Fig. 1. Relationship between solution salt concentration c (1 meq L^–1 = 1 mmol_c L^–1), osmotic pressure head h, and electrical conductivity EC. The plotted data are EC measurements made on the irrigation waters used in Skaggs et al. (2006) and UNSATCHEM (imnek et al., 1996) computations of EC and h based on the composition of the same waters. The solid lines are fits to the data. A common dilute-solution approximation, EC = 0.1c, is shown for reference (dashed line).