Soils and River Water Chemistry

In the following discussion, the same conditions as presented in Fig. 7-4 are considered same granitic parent material, same age, same elevation, and good drainage. The terms low , very low , etc., describing concentrations of an element in solution. 

4 The lower mineral compartment. Inthiscom-partinent, the pH is broadly the same in all soils, ranging from slightly alkaline to alkaline (Fig. 7-4). Where smectite is formed. Mg is sequestered within this compartment. The pH is too high to allow soluble forms of Al, Fe, and P. The load carried to the 

If some Ca is retained within the soil by CaCO precipitation, one would expect the soil solution to be Ca-saturated in regard to calcite therefore, the Ca concentration in the river water would also be high. 

While the schematic approach presented here is relatively simple, in reality things are more complicated. This is mainly due to two factors (1) the complexity of the hydrological dynamics of the watersheds, and (2) some unique soil processes, either natural or human-induced. 

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