经营时间梯度上的毛竹林碳氮动态特征

应用典型样方法对不同经营方式和经营持续时间的毛竹林碳氮贮量变化特征进行了研究。结果表明,施肥降低毛竹林系统碳氮贮量,垦复增加毛竹林系统碳氮贮量。两种经营模式毛竹林系统碳氮贮量的分布格局均以土壤层最大,植被层次之。其中,碳贮量土壤层占63.25%~86.32%,植被层占13.17%~35.15%;氮贮量土壤层占94.44%~98.15%,植被层占1.62%~5.12%。施肥、垦复对竹林系统碳氮贮量的影响主要通过对土壤层碳氮贮量的改变来实现。不同经营时间毛竹林土壤碳氮贮量排列顺序不同,施肥毛竹林土壤碳贮量的排列顺序为对照>施肥13 a>施肥5 a,氮贮量的排列顺序为对照>施肥5 a>施肥13 a;垦复毛竹林土壤碳氮贮量的排列顺序为垦复3 a>垦复10 a>对照。经营模式和经营时间梯度上毛竹林土壤碳氮贮量变化的不同步,造成了土壤碳氮比差异较大。其中,施肥毛竹林土壤碳氮比为18~39,垦复土壤碳氮比为13~16,施肥毛竹林碳氮比变化幅度较垦复毛竹林更剧烈,碳氮比的剧烈变化可能对土壤微生物群落和持续立地生产力产生不良影响。施肥和垦复均能够有效提高地上部分的碳氮贮量,但不同经营模式和经营时间的毛竹林碳氮分布格局不同。施肥毛竹林的碳氮比为260,垦复毛竹林的碳氮比为167,毛竹林碳氮分布格局的多样性为毛竹制定专属的培育措施提供了可能。

The Dynamic Characteristics of Carbon and Nitrogen Storage in Phyllostachys edulis Forest with Operating Time

In order to understand the variation of carbon and nitrogen storage and the ration of carbon to nitrogen of Phyllostachys edulis forest with different modes of operation and operating duration, this study was designed to test the dynamic characteristics of carbon and nitrogen storage by typical sample method in Yongan city, Fujian Province and Anfu County, Jiangxi Province. The result showed that the carbon and nitrogen storage decreased in P. edulis forest with fertilization and increased in P. edulis forest with reclamation. The carbon and nitrogen storage of soil layer was the largest, followed by the vegetable layer for both the moso bamboo forests. The proportion of soil layer carbon storage was 63.25%-86.32% and the vegetable layer was 13.17%-35.15%. The nitrogen storage of soil layer was 94.44%-98.15% and the vegetable layer was 1.62%-5.12% . The carbon and nitrogen storage of moso bamboo system was affected by the carbon and nitrogen storage of soil layer. There was a significant difference for the moso bamboo carbon and nitrogen storage in different operating time. The carbon storage of moso bamboo with fertilization was in the order of control forest>moso bamboo forest with 13 years fertilization>moso bamboo forest with 5 years fertilization and the nitrogen storage was in the order of control forest >moso bamboo forest with 5 years fertilization >moso bamboo forest with 13 years fertilization. The carbon and nitrogen storage of moso bamboo forest with reclamation was in the order of moso bamboo forest with 3 years reclaim>moso bamboo forest with 10 years reclamatiom >control forest. The change of carbon storage was not compatible with the nitrogen storage. Thus the value of C:N was amplitude largely. The ratio of C:N was from 18 to 39 in forest with fertilization and was from 13 to 16 in forest with reclamation. The amplitude was more violently in forest with fertilization. Those changes may damage the site sustained productivity. The carbon and nitrogen storage increased due to treatment of fertilization and reclamation. However, the carbon and nitrogen storage of vegetation layer distribution pattern was different for different types of moso bamboo. The difference of the carbon and nitrogen storage implied the exclusive management measures can be designed for the P. edulis forest.