Importance. Plants generally concentrate their roots in and obtain most of their vital nutrients from this layer. Actual depth of the topsoil layer can be measured as the depth from the surface to the first densely packed soil layer known as subsoil.
What is the main component of soil?
Soil is composed of a matrix of minerals, organic matter, air, and water. Each component is important for supporting plant growth, microbial communities, and chemical decomposition. Image courtesy of FAO. The largest component of soil is the mineral portion, which makes up approximately 45% to 49% of the volume.
How is topsoil formed?
Topsoil formation is an incredibly slow process, typically taking 100 years for every inch of soil. It is formed from the weathering of rocks and the subsequent addition of organic material from decaying plants and animals. This enriches the soil and adds the nutrients essential to support plant life.