Soil is a complex entity that is made up of various minerals, elements, air, water, organic matter and living organisms. Number of factors influence soil formation. Climate, the macro and micro organisms it harbors and topography are some of the factors that affect the formation of soil. Soil also undergoes constant changes because of the activity of living organisms present in it. Microorganisms, such as fungi and bacteria, and larger organisms, such as earthworms, beetles and termites, have a constant influence on soil makeup. All these factors results in different types of soil.
Weathering of rocks like limestone, quartz, granite and shale is responsible for the formation of sandy soil. Sandy soil is of light, dry and extremely porous nature. It is composed of 80 to 100 percent sand and a small percentage of silt and clay. The water-retentive properties of sandy soil are low, making it the least-preferred type of soil for gardens. Such a garden needs to be watered and fertilized frequently.
One of the most fertile types of soil, silty soil is composed of minerals and fine organic particles. The composition of silty soil is similar to that of sandy soil, but the particles are larger in size. Silty soil is dark in color. It has more nutritional content than sandy soil. The loose structure of silty soil makes it easy to work with when moist. Almost any type of plant can be planted in silty soil.
Clay soil is a fine-textured soil with a high percentage of clay particles. The high clay content means that this type of soil binds together well. Clay soil has excellent water- and nutrient-retention capabilities that translate into less fertilization and watering. The high clay content and sticky nature means that it is difficult to work with clay soil. Clay soil can be identified easily because of its sticky and gluey texture when wet. The disadvantage of clay soil is that it offers poor drainage. This is detrimental to plant health, especially when the ground is thawing or when it rains heavily.
Equal amounts of clay, silt and sand go together to make loamy soil. Loamy soil is the most ideal soil for gardens. It possesses good drainage properties, but is still excellent at holding moisture and nutrients. Loamy soil requires little care. Adding organic fertilizers improves the nutrient capacity of the soil.
Chalky and Peaty Soil
Chalky and peaty soil is not suited for gardening or crop production. Chalky soil has high alkalinity and also has stones and pebbles mixed with it. Peaty soil is highly acidic and has a high content of organic matter. The acidity of the soil means that the organic matter does not decompose to the extent that it needs to to make the soil nutritive.