【摘要】 土壤呼吸及其对温度的敏感性是预测碳循环过程的重要参数,近年来受到了广泛关注。但在黄土高原地区,不同深度土壤微生物呼吸特征及其对温度变化响应的相关研究尚未见报道。本研究选取黄土高原云雾山草原自然保护区围封30年的典型草地作为研究地点,采集了不同深度的土壤样品(0-10、10-20、20-30、30-40、40-50、50-60cm),在室内25和35℃条件下对土壤样品进行培养,探讨不同深度土层的土壤呼吸及其对温度敏感性的变化。结果表明,土壤有机碳、全氮、有效氮、速效磷,全磷及微生物生物量碳氮含量均随土层深度的增加而显著降低(P<0.05)。随着培养时间和土层深度的增加,两个温度培养下的土壤呼吸速率和土壤呼吸累积碳释放量均显著下降(P<0.05)。然而,随着土层深度增加,土壤呼吸温度敏感性呈上升趋势。冗余分析表明,土壤呼吸速率与土壤性质均有较好的正相关,而土壤呼吸温度敏感性与各土壤因子呈负相关。更多还原

【Abstract】 Soil respiration and its temperature sensitivity are two important parameters to predict carbon cycling.In the Loess Plateau region,however,soil microbial respiration and its temperature sensitivity at different soil depths have not been investigated.This study focused on the characteristics of soil microbial respiration and temperature sensitivity at different soil depths,by taking advantage of a typical grassland in the Yunwu Mountain Natural Conservation area of the Loess Plateau,which has been fenced for 30 years.In this study,soils were sampled from different soil layers(0-10,10-20,20-30,30-40,40-50,and 50-60cm)and incubated at 25 ℃ or 35℃,and the changes of soil respiration were examined.We found that soil organic carbon,total nitrogen,available nitrogen,available phosphorus,total phosphorus,microbial biomass carbon,and microbial nitrogen contents decreased significantly with increasing soil depth(P<0.05).In addition,soil respiration rate and cumulative C loss by respiration at both temperatures significantly decreased with increasing incubation period and soil depth(P<0.05).However,temperature sensitivity showed an increasing trend with increasing soil depth.Redundancy analysis showed that soil respiration rate was positively correlated with soil properties,while temperature sensitivity of soil respiration was negatively correlated with all soil factors.更多还原