|Soil type usually refers to the different sizes of mineral particles in a particular sample. There are twelve types of soil. The kind of soil in an area helps determines what type of plants can grow. Alfisols, Aridisols, Entisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, Gelisols, Andisols, and Vertisols are the soil types. A scientist who studies soil is called a pedologist.
Soil Formation: Soil is formed by the break up of rocks by natural agents such as wind, water, and other natural phenomena. There are many layers of soil invariably associated with varying organic matter and fertility.
Soil Layers:Top Soil: The top, organic layer of soil, made up mostly of leaf litter and humus (decomposed organic matter). This is the fertile layer of the soil.
Sub-soil: It contains clay and mineral deposits (like iron, aluminum oxides, and calcium carbonate) that it receives from layers above it when mineralized water drips from the soil above.
Regolith: Plant roots do not penetrate into this layer; very little organic material is found in this layer.
Rock-bed: The unweathered rock (bedrock) layer that is beneath all the other layers.
Directions: Answer the following questions.