The more clays, the more fertile a soil , because nutrients tend to adhere to clay-sized particles. These clay particles are is suspension in water within the soil, and serve to hold electrically charges ions, of which the most important are the bases , such as calcium, magnesium, potassium, and sodium. Plants can have a high base status or low base status , depending on the amount of clays within a soil. Acids are bad for soils because they tend to occupy places on the clay particles held by nutrient bases. The more acid the soil, the more fertilization is required.
Soil acidity is measured using a pH scale .
Structure refers to the shapes of the peds, such as blocky or granular, or angular or rounded. Minerals found in soil that are derived from the original parent material are called primary minerals . Primary minerals are usually composed of two elements, silicon and oxygen, which together make up silicon dioxide, or sand and quartz. Secondary minerals are those minerals developed from primary minerals by chemical alteration. Clay minerals are secondary minerals.