What are the three layers of soil?

Question

What are the three layers of soil?

Answer 1

1) Chuck Norris

2) Cuck Norris

3) All of the above

Answer 2

A. top soil

B. sub soil

C. parental/bed rocks

Answer 3

The uppermost layer or cover is thin, like a cloth or tarp, a carpet of skin over the top of the soil. It is lacking in life due to exposure to atmospheric influences, especially heat, sunlight, and wind. It should be as thin as possible, perhaps no more than an eighth of an inch thick. This thinness can be achieved and preserved by protecting the topsoil with a covering such as mulch, crop residues, or by applying a thin coating of barnyard manure. Fallowing land will deepen this infertile cover layer. For this reason, fallowing should be avoided.

The second layer below the top skin of the soil is the first decay zone, which may be from four to six inches deep. The dimensions of this and all other zones will vary considerably due to the influences of air, moisture, temperature, and the physical chemical and biological conditions that exist in the soil. In fact they are not truly separate, well-defined layers.

In this second layer, the first phase of decomposition of organic materials takes place&endash;the first stage of decomposition. If putrefaction occurs during the decomposition, various gases are formed and released that are harmful to some beneficial kinds of microorganisms and these gases hinder plant growth. This stage of disintegration will come to an end as soon as sufficient oxygen is present, which requires that the soil granules not be too small and not be disturbed too much from the position they naturally occupy.

Excessive deep plowing disturbs the first decomposition zone, slowing down or preventing oxygenation. This is the major reason deep plowing is harmful and should be avoided.

The third layer below the surface of the soil is the second decomposition zone. It may occur at depth of six to ten inches, but varies both in thickness, and depth below the soil surface. The micro-fauna, including mites and springtails among others, live in great abundance here. They further decompose the organic matter of the cell walls of the material consumed, leaving only the "cell pulp." In this layer are the beginnings of feeder roots, which are not more fully developed because decomposition in this layer has not reached the stage which makes nutrients available for plant use and thereby attractive to the roots.

Answer 4

top soil

subsoil

bedrock

all the soil origin from bedrock

Answer 5

Most soils have four layers.

The top layer is called the organic layer. This layer is about an inch thick and takes from 100 to 600 years to form. Within this layer, living things carry on with their life activities. Also in this layer are millions of dead plant and animal organisms that are slowly decomposing, or rotting, away. As these once-living things decay, the organic layer becomes rich in nutrients. If you dig more than an inch or two deep, you might be past this layer already!

Section A is called the upper soil layer. This is where you will find many plant roots, different types of fungus, and other very tiny living things. This soil is dark in color because there is are so many chemical reactions taking place as living things grow and die. A great deal of bacteria is found in this layer. The bacteria help make chemical reactions happen so that materials of the earth can be recycled. This layer is usually about a foot deep.

Section B is the middle soil layer. It has less living and once-living things and less of the darker topsoil. The soil here has less air, too. Because of these characteristics, plants do not grow well here. You will find fewer roots and fewer signs of life. At about two to three feet deep, you are digging into the subsoil. Often, you might find signs of human activity in the upper soil layer and the subsoil. A broken piece of pottery, or an arrowhead may have been buried this deeply.

The last layer, section C, is lowest layer. In this layer you will find that the soil may have an orange or yellowish color. It may be more sandy or have more gray clay. In this layer you will see that there are many pebbles and rocks. This layer has the least amount of living and once-living things. If you are digging a hole and you get more than two or three feet deep, your shovel may begin to hit many rocks. If this happens, then you are probably in the lowest soil layer.

Answer 6

A. Subsoil

B. Topsoil

C. Bedrock

Answer 7

► Soil is made up of several layers—we call the set of layers the “soil profile.”  The major layers of the soil profile are (from top to bottom):



·        Organic Layer:  The top layer of soil is called the “Organic layer” or “topsoil.”  This rich, dark layer has many nutrients to support plant growth.



·        Subsoil:  The next soil layer down from the topsoil is the subsoil.  This layer of soil has a high mineral content, which comes from weathering of the bedrock underneath.  The subsoil has some organic content, but doesn’t support plant growth very well because it lacks nitrogen and phosphorus nutrients.



·        Mineral layer:  The lowest level of the soil has almost no organic material in it, and is almost all mineral material.  The mineral layer doesn’t support plant growth.  It is derived from weathering of the underlying bedrock layer, and is mostly sand and rock.



·        Bedrock:  Deep down, under the soil layers is the bedrock.  This rock is the “parent material” for the mineral part of soil—that means that all of the mineral components of soil come from the bedrock.  As the bedrock layer gets weathered (broken down), the minerals move into the upper layers of the soil.







What is a Soil Component?    ÃƒÂƒÃ‚£



►  Soil has many “Components.”  By “components” we mean the different types of materials that make up the soil.  Each soil layer can have some or all of the different types of soil components—which soil components are most abundant in a particular layer determines the characteristics of that soil layer.  If we want to understand the science of soil, we need to understand how the different soil components make the soil behave the way it does.  There are many millions of different materials that make up soil, but they can all be grouped into two large categories:  Organic material and Mineral material.



·        Organic Material:  Any material (molecules) in soil that comes from the break down of plant or animal material is called “organic.”  Some parts of plants and animals break down very quickly, and some break down more slowly.  Think about a squashed tomato.   The inside of the tomato is very soft and watery—this part would break down very quickly in the environment.  The outside of the tomato—the tomato skin—is much tougher, and would break down very slowly.  The parts of plants and animals that break down very slowly—like tomato skins, or wood, or the skin of cactus leaves—are more important in soil, because they stick around longer.



·        Mineral Material:  The part of the soil that comes from the weathering of bedrock is called the “mineral material” of soil.  This component of soil includes large particles—like sand and gravel—and very tiny particles—like silt and clay.  Mineral material in soil is very important as a source of mineral nutrients for plants (like Iron or Calcium), but doesn’t contain organic nutrients (like vitamins).

Answer 8

There are 3 soil horizons. A, B, and C.

The A horizon is the topmost. It is usually darker and full of organic matter.

The B horizon is clay based sol and does not have the organics that the A horizon does.

The C horizon is the soil just above the bedrock. It is not much more than parts of the bedrock that have started to break down with some clay soils as well.