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COURSE LECTURE NOTES:

| SCIENCE | MATTER | SOLAR SYSTEM | PLANETS | ATMOSPHERE | WIND and TEMPERATURE | HUMIDITY | WEATHERING | SOIL | SEASONS | MASS WASTING | SEASONS and CLIMATE | WIND WORK | STREAMS | LAND FORMS | GROUND WATER | CAVES/KARST | THE OCEAN | TIDES & ESTUARIES | WAVES | GLACIERS | GLACIAL LANDFORMS | VOLCANOES | VOLCANOES | CHON | PLATE TECHTONICS | EARTHQUAKES | ROCKS | CLIMATE CHANGE |

SOIL

Soil is an essential ingredient to life on the continents. Without it there would be no life there.

1. The following are notes from the movie "Planet Under Pressure", "The Living Soil"

    Soil is an amazing substance, a self-sustaing machine that, in nature, requires no matainence. Nature uses
    the turn-over system by recycling most nutrients. The forest have existed for millennia without artificial help.
    To begin with, rock contains most of the nutrients necessary for plant growth, but it is not readily available
    in the rock form. Weathering breaks the rock down into smaller peices, until it gets to the smallest/finest;
    sand, silt and clay.Clay is the finest. But, sand, silt, and clay alone do not make soil. Sand will not retain
    water and silt and clay are too dense (pores are too small) to allow much water in.

    Another Ingredient is required. That is "humus". Humus is the result of decaying plant life. The plants and/or
    leaves die. Then they disintegrate, decompose and finally turn into humas. Without humus there would be no
    forests, no plant life at all. It is a case of the living, thriving on the dead. (sound familiar? like maybe the "circle
    of life?") Humus is a store house of nutriants.

    Plants really do not do a good job of taking in nutriants. The root hairs are not big enough, so millions of years
    ago plants formed a symbiotic relationship with fungi. This extended their reach a thousand fold. In return the
    plant provides carbon based food to the fungi.

    A problem still exists. Nitrogen and potassium are required for plant growth. There is plenty of nitrogen
    available in the atmosphere, but not in readily useable form. Nitrogen is a stubborn element. Its molecule
    is made up of two tightly bound attoms. The roots and fungi do not have the energy to break the bond to
    release the atoms. this requires a 'soil mechanic'. This is a bacteria called a nitrogen fixer. The bacteria
    absorbs nitrogen from the atmosphere and cracks it for its own use. The fungi then eat the bacteria and/or
    its waste

    In order to obtain nitrogen faster plants obtain it from humus. This takes specialized organisms called
    decomposers, "the undertakers of the world". These organisms break down the nitrogen in the humus
    so that there is an ample supply for the plants. This is the circle, from live plants to humus and back to
    living plants. The system slows the release of nitrogen by forming modules of small particles of humus
    surounded by particles of silt and clay. The humus releases particle of sugar that glue the silt and clay to it.
    The more glue the more particles. The modules join togather to form larger modules until they make up
    the top soil of the area. Insects also eat the humus and pass the waste product to the fungi.

    Soil is a system in a delicate balance. Humans have upset that balance in several ways; by over intensifying
    planting, by destroying the humus by plowing to deep, by not rotating crops, and by use of chemicals. we
    can assemble the ingrediants of soil and grow crops in it, but nothing on the scale of nature. And, it is a one
    way trip. At the end the nutriants are lost to the system and must be replaced.

2. Soil Layers

    O - Horizon A- Horizon E - Horizon B - Horizon C - Horizon K - Horizon

3. Koppen's Climate Classifications

Climate is the general local weather pattern, and is a result of the circulation of the atmosphere. Soil development
depends on climate. the faster the erosion of rock, the faster the soil builds.

    Climate A - rain forest
    Climate B - desert, hot, dry
    Climate C - has winter and summer, winter is mild
    Climate D - has winter and summer, winter is severe
    Climate E - Polar desert, very cold occasional storms
    Climate H - Mountain climates that vary with altitude

4. Soil types

    A - soil type = Ultisol - most weathering, not good for farming
    B - soil type = Aridisol - desert, not much littering
    C & D - soil type = Alfisol - great for growing stuff
    E - soil type = Inceptisol

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