Topsoil

Top Soil is the upper, outermost layer of soil, generally the top 2 to 8 inches. It has the most concentration of organic matter and microorganisms, and is where most of the Earth's biological soil activity occurs. Plants regularly concentrate their roots in, and obtain most of their nutrients from this layer. The actual depth of the topsoil layer can be purposeful as the depth from the surface to the first densely packed soil layer known as subsoil.

As one of the layers of soil on the Earth's surface, topsoil nowadays referred to as the A horizon. This layer is shaped from the deposition of eroded material as well as decaying organic matter. A variety of soil mixtures are sold commercially as topsoil, usually for use in civilizing gardens and lawns, or for ideal growing conditions in container gardens, by using potting soil, for example.

A most environmental concern known as topsoil corrosion occurs when the topsoil layer is blown or washed away. Without topsoil, little plant life is feasible. It takes approximately 100 years for one inch of topsoil to be deposited, if there is the correct ratio of organic material, inorganic material and moisture. This can be improved by using the terra preta system. However, there is 25 billion tons of topsoil absent each year.