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: 2103114
• 负责人: Andrew Grandy
• 金额: $ 26万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2103114&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）来生存，但植物在何处、何时以及如何从土壤中获得足够的N仍然是一个谜。这种N困境限制了生产力，并导致在自然和管理系统中预测和管理N循环的挑战。该项目探讨了一个新的，更全面的角度对陆地氮循环，包括从土壤中的N的多种来源。这项研究的重点是以前被忽视的矿物相关有机物（MAOM）作为一个潜在的主要驱动力的氮供应给植物的作用。长期以来的理论认为MAOM在很大程度上是植物和微生物无法进入的，但新出现的证据强调了重新审视这种批发分类的必要性。本工作探讨了潜在的氮供应能力的MAOM的土壤周围的根，一个关键的营养热点。最终，研究结果提供了新的见解MAOM的作用，作为介质的生物可利用的N，这将挑战我们的基本理解的过程，调节土壤氮循环在陆地生态系统。这项工作涉及参与俄克拉荷马州州立大学的一个项目，该项目旨在增加代表性不足的人口在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合作，开发一个由学生主导的研讨会和视频系列土壤生物地球化学与土壤有机质和MAOM管理的具体相关性。总体目标是量化和表征MAOM的内在和植物介导的能力，以提供生物可利用的N。指导性假设强调MAOM-N供应对MAOM的内在物理化学性质的依赖性，MAOM相对于其他形式的土壤有机质的生物利用度，以及可以促进MAOM中N的动员的植物-微生物机制。该项目追求以下目标：1）检查土壤因素调节植物和微生物获得MAOM-N; 2）确定驱动MAOM-N动员的机制; 3）评估植物投资地下碳和MAOM-N动员之间的反馈。本研究利用实验室和温室实验评估土壤的地球化学性质。实验操作与稳定同位素示踪相结合，允许跟踪MAOM衍生的N进入生物可利用的池，以及微生物和植物的吸收。该奖项反映了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。

项目成果

The nitrogen gap in soil health concepts and fertility measurements

• DOI: 10.1016/j.soilbio.2022.108856
• 发表时间: 2022-10
• 期刊: Soil Biology and Biochemistry
• 影响因子: 9.7
• 作者: A. S. Grandy;Amanda B. Daly;Timothy M. Bowles;A. Gaudin;Andrea Jilling;Andrea Leptin;M. McDaniel;Jordon Wade;Hannah Waterhouse