Post on 22-Feb-2016
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SOIL ORIGINSSoil Science
Introduction to Agriculture
IN OUR WORDS: 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!
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 BEGINS WITH SOIL 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
ALL OF THE PROTEINS HUMANS RECEIVE COME FROM PLANTS EITHER DIRECTLY OR INDIRECTLY
Most of the food we eat is dependent upon soil Fruits Grains Vegetables
Most agricultural animals eat grass and grain
ALL SYSTEMS AND ORGANS OF AN ANIMAL’S BODY CONTAIN MINERALS
Minerals come from the soil Direct contact with soil Through plants that have extracted the
minerals from the soil Examples: calcium and phosphorus
SOIL HAS 4 COMPONENTS
MINERALS Minerals are
inorganic Have chemical
and physical properties that cause the pieces/minerals to clump together in ways to form rock
AIR Along with water fills in the gaps left in
soil by the grouping together of the mineral particles
WATER Along with air fills in the gaps left in the
soil by the grouping together of the mineral particles
ORGANIC MATTER (HUMUS) 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
ALL SOIL COMES FROM MATTER KNOWN AS PARENT MATERIAL
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
ORGANIC SOILS 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
EVERGLADES PEAT BOGS
INORGANIC SOILS 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
THE MATTERHORN IN ANTARCTICA
SAND TUFA
SOIL EROSION