长期施氮对暖温带油松林土壤呼吸及其组分的影响  

Effects of Long-Term Nitrogen Application on Soil Respiration and Its Components in Warm-Temperate Forest of Pinus tabulaeformis

作　　者：杨璐 汪金松 赵博[1] 赵秀海[1] Yang Lu;Wang Jinsong;Zhao Bo;Zhao Xiuhai(Research Center of Forest Management Engineering of National Forestry and Grassland Administration, Beijing Forestry University Beijing 100083;Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences Beijing 100101)

机构地区：[1]北京林业大学国家林业和草原局森林经营工程技术研究中心,北京100083 [2]中国科学院地理科学与资源研究所生态系统网络观察与模拟重点实验室,北京100101

出　　处：《林业科学》2021年第1期1-11,共11页Scientia Silvae Sinicae

基　　金：国家重点研发计划重点专项项目(2017YFC0504103);中央高校基本科研业务费专项资金(BJFUKF201913)。

摘　　要：【目的】比较长期施氮下不同氮水平间暖温带油松天然林土壤呼吸速率、自养呼吸速率和异养呼吸速率差异,揭示土壤呼吸各组分变化的主要影响因子,以期为评价区域森林长期施氮对土壤呼吸的影响提供科学依据。【方法】在山西太岳山油松天然林进行10年(2009—2018)的氮添加试验,设置4个氮添加处理:对照(CK,0 kg N·hm-2 a-1)、低氮(LN,50 kg N·hm-2 a-1)、中氮(MN,100 kg N·hm-2 a-1)和高氮(HN,150 kg N·hm-2 a-1),于2016—2018年生长季对土壤呼吸速率、自养呼吸速率和异养呼吸速率进行监测。【结果】在长期(8~10年)施氮下,相比对照,LN、MN和HN处理的年均土壤呼吸速率分别降低21.9%、27.3%和29.1%,年均异养呼吸速率分别降低21.8%、36.6%和31.4%,而土壤自养呼吸速率未改变,土壤pH值下降0.07、0.37、0.78个单位,微生物生物量碳含量下降了11.3%、14.5%、14.7%,但长期施氮未改变土壤有机碳、全氮和细根生物量;异养呼吸速率与土壤微生物生物量碳及自养呼吸速率与细根生物量均呈显著的线性正相关(P<0.01);不同处理下土壤自养呼吸速率和异养呼吸速率与土壤温度均呈显著的指数正相关(P<0.05);长期施氮可提高土壤自养呼吸的温度敏感性(Q10)(CK=2.19、LN=2.90、MN=2.86、HN=2.34),但会降低土壤异养呼吸的Q10值(CK=2.72、LN=2.23、MN=2.12、HN=2.27);土壤呼吸速率与土壤湿度的关系不显著;土壤温度和土壤湿度双因子模型可分别解释自养呼吸速率和异养呼吸速率的28.7%~42.0%(P<0.05)和64.9%~78.1%(P<0.001)。【结论】长期施肥未明显改变土壤自养呼吸速率。长期施氮通过抑制土壤异养呼吸使土壤总呼吸降低。长期氮添加对自养呼吸和异养呼吸Q10的影响不一致,而呼吸底物的可利用性和土壤微生物活性的变化是主要因素。为提高土壤呼吸及其组分预测模型的精度,应综合考虑细根生物量及呼吸底物的长期变化。【Objective】The objective was to explore the differences of soil respiration and its components among different levels of nitrogen addition of the natural forest of Pinus tabulaeformis under long-term nitrogen enrichment,to reveal the main influencing factors of the changes in the respiration of soil components,and to provide a scientific basis for evaluating the effect of long-term nitrogen application on soil respiration in regional forests.【Method】We conducted a 10-year nitrogen addition experiment(2009-2018)in a P.tabulaeformis forest in Taiyue Mountain,Shanxi Province,with four levels of nitrogen addition including control(CK,0 kg N·hm-2 a-1),low nitrogen(LN,50 kg N·hm-2 a-1),medium nitrogen(100 kg N·hm-2a-1),and high nitrogen(HN,150 kg N·hm-2 a-1).Soil respiration and its components were measured monthly in growing seasons from 2016-2018.【Result】Mean annual soil respiration rate was significantly decreased by 21.9%,27.3%,and 29.1%;and mean annual heterotrophic respiration rate was significantly reduced by 21.8%,36.6%,31.4%under LN,MN and HN,respectively,compared with the control.Long-term nitrogen addition had no significant effect on soil autotrophic respiration rate.Meanwhile,soil pH and soil microbial biomass carbon were significantly decreased by 0.07,0.37,0.78 units and 11.3%,14.5%,14.7%under LN,MN and HN,respectively relative to the control.However,soil organic carbon,total nitrogen and fine root biomass were not altered by nitrogen enrichment.There was a significant linear relationship between heterotrophic respiration and soil microbial biomass carbon;autotrophic respiration also exhibited a significant linear correlation with fine root biomass.The long-term nitrogen addition significantly increased temperature sensitivity(Q10)of soil autotrophic respiration(CK=2.19,LN=2.90,MN=2.86,HN=2.34),but decreased the Q10 values of soil heterotrophic respiration(CK=2.72,LN=2.23,MN=2.12,HN=2.27).Soil respiration were not correlated with soil moisture(P>0.05).In addition,two-factor models combini

关 键 词：长期施氮 油松天然林 自养呼吸 异养呼吸 温度敏感性 

分 类 号：S718.56[农业科学—林学]