Which layer of soil indicates fertility?

The A horizon, or topsoil, is the layer of soil that most significantly indicates fertility. This layer is rich in organic matter, nutrients, and microorganisms, which are essential for plant growth. The abundance of nutrients in the A horizon supports various forms of life, including plants, which rely on this nutrient-rich layer for their survival and growth.

Topsoil contains a mix of decomposed organic material, minerals, air, and water, which creates an ideal environment for roots to grow and access what they need from the soil. The presence of humus, which is formed from decayed plant and animal materials, enhances nutrient retention and soil structure, further contributing to its fertility.

In contrast, the B horizon or subsoil typically has fewer nutrients and is often denser, consisting more of minerals leached from the A horizon. The C horizon, or parent material, consists of weathered rock and does not provide the necessary nutrient content required for plant growth. The organic layer, while important, is usually not considered a part of the soil profile in the way that the A, B, and C horizons are; it represents freshly decomposed material rather than a developed soil layer.

Thus, the A horizon is the most crucial layer for indicating soil fertility