that layer of earth in a well-developed soil lying immediately below the A-horizon, and which contains build up of natural matter leached from area grounds.
instantly underneath the A-horizon; contains build up of natural matter leached from area soils
that level of earth in a well-developed earth lying straight away below the A-horizon, and containing build up of organic matter leached from surface soils.
instantly underneath the A-horizon; contains build up of organic matter leached from surface grounds
How would you define b-horizon?