Understanding Soil Types

Understanding Soil Types

Soil is composed of four main elements: mineral matter, water, air and organic matter. Grains of sand, finely pulverized rock or pebbles are mineral matter. The size, proportions and type of mineral matter give the soil its basic texture, which determines its type. Broadly defined, the four soil types are sand, clay, silt and loam. Sandy soil is light and easy to dig, warms quickly in the spring and is rich in oxygen. However, sandy soil doesn't hold much moisture or many plant nutrients. Silty soil has a lighter texture than clay but is heavier than sand. Small silt particles travel easily in water, so soil in low places near rivers and streams often has a silty character. Porr draniage and surface crusting are the main problems you will have when gardening in silty soil. Loam is the a good balance of clay, silt and sand, and a generous amount of organic matter. Clay soil is heavy and difficult to dig and has little pore space for oxyen. Clay often contains plenty of plant nutrients, but the nutrients may be not be available to plants because of the soil's thight texture. Clay soil tends to stay wet for a long time after heavey rains, and may drain poorly. When clay dries out it becomes rock hard. It is encouraging to know that clay soil becomes terricic garden soil if a sufficient amount of organic matter is added.