尾巨桉人工林土壤呼吸对林下植被管理措施的响应  

Response of soil respiration to understory vegetation management in Eucalyptus urophylla×E.grandis plantation

作　　者：竹万宽[1] 许宇星[1] 王志超[1] 杜阿朋[1] ZHU Wankuan;XU Yuxing;WANG Zhichao;DU Apeng(National Positioning Observation and Research Station of Eucalyptus Forest Ecosystem in Zhanjiang,Guangdong,Research Institute of Fast-growing Trees,Chinese Academy of Forestry,Zhanjiang 524022,Guangdong,China)

机构地区：[1]中国林业科学研究院速生树木研究所广东湛江桉树林生态系统国家定位观测研究站,广东湛江524022

出　　处：《浙江农林大学学报》2023年第1期164-175,共12页Journal of Zhejiang A&F University

基　　金：广东省林业科技创新项目(2018KJCX014);广东林业生态定位监测网络平台建设项目(2021CG535);林草科技创新平台运行项目(2022132113)。

摘　　要：【目的】探究不同林下植被管理措施对雷州半岛尾巨桉Eucalyptus urophylla×E.grandis人工林土壤呼吸及其组分的影响,为准确评估桉树人工林土壤碳循环提供科学依据。【方法】以尾巨桉人工林为研究对象,实施物理和化学(施用除草剂)方式去除林下植被,并以未去除为对照。采用LI-8100A土壤碳通量自动测量系统,对土壤总呼吸及其组分速率、土壤温度和湿度(5 cm深处)进行为期1 a的连续监测。【结果】物理和化学去除林下植被极显著降低了土壤总呼吸及其组分(化学去除的根系呼吸除外)(P<0.01),且物理去除的土壤总呼吸速率(3.45μmol·m^(−2)·s^(−1))显著低于化学去除(4.15μmol·m^(−2)·s^(−1))(P<0.01)。2种方式的矿质土壤呼吸速率和凋落物层呼吸速率无显著差异(P>0.05),根系呼吸速率表现为物理去除(1.02μmol·m^(−2)·s^(−1))显著低于化学去除(1.37μmol·m^(−2)·s^(−1))(P<0.05)。凋落物层呼吸、矿质土壤呼吸、根系呼吸对土壤总呼吸的贡献率分别为36.45%~39.40%、26.34%~31.29%、30.10%~39.40%。土壤总呼吸速率及其组分最高值出现在雨季(4—10月),根系呼吸速率最低值出现在7—8月。土壤总呼吸速率与土壤温度、湿度双因子拟合模型最优,能解释土壤总呼吸速率变异的75.1%(物理去除)、60.9%(化学去除)、57.1%(对照);凋落物呼吸速率时间变异主要由土壤湿度调控;根系呼吸速率与土壤温度无显著相关性,与土壤湿度呈显著负相关(P<0.05)。土壤总呼吸的温度敏感性(Q10)从大到小依次为物理去除(2.12)、化学去除(1.95)、对照(1.93)。【结论】林下植被去除通过改变林内生物和非生物因素共同作用于土壤呼吸,且物理去除林下植被相比于化学去除能更大程度降低桉树人工林土壤总呼吸速率,降低森林土壤碳排放。[Objective]This study aims to investigate the impact of different understory vegetation management measures on soil respiration and its components in Eucalyptus urophylla×E.grandis plantation on Leizhou Peninsula,so as to provide a reference for accurate evaluation of soil carbon cycle in Eucalyptus plantation.[Method]Understory vegetation removal was conducted in 2 ways(physical removal and herbicide treatment)in E.urophylla×E.grandis plantation,and the non-removal group was used as the control.The LI-8100A automatic soil carbon flux measurement system was used to continuously monitor total soil respiration and its component rates,soil temperature and humidity(5 cm deep)for 1 year.[Result]Physical and chemical removal of understory vegetation significantly reduced total soil respiration and its components(except chemical removal of root respiration)(P<0.01).In addition,the total soil respiration rate of physical removal(3.45μmol·m^(−2)·s^(−1))was significantly lower than that of chemical removal(4.15μmol·m^(−2)·s^(−1))(P<0.01).There was no significant difference between the two approaches in mineral soil respiration rate and litter layer respiration rate.The root respiration rate showed physical removal(1.02μmol·m^(−2)·s^(−1))was significantly lower than that of chemical removal(1.37μmol·m^(−2)·s^(−1))(P<0.05).The contribution rates of litter layer respiration,mineral soil respiration,and root respiration to total soil respiration were 36.45%−39.40%,26.34%−31.29%,and 30.10%−39.40%,respectively.The highest value of total soil respiration rate and its components occurred in the rainy season(April−October)and the lowest value of root respiration rate occurred in July and August.The fitting model of soil total respiration rate with soil temperature and humidity was the best,which could explain 75.1%(physical removal),60.9%(chemical removal)and 57.1%(control)of the variation of soil total respiration rate.The temporal variation of litter respiration rate was mainly controlled by

关 键 词：林下植被去除 土壤呼吸 土壤温度 土壤湿度 尾巨桉人工林 

分 类 号：S714.5[农业科学—林学]