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.

健康的土壤支持粮食生产，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团聚体组成，这些团聚体代表着颗粒(例如粘土)和有机物(由植物和微生物产生)结合成更大的单位。这些较大的集合体单元的排列方式控制着集合体之间的孔隙形状，从而控制着孔隙网络的特征。因此，团聚体的排列决定了水分如何流过土壤。有趣的是，聚集体有一个生命周期：它们形成，在很大程度上未知的时间段内持续，然后降解。最近的几项研究表明，集合体在这个生命周期中移动的速度受降雨量、温度和土地利用模式的变化控制。这项研究的目的是在不同尺度上建立环境驱动因素和总体生命周期之间的明确联系：从非常小的个体集合体，到它们的安排和对通过土壤剖面的水流的影响，最后，它们如何影响山坡、区域和大陆尺度的水流。在这些更广泛的尺度上，这项研究将揭示这些聚集的生命周期和安排对土壤水分、植被和气候的影响。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，促进建立预测气候变化对水资源、粮食生产和生态系统的影响的模型，并促进制定适应未来环境现实的战略。这项研究的目标是将土壤团聚体的生命周期和排列与水流、碳循环和从土壤颗粒到大陆尺度的生物地球化学通量联系起来。团聚体土壤有机碳(SOC)是引起土壤孔隙和水力性质的关键结构成分，在更广泛的土层和土壤尺度上可以观察到。因此，通过研究控制土壤团聚体形成和崩塌速度的生物和非生物机制，研究人员可以量化和预测土壤结构对气候和土地利用变化的结构反应--这些特征在当前的建模框架中基本上被忽视了。为了实现这一目标，我们的多学科团队将利用来自现有环境观测站(例如，美国农业部、NSF资助的长期研究地点)和国家生态观测网络站点的土壤样本和数据，以及代表气候、土地利用和土壤质地梯度的辅助数据(例如，自然资源保护局土壤气候分析网络和遥感产品)：1)通过操纵实验来研究土壤团聚体形成和坍塌、排列和孔隙几何的生物和非生物驱动因素，这些实验量化了结合剂丰度、矿物表面积和超载压力的影响，这些影响随土壤深度而变化。在这些轨迹上；2)将团聚体形成和崩解的总速率与微生物活动速率和有机碳矿化速率联系起来；3)量化团聚体排列如何以及在多大程度上影响孔隙度，从而影响土壤水分和碳通量随深度的变化；4)开发利用遥感土壤水分和地表植被特性来预测土壤团聚体深度分布和相关性质的新工具；5)将从单个团聚体到土壤颗粒尺度的经验量化土壤过程的机械理解集成到山坡到流域尺度的模型中，以预测土壤对土壤孔隙发育变化的生物地球化学响应；以及，6)模拟改变团聚体生命周期和安排对土壤系统的生物地球化学以及由此对气候的反馈所产生的大陆尺度效应。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的能力的理解，阐明影响生态系统中水和碳的通量、转化和储存的物理、化学和生物地球化学过程。该奖项是通过土壤中的信号(SITS)“征集”颁发的，这是美国国家科学基金会和美国农业部国家粮食和农业研究所(USDA NIFA)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智力优势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