Mineralogy Mineral composition affects the soil’s nutrient availability, structural characteristics, water dynamics, and overall fertility. Soil Health: Soil Structure & Texture Mineralogy Plant Available Water Cation Exchange & pH Salinity & Sodicity Different types of clay minerals impart unique characteristics to soil, influencing fertility and crop yield potential. Understanding the soil’s mineral profile will help growers determine the nutrient and water management requirements particular to their field. When highly reactive clays, such as smectites and vermiculites, dominate the fine earth fraction, the soil’s cation exchange capacity (CEC) is high and the soil will retain large quantities of plant nutrients. Mineral composition affects physical soil properties as well. The crystal structure of smectite clay allows water molecules to squeeze between mineral layers causing the soil to swell when saturated and shrink as it dries out. Mineral composition also determines the nutrient content stored in the soil before fertilization. Some types of minerals are high in magnesium while others provide more calcium or potassium. Knowing the soil’s initial nutrient availability allows growers to provide missing elements without over supplying those that are already abundant. The cracks on the surface of this soil show that it has a high content of shrink-swell clays. The cracks may extend several feet below the surface, causing irrigation water to infiltrate the soil unevenly across the field.