Hydraulic and salinity regime of two affected sites in the Yizre'el valley, Israel

Abstract

Abstract Causes of recent salinization of numerous plots in the Yizre'el Valley of Israel were examined through a detailed field study of two severely affected sites. in particular, the theory of artesian influence on salt build‐up in the upper cultivated soil layer was investigated. Two piezometer nests and 12 wells were installed to study the subsurface hydraulic regime. Water samples and soil extracts were taken to characterize the chemical composition down to 10m. No significant head differences were measured at the lower site, while at the upper site 96 per cent of the head that existed at the deep (7.5 m) artesian layer was dissipated within the overlying thick clay layer. Slight head differences were noted in the shallow layers. the deep‐lying, coarse‐textured aquifer differs markedly from the upper confining layers and constitutes an independent water body that has little relevance to surface processes. Chemical and hydrological analyses indicate that applied low‐quality irrigation waters May, be the primary cause of downward‐moving salinity and alkalinity which, in turn, affect soil permeability and site productivity.