Fig. 4. Effect of SAR and PWR on aggregate-size distribution of three soils ((a) Malibu, (b) Millox, and (c) Mokelumne) with different clay mineralogy. The figure shows the proportion of aggregates of size <0.25 mm after prewetting at 2 or 30 mm h^–1 with solutions of SAR 0, 20, and 50 and total chloride concentration of 6 mmol_c L^–1, and sieved according to the aggregate stability procedure (the error bar indicate the standard error of the mean).