模拟增温和改变降雨频率对干旱半干旱区土壤呼吸的影响

Effects of simulated temperature increase and change of rainfall frequency on soil respiration in arid and semi-arid areas

温度和降水是干旱半干旱区土壤呼吸的重要扰动因子,全球气候变化导致的未来干旱半干旱区增温和降水变率增大对土壤呼吸有着重要影响。研究通过人工设置P_(16×2.5mm)、P_(8×5mm)、P_(4×10mm)、P_(2×20mm)、P_(1×40mm)的降雨频率梯度和增温2℃左右的控制试验,探讨不同降雨频率和增温处理对干旱半干旱区土壤呼吸的影响,以及土壤呼吸与土壤温湿度的关系及其对降雨频率改变的响应。结果表明:降雨频率和增温单独对土壤呼吸具有极显著影响(P<0.001),但是两者之间并无交互作用(P>0.5);在降雨量一定的情况下,土壤呼吸速率随着降雨频率的减小而减小,即多频率小降雨事件激发的土壤呼吸速率大于小频率大降雨事件;增温促进土壤呼吸,提高了约11%的土壤呼吸。本结果有助于对未来干旱半干旱地区全球变暖背景下降雨格局的改变对土壤呼吸产生的影响进行预测,同时也为进一步估算该区域生态系统的碳收支提供参考数据。

Temperature and precipitation are important disturbance factors for soil respiration in arid and semiarid regions.The future increase in temperature and precipitation variability in arid and semi-arid regions caused by global climate change will have an important impact on soil respiration.The study was conducted through the artificial setting of P_(16×2.5mm),P_(8×5mm),P_(4×10mm),P_(2×20mm)and P_(1×40mm)rainfall frequency gradient and OTC temperature in‐crease of about 2℃.The study explored the effect of different rainfall frequency and temperature increase treat‐ment on the drought.The influence of soil respiration in arid areas,as well as the relationship between soil respi‐ration and soil temperature and humidity,and its response to changes in rainfall frequency.The results show that:rainfall frequency and warming alone have a very significant effect on soil respiration(P<0.001),but there is no interaction between the two(P>0.5);under a certain rainfall,the soil respiration rate increases with Rain‐fall frequency decreases and decreases,that is,the soil respiration rate triggered by multi-frequency small rain‐fall events is greater than that of small-frequency heavy rainfall events;increasing temperature promotes soil res‐piration and improves soil respiration by about 11%.This result is helpful to predict the impact of changes in rain‐fall patterns on soil respiration under the background of global warming in arid and semi-arid regions,and also provides reference data for further estimating the carbon budget of the regional ecosystem.