森林土壤融化期异养呼吸和微生物碳变化特征

发布时间：2018-04-25 09:12

  本文选题：微生物呼吸 + 微生物碳　； 参考：《生态学报》2017年08期

【摘要】：采用室内土柱培养的方法,研究在不同湿度(55%和80%WFPS,土壤充水孔隙度)和不同氮素供给(NH_4Cl和KNO_3,4.5 g N/m~2)条件下,外源碳添加(葡萄糖,6.4 g C/m~2)对温带成熟阔叶红松混交林和次生白桦林土壤融化过程微生物呼吸和微生物碳的激发效应。结果表明:在整个融化培养期间,次生白桦林土壤对照CO_2累积排放量显著高于阔叶红松混交林土壤。随着土壤湿度的增加,次生白桦林土壤对照CO_2累积排放量和微生物代谢熵(q_(CO_2))显著降低,而阔叶红松混交林土壤两者显著地增加(P0.05)。两种林分土壤由葡萄糖(Glu)引起的CO_2累积排放量(9.61—13.49 g C/m~2)显著大于实验施加的葡萄糖含碳量(6.4g C/m~2),同时由Glu引起的土壤微生物碳增量为3.65—27.18 g C/m~2,而施加Glu对土壤DOC含量影响较小。因此,这种由施加Glu引起的额外碳释放可能来源于土壤固有有机碳分解。融化培养结束时,阔叶红松混交林土壤未施氮处理由Glu引起的CO_2累积排放量在两种湿度条件下均显著大于次生白桦林土壤(P0.001);随着湿度的增加,两种林分土壤Glu引起的CO_2累积排放量显著增大(P0.001)。单施KNO_3显著地增加两种湿度的次生白桦林土壤Glu引起的CO_2累积排放量(P0.01)。单施KNO_3显著地增加了两种湿度次生白桦林土壤Glu引起的微生物碳(P0.001),单施NH_4Cl显著地增加低湿度阔叶红松混交林土壤Glu引起的微生物碳(P0.001)。结合前期报道的未冻结实验结果,发现冻结过程显著地影响外源Glu对温带森林土壤微生物呼吸和微生物碳的刺激效应(P0.05),并且无论冻结与否,温带森林土壤微生物呼吸和微生物碳对外源Glu的响应均与植被类型、土壤湿度、外源氮供给及其形态存在显著的相关性。
[Abstract]:Using the method of indoor soil column culture, we studied the conditions of different humidity (55%) and 80% WFPS (soil water-filled porosity) and different nitrogen supply (NH4Cl and KNO34.5g / m ~ (2)). Effects of exogenous carbon supplementation (glucose 6.4g C / m ~ (2)) on microbial respiration and microbial carbon during soil melting in temperate mature broad-leaved Korean pine mixed forest and secondary birch forest. The results showed that the accumulative CO_2 emissions of the secondary birch forest soil were significantly higher than those of the broadleaved Korean pine mixed forest soil during the whole melting period. With the increase of soil moisture, the accumulative CO_2 emission and microbial metabolic entropy of the secondary birch forest decreased significantly, while the soil of broad-leaved Korean pine mixed forest increased P0.05. The cumulative CO_2 emissions from two stand soils caused by Glu) were 9.61-13.49g C / m ~ (2)) significantly higher than that of the experimental application of glucose (6.4g C / m ~ (2)), and the soil microbial carbon increment caused by Glu was 3.65-27.18 g C / m ~ (-2), and that by Glu was 3.65-27.18 g C / m ~ (-2). The effect of DOC content was small. Therefore, this additional carbon release caused by the application of Glu may be derived from the decomposition of organic carbon inherent in the soil. At the end of thawing cultivation, the cumulative CO_2 emission caused by Glu in the soil of mixed broadleaved Korean pine forest was significantly higher than that of P0.001 in the secondary birch forest under two kinds of moisture conditions, and with the increase of soil moisture, the accumulation of CO_2 in the soil of mixed broadleaved Korean pine forest was significantly higher than that in the secondary birch forest. The cumulative CO_2 emission caused by soil Glu in both stands increased significantly (P 0.001). Application of KNO_3 alone significantly increased the cumulative CO_2 emissions caused by Glu in secondary birch forests with two different moisture levels (P0.01). Applying KNO_3 alone significantly increased the microbial carbon (P0.001N) caused by Glu in the soil of two kinds of moisture secondary birch forests, and increased the microbial carbon (P0.001N) caused by Glu in the soil of low-humidity broad-leaved Pinus koraiensis mixed forest by applying NH_4Cl alone. Combined with the reported results of unfrozen experiments, it was found that the freezing process significantly affected the stimulative effects of exogenous Glu on microbial respiration and microbial carbon in temperate forest soil. The responses of microbial respiration and microbial carbon to exogenous Glu in temperate forest soil were significantly correlated with vegetation type, soil moisture, exogenous nitrogen supply and their forms.
【作者单位】： 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室;中国科学院大学地球科学学院大气化学与环境科学系;长安大学地球科学与资源学院;Faculty
【基金】：国家自然科学基金(41175133,21228701,41275166,41321064,41575154)
【分类号】：S714
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本文编号：1800686