What is the term for soil that includes loam, humus, and living organisms?

The term for soil that incorporates loam, humus, and living organisms is topsoil. Topsoil is the uppermost layer of soil, characterized by a rich mixture of organic matter, minerals, and nutrients that support plant life. It is essential for plant growth and is where most biological activity occurs, including the presence of living organisms such as earthworms, fungi, and beneficial bacteria.

Loam, which is a well-balanced mixture of sand, silt, and clay, is particularly effective in retaining moisture and nutrients while allowing for good drainage and aeration. Humus, a component of organic matter, contributes to soil fertility, enhancing its ability to sustain plant growth.

In contrast, subsoil lies beneath the topsoil and typically has less organic material and fewer living organisms. It is often denser and less fertile than the upper layer. Clay and sand are specific types of soil textures; clay is fine-grained and holds water well, while sand is coarse and drains quickly. Neither clay nor sand on its own provides the nutrient-rich, biologically active characteristics found in topsoil. Thus, the combination present in topsoil makes it distinct and vital for an ecosystem's health.