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地表凋落物呼吸是土壤呼吸的一个重要组成部分,研究凋落物呼吸温度敏感性的变化特征及其影响因素对准确理解地区的土壤碳循环具有重要意义.本研究在黄土高原南部的一个典型人工刺槐林内(Robinia pseudoacacia L.),通过地表凋落物控制试验(对照处理,去除凋落物处理、倍增凋落物处理),研究凋落物呼吸温度敏感性的年际(2009~2013年)变化特征及其驱动因素.凋落物呼吸温度敏感性的年际差异显著(P<0.05):在对照处理下,其最小值为4.15,最大值为6.67,均值为5.10,变异系数为19%;在倍增凋落物处理下,其变化于1.17~6.52之间,均值为3.36,变异系数高达56%.凋落物呼吸温度敏感性的年际变异与年平均土壤水分、地表凋落物量以及二者的交互作用密切相关(P<0.01),同时对凋落物呼吸温度敏感性的贡献呈现出土壤水分大于地表凋落物量的趋势(对照处理:2.68和2.04;倍增凋落物处理:1.37和0.69).此外,地表凋落物倍增后,凋落物呼吸温度敏感性却减少了34%(3.36和5.10).同时,在对照处理下,大约有超过50%的地表凋落物碳滞留在该刺槐林生态系统中[215 g·(m~2·a)~(-1)和113 g·(m~2·a)~(-1)],但在倍增处理下,仅有24%的地表凋落物碳滞留在该林地生态系统中[430 g·(m~2·a)~(-1)和326 g·(m~2·a)~(-1)],即在该人工刺槐林生态系统中地表凋落物的增加未必意味着土壤有机碳储量的增加.因此,探究地表凋落物控制措施、土壤水分、地表凋落物量和凋落物呼吸温度敏感性之间的关系对准确理解地区的土壤碳循环具有重要意义.
Surface litter respiration is an important part of soil respiration, and it is of great importance to study the variation characteristics of respiration temperature sensitivity and its influencing factors to accurately understand the soil carbon cycling in this area. A typical artificial acacia (Robinia pseudoacacia L.) was used to study the characteristics of annual temperature variation (2009-2013) and its driving mechanism of litter respiration temperature sensitivity by controlling the litterfall litter (control treatment, litter removal and litterfall multiplication) (P <0.05): Under the control treatment, the minimum value was 4.15, the maximum value was 6.67, the average was 5.10 and the coefficient of variation was 19%. In the litterfall multiplication litterfall , With a mean value of 3.36 and a coefficient of variation of up to 56% .The interannual variability of litter respiration temperature sensitivity was closely related to annual mean soil moisture, litterfall and their interactions (P <0.01). At the same time, the contribution of temperature sensitivity to litter respiration showed a tendency of soil moisture greater than litter (litter treatments: 2.68 and 2.04; litter litter treatments: 1.37 and 0.69) .In addition, the litter respiration temperature sensitivity was decreased by 34% (3.36 and 5.10) after doubling of surface litter.At the same time, about 50% of the surface litter carbon remained in the locust forest (215 g · m -2 · a -1 and 113 g · m -2 · a -1) in the ecosystem, but only 24% of the surface litterfalls under doubled treatment Carbon sequestration in the forest ecosystem [430 g · (m -2 · a -1) and 326 g · (m -2 · a -1)], that is, in the Artificial Robinia Habitat ecosystem The increase of surface litter in the system does not necessarily mean the increase of soil organic carbon storage.Therefore, to explore the relationship between surface litterfall control measures, soil moisture, litterfall and litter temperature sensitivity to understand the soil carbon Recycling is of great significance.