Determining how Organic Matter is Stabilized using a Unique Set of Soil Samples from across the U.S.

土壤有机质（SOM）是维持地球上社会和生命的许多生态系统服务之间的重要联系。它是微生物的主要食物来源和植物生长所需水分的主要仓库。SOM还为植物储存营养物质，并吸收可能污染食物和水源的污染物。土壤还通过储存碳来帮助调节气候，否则这些碳将被释放到大气中并导致气候变化。该项目研究了土壤中保护SOM不被微生物完全消耗的过程，相反，可以增加其对环境变化的敏感性的过程。 研究人员还将研究气候变化和土地管理方式的变化如何影响SOM的数量和稳定性。该项目涉及大量的研究人员和实验室进行广泛的SOM分析。它利用了国家生态观测网络（氖）已经收集的土壤样本，这是NSF在环境监测方面的一项重大投资，覆盖了整个美国。这些样本将被保存，并从这个项目的结果完全公开的数据通过web.The一个新的范式的演变，在那里的主要控制SOM动力学是依赖于分子结构比其他土壤和生态系统的属性，创造了一个知识空白，在我们的能力来预测SOM对环境变化的反应。不同SOM稳定机制的转换控制之间的关系，从在广泛的空间尺度上操作的远端因素（例如，气候）到在更精细的空间尺度上操作的近端控制（例如，土壤物理化学性质）定义不清。调查人员将通过量化SOM稳定的主导机制与生态系统控制规模（即，细尺度，近端与宽尺度，远端）在大陆尺度系统的土壤类型和生态域，利用土壤样本收集的氖的建设。该项目将是第一个大陆规模的SOM脆弱性评估，并将产生新的，预测性的见解控制SOM稳定性跨土壤类型，土地利用类型和环境梯度。研究结果将大大提高我们对SOM动态的理解，这本身就是一个基本的科学进步，同时也使土壤在生态系统和耦合碳气候模型中的表现更好。该项目代表了开放的、面向社区的研究的新标准，支持来自大学、政府和非政府机构的研究人员的参与。它将通过主要科学网络促进合作，这些网络对于以解决社会面临的复杂问题所需的规模开展科学研究越来越有必要。研究生和本科生将通过参与这项研究接受土壤科学的科学方法的培训，从中获得的见解将为决策者和资源管理者关于碳封存和生态系统服务的决策提供信息。

Soil organic matter (SOM) is a critical linkage among many ecosystem services that sustain our society and life on Earth. It is the primary food source for microbes and the principal storehouse of water necessary for plant growth. SOM also stores nutrients for plants and absorbs pollutants that otherwise could contaminate food and water supplies. Soils also help regulate climate by storing carbon that would otherwise be released to the atmosphere and contribute to climate change. This project investigates processes in the soil that protect SOM from being completely consumed by microbes and conversely, processes that could increase its sensitivity to environmental changes. The researchers will also study how climate change and changes in how land is managed affect the amount and stability of SOM. The project involves a large number of researchers and laboratories in conducting a wide range of SOM analyses. It takes advantage of soil samples already collected by the National Ecological Observatory Network (NEON), a major NSF investment in environmental monitoring that covers the entire United States. The samples will be preserved and the data that results from this project made fully public via the web.The evolution of a new paradigm, where the primary controls on SOM dynamics are less dependent on molecular structure than on other soil and ecosystem properties, has created a knowledge gap in our ability to predict the response of SOM to environmental change. The relationships among shifting controls over different SOM stabilization mechanisms, ranging from distal factors operating at broad spatial scales (e.g., climate) to proximal controls operating at finer spatial scales (e.g., soil physicochemical properties), are poorly defined. Investigators will test the emerging paradigm by quantifying relationships between the dominant mechanisms of SOM stabilization and the scale of the ecosystem controls (i.e., fine-scale, proximal vs. broad-scale, distal) across a continental-scale system of soil types and ecological domains, utilizing soil samples collected during the construction of NEON. This project will be the first continental-scale assessment of SOM vulnerability and will yield new, predictive insights into controls on SOM stability across soil types, land-use types and environmental gradients. The results will significantly improve our understanding of SOM dynamics, a fundamental scientific advancement in its own right, while also enabling better representation of soils in ecosystem and coupled carbon-climate models. The project represents a new standard in open, community-oriented research, supporting participation by researchers from universities, government and non-government agencies. It will facilitate collaboration through major scientific networks that are increasingly necessary to conduct science at the scale needed to address the complex issues facing society. Graduate and undergraduate students will receive training in state-of-the-science methods of soil science by participating in this research, and insights derived from it will inform decisions by policymakers and resource managers concerned with carbon sequestration and ecosystem services.