of subsequent plantation.

Method Four typical stands, namely Robinia pseudoacacia, Pinus tabulaeformis, Quercus mongolica and Quercus variabilis, were selected as the research objects. The soil physicochemical properties of 0 ~ 20 cm and 20 ~ 40 cm soil layers were determined, and the stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) were calculated, and the differences and correlations were analyzed.

Result The soil bulk density, porosity and water holding capacity of Q. mongolica forest were the smallest, and the difference of soil physical properties among other stand types was not significant. The contents of organic matter, total P and available P of R. pseudoacacia forest were higher, while the contents of total potassium (K) and available K were lower. The soil pH value of P. tabulaeformis forest was low, the soil acidification was serious, and the contents of organic matter, total N and alkali-hydrolyzed N were low. The soil contents of total N and alkali-hydrolyzed N were higher in Q. mongolica forest, and the Q. variabilis forest showed lower P content and higher K content. According to the stoichiometric characteristics of soil C, N and P, C∶N, C∶P and N∶P of the four stand types in this study area ranged from 18.87 to 40.54, 25.10 to 95.32, and 0.95 to 6.06 in the 0 ~ 40 cm soil layer. The soil C∶N of P. tabulaeformis forest was the highest, while C∶P and N∶P were the lowest. The C∶N of Q. variabilis forest was the lowest, and N∶P was the highest; Q. mongolica forest with the highest C∶P.

Conclusion In this study area, soil organic matter mineralization rate was low, and plant growth was limited by N. The N limitation of P. tabulaeformis forest is the most serious, and the soil organic matter of Q. variabilis forest is more easily mineralized and decomposed, and the degree of N limitation is weak.