Recovery and Relative Influence of Root, Microbial, and Structural Properties of Soil on Physically Sequestered Carbon Stocks in Restored Grassland
Recovery and Relative Influence of Root, Microbial, and Structural Properties of Soil on Physically Sequestered Carbon Stocks in Restored Grassland
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土壤根系、微生物和结构特性对恢复草地物理固存碳储量的恢复和相对影响
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发表时间：
2017
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通讯作者：
J. Blair
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作者：
D. Scott;S. Baer;J. Blair
管理土壤固碳有助于缓解大气中二氧化碳的增加。为了最大化这种生态系统服务，需要更多地了解影响碳固存的因素。本研究的目的是 (i) 量化草原恢复时间序列中根系、微生物生物量和组成以及土壤结构的恢复，以及 (ii) 使用结构方程模型开发基于数据的假设，了解物理和生物土壤特性对土壤碳聚集体分数诊断封存碳的相对影响。地下植物生物量和组织质量（C/N 比）、土壤微生物生物量碳、磷脂脂肪酸 (PLFA) 浓度、土壤结构和土壤对耕地、恢复 1 至 35 年的草原 (n = 6) 以及从未耕种的（原生）草原中的大块土壤和每个骨料部分中的碳储量进行了量化。经过 35 年的恢复，根生物量、微生物生物量 C、丛枝菌根真菌 (AMF) PLFA 生物量随时间顺序增加，类似于原生草原。土壤结构的许多方面（即容重、骨料部分的比例质量和骨料平均加权直径）和土壤部分之间的 C 分布，包括微观内宏观骨料部分中的 C（隔离的 C），也成为恢复 35 年内原生草原的代表。在整个时间序列中，土壤总碳储量和物理保护碳以相似的速率分别增加（分别为 23 克和 27 克 C 米 -2 年 -1）。经过 35 年的修复，总碳库的 50% 得到了物理保护。由这些数据建立的结构方程模型假设微生物生物量C和AMF生物量（微生物组成）对物理保护的C具有最强的因果影响。该模型需要使用独立的站点进行测试，以实现更大的推论。
Managing soil to sequester C can help mitigate increasing CO₂ in the atmosphere. To maximize this ecosystem service, more knowledge of factors influencing C sequestration is needed. The objectives of this study were to (i) quantify recovery of the roots, microbial biomass and composition, and soil structure across a chronosequence of grassland restorations and (ii) use a structural equation model to develop a data-based hypothesis on the relative influence of physical and biological soil properties on the soil C aggregate fraction diagnostic of sequestered C. Belowground plant biomass and tissue quality (C/N ratio), soil microbial biomass C, phospholipid fatty acid (PLFA) concentrations, soil structure, and soil C stocks in the bulk soil and each aggregate fraction were quantified from a cultivated field, prairies restored for 1 to 35-yr (n = 6), and a never-cultivated (native) prairie. Root biomass, microbial biomass C, arbuscular mycorrhizal fungi (AMF) PLFA biomass across the chronosequence increase to resemble native prairie following 35 yr of restoration. Many aspects of soil structure (i.e., bulk density, proportional mass of aggregate fractions, and aggregate mean weighted diameter) and the distribution C among soil fractions, including C in the micro-within-macro aggregate fraction (sequestered C), also became representative of native prairie within 35 yr of restoration. Total soil C stock and physically protected C increased at a similar rate (23 and 27 g C m⁻² yr⁻¹) respectively, across the chronosequence. After 35 yr of restoration, 50% of the total C pool was physically protected. The structural equation modeling developed by these data hypothesizes that microbial biomass C and AMF biomass (microbial composition) have the strongest causal influence on physically protected C. This model needs to be tested using independent sites to achieve greater inference.