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Soil Science Introduction to Agriculture. Soil Origins. Soil is the material covering the face of the earth that supports the growth of plants, including soil built up artificially by people who modify or move it. Soil – the source of life….. MOST PRECIOUS RESOURCE
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Soil Science Introduction to Agriculture Soil Origins
Soil is the material covering the face of the earth that supports the growth of plants, including soil built up artificially by people who modify or move it. • Soil – the source of life….. MOST PRECIOUS RESOURCE • Only a thin layer, but our life depends on it! In our words:
Compare soil to the peeling on an apple • Thickness is not uniform • Very thin layer compared to the thickness of the earth • Without soil, few plants would survive and animal life would be non-existent
Food chain: the progression of food energy from one species to the next • Grass grows in soil, takes up nutrients and water from soil to combine with sunlight to produce plant protein • Animal #1(moth) eats the grass and converts that energy into animal protein • Animal #2 (frog) eats #1 (moth) and converts into animal tissue • Eventually animal #3 (top of chain) dies and the body is broken down and becomes part of the soil Food chain begins with soil
Most of the food we eat is dependent upon soil • Fruits • Grains • Vegetables • Most agricultural animals eat grass and grain All of the proteins humans receive come from plants either directly or indirectly
Minerals come from the soil • Direct contact with soil • Through plants that have extracted the minerals from the soil • Examples: calcium and phosphorus All systems and organs of an animal’s body contain minerals
Minerals are inorganic Have chemical and physical properties that cause the pieces/minerals to clump together in ways to form rock minerals
Along with water fills in the gaps left in soil by the grouping together of the mineral particles air
Along with air fills in the gaps left in the soil by the grouping together of the mineral particles water
Material in soil that is derived from living sources (plants and animals) Carbon is the common element in organic substances and identifies a material as organic Can be either living or nonliving in nature Organic matter (humus)
Parent material can be organic (at one time living or from a living organism) or inorganic (mineral or inorganic origin) Most soils are a combination of organic and inorganic All soil comes from matter known as parent material
Develops from grass and vegetation that has grown and died for thousands of years where after dying, the plant falls to the ground and begins to decay… decayed plant material accumulates and forms soil that may be several feet thick • Characteristically black and productive, but not very abundant • Largest deposits are in Southern Florida where land have been reclaimed from the Everglades • Also some deposits in the North and Pacific NW from reclaiming peat bogs Organic soils
Everglades Peat bogs
Soil originating from minerals are the result of decomposition of rock materials • Wearing of the rock by actions of weather to break down or dissolve the minerals • Wind • Sleet • Snow • Rain • Repeated wetting and drying • Water • Freezing and thawing of water in cracks of rock • The weathering of rocks is a slow process that occurs over thousands and millions of years Inorganic soils
