Final answer:
A Brown Soil under pasture would likely have a well-developed A horizon or topsoil rich in organic matter, and a B horizon or subsoil with accumulated finer materials, in its sequence of soil horizons.
Step-by-step explanation:
A Brown Soil under pasture is most likely to have a particular sequence of soil horizons. The soil profile typically includes, from the surface downward, the following layers: the O horizon, A horizon, B horizon, and C horizon. Each of these horizons has distinct characteristics:
- O horizon - Contains fresh organic matter and humus which aids in nutrient enrichment and moisture retention.
- A horizon - This layer is often considered the topsoil. It is a combination of organic material and inorganic products of weathering, rich in nutrients, and where most microbial processes take place.
- B horizon - Referred to as the subsoil, it's primarily formed by the accumulation of fine material that has moved down from the above layers.
- C horizon - Known as the soil base, it contains the parent material, and is the transition layer above the bedrock.
The topsoil is critical for plant life, and in a Brown Soil under pasture, is expected to be well-developed with the A horizon being pronounced due to ongoing organic matter accumulation from the pasture. The B horizon, serving as the subsoil, below the A horizon, would similarly show signs of enrichment from materials percolating downwards.