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[目的]研究土壤呼吸对气候变暖和干旱的响应,阐明全球气候变化与土壤碳排放之间的反馈关系。[方法]采用红外辐射增温和林内穿透雨减少技术模拟气候变暖和干旱,通过LI-8100土壤CO2通量测定系统对生长季土壤呼吸速率进行观测,分析了干旱年不同处理(对照、增温+减雨、增温、减雨)对土壤呼吸速率的影响。[结果]显示:生长季,以上4种处理的土壤呼吸速率分别为1.78、1.84、2.02和2.01μmol·m~(-2)·s~(-1),5 cm土壤温度和土壤湿度分别可以解释土壤呼吸速率变异的68.2%87.5%和51.0%66.6%。干旱期,以上4种处理的土壤呼吸速率均低于生长季,增温处理降低了土壤呼吸速率与土壤温度的相关性,但增加了土壤呼吸速率与土壤湿度的相关性。[结论]干旱年内,土壤温度和湿度是影响该区土壤呼吸速率的主要环境因子,干旱期增温处理引起土壤湿度对土壤呼吸的限制作用削弱了气候变暖与土壤碳排放之间的正反馈作用。
[Objective] The research aimed to study the response of soil respiration to climate warming and drought and clarify the feedback relationship between global climate change and soil carbon emission. [Method] The climate warming and drought were simulated by infrared radiation warming and in-forest penetration rain reduction. The soil respiration rate in growing season was observed by LI-8100 soil CO2 flux measurement system. The effects of different treatments in drought year Temperature + rainfall, warming, rainfall) on soil respiration rate. [Result] The results showed that in the growing season, the soil respiration rates of the above four treatments were 1.78, 1.84, 2.02 and 2.01 μmol · m -2 · s -1, respectively, and the soil temperature and soil moisture at 5 cm Explain 68.2% 87.5% and 51.0% 66.6% of the variance of soil respiration rate. During the drought period, the soil respiration rates of the above four treatments were lower than those of the growing season, and the warming treatments reduced the relativity of soil respiration rate and soil temperature, but increased the relativity of soil respiration rate and soil moisture. [Conclusion] The soil temperature and humidity were the main environmental factors affecting the soil respiration rate during the drought year. The limiting effect of soil moisture on soil respiration caused by warming during the drought period weakened the positive feedback between climate warming and soil carbon emission effect.