西双版纳橡胶林土壤呼吸季节变化及其影响因子  

Seasonal Change of Soil Respiration and Its Influence Factors in Rubber (Hevea brasiliensis) Plantation in Xishuangbanna,SW China

作　　者：周文君[1] 沙丽清[1] 沈守艮[1] 郑征[1] 

机构地区：[1]中国科学院西双版纳热带植物园

出　　处：《山地学报》2008年第3期317-325,共9页Mountain Research

基　　金：云南省自然科学基金(2004C0052M);中国科学院知识创新工程重大项目(KZCX1-SW-01)资助~~

摘　　要：橡胶(Hevea brasiliensis)林是热带地区重要的经济林,其土壤碳排放除受温度、湿度等非生物因子影响外,还受到橡胶林独特物候特征的影响。为探讨橡胶林土壤呼吸季节变化与生物、非生物因子的关系,本实验再西双版纳橡胶林内设去除凋落物(NL)和对照(CK)两种处理,自2005-08到2006-08,用IRGA法测定土壤呼吸速率(SR),同时测定温、湿度因子;记录橡胶林的物候节律;每月中旬测定叶面积指数;进行为期一年的细根生长和分解试验。结果表明:1)两种处理SR有明显的季节变化,且趋势相同,即雨季(CK:14.10mgCO2·m-2·min-1;NL:13.00mgCO2·m-2·min-1)>干热季(CK:9.91mgCO2·m-2·min-1;NL:9.70mgCO2·m-2·min-1)>雾凉季(CK:10.87mgCO2·m-2·min-1;NL:10.33mgCO2·m-2·min-1);2)通过温度、湿度与SR的相关分析和回归方程模拟,表明两处理各季节SR与温度因子、湿度因子相关关系不同;影响SR的主导因子在雨季为湿度因子,雾凉季是温度因子,干热季SR受到温、湿度因子的双重制约。3)在雨季,凋落物对土壤呼吸影响显著(p=0.036),在干热季和雾凉季影响不显著(p=0.701,p=0.308);4)细根生长试验和LAI的测定结果表明两处理的土壤呼吸速率季节变化与橡胶树生长节律基本一致,生长旺盛期(雨季,5～10月)>生长减缓期(雾凉季,11～12月)>生长恢复期(干热季,3～4月)>相对休眠期(雾凉季,1～2月);5)通过主成分分析,土壤呼吸源的季节变化是影响橡胶林土壤呼吸的第一主成分,方差贡献率为65.98%,第二主成分是地上部分光合产物的输入,方差贡献率为34.02%。两成分可完全解释土壤呼吸的季节变化。故橡胶林的SR季节变化是温度因子、湿度因子及橡胶树生长季相变化协同作用的结果。One-year in-situ study was carried out to investigate the seasonal variation of soil respiration rate （SR） and its relationship with abiotic factors and biotic factors in rubber plantation in Xishuangbanna, Southwest China. Two treatments were designed： with litter （CK） and no litter （NL）. SR was measured by IRGA from Aug. 2005 to Aug. 2006, and soil temperature at 5 cm depth （ T5 ） , cell temperature （Tcell） , soil volumetric water content （ SWC ） were observed concurrently, The rubber phenology including Leaf area index and the dynamics of fine root growth and died fine roots decomposition were observed for one year. Results showed： 1. SR of both treatments were relatively high during the rainy season （May- Oct. CK： 14.10 mg CO2 · m^-2 · min^-1 ; NL：13.00 mg CO2 ·m^ -2·min^-1 ）, low in the fog-cool season（Nov. - Feb. CK：9.91 mgCO2 ·m^-2 ·min^-1 ; NL：9.70mgCO2 ·m^-2·min^ -1 ） , and intermediate in the dry season （Mar. - Apr. CK： 10.87 mg CO2 · m^2 · min^-1 ; NL： 10.33 mg CO2 · m^-2 · min^-1）. 2. Regression analysis demonstrated that the relationship between SR and T or SWC were different in three seasons, and the rate of SR was predominantly controlled by SWC in rainy season, by temperature in the fog-cool season, and by both in the dry season of the both treatments. 3. Contribution of above - ground litter decomposition to soil respiration varied seasonally （p 〈 0.01 ）, with a rank of rainy season （7. 92% ） 〉 dry season （5.22%） 〉 fog-cool season （ 1.74% ） , which affected by the seasonal input and decomposition of above-ground litter. 4. SR seasonal dynamics of NL and CK were similar to the rubber tree growth dynamics, that was the SR in rubber main growth phase （ May - Oct. , rain season） 〉 late growth phase （ Nov. - Dec. , early fog-cool season） 〉 early growth phase （Mar. - Apr. , dry season） 〉 resting phase （Jan. ＆ Feb. late fog-cool season）. 5. Based on principal components analysis （PCA） , the

关 键 词：橡胶林 土壤呼吸 生长节律 温度 土壤含水量 

分 类 号：S718.5[农业科学—林学]