Final answer:
Each layer of the soil profile differs mainly in color, texture, and depth, with distinct layers known as horizons formed over time influenced by factors like age, climate, biological activity, and relief.
Step-by-step explanation:
The layers constituting the soil profile differ in three main ways: color, texture, and depth. Soil profiles are diverse and may have layers, or horizons, that vary based on several factors. For instance, over time, through processes like weathering and decomposition, soils develop these horizons which have distinct physical and chemical properties.
The O horizon consists largely of decomposing organic material, enriching the soil with nutrients and enhancing its ability to retain moisture. The A horizon, or topsoil, is where organic material mixes with inorganic substances, making it vital for plant growth. Below that, the B horizon acts as a repository for materials that have moved downward from the A horizon, often denser due to the accumulation of fine materials. Lastly, the C horizon contains the parent material that forms the basis of the soil, which may have been transported from elsewhere.
Factors such as age, climate, biological factors, and relief shape the development and characteristics of these soil layers, making each soil horizon distinct. Over time, soils tend to become thicker, more developed, and substantially altered. However, the rate at which these changes occur can vary dramatically depending on the age of the soil and environmental conditions.