Many aspects of plant water use -- particularly in response to soil drought -- may have as their basis the alteration of hydraulic conductance from soil to canopy. The regulation of plant water potential (Psi) by stomatal control and leaf area adjustment may be necessary to maximize water uptake on the one hand, while avoiding loss of hydraulic contact with the soil water on the other. Modellin...

[1] Prediction of flow through variably saturated porous media requires accurate knowledge of the soil hydraulic properties, namely the water retention function (WRF) and the hydraulic conductivity function (HCF). Unfortunately, direct measurement of the HCF is time consuming and expensive. In this study, we derive a simple closed-form equation that predicts the saturated hydraulic conductivity...

The scaling theory approach has been widely used as an effective method to describe the variation of soil hydraulic properties. In conventional scaling, reference retention curves and scaling factors are determined from minimization of residuals. Most previous studies have shown that scaling factors are lognormally distributed. In this study, we derived physically based scaling factors, assumin...

[1] In the past, texture-based classification of soils has been used for grouping soils in variably saturated water flow and solute transport studies. Classification of soils becomes especially important for large-scale studies where the spatial and temporal variability in the hydraulic properties of soils exceeds the field sampling capabilities. Although soiltexture-based classification has be...

The study was conducted to evaluate hydraulic conductivity functions in relation to some soil chemical properties in an oxisols of the tropics. Field and laboratory studies were carried out and data collected, subjected to statistical analytical procedure for computing coefficient of variability and correlation among soil properties. Results of the study showed that hydraulic conductivity funct...

Soil absorption systems (SAS) are used commonly to treat and disperse septic tank effluent (STE). SAS can hydraulically fail as a result of the low permeable biomat zone that develops on the infiltrative surface. The objectives of this experiment were to compare the hydraulic properties of biomats grown in soils of different textures, to investigate the long-term acceptance rates (LTAR) from pr...

The unsaturated soil hydraulic properties are often described using Mualem–van Genuchten (MVG) type analytical functions. Recent studies suggest several shortcomings of these functions near saturation, notably the lack of second-order continuity of the soil water retention function at saturation and the inability of the hydraulic conductivity function to account for macroporosity. We present a ...

soil hydraulic properties such as soil water characteristic curve are necessary prerequisite for modeling water movement and solute transport. direct methods of estimating these hydraulic properties are time consuming and costly. indirect methods, such as pedotransfer functions, estimate the hydraulic parameters using easy-to-measure soil properties like particle size distributions, bulk densit...

It is common for subsurface flow to transition between porous and fractured media. Two examples include vertical infiltration of precipitation through a permeable soil overlying a fractured bedrock, and horizontal ground water flow through a combination of porous and fractured geologic units. A reduction in flow or flow impedance may occur across these interfaces caused by head losses associate...