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

管理水资源需要充分了解水循环。然而，目前的理解可能遗漏了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，最近被发现在几十年的时间里，随着降水模式的变化，变化的速度比之前想象的要快。土壤结构的波动改变了地表附近可储存的水量以及水在土壤中流动的容易程度。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如何共同作用或被土壤性质改变。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-水分对不同环境条件的反应。这项研究可能会通过开发下一代模型来满足这一需求，该模型包括美国当地土壤的生物、物理和化学相互作用。通过这些模式的开发，将培训5名在STEM领域代表性不足的少数族裔教师、4名博士后学者和10名本科生研究人员。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，并纳入四所大学的现有课程。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。这项研究可能会改进对未来水资源、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(经验模型和过程模型)，将土壤结构和功能联系起来，以加强对数十年至数百年时间尺度上的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上收集的土壤、植物和水生微生物群数据(NSF堪萨斯建立的激励竞争研究计划的一部分，EPSCoR)和大陆规模的土壤数据库(例如，美国农业部国家合作土壤调查土壤特征数据库)进行参数化。将开发结构方程、二维泥炭、流域和大陆尺度模型，以检查和说明土壤水力特性(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：从机理上理解大孔随气候的演变；开发依赖气候的泥炭、流域和大陆尺度模式的土壤迁移函数；土壤微生物群落对土壤结构变化的预测能力；从机理上理解土壤大孔-地形-山坡结构-气候相互作用；以及从气候诱导的大孔变化到生物地球化学和从泥炭到大陆尺度的水循环的量化。本文提出的建模工具有望随着时间的推移解决环境可持续性问题，并增强对陆地-大气动态、地下水储存、地下水位波动和洪水事件的预测能力。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管理营养通量，并最终将有助于缓解全国范围内的问题，如管理氮循环和墨西哥湾死区。最后，这项工作将测试一项新的生命法则(ROL)：生命对气候驱动的土壤结构变化的反应，促使综合陆地反应的出现，比通常认为的更快。这一奖项反映了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。

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.