Fig. 4. Sensitivity of K_s to changes in organic matter (OM) content, at three levels of sand content (20, 50, 80%) and five levels of bulk density (D_b) (1.0, 1.2, 1.4, 1.6, 1.8 g cm^–3), estimated from three different data sets, using sand and clay content (%), D_b (g cm^–3), and OM content (%) as input. The range of soils is shown, for which the estimated K_s decreases when OM content is increased. Different colors designate soils with different levels of D_b. (EUR–the European data set; HUN–the Hungarian data set; USA–the U.S. data set).