不同经营措施对毛竹林土壤呼吸温度敏感性的影响

Effects of Different Managements on Temperature Sensitivity of Soil Respiration of Phyllostachy edulisForest

【目的】森林经营与管理降低土壤呼吸是实现CO2减排的重要手段。全球气候变暖背景下,确定不同经营措施对毛竹林土壤呼吸温度敏感性的影响有助于揭示毛竹林地下生态过程对气候变化的响应和适应,并有助于了解毛竹林土壤呼吸对气候变化的正负反馈。【方法】以无经营毛竹纯林为对照(Ⅰ),以垦复(Ⅱ)、施用除草剂(Ⅲ)、劈草(Ⅳ)毛竹纯林为研究对象,采用壕沟法和凋落物移除法区分了各组分呼吸,利用LI-8100测定了土壤呼吸速率及5cm土壤温度,并分析了土壤呼吸温度敏感性(Q10)。【结果】①土壤呼吸及组分呼吸与5cm处土壤温度呈指数相关;②土壤总呼吸Q10冬季>夏季>春季>秋季。垦复、施用除草剂、劈草均降低了土壤总呼吸温度敏感性;③根呼吸Q10夏季>冬季>春季>秋季。垦复、施用除草剂、劈草均降低了根呼吸温度敏感性;④凋落物呼吸Q10夏季>冬季>秋季>春季。垦复、施用除草剂、劈草均降低了凋落物呼吸温度敏感性;⑤矿质呼吸Q10春季>冬季>夏季>秋季。垦复增加了矿质呼吸温度敏感性,施用除草剂、劈草降低了矿质呼吸温度敏感性。【结论】相对降低土壤表面CO2通量和土壤呼吸适应未来全球气候变化而言,施用除草剂是本研究区毛竹林经营较为合理的方式。

【Objective】 Forest management is recognized as an important way to mitigate CO2 emission from soils.Under the global warming,understanding the effects of different managements on temperature sensitivity of soil respiration is helpful to determine the response and adaptation of under-ground processes to climate change and to identify the positive/negative feedbacks of soil respiration to climate change.【Method】 Our study included four treatments： control（Ⅰ）,reclamation（Ⅱ）,herbicide application（Ⅲ） and herb-chopping（Ⅳ）.Trenching and litter removal were used to separate the components of soil respiration and LI-8100 was used to measure soil respiration and soil temperature at depth of 5 cm.Exponential model was employed to describe temperature sensitivity of soil respiration（Q10）.【Results】 ① Components of soil respiration were exponential with soil temperature at depth of 5cm;② Q10 of total soil respiration was in an order of Winter 〉 Summer 〉 Spring 〉 Autumn.Reclamation,herbicide application and herb-chopping decreased Q10 of total soil respiration.③ The order of Q10 of root respiration was Summer 〉Winter 〉 Spring 〉 Autumn.All managements reduced Q10;④ Q10 of litter respiration was in an order of Summer 〉 Winter 〉 Autumn 〉 Spring.Reclamation,herbicide application and herb-chopping declined Q10;⑤ Q10 of mineral respiration was in an order of Spring〉Winter 〉 Summer 〉 Autumn.Reclamation increased Q10 while other two managements decreased Q10.【Conclusion】 Given mitigation of CO2 emission and adaptation of soil respiration to global climate change,herbicide application may be a relatively reasonable management for Moso bamboo forest in this area.