نتایج جستجو برای: water retention in soil

تعداد نتایج: 17126844  

ژورنال: علوم آب و خاک 2019

Nowadays, the Beerkan computational algorithms (BESTslope and BESTsteday) are known as the suitable indirect methods for estimating soil saturated hydraulic conductivity (Ks) and sorptivity (S), as well as the scale parameter (hg) in van Genuchten soil water retention equation through the data collected in the Beerkan infiltration experiment and other required data. The purpose of this study wa...

2004
Kálmán Rajkai Sándor Kabos M.Th. van Genuchten

The unsaturated soil hydraulic functions involving the soil–water retention curve (SWRC) and the hydraulic conductivity provide useful integrated indices of soil quality. Existing and newly devised methods were used to formulate pedotransfer functions (PTFs) that predict the SWRC from readily available soil data. The PTFs were calibrated using a large soils database from Hungary. The database c...

Mojtahedi, Ali, Akhavan, Sahar , Ebrahimi, Soheila , Movahedi Naeini, Alireza , Navabian, Maryam , Shabanpour, Mahmoud ,

Background: Organic manures are the source of many pathogenic bacteria which could be dangerous for human health. Bacterial transmission and retention in soil is important for processes ranging from contaminant degradation during in situ bioremediation to transport of pathogenic bacteria into groundwater. Methods: The aim of this study was to evaluate the transport of Escherichia coli and chl...

2005
Marcel G. Schaap

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 ...

2003
A. JOHNSON D. PATEL

We present a new method of characterizing the void structures of soils from water retention curves as the primary source of data. The method avoids the problems of other current approaches, which use smoothing curves and can miss the subtleties of soil structure, and usually ignore the shielding of large pores by the small connecting throats surrounding them. In the new method, software we have...

2008
Haishen Lü Yonghua Zhu Todd H. Skaggs Zhongbo Yu

In the hilly regions of China, developing sustainable agriculture requires implementing conservation management practices that prevent soil erosion and conserve soil and water resources. In the semiarid northwest Loess Plateau, the primary conservation management practice is terracing. Numerical simulation of soil water dynamics in terraces is potentially an efficient means of investigating the...

Journal: :آب و خاک 0
بهزاد قنبریان علویجه عبدالمجید لیاقت

abstract saturated water content is one of the important parameters which its measurement is necessary in estimation of soil water retention and unsaturated hydraulic conductivity curves. in several researches, saturated water content is assumed to be equal to soil total porosity. in some others, its value is estimated by pedotransfer functions using readily available parameters, such as bulk d...

2017
Upendra M. Sainju

Nitrogen balance in agroecosystems provides a quantitative framework of N inputs and outputs and retention in the soil that examines the sustainability of agricultural productivity and soil and environmental quality. Nitrogen inputs include N additions from manures and fertilizers, atmospheric depositions including wet and dry depositions, irrigation water, and biological N fixation. Nitrogen o...

B. GHAHRAMAN R. MOAZEN ZADEH

The majority of hydraulic processes under a natural condition in a field are carried out under unsaturated flow conditions. The soil moisture retention curve (SMRC) is the most important hydraulic characteristic of an unsaturated soil whose knowledge is of prime importance in soil-water studies such as soil conservation, soil erosion, land evaluation, soil reclamation, and water resources manag...

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