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1. A layer of hard subsoil or clay. Also called caliche.
2. Hard, unbroken ground.
3. A foundation; bedrock.
(Physical Geography) a hard impervious layer of clay below the soil, resistant to drainage and root growth
1. any layer of firm detrital matter, as of clay, underlying soft soil.
2. hard, unbroken ground.
A compacted layer of soil that is difficult for roots or water to penetrate. It often forms just below the depth of plowing, when plowing, year after year, is always to the same depth.