Effects of temperature and root additions on soil carbon and nitrogen mineralization in a predominantly permafrost peatland
Effects of temperature and root additions on soil carbon and nitrogen mineralization in a predominantly permafrost peatland
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温度和根系添加对永久冻土泥炭地土壤碳和氮矿化的影响
DOI：
10.1016/j.catena.2018.02.026
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发表时间：
2018
期刊：
影响因子：
6.2
通讯作者：
Wang Mingquan
中科院分区：
文献类型：
--
作者：
Song Yanyu;Song Changchun;Hou Aixin;Ren Jiusheng;Wang Xianwei;Cui Qian;Wang Mingquan
大约三分之一的北方泥炭地位于永久冻土区。冻土泥炭地土壤有机质和植物根系生物量易受未来全球变暖的影响。然而，以前的研究主要集中在SOM矿化温度升高的反应，没有分析潜在的相互作用的影响，增加植物根系生物量。以大兴安岭高纬度多年冻土泥炭地为研究对象，研究了温度和根系添加对土壤碳氮矿化的影响及其驱动机制。通过室内培养试验，研究了温度升高和添加羊鞭草根系对浅层（0-15 cm）和深层（15-30 cm）土壤碳矿化、有效氮含量、微生物量碳（MBC）、溶解性有机碳（DOC）和酶活性的影响。我们的研究结果表明，温度升高显着增加土壤碳矿化。浅层土壤和深层土壤碳矿化速率的Q_（10）值分别为3.95和2.91。与此相反，土壤MBC和DOC显著下降，证实了活性碳是变暖条件下微生物矿化活动的主要驱动力。温度升高显著提高了浅层土壤氮素净矿化速率和两层土壤的净硝化速率。在高温下，氨化速率在浅层土壤中增加，但在深层土壤中下降。培养温度的升高导致浅层土壤β-葡萄糖苷酶活性显著升高，转化酶活性显著降低。这表明复杂底物酶的产生增加，而简单底物获取酶的产生减少。根系的添加显著增加了土壤C矿化，促进了土壤微生物转化酶的分泌。这些结果表明，未来气候变暖在北方高纬度地区将显着刺激土壤碳和氮矿化的冻土泥炭地。此外，植物根系的增加会促进碳的积累，甚至可能增强土壤碳矿化对温度的响应，显著影响高纬度冻土泥炭地土壤碳平衡。
Approximately one-third of northern peatlands are within permafrost regions. Soil organic matter (SOM) and plant root biomass in permafrost peatlands are vulnerable to future global warming. However, previous studies have primarily focused on the response of SOM mineralization to increases in temperature without analysing the potential interaction effects of increased plant root biomass. This study investigated the influence of temperature and root additions on soil carbon and nitrogen mineralization as well as the mechanisms driving mineralization in a high latitude permafrost peatland in the Da Xing'an Mountains, Northeast China. We investigated changes in shallow soil (0–15 cm) and deep soil (15–30 cm) carbon mineralization, available N contents, microbial biomass carbon (MBC), dissolved organic carbon (DOC), and enzyme activities in response to increasing temperature andEriophorum vaginatumroot additions by using an incubation experiment. Our results indicate that elevated temperature significantly increased soil carbon mineralization. The Q10values of the carbon mineralization rates in the shallow soil and deep soil were 3.95 and 2.91, respectively. In contrast, the soil MBC and DOC decreased significantly, confirming that labile carbon is the main driving force of microbial mineralization activities under warming conditions. Elevated temperature significantly increased the shallow soil net N mineralization rates and increased the net nitrification rates in both soil layers. At high temperatures, ammonification rates increased in the shallow soil but decreased in the deep soil. The increase in the incubation temperature resulted in significantly increased shallow soil β-glucosidase activity and decreased invertase activity. This suggests the increased production of complex substrate enzymes, and decreased production of simple substrate-acquiring enzymes. The root additions significantly increased the soil C mineralization and stimulated the secretion of invertase by soil microorganisms. These findings indicate that future climate warming in the northern high latitude will significantly stimulate soil carbon and nitrogen mineralization in permafrost peatlands. Furthermore, increases in plant roots will enhance C accumulation and may even enhance the response of soil C mineralization to temperature, significantly impact the soil C balance in high latitude permafrost peatlands.