SitS: Collaborative Research: Soils are signaling shifts in aggregate life-cycles: What does this mean for water, carbon and climate feedbacks in the Anthropocene?

SitS：合作研究：土壤正在发出总体生命周期变化的信号：这对人类世的水、碳和气候反馈意味着什么？

• 批准号: 2034214
• 负责人: Li Li
• 金额: $ 23.3万
• 依托单位: Pennsylvania State Univ University Park
• 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: 2021-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2034214&HistoricalAwards=false
• 关键词: SitS; Collaborative; Research; Soils; signaling

Healthy soils support the production of food, store rainfall, transmit and filter groundwater, and provide habitat for plants, animals, and microbes. Much of the volume of these soils is comprised of aggregates that represent the binding of particles (e.g., clay) and organic matter (generated by plants and microbes) into larger units. How these larger aggregate units are arranged controls the shapes of pores between aggregates, and thus the characteristics of the pore network. As a result, aggregate arrangement governs how water flows through soil. Interestingly, aggregates have a life-cycle: they form, persist for largely unknown time periods, and then degrade. Several recent studies suggest that the speed at which aggregates move through this life-cycle is controlled by changes in rainfall, temperature, and land-use patterns. This research aims to make explicit linkages between environmental drivers and aggregate life-cycles across various scales: from very small individual aggregates, to their arrangements and effects on water flow through a soil profile, and, finally, how they influence water flow at hillslope, regional, and continental scales. At these broader scales, this study will uncover the role that these aggregate life-cycles and arrangements have on influencing soil moisture, vegetation and climate. Findings from this work will reveal how soils respond to changing climate and how those responses can in turn influence climate, facilitate model development for forecasting the impacts of climate change on water resources, food production and ecosystems, and promote the development of strategies to adapt to future environmental realities. The goal of this research is to mechanistically link soil aggregate life-cycles and arrangements to water flow, carbon cycling, and biogeochemical fluxes from soil particles to continental scales. Aggregate soil organic carbon (SOC) is a key structural component that gives rise to the soil pore and hydraulic properties observed at broader soil horizon and pedon scales. Thus, by examining both biotic and abiotic mechanisms governing rates of formation and collapse of soil aggregates, investigators can quantify and project the structural response of the soil fabric to changing climate and land use—features largely overlooked in current modeling frameworks. To accomplish this goal, our multi-disciplinary team will leverage soil samples and data from existing environmental observatories (e.g., United States Department of Agriculture, NSF-funded long-term research sites) and National Ecological Observatory Network sites, as well as ancillary data (e.g., Natural Resources Conservation Service Soil Climate Analysis Network and remotely sensed products), that represent gradients of climate, land use, and soil texture to: 1) investigate biotic and abiotic drivers of soil aggregate formation and collapse, arrangement, and pore geometry through manipulative experiments that quantify the influence of binding agent abundance, mineral surface area, and overburden pressure, which varies with soil depth, on these trajectories; 2) relate gross rates of aggregate formation and collapse to rates of microbial activity and SOC mineralization; 3) quantify how and to what degree aggregate arrangements influence porosity and, thus, water and C fluxes with depth; 4) develop new tools that leverage remotely-sensed soil moisture and vegetation properties at the soil surface to predict depth distributions of soil aggregate and related properties; 5) integrate a mechanistic understanding of empirically quantified soil processes from the individual aggregate to the pedon scale into hillslope- to watershed-scale models to project soil biogeochemical responses to changes in soil pore development; and, 6) model the continental-scale effects of changing aggregate life-cycles and arrangements on the biogeochemistry of soil systems and resulting feedbacks to climate. Advances from this research will improve understanding of soil capacity to perform ecosystem services now and in the future, elucidating physical, chemical, and biogeochemical processes affecting fluxes, transformation, and storage of water and C in ecosystems.This award was made through the Signals in the Soil (SitS)" solicitation, a collaborative partnership between the National Science Foundation and the United States Department of Agriculture National Institute of Food and Agriculture (USDA NIFA).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.

健康的土壤支持食物的生产，储存降雨，传输和过滤地下水，并为植物，动物和微生物提供栖息地。这些土壤的大部分体积由代表颗粒结合的聚集体组成（例如，粘土）和有机物（由植物和微生物产生）形成更大的单元。这些较大的聚集体单元如何排列控制聚集体之间的孔的形状，从而控制孔网络的特征。因此，团聚体的排列决定了水如何流过土壤。有趣的是，聚集体有一个生命周期：它们形成，持续很大程度上未知的时间段，然后降解。最近的几项研究表明，聚集体在这一生命周期中的移动速度受到降雨量、温度和土地利用模式变化的控制。这项研究的目的是明确的环境驱动因素和聚合物的生命周期之间的联系，在不同的尺度：从非常小的个人聚合物，他们的安排和对水流通过土壤剖面的影响，最后，他们如何影响水流在山坡上，区域和大陆尺度。在这些更广泛的尺度上，这项研究将揭示这些总的生命周期和安排对影响土壤水分，植被和气候的作用。这项工作的结果将揭示土壤如何对气候变化作出反应，以及这些反应如何反过来影响气候，促进模型的开发，以预测气候变化对水资源、粮食生产和生态系统的影响，并促进制定适应未来环境现实的战略。本研究的目的是从机制上联系土壤团聚体的生命周期和安排，水流量，碳循环，从土壤颗粒到大陆尺度的地球化学通量。土壤团聚体有机碳（SOC）是影响土壤孔隙和水力性质的重要结构组分。因此，通过研究生物和非生物机制的形成和崩溃的土壤团聚体的速率，调查人员可以量化和项目的土壤结构变化的气候和土地利用功能的结构响应，在目前的建模框架很大程度上被忽视。为了实现这一目标，我们的多学科团队将利用现有环境观测站的土壤样本和数据（例如，美国农业部、国家科学基金会资助的长期研究站点）和国家生态观测站网络站点，以及辅助数据（例如，自然资源保护局土壤气候分析网络和遥感产品），代表气候、土地利用和土壤质地的梯度，以便：1）通过量化结合剂丰度、矿物表面积和上覆压力（随土壤深度变化）的影响的操纵性实验，研究土壤团聚体形成和塌陷、排列和孔隙几何形状的生物和非生物驱动因素，2）将骨料形成和坍塌的总速率与微生物活动和SOC矿化速率相关联; 3）量化骨料排列如何以及在何种程度上影响孔隙度，从而影响水和C通量随深度的变化; 4）开发远程利用的新工具-通过对土壤水分和地表植被特性的监测，预测土壤团聚体及其相关特性的深度分布;（5）将从个体团聚体到土壤尺度的经验量化土壤过程的机理理解整合到山坡到流域尺度的模型中，以预测土壤孔隙发育变化的土壤生态地球化学响应; 6）模拟土壤系统中团聚体生命周期和结构变化对土壤生态地球化学的大陆尺度影响及其对气候的反馈。这项研究的进展将提高对土壤现在和未来执行生态系统服务能力的理解，阐明影响生态系统中水和C的通量、转化和储存的物理、化学和生物地球化学过程。国家科学基金会和美国农业部国家粮食和农业研究所之间的合作伙伴关系该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

From Soils to Streams: Connecting Terrestrial Carbon Transformation, Chemical Weathering, and Solute Export Across Hydrological Regimes

• DOI: 10.1029/2022wr032314
• 发表时间: 2022-06
• 期刊: Water Resources Research
• 影响因子: 5.4
• 作者: H. Wen;P. Sullivan;S. Billings;H. Ajami;Alejandro Cueva;A. Flores;D. Hirmas;A. Koop;K. Murenbeeld;Xi Zhang;Li Li-Li

Root distributions, precipitation, and soil structure converge to govern soil organic carbon depth distributions

• DOI: 10.1016/j.geoderma.2023.116569
• 发表时间: 2023-09
• 期刊: Geoderma
• 影响因子: 6.1
• 作者: Ligia F. T. de Souza;D. Hirmas;P. Sullivan;D. Reuman;M. Kirk;Li Li-Li;H. Ajami;H. Wen;M. V. Sarto;T. Loecke;Aoesta K. Rudick;C. Rice;S. Billings

Drier streams despite a wetter climate in woody-encroached grasslands

• DOI: 10.1016/j.jhydrol.2023.130388
• 发表时间: 2023-11
• 期刊: Journal of Hydrology
• 影响因子: 6.4
• 作者: K. Sadayappan;R. Keen;K. M. Jarecke;Victoria Moreno;J. Nippert;Matthew F. Kirk;Pamela L. Sullivan;Li Li-Li

Is macroporosity controlled by complexed clay and soil organic carbon?

• DOI: 10.1016/j.geoderma.2023.116565
• 发表时间: 2023-09
• 期刊: Geoderma
• 影响因子: 6.1
• 作者: A. Koop;D. Hirmas;S. Billings;Li Li-Li;Alejandro Cueva;Xi Zhang;H. Wen;A. Nemes;Ligia F. T. de Souza-Lig