施氮对桉树人工林生长季土壤温室气体通量的影响  

Effects of nitrogen application on soil greenhouse gas fluxes in a Eucalyptus plantation during the growing season

作　　者：李睿达 张凯[1,2] 苏丹[1,2] 逯非[1] 万五星[1,3] 王效科[1] 郑华[1] 

机构地区：[1]城市与区域生态国家重点实验室中国科学院生态环境研究中心,北京100085 [2]中国科学院大学,北京100049 [3]河北师范大学生命科学学院,石家庄050016

出　　处：《生态学报》2015年第18期5931-5939,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金(31170425);中国科学院知识创新工程重要方向项目(KZCX2-EW-QN406);中国科学院战略性先导科技专项子课题(XDA05060102)

摘　　要：施肥是维持短期轮伐人工林生产量的重要手段,为了提高肥料利用效率,缓释氮肥逐渐成为广泛采用的氮肥种类。评估缓释肥施用对人工林生长季土壤温室气体通量的影响对于全面评估人工林施肥的环境效应具有重要意义。以我国南方广泛种植的桉树林为对象,采用野外控制实验研究了4种施氮处理(对照CK:0 kg/hm2;低氮L:84.2 kg/hm2;中氮M:166.8 kg/hm2;高氮H:333.7 kg/hm2)对土壤-大气界面3种温室气体(CO2、N2O和CH4)通量的影响,结果表明:(1)4种施氮水平下CO2排放通量、N2O排放通量和CH4吸收通量分别为276.84—342.84 mg m-2h-1、17.64—375.34μg m-2h-1和29.65—39.70μg m-2h-1;施氮显著促进了N2O的排放(P<0.01),高氮处理显著增加CO2排放和显著减少CH4吸收(P<0.05),且CO2排放通量与CH4吸收通量随着施氮量的增加分别呈现增加和减少的趋势;(2)生长季CO2和N2O排放呈现显著正相关(P<0.01),CO2排放和CH4吸收呈现显著负相关(P<0.05),N2O排放和CH4吸收呈现显著负相关(P<0.01);(3)土壤温度和土壤水分是影响CO2、N2O排放通量和CH4吸收通量的主要环境因素。结果表明:施用缓释肥显著增加了桉树林生长季土壤N2O排放量,且高氮处理还显著促进CO2排放和显著抑制CH4吸收,上述研究结果可为人工林缓释肥对土壤温室气体通量评估提供参数。Fertilization plays a vital role in maintaining the productivity of short-rotation plantations. Eucalyptus plantations are one of the fast-growing and high-yield plantations around the world and are numerous in south China. In order to improve nitrogen use efficiency, slow-release nitrogen fertilizers are being widely adopted. However, few studies have been done to assess the effect of slow-release fertilizer on the soil-atmosphere exchange of greenhouse gases （ GHGs）, such as carbon dioxide （ CO2） , nitrous oxide （ N2 O）, and methane （ CH4 ）. To clarify temporal changes of soil GHGs fluxes following slow-release N fertilizer application, field control trims with four levels of N application （Control： 0 kg/hm2; Low N： 84.2 kg/hm2; Medium N： 166.8 kg/hm2; High N： 333.7 kg/hm2） were initiated in a Eucalyptus plantation in Guangxi,southern China. At the beginning of growing season, the nitrogen fertilizer, urea formaldehyde （a kind of slow-release fertilizer）, was applied according to the local fertilization practice （once a year）. Static chamber and gas chromatography techniques were used to quantify soil GHGs exchange monthly during the study period from May to November 2013. Environmental factors, such as soil temperature at 5 cm depth and soil water content at 10 cm depth, were synchronously monitored while the GHGs were collected. Before N application, no significant differences were observed for soil GHGs fluxes in all N application treatments. The results showed that （ 1 ） CO2 emission fluxes, N20 emission fluxes, and CH4 absorption fluxes under four levels of nitrogen application were 276.84--342.84 mg m-2 h-1 , 17.64--375.34 μg m-2 h-1 and 29.65--59.70 μg m-2 h-1, respectively. Fertilization resulted in a remarkable but short increase in soil respiration over the first 2 to 3 months during the observation period, and the differences in soil respiration between the High N treatment and the control treatment were significant. Nitrogen application significantly increas

关 键 词：桉树人工林 缓释氮肥 温室气体通量 

分 类 号：S792.39[农业科学—林木遗传育种]