黄土丘陵区不同密度刺槐和油松人工林 土壤理化性质与化学计量特征.

[Objective] The aims of this study are to explore the response characteristics of soil physical and chemical properties and stoichiometric characteristics to stand density of Robinia pseudoacacia and Pinus tabuliformis plantations in loess hilly region, and to provide scientific basis for plantation management in loess hilly region. [Methods] The soil bulk density, water content, soil organic carbon（SOC）, total nitrogen（TN） and total phosphorus（TP） contents of two plantations were measured and analyzed. The variation characteristics and vertical variation characteristics of each index with different density gradients were studied by single factor variance analysis method, and the correlation between each index was analyzed by multi-factor correlation analysis method. [Results]（1） In the vertical distribution characteristics, the SOC and TN contents of each stand showed a significant decreasing trend with the increase of soil depth. There was no significant difference in soil bulk density and TP content.（2） Robinia pseudoacacia forest density had no significant effect on soil bulk density, water content, N∶P and other indicators. SOC, TN, TP and C∶N of low density Robinia pseudoacacia forest were significantly higher than those of other densities.（3） Pinus tabulaeformis forest density had no significant effect on soil bulk density, C∶N, C∶P, N∶P and other indicators. The contents of SOC, TN and TP in high density pine forest were significantly higher than those in other density pine forest.（4） Under the same density, the soil bulk density and water content of Robinia pseudoacacia forest were higher than those of Pinus tabulaeformis forest. The SOC, TN, C∶N, C∶P, N∶P were lower than those of Pinus tabulaeformis forest, except for C∶N, the differences were significant. [Conclusion] The contents of SOC, TN and TP in low-density Robinia pseudoacacia forest were higher, while the contents of SOC, TN and TP in high-density Pinus tabulaeformis forest were higher, and the soil quality of Pinus tabulaeformis forest was relatively better than that of Robinia pseudoacacia forest. [ABSTRACT FROM AUTHOR]