Definition - What does Topsoil mean?
Topsoil is the upper layer of native soil. The highest concentration of microorganisms and organic matter can be found in these top two to eight inches of soil; however, the amount of organic matter varies in different soil types.
Most of the earth’s biological soil activity can be found in this layer. Topsoil is also the layer in which plants generally concentrate their roots.
MaximumYield explains Topsoil
There are four different elements that make up the composition of soil. These elements are water, air, mineral particles, and organic matter. The amount of these elements can vary, which is why many gardeners check the soil conditions before planting. These conditions are important because topsoil is the layer that plants absorb their most important nutrients from.
It should also be noted that topsoil differs from gardening soil and quality soil that is sold under the same name. Many forms of soil that are sold for gardening contain a mixture of many different mediums and soil types. For example, potting and gardening soil can contain organic matter, bark, and husks but not contain any actual soil. In addition, topsoil is used differently than most potting or garden soils. For example, topsoil is not often used for potted plants, but is used for large-scale landscaping.