A horizon


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Related to A horizon: C horizon, B horizon

A horizon

n.
In ABC soil, the uppermost, darkest zone that is rich in organic matter. Also called zone of eluviation, zone of leaching.

A horizon

n
(Physical Geography) the top layer of a soil profile, usually dark-coloured and containing humus and from which soluble salts may have been leached. See B horizon, C horizon

A horizon


n.
the topsoil in a soil profile.
[1935–40]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.A horizon - the top layer of a soil profileA horizon - the top layer of a soil profile; usually contains humus
humus - partially decomposed organic matter; the organic component of soil
References in classic literature ?
In another direction were to be seen some of the sources of the Oregon, or Columbia, flowing to the northwest, past those towering landmarks the Three Tetons, and pouring down into the great lava plain; while, almost at the captain's feet, the Green River, or Colorado of the West, set forth on its wandering pilgrimage to the Gulf of California; at first a mere mountain torrent, dashing northward over a crag and precipice, in a succession of cascades, and tumbling into the plain where, expanding into an ample river, it circled away to the south, and after alternately shining out and disappearing in the mazes of the vast landscape, was finally lost in a horizon of mountains.