【摘要】 研究小叶锦鸡儿(Caragana microphylla)人工灌木林土壤化学计量特征,有助于阐明林下土壤养分分配及限制因素,为人工灌-草生态系统物质平衡和稳定维持提供理论依据。以内蒙古中部农牧交错区天然草地为对照(CK),比较相同林龄不同密度人工小叶锦鸡儿灌木林下0～50 cm土层土壤有机碳、总氮和总磷含量及其化学计量特征。结果表明(1)与天然草地相同,小叶锦鸡儿人工灌木林土壤SOC和TN在0～5 cm出现明显地"表聚性",且随着土壤深度的增加逐渐降低。(2)该研究区土壤释放P素能力较强且含量相对稳定,但C素和N素含量总体偏低;其间,C/P受控于土壤SOC含量,N/P受控于TN含量,C/N受林分密度影响较小,相对稳定。(3)在土壤养分平衡过程中,该地区低密度林(1200棵hm-2)各土层C、N、P含量均显著高于中、高密度林,促进了土壤C素和N素的积累与循环,有助于改善土壤环境。更多还原

【Abstract】 Learning the stoichiometric characteristics of soil carbon(C), nitrogen(N), and phosphorus(P) would help to know soil nutrient allocations and their limiting factors and would provide theoretical foundation for the material balance and stabilization in the artificial shrub-grass ecosystem. Taking the natural pasture as control(CK), we analyzed the contents of soil C, N, P and their stoichiometric ratios in Caragana microphylla with different densities at0-50 cm soil depth in the interlocked agro-pasturing area of central Inner Mongolia. Compared with CK, the contents of soil nutrients in the test sites decreased with soil depths. Soil total P(TP) was relatively stable and the capability of soil releasing P was strong, while the contents of soil organic C(SOC) and total N(TN) were deficient. In addition, there were linear relationships among the contents of SOC, TN, TP and their stoichiometric ratios in the test sites with different densities of Caragana microphylla. The ratios of C/P and N/P were controlled by the contents of SOC and TN, respectively. The 1200 plants hm-2 of planting density was the most appropriate, with the high contents of SOC, TN and TP, which promoted the accumulation and turnover of soil C and N.更多还原