Knowledge of soil profile

 About Soil profile

Soil Profile refers to the layers of soil; horizon A, B, and C. If you're wondering what horizon A is, here's your answer: horizon A refers to the upper layer of soil, nearest the surface. It is commonly known as topsoil. In the woods or other areas that have not been plowed or tilled, this layer would probably include organic litter, such as fallen leaves and twigs . The litter helps prevent erosion, holds moisture, and decays to form a very rich soil known as humus. Horizon A provides plants with nutrients they need for a great life.

The layer below horizon A, of course, has to be horizon B. Litter is not present in horizon B and therefore there is much less humus. Horizon B does contain some elements from horizon A because of the process of leaching. Leaching resembles what happens in a coffee pot as the water drips through the coffee grounds. Leaching may also bring some minerals from horizon B down to horizon C.

If horizon B is below horizon A, then horizon C must be below horizon B. Horizon C consists mostly of weatherized big rocks. This solid rock, as you discovered in Soil Formation, gave rise to the horizons above it.Soil profiles look different in different areas of the world. They are affected by climate and other things.

Soil Types

Sand, silt, and clay are the basic types of soil. Most soils are made up of a combination of the three. The texture of the soil, how it looks and feels, depends upon the amount of each one in that particular soil. The type of soil varies from place to place on our planet and can even vary from one place to another in your own backyard.

Soil Conservation

Soil erosion, caused by wind and rain, can change land by wearing down mountains, creating valleys, making rivers appear and disappear. It is a slow and gradual process that takes thousands, even millions of years. But erosion may be speeded up greatly by human activities such as farming and mining. Soil develops very slowly over a long period of time but can be lost too quickly. The clearing of land for farming, residential, and commercial use can quickly destroy soil. It speeds up the process of erosion by leaving soil exposed and also prevents development of new soil by removing the plants and animals that help build humus.

Today's farmers try to farm in a way that reduces the amount of erosion and soil loss. They may plant cover crops or use a no-till method of farming. Soil is an important resource that we all must protect. Without soil there is no life.

Soil sampling

Materials:
    10" piece of PVC pipe, 1" diameter
    wooden block
    hammer
    10" piece of dowel that fits inside the PVC pipe
    white paper
    pencil, colored pencils
    magnifying glass
    plastic knife
    zip-lock bags

1)Select a soil sampling sight. Place one end of the PVC pipe on the ground. Place the wooden block on top and carefully pound the pipe into the soil using a hammer. For safety, wear a work glove on the hand that holds the pipe. Pound it in until about 4" are sticking out of the ground.

2) Grab the pipe and twirl it gently in a circle to loosen it up. Tap it on the sides with hammer if necessary. Then carefully pull the pipe out, making sure the soil is still inside.

3) Push the soil out carefully with a dowel. Make sure to lay the soil on a flat surface. White paper works well.

4) Without breaking it, observe the soil very closely. Pay close attention and jot down anything you find interesting.
    How is the top part of the soil different from the bottom?
    Does the color change along the surface of the soil?
    Do you see layers of different types of soil?
    What can you observe about the soil?
    Is anything living in the soil?

5) Draw a look-a-like picture of your soil sample. Make sure you draw what you find out. Use colors and label anything interesting.

6) Once you are satisfied with your drawing you can then estimate more. Cut the soil sample down the middle lengthwise with a plastic knife. Look inside. Note anything interesting.

7) Look at the different things using a magnifying glass.

8) Carefully pull it apart. Separate the soil's different parts into categories. You are probably going to find three or four groups. You might find more.

9) Place categories in plastic bags. You may now make a display for others. Tape the bags around your picture. You can now draw arrows to that part of your drawing

Reference : thinkquest.org

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