Thesis
Estimating the upper limit of the soil water holding capacity using hydraulic properties and computer simulation modeling
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/102403
Abstract
Soil water storage and dynamics are of critical importance for a variety of processes in terrestrial ecosystems, including agriculture. Many of those systems are under significant pressure in terms of water availability and use. Therefore, assessing alternative scenarios through hydrological models is an increasingly valuable exercise. Soil water holding capacity is generally defined and simplified by the concepts of soil field capacity and plant available water, which are directly related to soil physical properties. These concepts define the energy status of water in the root system and closely interact with plant physiological processes. Furthermore, these concepts play a key role in the environmental transport of nutrients and pollutants. Soil physical properties (e.g. saturated hydraulic conductivity, total porosity and water characteristic curve) are required as input for field-scale soil water redistribution models. These properties are normally not easy to measure, and estimation through pedotransfer functions is often inadequate. Our objectives are to improve the field estimation of the upper limit of the soil water holding capacity (Drained Upper Limit, DUL) and its application to hydrological modeling by: (1) Applying new methodologies for determining soil physical parameters necessary as input for hydrological models; and (2) evaluating water holding capacity upper limit of two contrasting sites measured in-situ and estimated using a soil water redistribution model. Soil physical properties (saturated hydraulic conductivity and determination of water characteristic curves) were quantified using core-based undisturbed laboratory methodologies for two different soils (silt loam and sandy loam) and used as input for a soil water redistribution model (finite difference solution of Richard’s equation). Soil water redistribution were monitored after a controlled water application monitored using two soil water sensors (Decagon Devices 5TM capacitance probe and UMS T4 tensiometers). These measurements were used to establish the volumetric water content at the drained upper limit in both soils, which were compared with simulation model outputs.
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Details
- Title
- Estimating the upper limit of the soil water holding capacity using hydraulic properties and computer simulation modeling
- Creators
- Rodrigo Andres Ferreyra
- Contributors
- Claudio O. Stockle (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525065901842
- Language
- English
- Resource Type
- Thesis