نتایج جستجو برای: soil moisture retention curve

تعداد نتایج: 395269  

2012
Rivka Reichman Scott R. Yates Todd H. Skaggs Dennis E. Rolston

Pesticide volatilization from agricultural soils is one of the main pathways in which pesticides are dispersed in the environment and affects ecosystems including human welfare. Thus, it is necessary to have accurate knowledge of the various physical and chemical mechanisms that affect volatilization rates from field soils. A verification of the influence of soil moisture modeling on the simula...

Journal: :تحقیقات مهندسی کشاورزی 0
علی اصغر خوشنود یزدی مربی آموزشکده کشاورزی شیروان، دانشگاه فردوسی مشهد بیژن قهرمان استادیار گروه آبیاری دانشکده کشاورزی، دانشگاه فردوسی مشهد

the arya and paris model is a commonly accepted method to translate a particle-size distribution curve into a corresponding soil moisture characteristic curve using scaling parameter (α). the scaling parameter, in the original model of arya and paris (1981), was assumed constant (α=1.38) for all soil texture classes. in recent years, several studies have shown that α is not constant and its qua...

Journal: :پژوهش آب در کشاورزی 0
امید بهمنی استادیار دانشگاه بوعلی سینا. بهرام رمضانی دانشجوی سابق کارشناس ارشد دانشگاه بوعلی سینا.

soil water retention curve (swrc) is important in the studies of soil and water relationship, soil conservation, irrigation scheduling, drainage, solute transport, plant growth and crop water stress. the performance of 10 models (simons et al., libardy et al., campbell, farrell and larson, van genuchten, brooks and corey, driessen, exponential bruce-luxmore, power bruce-luxmore, and rogowski) w...

Journal: :Computer and Information Science 2011
Ali Keshavarzi Fereydoon Sarmadian Reza Labbafi Abbas Ahmadi

Study of soil properties like field capacity (F.C) and permanent wilting point (P.W.P) plays important roles in study of soil moisture retention curve. Pedotransfer functions (PTFs) provide an alternative by estimating soil parameters from more readily available soil data. In this study, a new approach is proposed as a modification to a standard fuzzy modeling method based on the table look-up ...

Journal: :تحقیقات مهندسی کشاورزی 0
بهزاد قنبریان علویجه دانشجوی سابق کارشناسی ارشد عبدالمجید لیاقت دانشیار دانشکده مهندسی آب و خاک دانشگاه تهران مهدی شرفا استادیار دانشکده مهندسی آب و خاک دانشگاه تهران سامان مقیمی عراقی استادیار دانشکده فیزیک دانشگاه صنعتی شریف.

the soil water retention curve (swrc) is a basic characteristic of the determination of soil hydraulic properties, including unsaturated hydraulic conductivity. measurement of this curve is essential to research, thus scientists have focused on indirect methods such as pedotransfer functions and empirical relationships to estimate swrc easily. since there is a close relationship between swrc an...

Journal: :journal of agricultural science and technology 2012
hojat emami mohammad reza neyshabouri mahdi shorafa

soil quality is a necessary indicator of land management. different indices are applied to evaluate farming systems, soil types and land uses based on soil quality. the slope of retention curve at its inflection point has been defined as soil physical quality index (si) but the relationships between si and penetration resistance (pr), the least limiting water range (llwr), and available water c...

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...

2006
Troy D. Heithecker Charles B. Halpern

Green-tree or structural retention is becoming increasingly common as a method of regeneration harvest in the Pacific Northwest. Amelioration of microclimatic stress is assumed to be one mechanism by which overstory retention enhances the survival of forest organisms and the potential for ecosystem recovery following timber harvest. We examined patterns of transmitted light (photosynthetic phot...

Journal: :تحقیقات مهندسی کشاورزی 0
بهزاد قنبریان علویجه دانشجوی دکتری دانشکده آب و خاک پردیس کشاورزی و منابع طبیعی دانشگاه تهران عبدالمجید لیاقت دانشیار گروه آبیاری و آبادانی دانشکده آب و خاک پردیس کشاورزی و منابع طبیعی دانشگاه تهران سمانه سهرابی دانشجوی کارشناسی ارشد گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز

soil hydraulic properties such as saturated and unsaturated hydraulic conductivity play an important role in environmental research. since direct measurement of these soil hydraulic properties is time-consuming and costly, indirect methods such as pedotransfer functions and artificial neural networks (ann) were developed based on readily available parameters. in this study, the use of ann to pr...

2006
Rashid Al-Yahyai Bruce Schaffer Frederick S. Davies Rafael Muñoz-Carpena

Soil-water characteristic curves were determined for Krome calcareous very gravelly loam soil in the laboratory and in situ in an orchard. In the laboratory, soil-water retention was determined with a pressure plate and pressure Tempe cells for soil collected from vegetable fields. In the orchard, soil-water suction measured with tensiometers was compared to volumetric soil-water content (E) de...

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