不同生产力水平毛竹林碳氮磷的分布格局和计量特征

Distribution Patterns and Stoichiometry Characteristics of C,N,P in Phyllostachys edulis Forests of Different Productivity Levels

以南亚热带中心分布区的毛竹林为研究对象，比较不同生产力水平（Ⅰ：30000±1000 kg·hm -2 a -1；Ⅱ：34000±1000 kg·hm -2 a -1；Ⅲ：37000±1000 kg·hm -2 a -1；Ⅳ：42000±1000 kg·hm -2 a -1；Ⅴ：47000±1000 kg·hm -2 a -1）毛竹林植被和土壤的碳、氮、磷含量及计量特征，探讨生产力水平对毛竹林及土壤碳、氮、磷分布格局及化学计量特征的影响。结果表明：生产力水平对毛竹林植被碳和磷元素在不同器官间分配比例的影响较小，对氮素分配比例的影响较大；除竹叶碳元素分配比例在不同生产力水平间的差异达到显著水平外（P ＜0.01），各器官间碳、磷含量在不同生产力水平间差异均不显著；除竹秆外，毛竹不同器官氮分配比例在不同生产力水平间的差异均极显著（P＜0.01）；生产力水平对毛竹林植被 C∶N、C∶P、N∶P计量比值的影响较小，在不同生产力水平间的差异均未达到显著水平（P＜0.01），毛竹林主要养分元素的计量比具有内在的稳定性，符合“内稳性假说”；生产力水平对林地土壤碳、氮、磷、水解氮和有效磷含量有显著影响，土壤 C∶N、C∶P、N∶P 和 H-N∶A-P 在不同生产力间的差异均达到了极显著水平（P＜0.01）；当土壤N∶P＜14时，主要受到氮元素的限制，本研究中土壤N∶P为4.50～13.89，反映了研究区毛竹林主要受到氮元素的限制，受磷元素的限制较少，且 N∶P 比值随着生产力的提高呈降低的趋势，有可能成为未来毛竹林退化诊断的生态指示指标；毛竹林植被主要养分计量值与土壤主要养分计量值的相关性分析表明，二者间的相关性未达到显著水平。

Phyllostachys edulis forests and soil in their central distribution area in subtropical China were selected as research object. This study discussed the effects of productivity level （Ⅰ： 30 000 ± 1 000 kg·hm -2 a -1;Ⅱ： 34 000 ± 1 000 kg·hm -2 a -1;Ⅲ：37 000 ± 1 000 kg·hm -2 a -1;Ⅳ：42 000 ± 1 000 kg·hm -2 a -1;Ⅴ：47 000 ± 1 000 kg·hm -2 a -1 ） on the distribution of carbon （ C ） , nitrogen （ N ） and phosphorus （ P ） and their stoichiometric characteristics of Phyllostachys edulis and soil by comparing C,N and P content of Phyllostachys edulis and soil,and their stoichiometric characteristics,which could provide theory evidence for long-term productivity maintenance in Phyllostachys edulis forests. The result showed that the productivity level had less effect on the distribution of plant C and P in different organs,and had more effects on N distribution. The difference of the distribution pattern of C and P of each organ in different productivity levels was not significant,except leaf C （P〈0. 01）. Except bamboo stem,N distribution pattern in different organs in different productivity levels reached a highly significant level （ P 〈0. 01 ） . The productivity levels had less impact on the stoichiometry of plant C∶N,C∶P and N∶P,the difference in different productivity levels did not reach a significant level. Stoichiometry of main nutrients in Phyllostachys edulis forests was inherently stable, in line with “internal stability hypothesis”. The productivity levels had significant impact on soil C,N,P,hydrolyzable N and available P,soil C∶ N,C∶ P,N∶ P,H-N∶ A-P reached a highly significant level in different productivity levels （ P 〈0. 01）. When N∶P 〈 14,the forests was mainly limited by N. In this study,soil N∶P was 4. 50 -13. 89,indicating Phyllostachys edulis forests in research area was mainly limited by N,rather than P. N∶P decreased with the increase of productivity level,soil N∶P was index to represent Phyllostachys edulis forests degradation succession process. Analysis the correlation between stoichiometry value of main nutrient of plant and soil indicated no significant level between the two.