The top layer of soil, known as topsoil, is usually the most fertile because it contains a high concentration of organic matter, nutrients, and microorganisms that are essential for plant growth.
Soil is made fertile by many things: ⤵
- Leaves, plants, and other natural materials fall on the soil's surface and break down over time. This creates a layer full of organic matter, which releases nutrients that plants need to grow.
- Nutrients from broken-down organic matter gather in the topsoil, making it rich in nutrients that plants require, like nitrogen, phosphorus, and potassium.
- Topsoil holds many helpful tiny organisms like bacteria and fungi. These organisms break down organic matter and release nutrients in forms that plants can use.
- Plant roots are mainly in the topsoil layer, so they can easily access the nutrients and water there.
- The topsoil layer usually has a loose and crumbly structure, which lets water and roots move through it easily. This helps plants get the water and nutrients they need.
- Even though erosion can take away topsoil, it often leaves nutrients in lower layers. This helps the topsoil stay fertile.
- People often add fertilizers and organic matter to the topsoil to make it even more fertile for farming.