亚热带天然次生林演替对土壤氮矿化的影响机制  

Mechanisms underlying the impacts of subtropical natural secondary succession on soil nitrogen mineralization

作　　者：孙嘉雯 施秀珍 邵雅琪 冯鼎 王建青 刘宝[3] 邹秉章 王思荣 黄志群 SUN Jiawen;SHI Xiuzhen;SHAO Yaqi;FENG Ding;WANG Jianqing;LIU Bao;ZOU Bing-zhang;WANG Sirong;HUANG Zhiqun(Cultivation Base of State Key Laboratory of Humid Subtropical Moun-tain Ecology,Fuzhou 350117,China;School of Geographical Science,Fujian Normal University,Fuzhou 350117,China;College of Forestry,Fujian Agriculture and Forestry University,Fuzhou 350117,China;Fujian Shang-hang Baisha Forestry Farm,Longyan 362300,Fujian,China)

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350117 [2]福建师范大学地理科学学院,福州350117 [3]福建农林大学林学院,福州350117 [4]福建上杭白砂国有林场,福建龙岩362300

出　　处：《应用生态学报》2025年第1期59-66,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金面上项目(32071631);福建省自然科学基金杰出青年项目(2023J06024)资助。

摘　　要：为探究亚热带天然次生林演替过程中土壤氮矿化的变化规律及其影响机制,本研究利用空间替代时间的方法,以5个不同发育阶段的天然次生林(林龄分别为5、8、21、27、40年)为研究对象,并以>100年的原始天然林为对照。采用微宇宙培养法测定土壤净氮矿化速率,同时测定土壤理化性质、微生物生物量和林下植被多样性。结果表明:土壤净氮矿化速率随天然次生林演替进程显著增加,不同林龄天然次生林土壤净氮矿化速率变化范围为(-0.04±0.01)~(0.39±0.04)mg·kg^(-1)·d^(-1),原始天然林的净氮矿化速率(0.73±0.12 mg·kg^(-1)·d^(-1))显著高于次生林。随机森林分析显示,土壤全氮和碳氮比是影响土壤净氮矿化速率的显著预测因子。回归分析结果表明,土壤微生物生物量碳与净氮矿化速率呈显著正相关;林下灌木层丰富度与土壤净氮矿化速率呈显著相关。结构方程模型显示,林龄通过降低土壤pH间接或直接促进土壤微生物生物量碳,土壤微生物生物量碳和碳氮比分别对净氮矿化速率有显著正影响和负影响。综上,土壤碳氮比和微生物生物量碳是调控天然次生林演替影响土壤氮矿化的重要因子。To explore the changes in soil nitrogen(N)mineralization and underlying mechanisms during the suc⁃cession of subtropical natural secondary forests,we employed a space⁃for⁃time substitution approach to study five forests at different developmental stages(i.e.,5,8,21,27,and 40 years),with the primary forests over 100 years old as a control.We measured soil net N mineralization rate under microcosm cultivation,as well as soil physi⁃cochemical properties,microbial biomass,and the richness of understory.The results showed that soil net N mine⁃ralization rates significantly increased with the succession of natural secondary forests,which varied from(-0.04±0.01)to(0.39±0.04)mg·kg^(-1)·d^(-1).The net N mineralization rate in primary forests(0.73±0.12 mg·kg^(-1)·d^(-1))was significantly higher than that in secondary forests.Results of random forest analysis showed that soil total N and carbon⁃to⁃nitrogen ratios were significant predictors of soil net N mineralization rates.Regression analysis showed that soil microbial biomass carbon significantly and positively correlated with soil net N mineralization rates.The understory shrub layer richness was significantly correlated with net soil N mineralization rate.Structural equa⁃tion models showed that forest ages had a direct positive effect on soil microbial biomass carbon,and an indirect one via reducing soil pH.Soil microbial biomass carbon and soil carbon⁃to⁃nitrogen ratios had significantly positive and negative effects on soil net N mineralization rates,respectively.In conclusion,soil carbon⁃to⁃nitrogen ratio and microbial biomass carbon were important factors regulating the impacts of natural secondary forest succession on soil N mineralization.

关 键 词：氮矿化 土壤微生物量 天然次生林 林龄 森林恢复 

分 类 号：S714.2[农业科学—林学]