A soil at pH 7.0 contains 4% humus, 10% montmorillonite, 10% vermiculite, and 10% Fe, Al oxides. What is its approximate cation exchange capacity?  Calculate the number of grams of Al3+ ions needed to...

A soil at pH 7.0 contains 4% humus, 10% montmorillonite, 10% vermiculite, and 10% Fe, Al oxides. What is its approximate cation exchange capacity?  Calculate the number of grams of Al3+ ions needed to replace 10 cmolc of Ca2+ ion from the exchange complex of 1 kg of soil.

A soil has been determined to contain the exchangeable cations in these amounts: Ca2+ = 9 cmolc, Mg2+ = 3 cmolc, K+ = 1 cmolc, Al3+ = 3 cmolc. (a) What is the CEC of this soil? (b) What is the aluminium saturation of this soil?