INTRODUCTION: Increasing global population and demand for food steadily increase the pressure on global fresh water, most significantly in arid and semi-arid regions. The problem is expected to worsen due to global warming. A possible strategy to fulfill the demand for irrigation water is the use of marginal, low-quality water, LQW (i.e., saline water, treated-waste-water, TWW). The use of LQW for irrigation may have negative effects on crop yield, on soil structure and hydraulic properties due to soil sodification, and on soil and groundwater salinization and contamination (see e.g., Assouline et al., 2015).Application of the aforementioned strategy, therefore, must carefully consider potential long-term risks posed by intensive use of LQW on the sustainability of the irrigated soil-crop systems and on the quality of the underlying water supplies. From the agronomic point of view, the challenge for irrigation with LQW is how to cope with these negative effects while maintaining acceptable crop yields. The widely applied solution to this problem is based on the leaching requirement (LR) concept (see e.g.,van Schilfgarrde et al., 1974), which, in turn, promotes salt removal from the soil by applying excess amounts of irrigation water. Results of a detailed numerical analysis of soil salinity control under conditions of drip irrigation done by our research group (Russo et al., 2009) suggested that in contrast to predictions based on the LR concept (e.g., Ayers and Wetscott, 1985), when low-quality water is used, damage to crops yield is unavoidable, and salt in the groundwater may increase substantially. It is clear, therefore, that soil salinity management will remain a major challenge for future irrigation, requiring improved irrigation-management schemes with emphasis on minimizing damage to agricultural productivity and environment quality.