Fig. 1. Effect of soil moisture content on the soil solution ionic strength (top) and pH (bottom) for several Vertisols (V, left) and an Oxisol (O, right); S = saline, G = gypsiferous, C = calcareous. Ionic strength estimated from the electrical conductivity. The solid gray lines without data represent the expected ionic strength that would result from a decrease in moisture content without any interaction with the soil solid phase. The vertical bars represent the standard deviations from the mean of four replicates.