Revealing Soil Hydraulic Properties

了解土壤中的水储存和运动对于解决广泛的农业、工程和环境问题至关重要。控制水分储存和运动的土壤水力特性在时间和空间上都是高度可变的，用现有技术很难测量。本研究旨在开发使用更容易测量的土壤热和电性质值来估计土壤水力性质值的模型。科学家和工程师可以将这些模型与现有的测量技术一起使用，以解决与食品、能源和环境安全有关的广泛的国家和全球挑战。该项目还将为博士后学者以及研究生和本科生研究人员提供培训机会。土壤水力特性控制着土壤含水量的变化，从而驱动陆地水文循环的无数过程。因此，测量和预测土壤水力特性的能力至关重要，但仍然是水文科学的主要限制。由于土壤结构对水力、电性和热性的相关影响，假设更容易测量的土壤电性和热性可以一起作为确定水力特性的替代指标。该研究旨在更好地理解完整土壤的水力、电性和热性之间的基本关系，并开发从替代电性和热性数据中原位估计土壤水力特性的方法。热时域反射计传感器将用于测量来自北卡罗莱纳州和爱荷华州现场的完整和重新包装样品的土壤电、热和水力特性，以及现场测量。收集的数据集将支持研究团队以及更广泛的研究社区的建模工作。如果成功，该工作将立即实现目前任何现有方法都无法实现的原位水力特性测定。由于基本测量是热学和电学性质，因此基本方法也可以扩展到一系列传感平台。该项目将包括研究生和本科生的研究经验（REU）培训机会，以及为非附属研究人员提供的关于土壤热学和电学性质测量的短期课程。提议的努力旨在促进对基本水文过程的发现和理解，同时促进不同学生和其他研究人员的教学、培训和学习。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。

Understanding of water storage and movement in soil is critically important to solve a wide range of agricultural, engineering, and environmental problems. The soil hydraulic properties that control water storage and movement are highly variable in time and space, and difficult to measure with existing technologies. This research seeks to develop models that use more easily-measured soil thermal and electrical property values to estimate soil hydraulic property values. These models can be used with existing measurement technologies by scientists and engineers working to address a wide range of national and global challenges related to food, energy, and environmental security. The project will also provide training opportunities for a post-doctoral scholar, and both graduate and undergraduate student researchers.Soil hydraulic properties control transitions in soil water content, thereby driving myriad processes in the terrestrial hydrologic cycle. Capability to measure and predict soil hydraulic properties is thus critically important, yet remains a major limitation for the hydrologic sciences. Owing to relatable influences of soil structure on hydraulic, electrical, and thermal properties, it is hypothesized that more-easily measured soil electrical and thermal properties can be used together as surrogates to determine hydraulic properties. The proposed investigation seeks both to better understand fundamental relationships among soil hydraulic, electrical, and thermal properties for intact soils, and to develop approaches for in situ estimation of soil hydraulic properties from surrogate electrical and thermal property data. Thermo-time domain reflectometer sensors will be used to measure soil electrical, thermal, and hydraulic properties of intact and repacked samples from field sites in North Carolina and Iowa, as well as for in situ measurements in the field. The collected dataset will support modeling efforts for the research team as well as the broader research community. If successful, the proposed work will immediately enable in situ hydraulic property determinations that are not currently possible with any existing approaches. And because the fundamental measurements are thermal and electrical properties, the basic approach can also potentially be extended to a range of sensing platforms. The project will include both graduate and undergraduate research experience (REU) training opportunities, and a short-course for non-affiliated researchers on the measurement of soil thermal and electrical properties. The proposed effort aims to advance discovery and understanding for fundamental hydrological processes while promoting teaching, training, and learning for diverse students and other researchers.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.