四川龙溪-虹口常绿阔叶林凋落物与土壤碳、氮、磷化学计量特征分析

以龙溪虹口海拔873～2 211 m的常绿阔叶林为研究对象,通过野外采集和室内分析,探讨了常绿阔叶林土壤与凋落物有机碳(C)、氮(N)、磷(P)生态化学计量特征对海拔、土层和森林类型的响应特征。结果表明:①随着海拔的上升,不同土层的土壤和凋落物有机碳、氮、磷含量均呈现出增加的趋势;土壤和凋落物有机碳、氮、磷含量与海拔呈极显著正相关关系。②土层厚度与土壤N/P和C/P显著负相关,海拔和森林类型与凋落物C/P显著负相关,森林类型仅与凋落物N/P显著负相关。③研究区内土壤和凋落物C/N高于中国森林系统土壤和凋落物C/N,表明凋落物分解速度较慢,矿化和腐殖化程度较低,土壤硝酸盐淋溶风险较低,养分贮藏能力较好。土壤氮、磷含量与凋落物C/N和C/P显著负相关,说明该地区凋落物分解受土壤氮、磷元素共同的限制。研究结果可为探讨森林土壤养分供应和限制因素以及研究区域内土壤质量评价和森林管护提供科学依据。

C,N, P Stoichiometric Characteristics Analysis of Litter and Soil in Evergreen Broad-leaf Forest in Longxi-Hongkou Reserve of Sichuan Province

Taking the evergreen broad-leaf forest in Longxi-Hongkou reserve of Sichuan province as object, this paper explored the effect of evergreen broad-leaf forest soil and characteristics of ecological stoichiometry of total organic carbon, nitrogen and phosphorus in soil and litter in response to altitude, soil layer and forest type. The results indicated that: ① The contents of C, N and P in soil and litter showed rising trend along with elevation increasing. All these contents were significantly and positively correlated with elevation. ② The soil depth was significantly and negatively correlated with N/P and C/P in soil. The elevation and forest type were significantly and negatively correlated with C/P of litter, while only forest type was significantly and negatively correlated with N/P of litter. ③ The C/N ratios of soil and litter were higher than that of forest ecosystem in China, indicating the litter decomposition rate was slow, degree of mineralization and humification was lower, risk of soil nitrate leaching was lower, and nutrient storage capacity was better. Soil N & P contents were significantly and negtively correlated with C/N and C/P of litter indicated that litter decomposition in this area was restricted both by nitrogen and phosphorus elements in soil. These research findings may provide scientific basis for studying soil nutrient supply and its limiting factors in Longxi-Hongkou forest and evaluating soil quality and forest managing ability there.