نتایج جستجو برای: water retention in soil
تعداد نتایج: 17126844 فیلتر نتایج به سال:
gol-e-gohar iron ore mine of sirjan in southern part of iran is a large open pit that operates below the groundwater table and during mining operation, dewatering is required to prevent operation processes from flooding. current operation is going on by digging wells in or out of the pit and pumping to prevent flooding. as a result of the former dewatering operation a vast deep cone of depressi...
soil water retention curve is one of the crucial input parameters in any modeling study on water flow and solute transport in soils. direct measurement of soil water retention curve is time-consuming and costly. alternatively, pedotransfer functions (ptfs) may be used to indirectly estimate the soil water retention curve from easily measured soil properties. many equations for the soil water re...
to examine hydraulics of lnapls in soil, the retention curves of diesel fuel and water were both determined by hanging column method. the soil retention parameters were obtained based on van genuchten, brooks-corey and campbell’s models. in addition, the soil hydraulic conductivity for both fluids were predicted based on mualem- brooks-corey, burdine- brooks-corey, mualem-van genuchten and camp...
Puddling is the most common method of land preparation for lowland rice cultivation. The purpose of this study was to assess the influence of various intensities of puddling on percolation rate, water retention by soil and the amount of water used for different puddling intensities in three dominant soil textures of paddy fields in Guilan province. Undisturbed soil samples were taken from 3 dif...
In order to assess hydraulics of LNAPLs in soil, the soil retention curves of petroleum and water were both determined through hanging column method. And, the hydraulic conductivity of petroleum and water were determined by steady head method. The water and petroleum hydraulic conductivities were 7.27 and 57.84 cm.day-1, respectively. The soil retention parameters were obtained based on van Gen...
solute transport processes are affected by soil pore water velocity distribution. pore size distribution, which can be used to infer pore water velocity distribution, can be estimated from a soil water retention curve (n). in this study, a solute breakthrough curve was simulated using soil hydraulic parameters in four different soils. to evaluate the proposed model, predictions were compared to...
Agricultural residues and various other materials are currently being used as additives to improve the physical and chemical properties of soil. Iran is located in an arid and semiarid region, so using strategies to reduce water use will reduce the problem water scarcity. The use of superabsorbent to increase water uptake and retention is one of the solutions that have been applied to improve w...
soil hydraulic properties are key soil physical characteristics that are required to conduct soil and water related studies such as irrigation and drainage. in this study, three indirect methods: inverse modeling, pedo-transfer function, and the semi-physical method of arya et al., were compared in a sandy loam soil to estimate soil moisture retention and unsaturated hydraulic conductivity curv...
Long-term records of nitrogen in deposition and streamwater were analysed at 30 sites covering major acid sensitive regions in Europe. Large regions of Europe have received high inputs of inorganic nitrogen for the past 20-30 years, with an approximate 20% decline in central and northern Europe during the late 1990s. Nitrate concentrations in streamwaters are related to the amount of N depositi...
drought is transient phenomenon , slow , repetitive and integral part of the climate of each region. drought begins with a substantial reduction in precipitation over the long-term average rainfall and over time, reduced soil moisture and surface and ground water resources will continue to decrease. this phenomenon is the most important in bakhtegan basin because of its importance in strategic ...
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