نتایج جستجو برای: hydraulic gradient and soil texture

تعداد نتایج: 16890477  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی و علوم دریایی 1388

this research was conducted in two protect and destroy region in the middle zagros, in illam province. in order to identification of ecological species group and evaluate density of regeneration, effect of many factors such as protection, vegetation, physiographic factors, physical and chemical properties of soil in study locations were studied. to achieve these purpose number of 54 plots using...

Journal: :آب و خاک 0
رسول قبادیان کامران محمدی

abstract information on spatial and temporal variations of soil hydraulic conductivity (k) is essential to improve soil and water management. however several techniques have been proposed for measuring of soil hydraulic conductivity above water surface table, but reliability and easy use of these methods in various conditions were always concern for engineers. the purposes of this study are mea...

Journal: :تحقیقات آب و خاک ایران 0
خالد سلطان نژاد دانشجوی کارشناسی ارشد سازه‏های آبی، گروه آبیاری و آبادانی دانشگاه تهران علی رئیسی استبرق استادیار گروه آبیاری و آبادانی دانشگاه تهران جمال عبدالهی بیک مربی گروه آبیاری و آبادانی دانشگاه تهران محمدحسین امید استاد گروه آبیاری و آبادانی دانشگاه تهران

piping sometimes is occurred due to seepage of water in hydraulic structures. the continuty of this phenomenon decreases the safety or caused the failure of a structure. in this work, experimental tests were carried out on statically compacted natural and randomly reinforced silt sandy soil samples. the randomly reinforced samples were prepared with different lengths and percentages of an artif...

Journal: :تحقیقات آب و خاک ایران 0
آرش کرمی کارشناسی ارشد، دانشگاه تهران قوام الدین زاهدی دانشیار، دانشگاه تهران جهانگیر فقهی دانشیار، دانشگاه تهران

some soil physical and chemical characteristics were analyzed in order to reveal the relationship between forest soils and regeneration patches. gorazbon district of kheyrud was selected as a case study for the research area. all regeneration patches were recorded using gps device. to assess the spatial structure and to quantify the metrics of regeneration patches, analyzing of landscape metric...

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...

Journal: :آب و خاک 0
مریم علیزاده فرهاد میرزایی تیمور سهرابی

abstract rice can be cultivated in various soils but soil with heavy texture and low permeability is more appropriate for its growth than other types of soil texture. it’s assumed that existence of zeolite in soil can be effective for moisture retention and avoiding of occurrence of crack in soil. in order to investigation of the effect of zeolite on moisture status and hydraulic properties of ...

ژورنال: علوم آب و خاک 2019

Simulation of water and salt transfer in soil is very effective in managing optimal water and fertilizer use in the field. In this study, the HYDRUS-1D model was used to simulate the transfer of water and bromide in a laboratory column of soil with clay loam texture. Soil hydraulic parameters (including air entry point) α, (saturated hydraulic conductivity) ks, (residual moisture content) θr (s...

2003
Jose M. Soria Feike J. Leij Rafael Angulo-Jaramillo Carlos Fuentes Randel Haverkamp J.-Yves Parlange

Accurate knowledge of water fluxes in the vadose zone of watersheds is important for applications such as water resources management and climate forecasting. Most, if not all, large-scale studies follow a pragmatic approach where simplifying assumptions have to be made regarding problem formulation and estimation of hydraulic properties. This study investigates simplifications in both regards t...

2005
M. M. VILLAGRA P. MICHIELS R. HARTMANN

Experimentally determined values of unsaturated soil hydraulic conductivity are presented for an Alfisol of the county of Piracicaba, S.P., Brazil. Simultaneous measurements of soil water content and pressure head are made along a 125 m transect within an irrigated field during the internal drainage process. Calculations of the soil hydraulic conductivity were made using the instantaneous profi...

2006
Mingxiang Xu Yunge Zhao Guobin Liu G. V. Wilson

Soil quality has been significantly degraded in the Loess Plateau of China by soil erosion. Our objectives were to (i) identify regional-scale soil quality factors (groupings), (ii) select soil attributes within these factors that can be used as indicators of soil quality, and (iii) determine the impact of land use on these soil quality factors and indicators for the Loess Plateau in China. Soi...

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