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