Besides rock particles, minerals, air, and water, soil is composed of organic matter, which is the decomposed remains of plants and animals. This organic matter plays a crucial role in soil fertility and health.

Here's a breakdown of what makes up soil:

1. Mineral Matter:

* Sand: Large particles, gritty texture.

* Silt: Medium-sized particles, smooth texture.

* Clay: Fine particles, sticky texture.

2. Organic Matter:

* Humus: Decomposed plant and animal remains, dark brown or black in color. It provides nutrients, improves water retention, and enhances soil structure.

* Living Organisms: Bacteria, fungi, insects, earthworms, and other microorganisms contribute to decomposition and nutrient cycling.

3. Air and Water:

* Air: Essential for root respiration and other biological processes.

* Water: Carries nutrients and facilitates chemical reactions.

4. Other Components:

* Nutrients: Essential elements like nitrogen, phosphorus, and potassium.

* Pollutants: Can be present in varying degrees depending on human activity.

The proportions of these components vary depending on the type of soil. For example, sandy soils have a high proportion of sand, while clay soils have a high proportion of clay. The ratio of these components determines the soil's texture, structure, fertility, and water-holding capacity.