土壤呼吸是陆地生态系统碳循环的关键指标,决定了土壤源二氧化碳(CO_2)进入大气的通量,对预测全球气候变化背景下区域乃至全球碳循环变化具有重要意义.本文通过室内短期培养试验测定了中国北方草地样带土壤样品的呼吸速率,研究了北方草地土壤呼吸的区域尺度格局及其与主要调控因子的关系.结果表明:土壤呼吸速率自西向东随年均降水量(MAP)增加呈逐渐增加的趋势,变化范围为0.35 ~ 2.09 mug CO_2 -C·g~(-1)·h~(-1).其中,MAP <100 mm 时,土壤呼吸速率为0.35 ~ 0.73 mug CO_2 -C·g~(-1)·h~(-1);100 mm
英文摘要:
Soil respiration is one of the most important variables in terrestrial ecosystem progresses and global carbon cycle,and determines the CO_2 flux from soil to atmosphere.Soil respiration also has great implications for predicting regional and even global carbon cycle changes under the background of global climate change.We measured respiration rates of soil samples collected from northern China grassland transect by short term incubation experiment in laboratory.Results showed that soil respiration rates increased with mean annual precipitation (MAP) from west sites to east sites,ranging from 0.35 to 2.09 mug CO_2 -C ·g~(-1)·h~(-1).The variation range of soil respiration rates were 0.35 -0.73 mug CO_2 -C ·g~(-1)·h~(-1) with MAP <100 mm,0.57 -0.98 mug CO_2-C ·g~(-1)·h~(-1) with MAP between 100 mm and 200 mm and 0.83-2.10 mug CO_2 -C·g~(-1)·h~(-1) with MAP >300 mm,respec-tively.Soil respiration had a significant positive relationship with MAP,aboveground biomass,soil organic carbon and nitrogen content,while had a negative relationship with mean annual temperature and soil pH.Analysis of boosted regression tree showed that the predictors accounted for the explained variation included MAP (25.5%),aboveground biomass (23.6%),soil organic carbon content (18.3%) and soil organic nitrogen content (12.5%),and soil pH and mean annual temperature only explained 10.8% and 9.2% of the total variation,respectively.