What are the main characteristics of the O horizon?

Question

Leo Arens · Accepted Answer

Its called "O" for organic horizon and therefore consists mostly of plant material and the dead stuff that is in various stages of decay..

The "O" horizon is near the top of soil horizons and also contains a thriving ecosystem of decomposing bacteria. worms and other critters who break down the organic material. Over time, the O horizon becomes part of the A horizon.

Not all soils have an O horizon (e.g. grasslands don't), and most form in forests or places where there is abundant plant material.

Benjamin Awad · Answer

undefined The O horizon, also known as the organic horizon, is the topmost layer of the soil profile. Its main characteristics include:

1. Composed primarily of organic matter such as decomposed plant material.
2. Often dark in color due to the high concentration of organic material.
3. Contains a mix of living and decomposed organisms, including roots, insects, and microorganisms.
4. Has a loose and friable texture.
5. Serves as a crucial layer for nutrient cycling and organic material decomposition in the soil.