RAISE-SitS: Designing models to forecast how biogeochemical fluctuations in soil systems govern soil development, terrestrial water storage and ecosystem nutrient fluxes

管理水资源需要对水循环有充分的了解。然而，目前的认识可能缺少水循环的一个基本因素——土壤结构。土壤结构，即土壤颗粒和孔隙的排列，最近被发现随着降水模式的变化而变化的速度比以前认为的要快——在几十年的时间里。土壤结构的波动改变了可以储存在地表附近的水量以及水在土壤中流动的难易程度。虽然植物、动物和微生物可能在改变土壤结构方面起主导作用，但尚不清楚这些过程是如何共同起作用的，或者是如何被土壤性质所改变的。需要新的数学模型来研究这些观察到的土壤结构变化的原因，并检查植物-土壤-水对不同环境条件的反应。这项研究可能通过开发下一代模型来满足这一需求，这些模型包括来自美国当地土壤的生物、物理和化学相互作用。通过这些模型的发展，来自STEM领域代表性不足的少数民族的五名教师、四名博士后学者和十名本科研究人员将得到培训。这些发现将通过网络研讨会、在线工具和本地演示向社区传播，并整合到四所大学的当前课程中。这些模型将允许在不同的空间和时间尺度上评估土壤结构波动对生态系统过程的影响。该研究可以改善对未来水资源、土壤和相关生态系统服务的可用性和质量的预测。将在多个空间尺度上开发土壤生态系统模型（经验的和基于过程的），将土壤结构和功能联系起来，以便在几十年到几百年的时间尺度上加强对水和生物地球化学通量的预测。这些模型将使用在美国中部强降水梯度中收集的土壤、植物和水生微生物组数据进行参数化（EPSCoR是美国国家科学基金会堪萨斯州建立的刺激竞争研究计划的一部分）和大陆尺度土壤数据库（例如，美国农业部国家合作土壤调查土壤特征数据库）。将开发结构方程、二维土壤、流域和大陆尺度模型，以检查和解释土壤水力特性（例如大孔隙和Ksat）与陆地生物地球化学通量之间的相互作用。这项工作的成果将包括：对气候下大孔演化的机制理解；土壤、流域和大陆尺度模式中气候依赖土壤转移函数的建立土壤微生物群落对土壤结构变化响应的预测能力土壤大孔隙-地形-山坡结构-气候相互作用机理研究从土壤到大陆尺度的生物地球化学和水循环的气候诱导大孔变化的量化。本文提出的建模工具有望解决环境随时间的可持续性问题，并增强预测陆地-大气动力学、地下蓄水、地下水位波动和洪水事件的能力。这些模型将提供社区可访问的工具，以检查土壤、水文和生物地球化学反馈如何控制养分流动，并最终将有助于缓解全国性问题，如管理氮循环和墨西哥湾死区。最后，这项工作将测试一个新的生命规则（RoL）：生命对土壤结构中气候驱动的变化的反应，促使综合陆地反应的出现，比通常认为的要快。该奖项反映了美国国家科学基金会的法定使命，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。

Managing water resources requires a full understanding of the water cycle. The current understanding may, however, be missing a fundamental factor of the water cycle-soil structure. Soil structure, the arrangement of soil particles and pores, was recently discovered to be changing faster than previously thought - over a few decades - in response to shifts in precipitation patterns. Fluctuations in soil structure alter the amount of water that can be stored near the surface and the ease with which water moves through the soil. Although plants, animals, and microbes may have dominant roles in altering soil structure, it is unclear how these processes work together or are modified by soil properties. New mathematical models are needed to study the causes of these observed alterations in soil structure and to examine plant-soil-water responses to varying environmental conditions. The research may fill this need by developing the next generation of models to include biological, physical, and chemical interactions from local soils in the US. Through the development of these models, five faculty from minority groups underrepresented in STEM fields, four postdoctoral scholars, and ten undergraduate researchers will be trained. The discoveries will be disseminated to the community through webinars, online tools, and local presentations as well as integrated into current curricula across four universities. The models will allow the effects of soil structure fluctuations on ecosystem processes to be evaluated at diverse spatial and time scales. The research may improve forecasting of future availability and quality of water resources, soils, and associated ecosystem services. Soil ecosystem models (empirical and process-based) will be developed at multiple spatial scales to link soil structure and function in order to enhance the prediction of water and biogeochemical fluxes on timescales of decades to centuries. These models will be parameterized using soil, plant, and aquatic microbiome data collected across a strong precipitation gradient in the central USA (part of NSF Kansas Established Program to Stimulate Competitive Research, EPSCoR) and continental-scale soil databases (e.g., the National Cooperative Soil Survey Soil Characterization Database, United States Department of Agriculture). Structural equation, 2-D pedon, watershed and continental scale models will be developed to examine and account for the interaction between soil hydraulic properties (e.g., macropores and Ksat) and terrestrial biogeochemical fluxes. Products from this work will include: a mechanistic understanding of macropore evolution with climate; development of climate-dependent pedotransfer functions for pedon, watershed, and continental-scale models; predictive capabilities for soil microbial community responses to changing soil structure; a mechanistic understanding of soil macropore-topography-hillslope structure-climate interactions; and quantification of climate-induced macropore changes to biogeochemistry and water cycles from the pedon to the continental scale. The modeling tools proposed here are expected to address environmental sustainability over time and enhance the ability to predict land-atmosphere dynamics, subsurface water storage, water table fluctuations, and flood events. These models will provide community-accessible tools to examine how soil, hydrologic and biogeochemical feedbacks govern nutrient fluxes, and will ultimately be useful toward alleviating nationwide problems such as managing the nitrogen cycle and the Gulf of Mexico dead zone. Finally, this work will test a new Rule of Life (RoL): Life's responses to climate driven changes in the soil fabric which prompt the emergence of integrated terrestrial responses that are more rapid than typically considered.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.