Agriculture sector is a major consumer of available fresh water. Increasing demand for fresh water in the various sectors has necessitated the use of treated waste water for irrigation. This water has marginal amount of salts which are known to affect the soil properties and crop growth. Hence a scientific approach is necessary to model the moisture uptake by plant roots under varying saline conditions. A numerical model is developed for solving the one dimensional Richards equation for moisture movement in variably saturated vadose zone. The root water uptake is incorporated in the model as the sink term as per the Ojha and Rai (1996) model, which is a non-linear root water uptake model. Combined water and salinity stress in the root water uptake is incorporated as per Feddes et al. (1978) and Mass and Hoffman (1977). Effect of varying salinity concentrations on the water uptake by plant roots and soil moisture dynamics in the root zone is studied on a 40 day period of crop growth. This is attained by providing fresh water and saline water irrigation with 15, 30 and 50 dS/m electrical conductivity. Irrigation field experiments of winter wheat crop were carried out to measure the crop parameters used in the analysis like leaf area index and root depth. The analysis to study the effect of salinity on soil water retention (SWR), hydraulic parameters and plant root water uptake was performed for silt loam (fine textured) and sandy loam (coarse textured) soils. The results show that the roots extract water at potential rate with fresh water, with no water uptake in the case of higher salinity as osmotic stress reaches permanent wilting phase. Overall, the root water uptake reduces as the concentration of salinity increases, even if there is no water stress. However, water stress was encountered at an earlier time in the case of sandy loam soil than in the case of silt loam. As the water content falls below the available moisture content, the water uptake is affected by water stress, which affects the growth and yield of crops. The results obtained from the study are useful in the better management of available water resources for irrigation practices in crop production.