Exploring links in the root trait - soil organic matter continuum

探索根性状 - 土壤有机质连续体中的联系

• 批准号: RGPIN-2016-05974
• 负责人: Munson, Alison
• 金额: $ 2.26万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683864
• 关键词: Exploring; links; root; trait; soil

Soils represent the largest terrestrial pool of stored carbon (C); this pool is important both as a potential source and also sink for atmospheric C. The future potential to sequester excess atmospheric C is greatest in soils which have previously lost organic matter (and C) through intensive use or degradation; these degraded soils represent an enormous land area on a global basis. For example, recent syntheses have suggested that on average, agricultural soils worldwide could sequester a supplemental 50 t ha-1. However, to effectively exploit this sequestration potential, we need to have a better understanding of the fate and paths of above and belowground plant litter (especially root litter) in relation to the different known mechanisms of stabilization in the soil (recalcitrance; protection in soil aggregates; chemical reactions with mineral surfaces). The current series of studies will focus on how diversity (specific and functional) and «effect» functional traits (morphological characters of plants) may influence soil C storage via the leaves, but especially root systems (root tissue chemistry; root soil exploitation traits; rooting depth etc), in both forest ecosystems and in grassland systems (collaboration with France). In current experiments with grassland soils planted with monocultures, we measured species and root trait effects on soil aggregation, pointing to the possibility of identifying specific root traits that may promote protection of soil C. This observation will be verified along gradients of tree diversity, with the hypothesis that increasing diversity (richness or functional) will be related to increasing both soil aggregation and chemical protection of C. We will also explore the feedback of traits on microbial community structure and function; indirect effects of traits on soil processes may be mediated by this compartment. In sub-boreal forest communities we will measure traits of eight understory plants, and decomposition rate in relation to traits will be tested by measuring mass loss of a common substrate in the rooting zone. This series of studies will increase our understanding of biodiversity effects on ecosystem function (several ecosystems) and the role of specific root characters (effect traits) on processes related to soil carbon stabilization. Land managers have the capacity to identify the situations (site, soil, chemistry) where the potential for soil C storage is greatest, that is, where the soils are further from carbon saturation. If studies such as proposed here can also begin to identify the combination of root traits that can maximize long term C storage in different soil types and ecosystems, we can propose management systems that could sequester C on a much larger scale, across both forest and agro-ecosystems. This progress is critical to reducing the potential impacts of global change and to maintaining and restoring productive ecosystems.

土壤是最大的陆地碳库(C)；这个库作为大气C的潜在来源和汇都是重要的。在以前由于集约利用或退化而失去有机物（和C）的土壤中，未来吸收过量大气C的潜力最大；这些退化的土壤在全球范围内代表了一个巨大的土地面积。例如，最近的综合研究表明，全世界的农业土壤平均可以额外吸收50吨公顷。然而，为了有效地利用这种封存潜力，我们需要更好地了解地上和地下植物凋落物（特别是根凋落物）的命运和路径，以及不同已知的土壤稳定机制（抗性、土壤团聚体的保护、与矿物表面的化学反应）。目前的一系列研究将集中在森林生态系统和草地系统（与法国合作）中，多样性（特异性和功能性）和“效应”功能性状（植物的形态特征）如何通过叶片影响土壤C的储存，尤其是根系（根组织化学；根系土壤利用性状；生根深度等）。在目前的单一栽培草地土壤实验中，我们测量了物种和根系性状对土壤聚集的影响，指出了确定可能促进土壤c保护的特定根系性状的可能性。这一观察结果将沿着树木多样性梯度进行验证。假设c的多样性（丰富度或功能）的增加与土壤团聚性和化学保护性的增加有关，我们还将探索性状对微生物群落结构和功能的反馈；性状对土壤过程的间接影响可能是由这个隔室介导的。在亚北方森林群落中，我们将测量8种林下植物的性状，并通过测量生根区共同基质的质量损失来测试与性状相关的分解速率。这一系列的研究将增加我们对生物多样性对生态系统功能（几个生态系统）的影响以及特定根系性状（效应性状）在土壤碳稳定相关过程中的作用的认识。土地管理者有能力识别土壤C储存潜力最大的情况（地点、土壤、化学），即土壤离碳饱和更远的地方。如果这里提出的研究也可以开始确定根系性状的组合，这些性状可以最大限度地在不同的土壤类型和生态系统中长期储存碳，我们就可以提出可以在森林和农业生态系统中更大规模地吸收碳的管理系统。这一进展对于减少全球变化的潜在影响以及维持和恢复生产性生态系统至关重要。