Estimating cation exchange capacity and clay content from agricultural soil testing data

Clay content and the ability to reversibly retain cations affect many essential chemical physical properties of soil, such as pH buffering carbon sequestration. Cation exchange capacity (CEC) base saturation are also commonly used criteria in soil classification. However, determination CEC particle-size distribution is laborious not included routine testing. In this study, pedotransfer functions including test (STCat; Ca2+ + Mg2+ K+), organic (SOC, %) explanatory variables were developed for estimating CEC, titratable acidity (TA; H+ Al3+) clay (clay, %). addition, reference values potential its components determined Finnish mineral soils. The mean extracted by 1 M ammonium acetate at 7.0 ranged from 14 (range 6.4−25) coarse soils 33 (21−45) cmol(+) kg-1 heavy soils, 42 (24−82) mull 77 (25−138) peat average SOC 27 160 kg-1, respectively. Titratable occupied 53% around 40% sites respectively, evidencing that it a prominent component these predominantly acidic STCat, explained 96% variation CEC. STCat can be especially containing over 30% clay. textured contrast, hampers based estimation content.