将溶解有机碳的化学结构与微生物群落组成与淹没诱导的土壤有机碳矿化联系起来。

Linking chemical structure of dissolved organic carbon and microbial community composition with submergence-induced soil organic carbon mineralization.

机构信息

Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China.

出版信息

Sci Total Environ. 2019 Nov 20;692:930-939. doi: 10.1016/j.scitotenv.2019.07.286. Epub 2019 Jul 19.

DOI:10.1016/j.scitotenv.2019.07.286

PMID:31539997

Abstract

Much research has been devoted to investigating how water-extractable organic carbon (DOC) concentration and microbial activity regulate soil organic carbon (SOC) mineralization when soils are saturated with water. However, the relationships of DOC chemical structure and microbial community composition with SOC mineralization, as well as the relative contributions of microbial decomposers and their substrates on the mineralization rate have rarely been examined. In a laboratory experiment, we incubated two typical cropland soils (an Entisol and a Mollisol) of China for 360 days under submerged and non-submerged conditions, and we evaluated the concentration and chemical structure of soil DOC, soil microbial metabolic potential and community composition by using total C/N analysis, solution-state H NMR, Biolog EcoPlates, and 16S rRNA amplicon sequencing, respectively. The results showed that submergence significantly increased DOC concentration (P < 0.01) and microbial activity (P < 0.001) and changed DOC chemical structure in the Entisol (P < 0.01). In the Mollisol, it significantly increased the rate (P < 0.01) and cumulative extent (P < 0.001) of SOC mineralization and DOC concentration (P < 0.01) as well as altering the composition of the microbial community (P < 0.001). Moreover, the SOC mineralization rate was better explained by microbial community composition (Entisol: SPC = -0.71, P < 0.001; Mollisol: SPC = 0.92, P < 0.001) than by DOC concentration (Entisol: SPC = 0.21, P > 0.05; Mollisol: SPC = 0.30, P < 0.05) or DOC chemical structure (Entisol: SPC = 0.12, P > 0.05; Mollisol: SPC = -0.45, P < 0.001). Our study revealed that the bacterial community composition had a close relationship to the rate of submergence-induced SOC mineralization in both soils, but only DOC concentration and chemical structure were effective predictors of mineralization rate in the low-pH Mollisol.

摘要

大量研究致力于调查当土壤饱和水时，可提取的有机碳（DOC）浓度和微生物活性如何调节土壤有机碳（SOC）矿化。然而，DOC 化学结构和微生物群落组成与 SOC 矿化的关系，以及微生物分解者及其底物对矿化速率的相对贡献，很少被研究。在一项实验室实验中，我们在淹没和非淹没条件下将中国的两种典型农田土壤（淋溶土和淋溶土）培养 360 天，并分别通过总 C/N 分析、溶液状态 H NMR、Biolog EcoPlates 和 16S rRNA 扩增子测序来评估土壤 DOC 的浓度和化学结构、土壤微生物代谢潜力和群落组成。结果表明，淹没显著增加了 DOC 浓度（P<0.01）和微生物活性（P<0.001），并改变了淋溶土中的 DOC 化学结构（P<0.01）。在淋溶土中，它显著增加了 SOC 矿化的速率（P<0.01）和累积程度（P<0.001）以及 DOC 浓度（P<0.01），并改变了微生物群落的组成（P<0.001）。此外，SOC 矿化速率与微生物群落组成的相关性（淋溶土：SPC=-0.71，P<0.001；淋溶土：SPC=0.92，P<0.001）优于与 DOC 浓度（淋溶土：SPC=0.21，P>0.05；淋溶土：SPC=0.30，P<0.05）或 DOC 化学结构（淋溶土：SPC=0.12，P>0.05；淋溶土：SPC=-0.45，P<0.001）。本研究表明，在两种土壤中，细菌群落组成与淹没诱导的 SOC 矿化速率密切相关，但只有 DOC 浓度和化学结构是低 pH 淋溶土矿化速率的有效预测因子。