نتایج جستجو برای: hydraulic gradient and soil texture

تعداد نتایج: 16890477  

Journal: :آب و خاک 0
متقیان متقیان محمّدی محمّدی

abstract the effect of land use type on soil functioning within an ecosystem can be assessed and monitored using soil quality attributes. such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. in ...

2013
Paolo Nasta Jasper A. Vrugt Nunzio Romano

[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...

R. Sedghi S. Bairami Y. Hoseini

ABSTRACT-Determining hydraulic conductivity of soil is difficult, expensive, and time-consuming. In this study, Algorithm Genetic and geostatistical analysis and Neural Networks method are used to estimate soil saturated hydraulic conductivity using the properties of particle size distribution. The data were gathered from 134soil profiles from soil and lander form studies of the Ardabil Agricul...

Journal: :Plant, cell & environment 2006
R N Addington L A Donovan R J Mitchell J M Vose S D Pecot S B Jack U G Hacke J S Sperry R Oren

We investigated relationships between whole-tree hydraulic architecture and stomatal conductance in Pinus palustris Mill. (longleaf pine) across habitats that differed in soil properties and habitat structure. Trees occupying a xeric habitat (characterized by sandy, well-drained soils, higher nitrogen availability and lower overstory tree density) were shorter in stature and had lower sapwood-t...

ژورنال: سلامت و محیط زیست 2019

Background and Objective: Groundwater resources are the most valuable resources of each country. Development of agricultural activities in Ardabil plain and over-use of fertilizers and pesticides, improper disposal of municipal sewage and industrial areas are responsible for groundwater pollution. Clean-up of groundwater resources is very difficult and expensive. One of suitable method in preve...

1999
Jiřı́ Šimůnek Radka Kodešová Molly M. Gribb Martinus T. van Genuchten

Data obtained from modified cone penetrometer experiments were used to estimate the hysteretic soil hydraulic properties with a parameter estimation technique which combined a numerical solution of the Richards equation with Marquardt-Levenberg optimization. The modified cone penetrometer was designed to inject water into a soil through a cylindrical screen, measure the infiltration rate with t...

2011
Donald M. Reeves Rishi Parashar Greg Pohll

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...

2001
Shmuel Assouline Daniel M. Tartakovsky

We present a new two-parameter expression for relative hydraulic conductivity (RHC) of partially saturated soils. It is based on the premise of Assouline et al. [1998] that soil structures evolve from a uniform random fragmentation process. This assumption allows us to derive hydraulic properties of soils (water retention curves and unsaturated hydraulic conductivity) from primary properties, s...

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