Root traits of contrasting crop genotypes and their influence on soil biogeochemical cycles

我的研究计划的长期目标是调查植物根系和土壤地球化学循环之间的联系。根直接与土壤相互作用，改变物理和生物化学环境，以支持植物生长。然而，我们的知识如何根间接影响土壤过程至关重要的农业生态系统功能超出作物生产，包括养分循环，土壤有机质的形成，结构稳定性，是相对有限的。解决我们对根系与土壤过程相互作用的知识的差距在农业系统中尤为重要，因为加拿大各地的农民正在放弃单一作物，由于全球市场和气候条件的变化，作物轮作日益多样化。预测在我们的农业系统中种植不同作物基因型的多样性对生态系统功能的影响，需要更好地表征它们的根系性状以及这些性状如何影响土壤地球化学循环。 我的计划将采取基于植物性状的方法来了解根系对植物生产力重要的营养循环的影响，以及对影响土壤质量和全球气候的碳动态的影响。我的研究计划的具体目标是调查根的化学和结构特征及其相互作用的影响：（1）根分解速率和土壤磷和氮的生物有效性;（2）根源碳在土壤团聚体和土壤微生物群落的命运;（3）根际化学和微生物群落结构的空间分布。我将使用已知的作物物种先验显着不同的结构，其根系和品种，已被遗传选择不同的植物组织化学在整个一系列的研究，检查根-土壤界面的过程中越来越复杂的五年计划。植物的稳定同位素标记将用于调查土壤中根源输入的命运，分子生物学技术将表征土壤微生物群落的根驱动结构，以及成像细胞外酶活性的新技术将用于阐明根对潜在养分生物利用度的影响。了解结构和化学多样的根输入的微生物处理将改善我们的预测植物养分供应和碳在不断变化的农艺和气候条件下的土壤中的命运。通过采取基于性状的方法来了解根系对土壤生态地球化学过程的影响，这项工作可以为利用理想的根系性状来提高作物生产力和生态系统功能的种植系统的设计提供信息。

The long-term objective of my research program is to investigate the link between plant roots and soil biogeochemical cycles. Roots directly interact with the soil to alter the physical and biochemical environment to support plant growth. However, our knowledge on how roots indirectly affect soil processes vital to agroecosystem functioning beyond crop production, including nutrient cycling, soil organic matter formation, and structural stability, is relatively limited. Addressing the gap in our knowledge on root interactions with soil processes is especially important in agricultural systems as farmers across Canada are abandoning monocultures for increasingly diverse crop rotations due to changing global market and climate conditions. Predicting the effects of growing a diversity of different crop genotypes in our agricultural systems on ecosystem function requires better characterization of their root traits and how those traits affect soil biogeochemical cycles. My program will take a plant traits based approach to understand root influences on nutrient cycles important to plant productivity as well as on carbon dynamics that affect soil quality and global climate. The specific objectives of my research program are to investigate the influence of root chemical and structural traits and their interactions on: (1) root decomposition rates and soil phosphorus and nitrogen bioavailability; (2) the fate of root-derived carbon in soil aggregates and the soil microbial community; and (3) the spatial profile of rhizosphere chemistry and microbial community structure. I will use crop species known a priori to differ markedly in the structure of their root systems and cultivars that have been genetically selected to vary in plant tissue chemistry throughout a series of studies that examine the root-soil interface with increasing complexity over the course of the five-year program. Stable isotope labeling of plants will be used to investigate the fate of root-derived inputs in soil, molecular biological techniques will characterize root-driven structuring of soil microbial communities, and novel techniques in imaging extracellular enzyme activities will be used to elucidate the influence of roots on potential nutrient bioavailability. Understanding the microbial processing of structurally and chemically diverse root inputs will improve our predictions of plant nutrient supply and the fate of carbon in the soil under changing agronomic and climate conditions. By taking a trait-based approach to understanding root influences on soil biogeochemical processes, this work can inform the design of cropping systems that exploit desirable root traits to enhance crop productivity and ecosystem function.