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了解土壤微生物呼吸对极端降水的响应对深入理解全球变暖趋势下降水格局的改变对土壤碳循环的影响具有重要意义.于2015年雨季(7~9月)在长武农田生态系统国家野外站,模拟了3种雨季降水量(最高600 mm;平均300 mm;最低150 mm)条件下两种降水形式(每次10 mm:P_(10),每次150 mm:P_(150)).利用土壤碳通量测量系统(Li-COR,Lincoln,NE,USA)监测不同降水条件下土壤微生物呼吸速率及其土壤水分、温度的变化.相同次降水量条件下,土壤微生物呼吸波动因雨季降水量变化而不同.P_(150)较P_(10)波动剧烈,600 mm降水量下土壤微生物呼吸变异系数分别为36%和33%;300 mm降水量下为28%和22%,150 mm降水量下依次为43%和29%.与P_(10)相比,P_(150)土壤微生物呼吸累积量在600 mm降水量下降低20%;但150 mm降水量下增加22%,300 mm降水量下二者无显著差异.土壤累积呼吸量与水分胁迫时间长短呈显著负相关(R2=0.75).全球变暖趋势下极端性降水事件增加对土壤微生物呼吸的影响不容忽视.
Understanding the Response of Soil Microbial Respiration to Extreme Precipitation It is of great importance to understand the effects of changes in precipitation pattern under global warming trends on soil carbon cycling. In the 2015 rainy season (July-September), the Changwu Farmland Ecosystem National Field Station , Two kinds of precipitation patterns (10 mm: P 10 (150 mm each time): P 150 (150)) were simulated under three kinds of rainy season rainfall (up to 600 mm; average 300 mm; minimum 150 mm) Soil carbon flux measurement system (Li-COR, Lincoln, NE, USA) was used to monitor the changes of soil microbial respiration rate and soil moisture and temperature under different precipitation conditions.Under the same precipitation condition, the fluctuation of soil microbial respiration was affected by the precipitation in the rainy season (150) were more violent than P10 (10), and the coefficient of variation of soil microorganism respiration was 36% and 33% respectively at 600 mm precipitation, 28% and 22% at 300 mm precipitation, 150 mm precipitation Compared with P_ (10), P_ (150) respiration of soil microbial biomass decreased by 20% at 600 mm precipitation, but increased by 22% at 150 mm precipitation and 300 mm precipitation There was no significant difference between the two.The cumulative soil respiration and water stress had a significant negative correlation (R2 = 0.75) Extreme precipitation events on soil microorganism respiration can not be ignored under the warming trend.