Collaborative Research: Mineral-associated organic matter: an overlooked source and mediator of bioavailable nitrogen

合作研究：矿物相关有机物：被忽视的生物可利用氮的来源和介质

• 批准号: 2400998
• 负责人: Andrea Jilling
• 金额: $ 37.46万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2400998&HistoricalAwards=false
• 关键词: Collaborative; Research; Mineral; associated; organic

Plants need nitrogen (N) to survive, but it remains a mystery exactly where, when, and how plants acquire enough N from the soil. This N dilemma limits productivity and leads to challenges in predicting and managing N cycling in natural and managed systems. This project examines a new, more holistic perspective on the terrestrial N cycle that encompasses multiple sources of N from the soil. The research focuses on the previously overlooked role of mineral-associated organic matter (MAOM) as a potential major driver of N supply to plants. Long-standing theories consider MAOM to be largely inaccessible to plants and microbes, but emerging evidence highlights the need to re-examine this wholesale classification. This work examines the potential N-supplying capacity of MAOM in the zone of soil surrounding roots, a critical nutrient hotspot. Ultimately, the results provide new insights into the role of MAOM as a mediator of bioavailable N, which will challenge our fundamental understanding of the processes that regulate soil N cycling in terrestrial ecosystems. The work involves participation in a program at Oklahoma State University, which aims to increase the participation of under-represented populations in STEM disciplines. The project also supports a collaboration with the Oklahoma Conservation Commission to develop a student-led workshop and video series on soil biogeochemistry with specific relevance to soil organic matter and MAOM management. The overarching objective is to quantify and characterize the intrinsic and plant-mediated capacity of MAOM to supply bioavailable N. The guiding hypothesis emphasizes the dependence of MAOM-N supply on the intrinsic physical-chemical properties of MAOM, the bioavailability of MAOM relative to other forms of soil organic matter, and plant-microbial mechanisms that can facilitate the mobilization of N from MAOM. The project pursues the following objectives: 1) Examine edaphic factors regulating plant and microbial access to MAOM-N; 2) Identify mechanisms driving MAOM-N mobilization; 3) Assess feedbacks between plant investment in belowground carbon and MAOM-N mobilization. The study assesses soils varying in geochemical properties using laboratory and greenhouse experiments. Experimental manipulations combined with stable isotope tracing allow for the tracing of MAOM-derived N into bioavailable pools, as well as uptake by microbes and plants.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.

植物需要氮（n）才能生存，但它仍然是一个谜，准确地在何时，何时以及如何从土壤中获取足够的n。该n难点限制了生产力，并在预测和管理自然系统和托管系统中的N循环方面面临挑战。该项目研究了陆生n周期的一种新的，更全面的观点，该观点涵盖了来自土壤的多个n来源。该研究的重点是以前被矿物相关有机物（MAOM）作为植物n供应的主要驱动力的作用。长期以来的理论认为，摩姆在很大程度上是植物和微生物无法获得的，但新兴的证据突显了重新检查这种批发分类的必要性。这项工作研究了MAOM在根周围的土壤区域（一个关键的养分热点）中的潜在N供应能力。最终，结果为MAOM作为生物可用性N的介体的作用提供了新的见解，这将挑战我们对调节陆地生态系统中土壤N循环的过程的基本理解。这项工作涉及参加俄克拉荷马州立大学的一项计划，该大学旨在增加代表性不足的人群在STEM学科中的参与。该项目还支持与俄克拉荷马州保护委员会的合作，以开发由学生主导的关于土壤生物地球化学的研讨会和视频系列，与土壤有机物和MAOM管理有具体关系。总体目的是量化和表征乳头提供生物可用性N的固有和植物介导的能力。指导假设强调了MAOM-N供应对MAOM的内在物理化学特性的依赖性，这是MAOM​​的生物可利用性，MAOM相对于其他形式的土壤有机物和植物性机械化的MAOM的生物利用性。该项目追求以下目标：1）检查调节植物和微生物接入MAOM-N的实现因素； 2）确定驱动MAOM-N动员的机制； 3）评估植物投资在地下碳和MAOM-N动员之间的反馈。该研究评估了使用实验室和温室实验的地球化学特性中的土壤。实验性操纵与稳定的同位素追踪结合在一起，可以将MAOM衍生的N介绍为可生物可用的池，以及微生物和植物的吸收。该奖项反映了NSF的法定任务，并认为通过基金会的智力和更广泛的影响，可以通过评估来进行评估，以审查Criteria。