摘要
研究不同海拔土壤有机碳矿化对深入认识不同海拔森林土壤有机碳动态变化具有重要意义.本文以武夷山低海拔和高海拔森林土壤为研究对象,通过室内模拟其在各自年平均气温(17、9℃)条件下的矿化培养试验,探讨土壤有机碳矿化特征的差异.结果表明:培养126 d后,尽管高海拔森林土壤的有机碳含量显著高于低海拔森林土壤,但低海拔和高海拔森林土壤在各自环境温度背景下的有机碳累积矿化量并无显著差异.一级动力学方程均能较好地模拟高低海拔森林土壤有机碳矿化特征,高海拔和低海拔森林土壤有机碳潜在矿化量(CP)和矿化速率常数均无显著差异,但低海拔土壤C_P/SOC值和矿化率显著高于高海拔土壤,表明在环境温度背景下,低海拔土壤固碳能力低于高海拔土壤.随着培养时间增加,高海拔土壤微生物生物量碳和微生物熵显著高于低海拔土壤,表明高海拔土壤微生物的碳同化量高于低海拔土壤微生物,有利于有机碳的积累.高海拔森林土壤中的β-葡萄糖甘酶和纤维素水解酶高于低海拔森林土壤,说明高海拔土壤微生物可能更多地分解活性碳.未来气候变暖可能暗示着会降低高海拔土壤有机碳固碳能力和微生物碳利用效率,从而导致土壤有机碳储量下降.
Examining the variations of soil organic carbon mineralization at different altitudes iscrucial for better understanding of soil organic carbon （SOC） dynamics. We selected the lowaltitude and high altitude broad-leaved forest soils in Wuyi Mountains as the research object, and incubated them under particular annual average temperature （17 and 9 ℃, respectively） in laboratory to investigate the difference of SOC mineralization characteristics. The results showed that the cumulative SOC mineralization had no significant difference between forest soils at low and highaltitude in a 126-day incubation period under ambient temperature. Soil organic carbon content of high altitude soil was significantly higher than that from low altitude. The dynamics of SOC mineralization could fitted by the firstorder kinetics. Both mineralization potential （C-P） and mineralization rate constant （K） values of two soils had no significant difference, but CP/SOC value and mineralization ratio were significantly higher at low altitude, indicating that the carbon sequestration capacity of low altitude soil was relatively lower than that of high altitude under ambient temperature. Soilmicrobial biomass carbon and microbial quotients were significantly higher than that of low altitude with the increase of incubation time, indicating that the ability of microbial carbon assimilation was greater at high altitude. On the other hand, the activities of β-1,4glucosidase and cellobiohydrolase in high altitude soil were higher, suggesting that more labile carbon would be decomposed by soil microbes. The carbon sequestration capacity andmicrobial carbon utilization efficiency in highaltitude soil would be reduced and thus result in adecline of soil organic carbon storage under the scenarios of climate warming.
出处
《应用生态学报》
CAS
CSCD
北大核心
2018年第3期748-756,共9页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(U1405231)
国家重点研发计划项目(2016YFD0600204)资助~~
关键词
有机碳矿化
海拔
微生物熵
代谢熵
酶活性
年均温
soil organic carbon mineralization
elevation
microbial quotient
soil metabolicquotient
enzymatic activity
mean annual temperature.
