Going underground: root traits and organic matter dynamics in grassland soils

全球粮食安全面临的一大挑战是需要维持和加强土壤的基本功能，这些功能是提供生态系统服务的基础，如碳储存和有效的养分循环，同时还需要保持经济上可行的产量。有几个因素调节土壤的功能，但最重要的是植物和土壤微生物群落之间的相互作用，它们调节土壤肥力和植物生长所依赖的生物地球化学过程。虽然人们越来越意识到植物和土壤微生物群落之间这种关系在功能上的重要性，但我们对其中涉及的机制的理解仍然很差。该项目通过测试基于特征的方法的有效性来应对这一挑战，该方法用于探索植被组成的变化如何影响土壤中的微生物群落及其功能，特别关注启动，即加强土壤中有机物质的分解。以草原作为模型系统，学生将检验这一假设，即草原植物物种之间的根系特征综合征的差异通过影响土壤中的微生物群落而成为土壤有机质的主要驱动因素。这些研究的信息将被用来开发一个基于特征的框架，用于预测土地利用变化导致的植物功能多样性的变化如何影响土壤微生物群落和土壤中有机质的启动，这是与土壤碳储存有关的关键功能。学生将接受在受控环境和野外使用最先进的生物和地球化学方法的培训。

A major challenge facing global food security is the need to maintain, and enhance, the essential functions of soil that underpin the delivery of ecosystem services, such as carbon storage and efficient nutrient cycling, whilst also maintaining economically viable yield. Several factors regulate the functioning of soils, but of central importance are interactions between plants and soil microbial communities, which regulate the biogeochemical processes on which soil fertility and plant growth depend. Whilst there is growing awareness of the functional importance of such relationships between plants and soil microbial communities, our understanding of the mechanisms involved remains poor. This studentship tackles this challenge by testing the efficacy of a trait-based approach for exploring how changes in vegetation composition impact microbial communities and their functioning in soil, with a particular focus on priming, i.e. enhanced breakdown of organic matter in soil. Using grasslands as a model system, the student will test the hypothesis that variation in root trait syndromes among grassland plant species act as major drivers of soil organic matter priming through their impact on microbial communities in soil. Information from these studies will be used to develop a trait-based framework for predicting how changes in plant functional diversity, resulting from land use change, impact soil microbial communities and the priming of organic matter in soil, a key function related to soil carbon storage. The student will be trained in the use of state of the art biological and geochemical approaches used controlled environments and in the field.