华西雨屏区巨桉人工林土壤呼吸对模拟氮沉降的响应  

Response of Soil Respiration to Simulated Nitrogen Deposition in an Eucalyptus grandis Plantation in the Rainy Area of Western China

作　　者：向元彬[1] 黄从德[1] 胡庭兴[1] 涂利华[1] 杨万勤[1] 李仁洪[1] 胡畅[1] 

机构地区：[1]四川农业大学林学院四川省林业生态工程省级重点实验室,雅安625014

出　　处：《林业科学》2014年第1期21-26,共6页Scientia Silvae Sinicae

基　　金："十一五"国家科技支撑计划项目(2006BAC01A11;2008BADC2B01)

摘　　要：通过野外原位试验,对巨桉人工林进行为期14个月的模拟氮沉降试验,施氮量为0(CK),5(L),15(M)和30(H)g N·m-2a-1,共4个处理。每月下旬采用红外CO2分析法测定土壤呼吸速率,并定量对各处理施氮(NH4NO3)。结果表明:华西雨屏区巨桉人工林土壤呼吸速率具有明显的季节动态变化,土壤呼吸速率均为1月最低,7月最高;施氮处理3个月后,随着施氮浓度增加,氮沉降对土壤呼吸的促进效应明显,如7月份L,M和H处理较CK土壤呼吸速率分别增加8.80%,22.62%和33.17%;氮沉降使该巨桉林分土壤每年向大气释放的CO2量增加了11.93%～30.82%;2008年4,7和10月土壤呼吸速率24 h平均值均表现为CK<L<M<H;引起巨桉人工林土壤呼吸速率变异的主导因子是土壤温度,土壤温度和湿度与土壤呼吸速率的双因素模型优于单因素模型,土壤温度和湿度共同解释了巨桉人工林土壤呼吸速率月动态的76.4%～90.5%;氮沉降量的增加使Q10值增大,表明氮沉降可能使土壤呼吸的温度敏感性增强。A simulated nitrogen deposition experiment in the field was conducted in a Eucalyptus grandis stand for 14 months.The levels of nitrogen deposition were 0（CK）,5 （L）,15 （M） and 30 （H） g N m-2 · a-1 respectively.The soil respiration was measured by infrared gas analyzers,and then NH4NO3 was added into N-treated plots in the last third of each month.Results showed that：The soil respiration in E.grandis forest displayed an obvious seasonal pattern in the rainy area of western China.The lowest rate occurred in January and the highest rate In July for the all treatments.After 3 months of nitrogen deposition treatment,the soil respiration was promoted significantly,especially in July,the respiration rate of treatment L,M,and H was 8.80%,22.62%,32.41% higher than CK,respectively.CO2 releases from the soil of E.grandis forest were increased by 11.93% to 30.82% after nitrogen deposition treatment.The average soil respiration rate in 24 hour was in an order of CK 〈 L 〈 M 〈 H in April,July and October 2008.The soil temperature was a key factor affecting soil respiration variation.The 76.4% ～ 90.5% of monthly variation in soil respiration could be explained by a two-factor model which was better than single-factor models （Rs =aW ＋ b,Rs =aebt）.The Q10 values were increased correspondingly with the N addition.The result indicated that nitrogen deposition might increase temperature sensitivity of soil respiration.

关 键 词：氮沉降 巨桉 土壤呼吸 华西雨屏区 

分 类 号：S718.55[农业科学—林学]