板栗林土壤不同组分呼吸对氮添加的响应

Response of soil respiration of different components to nitrogen addition in a Castanea mollissima plantation

通过原位进行控制、低氮和高氮(0,60,240 kg/(hm2·a))3个氮添加处理,采用挖壕沟法区分自养呼吸,研究板栗林土壤不同组分呼吸对氮添加的响应机制。结果表明:1)氮添加处理对土壤温度和湿度的影响均不显著(P>0.05);2)在控制处理样地中,土壤呼吸、异养呼吸和自养呼吸速率分别为(3.47±0.09)、(2.26±0.10)和(1.21±0.16)μmol/(m2·s),土壤不同组分呼吸对氮添加处理有不同的响应,低氮添加显著促进了土壤呼吸及不同组分呼吸(P<0.05),高氮添加则显著抑制了土壤呼吸及异养呼吸(P<0.01),而对自养呼吸无显著影响(P>0.05);3)在控制处理样地中,土壤呼吸、异养呼吸和自养呼吸的Q10值分别为2.44、1.93和4.10,氮添加处理可显著降低自养呼吸的Q10值(P<0.05),而对土壤呼吸和异养呼吸无显著影响(P>0.05)。

Three N addition treatments （0,60,240 kg/（hm^2· a）） in a Castanea mollissima plantation were applied and trench method was adopted for partitioning autotrophic respiration,which was designed to analyze the response mechanism of soil respiration of different components to nitrogen addition,The results showed that 1） nitrogen addition had no significant influence on soil temperature and moisture（P 〉 0.05） ; 2） total soil respiration,heterotrophic and autotrophic respiration rates in the control plot were （3.47 ± 0.09）,（2.26 ± 0.10） and （1.21 ± 0.16） μmol/（m^2· s）,respectively.The response of soil respiration of different components to nitrogen addition treatments varied.Low-N addition significantly stimulated total soil respiration,heterotrophic and autotrophic respiration （P 〈 0.05）,in contrast to that high-N addition significantly suppressed total soil respiration and heterotrophic respiration （P 〈 0.01）,but had no influence on autotrophic respiration （P 〉 0.05）.3） The Qt0 values of total soil respiration,heterotrophic and autotrophic respiration were 2.44,1.93 and 4.10,respectively.Nitrogen addition treatments significantly decreased Q10 value of autotrophic respiration （P 〈0.05）,but had no significant influence on total soil respiration and heterotrophic respiration.