EAR-PF Cracking the Critical Zone: Tree roots in fractures and a proposed mechanistic soil production function

EAR-PF 破解关键区域：裂缝中的树根和提出的机械土壤生产函数

• 批准号: 1452694
• 负责人: Jill Marshall
• 金额: $ 8.7万
• 依托单位: Marshall Jill A
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1452694&HistoricalAwards=false
• 关键词: EAR; PF; Cracking; Critical; Zone

Dr. Jill Marshall has been granted an NSF EAR Postdoctoral Fellowship to carry out a research and education plan at the University of California, Berkeley, in collaboration with the University of Colorado, Boulder. She will develop numerical models to describe the effect tree roots have on soil production. The investigation is important across a broad range of problems in critical zone science, from understanding landscape evolution to quantifying soils sustainability. The investigation will use data collected at three Critical Zone Observatories (Eel River, Boulder Creek, and Southern Sierra CZOs) that have patches of terrain with thin to no soils and bedrock exposures. This enables quantitative observations of tree roots growing in fractures across sites underlain by different lithologies and fracture patterns. The development of a biomechanical soil production model will allow for improved insight into the role of vegetation in soil sustainability and resilience. The education plan, based in Round Valley, CA (a rural region in the Eel watershed encompassing the Round Valley Indian Tribal Lands) has two components: multi-age field-based science activities directed at the school district's students and a LiDAR workshop for the Tribes' Natural Resource Department. The educational plans were developed with extensive community input and these synergistic activities meet the community's needs of expanding access to science activities and providing tools for future endeavors.Research in this project will test the hypothesis that depth-dependent soil production is a function of root pressures, variations in root density with depth, and tree sway modulated by rock properties. To develop a geomorphic transport law that describes how and why soil production rates vary with depth, this project will combine Discrete Element Method simulations incorporating bonded grains, rock properties, and field-derived values for root pressures at the bedrock interface from data collected at the three Critical Zone Observatories. A suite of bedrock-impeded tree roots will be monitored with force sensors to measure external root pressures generated from growth, diurnal fluctuations due to tree water fluxes, and torque about the tree base from wind and snow events. Hydrologic routing, net primary productivity, carbon storage in soils, and mineral supplies for the geochemical reactor are all linked to rates of soil production. By including tree-driven processes in a geomorphic process law for soil production, this project will enable numerical experiments that explore how the presence and absence of vegetation control surface and near-surface processes and landscape form.

吉尔马歇尔博士已被授予美国国家科学基金会博士后奖学金，在加州大学伯克利分校与科罗拉多大学博尔德分校合作开展研究和教育计划。她将开发数值模型来描述树根对土壤生产的影响。该调查在关键区域科学的广泛问题中非常重要，从了解景观演变到量化土壤可持续性。调查将使用在三个关键区观测站（鳗鱼河、博尔德溪和南塞拉利昂CZO）收集的数据，这些观测站有薄至无土壤和基岩暴露的地形斑块。这使得在不同岩性和断裂模式下的断裂中生长的树根的定量观察成为可能。生物力学土壤生产模型的发展将有助于更好地了解植被在土壤可持续性和恢复力中的作用。教育计划，总部设在圆谷，CA（鳗鱼流域的农村地区，包括圆谷印第安部落土地）有两个组成部分：多年龄的实地科学活动，针对学区的学生和LiDAR研讨会部落的自然资源部。教育计划的制定与广泛的社区投入，这些协同活动满足社区的需要，扩大获得科学活动，并提供工具，为未来的effortes.Research在这个项目中将测试的假设，即深度依赖的土壤生产是根压力的函数，根密度随深度的变化，和岩石属性调制的树摇摆。为了开发一个地貌运输法，描述土壤生产率如何以及为什么随深度变化，该项目将结合联合收割机离散元法模拟结合粘结颗粒，岩石特性，并从三个关键区观测站收集的数据在基岩界面根压力的字段派生值。一套的rock阻碍树根将与力传感器监测，以测量外部根的压力产生的增长，昼夜波动，由于树的水通量，和扭矩的树基地从风和雪事件。水文路由，净初级生产力，土壤中的碳储存，以及地球化学反应器的矿物供应都与土壤生产率有关。通过将树木驱动的过程纳入土壤生产的地貌过程法，该项目将能够进行数值实验，探索植被的存在和不存在如何控制地表和近地表过程和景观形式。