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为探明中亚热带地区常绿阔叶林演替序列土壤呼吸(Rs)的变化趋势及其影响机制,在福建省建瓯市万木林自然保护区选取演替时间分别为15年(演替初期)、47年(演替中期)和110年(演替后期)三个不同演替阶段,进行了为期1年的野外原位观测。结果发现:演替初期、中期和后期的Rs分别为2.38、3.32和3.91μmol·m–2·s–1,温度敏感性(Q10值)分别为2.64、1.97和1.79;与演替初期相比,演替后期的Rs显著增加64.29%,Q10值显著降低32.30%;不同演替阶段Rs的季节变化模式相似,温度和含水量可分别解释季节变化的69.5%(初期)、81.9%(中期)和61.3%(后期);回归分析发现,Rs与凋落物年归还量、细根生物量和土壤全氮和土壤有机质碳含量显著正相关。表明本研究区内植被演替促进了土壤碳排放,降低了土壤呼吸的温度敏感性;土壤碳输入增加、养分含量的提高和细根生物量增大是中亚热带常绿阔叶林Rs随演替进程逐渐增大的主要原因。
In order to find out the variation trend and its mechanism of soil respiration (Rs) in the succession series of evergreen broad-leaved forest in the subtropical region, the succession time of selection of Wanmulin Nature Reserve in Jian’ou City, Fujian Province was 15 years ), 47 years (mid-succession) and 110 years (late succession), a one-year field observation was conducted. The results showed that the Rs were 2.38, 3.32 and 3.91 μmol · m-2 · s-1 in the early, middle and late stages, and the values of Q10 were 2.64, 1.97 and 1.79, respectively. Compared with the early stage of succession , The Rs increased by 64.29% and the Q10 decreased significantly by 32.30% in the late succession. The seasonal variation patterns of Rs in different succession stages were similar. The temperature and water content explained 69.5% and 81.9% of the seasonal variation respectively, And 61.3% (later stage), respectively. Regression analysis showed that Rs was positively correlated with annual litterfall return, fine root biomass, soil total nitrogen and soil organic carbon. The results showed that the succession of vegetation in the study area promoted soil carbon emission and decreased the temperature sensitivity of soil respiration. Soil carbon input increased, nutrient content increased and fine root biomass increased, The main reason for the gradual increase of the process.