Revealing Soil Hydraulic Properties

了解土壤中水分的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。控制水分储存和运移的土壤水力性质在时间和空间上具有很大的变异性，用现有的技术很难测量。这项研究试图开发使用更容易测量的土壤热电属性值来估计土壤水力属性值的模型。科学家和工程师可以将这些模型与现有的测量技术结合使用，以应对与食品、能源和环境安全相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。土壤水力特性控制土壤水分含量的转变，从而推动陆地水文循环中的无数过程。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因素。由于土壤结构对水力、电学和热学性质的相关影响，可以假设更容易测量的土壤电学和热学性质可以作为确定水力性质的替代方法。这项拟议的研究旨在更好地了解完整土壤的水力、电学和热学性质之间的基本关系，并开发根据替代的电学和热学性质数据原位估计土壤水力性质的方法。温度-时间域反射仪传感器将用于测量来自北卡罗来纳州和爱荷华州野外现场的完整和重新包装的样品的土壤电、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，拟议的工作将立即实现现场水力特性测定，这是目前任何现有方法都不可能实现的。由于基本测量是热学和电学性质，基本方法也有可能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。这项拟议的工作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。

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.