华西雨屏区光皮桦林土壤呼吸对模拟氮沉降的响应  

Responses of Soil Respiration to Nitrogen Fertilization in Betulah luminifera Forest,Rainy Area of West China

作　　者：雒守华[1] 胡庭兴[1] 张健[1] 戴洪忠[1] 涂利华[1] 李仁洪[1] 黄立华[1] 

机构地区：[1]四川农业大学林学院,四川省林业生态l工程重点实验室,四川雅安625014

出　　处：《农业环境科学学报》2010年第9期1834-1839,共6页Journal of Agro-Environment Science

基　　金：国家“十一五”重大科技支撑计划项目(2006BA01A11-03);四川省重点学科建设项目(SZD0419)

摘　　要：从2008年1月至12月,对华西雨屏区光皮桦（Betula luminifera）林进行了模拟氮沉降试验,应用LI-8100土壤碳通量分析系统和气压过程分离（Barometric Process Separation,BaPS）技术分别研究了4个氮沉降水平0（CK）、5（L）、15（M）、30（H）g N.m^-2.a^-1下土壤呼吸的日变化和月动态。结果表明,土壤呼吸具有明显的季节动态,各处理土壤呼吸最高值均出现在7月份;氮沉降初期,各处理土壤呼吸差异不明显,5月份以后各氮沉降处理土壤呼吸开始表现出抑制效应,随着施氮浓度的增加,抑制效应愈加明显（CK〉L〉M〉H）;土壤呼吸日变化基本呈现单峰曲线,呼吸速率最高值一般出现在14：00—16：00。随着氮沉降的增加,对土壤呼吸产生的抑制效应增强,这可能与光皮桦林土壤本身的氮素状态有关。各处理土壤呼吸速率与土壤温度呈极显著指数正相关关系,对土壤呼吸与土壤温度和湿度的偏相关分析得出,温度能解释土壤呼吸的大部分变异（50.1%-79.8%）,是影响光皮桦林土壤呼吸的主导因子。随着氮沉降浓度的增加,土壤呼吸的Q10值减小,表明氮沉降可能降低了土壤呼吸的温度敏感性。Responses of soil respiration to simulated atmosphere nitrogen（N）deposition in Betula luminifera forest in rainy area of west Chi-na were studied from January to December in 2008.The LI-8100 Automated Soil CO2 Flux System and Barometric Process Separation（BaPS） technique were used to quantify the daily and monthly variation of soil respiration respectively,following four-levels of N deposition treatment 0（Control Check,CK）,5（Low-N,L）,15（Medium-N,M）,30（High-N,H）g N.m-2.a-1.Twelve plots,each with 3 m×3 m dimensions were established,surrounded by a 3 m wide buffer strip.Ammonium nitrate solution was sprayed monthly as 12 equal applications over the entire year.Results showed that：Soil respiration exhibited a clear seasonal pattern,with the highest rate observed in July in every treatment.Soil respiration exhibited significant repressive effect following the increment of N.For instance,the treatment of L,M,H was 27.6%,35.9%,47.7% lower than CK in July.Also daily variation of soil respiration from July to November,exhibited a similar pattern with a single-peak curve.The mean values of daily variation also revealed a negative response to increasing level of N addition.This result might imply the N saturation-response mechanisms of B.luminifera forest in rainy area of west China.Temperature was the leading factor of soil respiration vari-ation,could explain 50.1%~79.8% monthly variation of soil respiration.Then,following the N gradient the Q10 values decreased,indicated N deposition might reduce the temperature sensitivity of soil respiration.

关 键 词：氮沉降 土壤呼吸 光皮桦 华西雨屏区 

分 类 号：S714[农业科学—林学]