abstract the temperature of water entering the soil or variation in soil temperature has a direct impact on soil hydraulic conductivity via the effect on water viscosity. in this research, the time variability of soil saturated hydraulic conductivity (ks) was studied. the relation between soil temperature and fluid viscosity with hydraulic conductivity were also studied. the necessary experimen...

introduction: better use of water and soil resources in paddy fields, increase in rice production and farmer's income, installation of subsurface drainage system is necessary. the main goalof these systems, are aeration conditions improvement prevention of water logging, yield increase, land use increase and multiuse of the land. in different countries, installation of subsurface drainage cause...

due to the important role of subsurface drainage in managing the ground water level, there are many researches focused on finding a new and more economic way to develop subsurface drainage technologies. lack of proper drainage system in northern iran has caused huge implantation of rice and it is impossible to have second implantation in this region. one reason of insufficiency of current drain...

concerns about nitrate pollution in groundwater and downstream systems cause development of surface water management system to reduce losses of agricultural drainage water nitrate in subsurface drainage using subsurface irrigation from existing drainage lines, drainage water during the growing season and out of season is controlled. the overall objective of this study was to evaluate the effect...

the dominant traditional view to designing drainage systems explains drainage goals only in terms of crop yield increase and rhizosphere improvement while ignoring the environmental impacts of drainage projects. nowadays, this view has been changed into a new one in which both environmental and agricultural purposes are taken into consideration. depth and spacing of subsoil drains are important...

subsurface drainage systems are used to control the depth of the water table and to reduce or prevent soil salinity. water flow in these systems is described by the boussinesq equation, and the advection-dispersion equation coupled with the boussinesq equation is used to study the solute transport. the objective of this study was to propose a finite difference solution of the advection-dispersi...