HORT 2043 Lecture Notes - Lecture 7: Soil Life, Subsoil, Topsoil
19 Sep 2018
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Document Summary
Soil profile, soils develop in layers called horizons. A soil profile contains five horizons (hopefully: 1. Organic or o horizon: leaf litter and other organic matter on the surface, 2. Topsoil or a horizon: organic matter, roots, bacteria, fungi, small animals, subsoil or b horizon, low in organic matter, zone of accumulation of leached materials, 1. Final horizon is r or un-weathered bedrock (parent material) Top soil layer: air 25, water 25, mineral particles 45, organic matter 5, organisms, roots, humus. Testing for soil physical conditions the field method: push a spade (fork or shovel) into three sides of a soil, remove and lay un-dug side face up. Compacted soils (zones: probing the soil with a knife or pencil will help show areas of compaction, they tend to have large clods which don"t break up easily, absence of vertical cracks, shallow rooting.
