CAREER:Mineralogical and Biogeochemical Control of Phosphorus Transformation during Soil Development

土壤中磷的循环和生物有效性决定着生态系统的结构和功能。在土壤形成期间的特定土壤发育阶段，磷化学组成为评估磷、碳和其他养分的当代循环以及确定磷可用性的变化如何影响不同的生态系统过程（例如初级生产力）提供了有用的背景。在这个项目中，PI和他的团队将解决长期生态系统发展过程中土壤中磷成分的转化及其与有机碳循环的耦合。拟议的工作将改变目前的理解P动态及其耦合到陆地生态系统中的碳循环。这项工作也有重要的意义，在农业中的磷利用，并将促进磷肥料施用后的磷命运的理解。拟议的教育工作将通过开发课程、课程和STEM活动，以及培养地球科学教师，对怀俄明州各级学生的地球科学教育产生广泛影响。这项建议的研究，教育和推广的组成部分已经协同发展，以最大限度地提高对PI的影响，以及现有的校园外展organizations.The广受好评的步行者和Syers模型描述在成壤或土壤发育过程中的P转化是基于操作定义的P馏分作为测量化学提取，而不是P形态。因此，它在描述涉及磷与矿物和有机物相互作用的磷地球化学转化方面具有明显的局限性。此外，该模型是从潮湿的环境，并有有限的适用性，半干旱生态系统，因为该模型没有考虑风成尘沉降作为另一个重要的P输入在半干旱环境。因此，有一个很大的需要，开发基于磷形态的模型，可以准确地描述在潮湿和半干旱生态系统中的磷转化。在这个项目中，磷X射线吸收光谱将被用来确定磷的形态在土壤中，磷池的步行者和Syers模型，和风尘。将检查对比气候条件和/或母质的年代序列。提出了一个基于磷形态转化的生态系统发育模型。为了深入了解通过与矿物相互作用促进的有机磷和碳的耦合循环，将使用光谱和生物化学分析来表征与不同大小的土壤颗粒相关的土壤有机质中的磷形态。结果预计将有显着的影响，了解磷循环和生物利用度在陆地ecosystes.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Phosphorus (P) cycling and bioavailability in soils shapes ecosystem structure and function. At a given soil developmental stage during soil formation, the P chemical composition provides a useful context for evaluating contemporary cycling of P, carbon and other nutrients, and for determining how changes in P availability might affect diverse ecosystem processes, such as primary productivity. In this project, the PI and his team will address transformation of P composition in soils and its coupling to organic carbon cycling during long-term ecosystem development. The proposed work will transform the current understanding of P dynamics and its coupling to carbon cycling in terrestrial ecosystems. This work also has important implications for P utilization in agriculture and will advance the understanding of P fate after P fertilizer application. The proposed education work will have broad impacts on Earth Science education of various levels of students in the state of Wyoming through developing courses, curriculum and STEM activities, and preparing earth science teachers. The research, education and outreach components of this proposal have been developed synergistically to maximize the impact on the PI's, as well as existing on-campus outreach organizations.The well-received Walker and Syers model describing P transformation during pedogenesis or soil development is based on operationally-defined P fractions as measured by chemical extractions, rather than P speciation. Thus, it has significant limitations in describing P biogeochemical transformation involving P interactions with minerals and organics. Moreover, the model was developed from humid environment and has limited applicability to semi-arid ecosystems as the model does not consider aeolian dust deposition as another important P input in the semi arid environment. There is, therefore, a great need to develop P speciation-based models that can accurately describe P transformation in both humid and semi-arid ecosystems. In this project, P X-ray absorption spectroscopy will be used to determine P speciation in soils, the P pools of the Walker and Syers model, and aeolian dust. Chronosequences in contrasting climate conditions and/or parent materials will be examined. A P-speciation based transformation model during ecosystem development will be proposed. To gain insights into coupled cycling of organic P and carbon facilitated by interacting with minerals, P speciation in soil organic matter associated with soil particles of different size regimes will be characterized using spectroscopic and biochemical analyses. Results are expected to have significant implications for understanding P cycling and bioavailability in terrestrial ecosystems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.