نتایج جستجو برای: soil hydraulic parameters

تعداد نتایج: 769656  

Journal: :iran agricultural research 2007
m. parsinejad y. feng b. ghanbarian

soil water content is one of the most important parameters for estimating irrigation frequency and providing the plant’s water requirement. since measurement of soil water content is both expensive and time consuming, water movement models are used to estimate these values. in this study, leachw model was used to estimate soil water content for two “dry” (20-29 aug) and “wet” (1-6 jul) periods ...

2011
Tarek Selim Ronny Berndtsson Magnus Persson Fethi Bouksila Mohammad Aljaradin

Developing correlations between various soil parameters are considered the major challenge to diminish time and cost associated with field measurements. Soil hydraulic and physical properties were extensively characterized using tension disc infiltrometer and soil sampling in a silty clay agricultural field in Kalaat El-Andalous, Tunisia. Tension disc infiltrometer experiments were conducted at...

2008
Binayak P. Mohanty

39 S oil hydraulic parameters are essential input to most hydrologic and climatic models (Mohanty et al., 2002; Mohanty and Zhu, 2007). Th ey are used to defi ne the hydraulic characteristics of the soil vital in modeling soil moisture and fl ux in the unsaturated zone near the land–atmosphere boundary. At the scale of model applications, it is very important to defi ne the appropriate paramete...

2012
Chen Zeng Quanjiu Wang Fan Zhang

Knowledge of soil hydraulic parameters for the van Genuchten function is important to characterize soil water movement for watershed management. Accurate and rapid prediction of soil water flow in heterogeneous gravel soil has become a hot topic in recent years. However, it is difficult to precisely estimate hydraulic parameters in a heterogeneous soil with rock fragments. In this study, the HY...

Journal: :آب و خاک 0
هادی دهقان امین علیزاده سید ابوالقاسم حقایقی مقدم حسین انصاری

abstract using mathematical models for irrigation management have great impacts to increase irrigation efficiency and product amount, in fields. in this study, simulation results by swap model for moisture, compared with soil profiles moisture values, measured in the field. moisture data, measured at three wheat farms in the neyshabur plain, were used to predict moisture. results show good agre...

2009
D. D. Bosch

Steady-state and transient one-dimensional unsaturated flow in vertically stratified porous media are examined. Saturated hydraulic conductivity and the alpha parameter of the exponential hydraulic conductivity function were assumed to vary from soil layer to soil layer. The use of effective unsaturated hydraulic conductivity to compute matric potential in the soil profile is demonstrated. Resu...

2007
Jianting Zhu Michael H. Young

Upscaled soil hydraulic properties are needed for many large-scale hydrologic applications such as regional and global climate studies and investigations of land–atmosphere interactions. Many larger scale subsurface flow and contaminant transport studies also require upscaled hydraulic property estimates. The objectives of this study were to develop a methodology for upscaling hydraulic propert...

Journal: :تحقیقات آب و خاک ایران 0
پریسا مشایخی دانشجوی دکتری/دانشگاه شهرکرد شجاع قربانی دشتکی هیئت علمی محمدرضا مصدقی هیات علمی/دانشگاه صنعتی اصفهان حسین شیرانی هیات علمی/دانشگاه حضرت ولی عصر رفسنجان مهدی پناهی هیات علمی/موسسه تحقیقات خاک و آب کرج محمدرضا نوری هیات علمی/دانشگاه شهرکرد

in this study, hydrus2d/3d software was used to estimate the hydraulic parameters of van genuchten-mualem model via inverse modeling using double-ring infiltrometers data in 3 different soil textures. nine scenarios of inverse modeling (divided in three groups) were considered with different number (5, 4 and 3) of fitted hydraulic parameters for optimization. in the first group, simulation was ...

2007
Raghavendra B. Jana Binayak P. Mohanty

Soil hydraulic properties are needed in globaland regionalscale circulation models for hydrologic and climate forecasting. They are also necessary in pointand nonpoint-source contaminant transport models. Prediction accuracy of these models is highly dependent on the quality of the model parameters. Collecting the required soil hydraulic parameters by direct measurement at any model grid scale ...

2014
T. R. GINN

Stochastic modeling of soil water fluxes in the absence of measured hydraulic parameters requires a knowledge of the expected istribution of the hydraulic parameters in different soil types. Predictive relationships describing the hydraulic parameter distributions must be developed based on the common descriptors of the physical properties of soils (e.g., texture, structure, particle size distr...

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