模拟氮沉降对落叶松人工林土壤呼吸的影响  

Effect of Simulated N Deposition on Soil Respiration in a Larix olgensis Plantation Forest

作　　者：张娇[1] 郝龙飞[1] 王庆成[1] 付娇娇[1] 朱凯月 

机构地区：[1]东北林业大学林学院,哈尔滨150040

出　　处：《植物研究》2016年第4期596-604,共9页Bulletin of Botanical Research

基　　金：国家"十二五"科技支撑项目(2011BAD37B02)~~

摘　　要：在东北林业大学帽儿山实验林场26年生落叶松人工林中,连续2年(2013~2014年)施加NH_4NO_3模拟氮沉降试验((对照(CK,0 g·m^(-2)·a^(-1)N)、低氮(N1,5 g·m^(-2)·a^(-1)N)、中氮(N2,10 g·m^(-2)·a^(-1)N)、高氮(N3,15 g·m^(-2)·a^(-1)N)),研究不同氮沉降水平对土壤呼吸的影响。结果表明:(1)2013年模拟氮沉降处理均促进年平均土壤呼吸速率(P<0.05);(2)2014年中氮和高氮处理抑制年平均土壤呼吸和异养呼吸速率(P<0.05),低氮处理促进年均土壤呼吸速率(P<0.05),对异养呼吸速率影响不显著(P>0.05);(3)土壤微生物生物量碳在低氮处理下显著提高(P<0.05),在中氮和高氮处理下与对照间差异不显著(P>0.05);(4)土壤呼吸速率与5和10 cm土壤温度呈指数正相关关系(P<0.01),相比对照,各土层土壤呼吸温度敏感系数(Q_(10))均在低氮处理下增加,在中氮和高氮处理下则降低。不同水平的模拟氮沉降改变了土壤呼吸速率及其温度敏感性,表明短期内低水平氮沉降可加快土壤碳排放过程,相对较高水平氮沉降则减缓土壤碳排放过程。A two-year simulated N deposition experiment was conducted to explore the effects of different levels of nitrogen（N） deposition on soil respiration, with four different N supply levels, including control （CK, 0 g·m-2·a-1N）, low（N1 5 g·m-2·a-1N）, intermediate（N2, 10 g·m-2·a-1N）and high level（N3, 15 g·m-2·a-1 N） , in a 26-year-old Larix olgensis plantation forest in Mao＇ ershan experimental forest farm of northeast forestry university. Average annual soil respiration rate under different treatments was significantly promoted in the first year （ P 〈 0.05 ） ; Average annual soil respiration rate and heterotrophic respiration rate were significantly decreased under N2 and N3 treatments （ P 〈 0. 05 ）, respectively, and average annual soil respiration rate was significantly increased （P 〈 0. 05 ）, heterotrophic respiration rate had no difference compared with control（P 〉0.05）under N1 treatment, in the second year. Soil microbial biomass carbon was significantly increased under N1 treatment （ P 〈 0.05 ） , while N2 and N3 had no difference compared with control （ P 〉 0.05 ） ; Significantly positive exponential relationship was detected between soil respiration and soil temperature in 5 and 10 cm（P 〈0.01 ）. The temperature sensitivity of soil respiration（ Q10 ）in both soil layer was increased under N1 treatment and decreased under N2 and N3 treatments compared with control, respectively. Soil respiration rate and its temperature sensitivity were altered under different N deposition levels,suggesting that the progress of soil carbon emission was accelerated under low levels of N deposition and slowed down under relatively high levels of N deposition in a short period.

关 键 词：落叶松(Larix olgensis) 人工林 氮沉降 土壤呼吸 根呼吸 异养呼吸 

分 类 号：S718.55[农业科学—林学] S714.5