鼎湖山森林演替序列水文过程中总有机碳(TOC)变化规律及其对土壤碳平衡的贡献(英文)  

Dynamics of total organic carbon (TOC) in hydrological processes and its contributions to soil organic carbon pools of three successional forest ecosystems in southern China

作　　者：乔玉娜[1,2] 尹光彩[1,3] 罗艳[1] 刘艳 

机构地区：[1]中国科学院华南植物园,广东广州510650 [2]中国科学院研究生院,北京100049 [3]广东工业大学环境科学与工程学院,广东广州510006 [4]广西水土保持监测总站,广西南宁530023

出　　处：《生态环境学报》2009年第6期2300-2307,共8页Ecology and Environmental Sciences

基　　金：supported by National Basic Research Program of China (No. 2009CB421101);Natural Science Founda-tion of China (40730102, 30725006);Natural Sci-ence Foundation of Guangdong province (8351065005000001)~~

摘　　要：森林水文过程中的总有机碳转运对土壤有机碳平衡起着重要的作用,但我们对于水文过程对碳平衡的贡献机理所知甚少。本研究针对鼎湖山季风常绿阔叶林演替序列不同森林生态系统(马尾松林、针阔混交林和季风常绿阔叶林(简称季风林))的大气降水、穿透水、树干流、凋落物淋洗水以及地表径流中的总有机碳(TOC)进行了三年(2002年4月—2005年5月)观测,以此来分析水文学过程中TOC的变化规律和水文学过程对不同成熟度森林生态系统土壤有机碳积累的贡献。每场雨后进行水样的采集,采集的水样装入棕色玻璃瓶中,加硫酸至pH值小于2,放置于实验室冰箱冷藏待测。TOC用日本岛津公司生产的5000A型TOC-Ⅴ分析仪测定。研究结果及推论如下:鼎湖山森林水文学过程中TOC浓度和总量变化呈现规律性的变化。大气降水中的TOC浓度和总量分别为(3.65±0.59)mg·L-1和51.8104kg·hm-2·a-1,大气降水是鼎湖山森林生态系统水文循环过程中TOC的主要来源。穿透水(DTF)中TOC浓度和总量均为:松林>混交林>季风林,其中季风林TOC浓度显著低于其他两种林型。松林树干流的TOC浓度显著高于混交林和季风林。凋落物淋洗水TOC浓度和总量大小依次均为:松林>混交林>季风林,且三林型间存在显著差异(p<0.05)。径流中TOC浓度和总量均较小,且无明显差异。在湿季5月份,穿透水、树干流、凋落物淋洗水的TOC浓度呈现下降趋势。干季(10月)开始以后,穿透水、树干流、凋落物淋洗水中的TOC浓度又逐步回升。地表径流中TOC浓度干湿季变化趋势不明显。干季中各水文学分量TOC浓度大于湿季,但TOC总量呈现相反趋势。在森林水文学过程中,凋落物淋洗水所携带的有机碳量是土壤有机碳输入的最大项,季风林、混交林、松林中TOC总量分别为246.983kg·hm-2·a-1,255.187kg·hm-2·a-1和261.876kg·hm-2·a-1;其次是直接到达土壤表面The dynamics of total organic carbon （TOC） in hydrological processes are important for understanding carbon cycling in forest ecosystems. TOC was monitored in precipitation, throughfall, stemflow, litter leachate and runoff in subtropical climax forest ecosystem-monsoon evergreen broad-leaved forest （MBF）, and its two successional forests of natural restoration-mixed Pinus massonniana/broad-leaved forest （PBF）, and Pinus massoniana forest （PF） at Dinghushan Nature Reserve （DNR） in southern China for 3 years （from April, 2002 to May, 2005）. The major results and conclusions are as follows： TOC concentrations and fluxes of throughfall （DTF）, stemflow, and litter leachate in PF were higher than those in MBF and PBF. TOC concentrations in dry season were higher than that in rainy season, while TOC fluxes were in opposite situation. The contributions of different hydrological processes to forest SOC pools decreased in the order： litter leachate 〉DTF 〉stemflow. Forest canopy and litterappeared to be important sources for TOC. Therefore, large TOC fluxes imported to soils with small amount of outputs by runoff may result in SOC accumulation. The net inputs of organic carbon to soil profile from the hydrological processes in MBF, PBF and PF were （27.1 ± 1.65） g·m^-2 ·a^-1, （28.9 ± 2.79） g·m^-2 ·a^-1, （30.2 ± 2.65） g·m^-2 ·a^-1, respectively. This part of carbon is usually negligible because it is only a small proportion of SOC. However, this part of carbon could be imported into the soil through infiltration. Through soil filtration and adsorption, carbon should be distributed in soil evenly, which is helpful to long-term preservation of SOC.

关 键 词：鼎湖山 森林演替 水文过程 TOC浓度 TOC总量 

分 类 号：Q948[生物学—植物学]