亚热带地区典型林分氮保留能力的差异及δ^(15)N空间垂直分异特征  

Influence of Forest Type on Soil Nitrogen Retention and Spatial Heterogeneity Characteristics of Nitrogen Isotope in Subtropical China

作　　者：肖好燕 刘宝[3] 张宁[1,2] 刘娇娇[1,2] 桑昌鹏 周富伟 黄志群[1,2] 

机构地区：[1]湿润亚热带山地生态国家重点实验室培育基地,福州350007 [2]福建师范大学地理科学学院,福州350007 [3]福建农林大学林学院,福州350002

出　　处：《亚热带资源与环境学报》2015年第3期17-24,共8页Journal of Subtropical Resources and Environment

基　　金：国家自然科学基金项目(41371269);国家"973"项目-土壤有机碳形成与转化的生物学机制(2014CB954002);福建省杰出青年科学基金项目(2060203)

摘　　要：δ^(15)N空间垂直分异特征可以有效指示森林生态系统土壤氮保留能力。以中国亚热带典型林分(天然林、格氏栲人工林、杉木人工林、闽粤栲人工林、闽楠人工林)为对象,通过对比其当年生叶片、凋落物及不同深度的土壤氮稳定同位素,研究林分类型对植物、土壤氮稳定同位素的影响及森林生态系统垂直空间氮稳定同位素分异特征,并探讨了不同林分土壤氮保留能力的差异。结果表明:不同林分当年生叶片、凋落物及0~10 cm和10~20 cm土壤δ^(15)N均具有显著差异,其中杉木人工林中这些δ^(15)N值显著高于其他4种林分类型,δ^(15)N在0~40 cm土层随深度的增加而显著增加,40~100 cm各土层δ^(15)N差异均不显著。另外,不同林分叶片^(15)N富集指数(EF)存在显著差异,呈现出杉木人工林的EF值较接近于0的趋势。研究表明,与阔叶人工林相比,杉木人工林由于较高的土壤净硝化速率、硝态氮含量及叶片、凋落物、土壤δ^(15)N值和较接近于0的叶片^(15)N富集指数,其土壤氮保留能力较阔叶人工林和天然林更差。Spatial heterogeneity of nitrogen isotope （δ15 N ） is an effective indicator of soil nitrogen retention. We analyzed the δ15N in foliage, litter and soils in plantations of Castanopsis kawakamii, Cunninghamia lanceolata, Castanopsis fissa and Phoebe bournei and a natural forest, in order to explore the spatial characteristics ofδ15 N and compare nitrogen retention abilities among different forest types in subtropical China. The results showed that δ15N in foliage, litter and soil （0~20 cm depth） differed significantly among forest types and theδ15N was significantly higher in Cunninghamia lanceolate compared with the other four forests. The δ15N in the 0~40 cm soil depth significantly increases with soil depth but show no significant differences in δ15N of 40 ~100 cm soil depth. The 15N enrichment factor （ EF） in foliage of Cunninghamia lanceolata tends to be closer to zero than the other four forests. The net nitrification rate and net mineralization rate in Cunninghamia were significantly higher than plantations of Castanopsis kawakamii Castanopsis fissa and Phoebe bournei. Overall, our results indi-cate that soil nitrogen retention in Cunninghamia lanceolata was significantly lower than natural forest and broadleaved plantations in subtropical China.

关 键 词：不同林分 土壤剖面 氮饱和 氮矿化 杉木 

分 类 号：S718.5[农业科学—林学]