- Introduction - Prior knowledge - Soil and Dirt - What are soil Horizons? - Types of soil

- Types of soil according to origen - Bad uses of soil - Good uses of soil - Types of soil - Types of soil according to origen - How to conserve soil - Question - Where did soil come from? - How is soil formed? - Why do we need soil? - What is a ped and their types - Uses of soil -Why do plants grow better in soil than in sand?

-Can we lose soil?

-News

-Videos

-Quotes

-Posters

-Source

Soil is the very thin layer covering parts of the crust of the earth

that can be use to grow our food. Today soil is endangered by erosion.

The chief factors responsible for erosion are the overcultivation of

marginal soils, overgracing of vegetation by sheep and goats, the cutting

down of trees that anchor the soil, and the overpumping of groundwater

that leaves the soil dry.

Soil VRS. Dirt

The substance that

plants, trees, etc.

Grow in; earth;

poor/dry/acid/sandy

soil.

1.A substance that

is not clean, such as

dust or mud.

2.A dirt track.

Is it "soil" or "dirt?"

Well, it depends. It's kind of like when a farmer sees a stalk of corn, all

on its own, out in the middle of his soybeans - it "shouldn't otta' be

there!" If you find soil where it "shouldn't otta' be" (like on your mom's

nice, clean, kitchen floor, or all over your clothes) then it can be

considered "dirt" because it makes things "dirty". On the other hand, if

you find soil where it's supposed to be (outside) and doing what it's

supposed to do (holding up buildings, giving plants room to grow) then

you want to call it "soil" for sure!

Some people say that dirt is matter in the wrong place.

A soil horizon is a layer parallel to the soil surface, whose physical

characteristics differ from the layers above and beneath. Each soil type

has at least one, usually three or four horizons. Horizons are defined in

most cases by obvious physical features, chiefly color and texture. These

may be described both in absolute terms (particle size distribution for

texture, for instance) and in terms relative to the surrounding material,

i.e. ‘coarser’ or ‘sandier’ than the horizons above and below.

Horizon formation (horizonation) is a function of a range of geological,

chemical, and biological processes and occurs over long time periods.

Soils vary in the degree to which horizons are expressed.

They're the layers in the soil. The top layer is the O horizon. It's only

about an inch thick, but it is very healthy. The A horizon, or topsoil, has

roots, tiny microscopic bacteria and fungi, and lots of other small

creatures (like worms) running around in it. Next, is the B horizon which

is hard and not many plants and animals can get through it. At the

bottom is horizon C. C is the parent material that was used to form the

other three layers. It is even harder than B and not many things live

there.

In terms of soil texture, soil type usually refers to the different

sizes of mineral particles in a particular sample. Soil is made up in part

of finely ground rock particles, grouped according to size as sand, silt

and clay. Each size plays a significantly different role.

For example, the largest particles, sand, determine aeration and drainage

characteristics, while the tiniest, sub-microscopic clay particles, and are

chemically active, binding with water and plant nutrients. The ratio of

these sizes determines soil type: clay, loam, clay-loam, silt-loam, and so

on.

In addition to the mineral composition of soil, humus (organic material)

also plays a crucial role in soil characteristics and fertility for plant life.

Soil may be mixed with larger aggregate, such as pebbles or gravel. Not

all types of soil are permeable, such as pure clay.

There are many recognized soil classifications, both international and

national.

Soil consists of rock fragments mixed with varying amounts of organic

material. The origen of soils depend on the kind of rocks from which

they were formed rocks can be:

-Igneous, such as granite and basalt.

-Sedimentary, such as sand stone and limestone.

- Metamorphic, such as slate and marble.

HUMUS:

The organic constituent of soil, usually formed by the

decomposition of plants and leaves by soil bacteria is called humus.

CONCLUTION: The origin the soil is determined by the kind of

rock from which it was form and the composition of its organic content.

Overcultivation: When soil is over used it is depleted of essential

substances that plants need to grow.

Overgrazing: Soils get depleted of vegetation when animals feed

on it at a pace that cannot be sustained by replacement by new

vegetation.

Forest Depletion: The cutting down of trees that anchor the soil

leaves the soil barren.

Rotation of crops: Changing kinds of crops helps to preserve the

nutrients of the soil. Some crops tend to use different kinds of

components from the soil.

Leaving the soil fallow: Leaving the soil without use gives it time

to recover its nutrients.

Preserving forests and creating new ones: Vegetation prevents

erosion and helps to keep water sources.

Soil can be kept in good condition for farming by keeping it from

losing their nutrients. How to conserve a particular soil depends on the

characteristics of the soil in question and the kind of crop that is going or

has been planted. Soils, for example, generally lose nitrogen but it can

be replaced artificially.

It is important to prevent erosion. Soil must be properly watered to

keep it from drying. Soil must be kept from strong winds that may turn it

into dust. Lack of water and strong winds make a perfect combination

for producing erosion.

WHAT IS SOIL?

Soil is the upper layer of earth in which plants grow. It is a mixture

of rock fragments, clay minerals and organic matter: The organic matter

consists largely of partially decomposed plant debris called humus.

HOW DO PEOPLE USE SOIL RESOURCE?

Soil is used mainly in the production of food.

SOIL:

Any type of rock may form the parent material of a soil. The

particles of rock typically vary in size down to microscopic fineness and

are intimately mixed with dark, partly decomposed plant debris called

humus. The humus content decreases with dept a great many factors are

involved in the production of soil including microorganisms such as

bacteria and fungi. Soil is important natural resources because it is the

source from in which plants absorb nutrients with their roots. Plants

serve as sources of animal food. Green plants produce their own

nutrients from the soil.

SOIL NITROGEN:

Nitrogen is an element essential for the construction of proteins.

Nitrogen is the main component of air but the nitrogen we get comes

from the soil. Plants absorb Nitrogen and some plants such as beans of

lentils produce proteins that contain nitrogen, animals also produce

proteins and we human beings get most of our proteins from animal

flesh.

Soil comes from solid rock which makes up the bulk of the earth

crust. Soil originates in the weathering of rock, a complex disintegration

process whose result is a coat of rock fragments and clay minerals mixed

up with varying amounts of organic matter. Any type of rock may form

the parental material of soil. The particles of rock typically vary in size

down to microscopic fineness and are intimately mixed with dark, partly

decomposed plant debris called humus. The humus content decreases

with dept a great many factors are involved in the production of soil

including microorganisms such as bacteria and fungi. Soil is important

natural resource because it is the source from in which plants absorb

nutrients with their roots. Plants serve as sources of animal food. Green

plants produce their own nutrients from the soil.

Most of the soil here on earth has been around a long time. Soil is like a

turtle when it comes to making new soil; it can take hundreds or

thousands of years to make just one-inch more.

But soil has to start somewhere, right? It does. Soil forms from

its" parent material". This can be rocks, dead leaves, broken tree limbs

lying on the ground, and dead bugs. Heat, rain, ice, snow, wind, and

sunshine help to break the parent material down into smaller and smaller

pieces until it becomes soil.

Soil originates in the weathering of rock, a complex disintegration

process whose result is a coat of rock fragments and clay minerals mixed

up with varying amounts of organic matter.

There are thousands of different soils throughout the world. Soils are

formed through a combination of five important factors.

Parent Material Earthy materials, both mineral and organic. Parent

material can be a volcanic deposit such as ash; it can be sediment that

has been transported and deposited by wind or water; or it can be a

deposit left by glaciers.

Climate - Parent material is broken down into finer particles by a

process called weathering, which is controlled by the climate of a given

location. Temperature and water are major climatic forces that influence

weathering.

Living Organisms - Both plants and animals help to create soils. As they

die, plants and animals add organic matter to weathered parent material

to help form subsoil and topsoil. As animals dig through the soil, they

break it up, permitting more are and water to enter.

Topography - Topography is the hilliness, flatness, or amount of slope of

the land.

Time - The age of a soil must be considered in thousands and even

millions of years since it may take hundreds of years for these factors to

form one inch of soil from parent material.

The main reason we need soil, simply put is that it sustains life on

this planet, along with Fire, Water and Air. We need it to grow food. We

also need soil to grow trees and plants to provide us with oxygen to

breath, and to stand up in it. Life attains certain elements and

compounds necessary to maintain, expand, and produce more life. Aka

vitamins and minerals soil maintains life by allowing plants and

microorganisms to flourish within it, thus supporting other life forms...it

provides a place to anchor things of our livelihood. All life needs soil

because it is a vital part of the ecosystem. Without soil, plants could not

grow and all animals that eat plants, including humans, would not have

anything to eat.

Soil covers the earth and gives us foundation for buildings. Soil is very

important as it requires many years to form.

A ped is a single unit of soil structure (the shape of the soil). Soil

comes in several shapes:

granular -looks like cookie crumbs

blocky -blocks of different sizes

columnar -tall columns of soil that have a salt "cap" at the top

platy -thin, flat plates of soil stacked on top of each other

massive -very large clumps or clods of soil that are hard to break apart

The way a soil feels when you touch it is called its "texture." A soil that

feels "gritty" is made up of sand, the largest pieces of soil. A soil that

feels soft, silky or "floury" is made of the medium size soil pieces - silt.

The smallest size soil pieces, clay, feel "sticky" and are hard to squeeze.

We use soil to grow plants, nurture trees, freshen veggies and fruits

grow trees, crops, and build shelter.

Plant growth is a primary use of soil. It contains the necessary nutrients

and retains water. Its pH is a major factor in how effective soil is for

growing plants. The desired range is between 6.0 and 6.5. Fertile soil

allows plants to receive the proper chemical reactions in order to

stimulate growth. Soil's ability to accommodate a plant's root system is

also important for the growth of a plant.

Soil is a significant part of the construction industry. It is used as a

foundation for homes and buildings. Construction professional’s use a

process called soil compaction to increase the density of the soil and

ensure its stability. Compacting the soil also prevents soil settlement and

reduces water seepage. Soil scientists often measure the strength of soil

before a construction project to determine how easily the soil changes

shape and whether it is capable of maintaining under the weight of a

building. Working on the wrong type of soil may lead to cracks in the

foundation, leaks and floods.

Soil holds nutrients that plants need a lot better than sand or clay.

Clay is hard, so it makes it harder for roots of plants to grow down to

reach the water or nutrients under it.

Soil has millions of pores which hold and store nutrients, water,

and oxygen so it can distribute it throughout out the plant. Sand has too

much ventilation which will not be able to hold anything well.

The adequate soil depends on the plant being grown. Some plants

need more or less sand, more or less clay, and more or less organic

material. It all depends on the plant being grown.

Can we lose soil?

Yes. Soil "erodes" (washes or blows away) when there is nothing to help

it stay in place.

How can we keep our soil in place?

Plant some grass, trees or other plants in areas where the soil is eroding.

They help keep soil from moving around. Farmers have ways to keep the

soil on the land so that they can grow food for us to eat. They use special

machinery when they plant their crops, and they plant windbreaks.

Windbreaks are rows of trees that are planted next to fields to keep the

wind from blowing the soil away.

When we try to save our soil it is called "soil conservation."

Conservation is the best way to be sure that we have land to live on now

and in the future.

Soil and Strong Winds.

Today in China strong winds are sweeping millions of tons of

loose soil into the air in late winter and early spring. The dust storms

leave desert behind. Harvests in China have been declining as a result of

such ecological catastrophes, and its worried government is trying

various schemes to keep the remaining soil in place.

The problem of soil erosion is not confined to China: erosion by

water as well as by wind contributes to the loss of farmland soils in

much of the world faster than new soil is formed. Iowa has lost about

half its topsoil in the past 150 years.

http://www.youtube.com/watch?v=5h7rqIsOleU

http://www.youtube.com/watch?v=PK85skEXDQ8&feature=fvsr

http://www.youtube.com/watch?v=Ct6hNc4GLbQ&feature=fvwrel

http://www.youtube.com/watch?v=02MxCrzcFXY&feature=relmfu

All over the land are vast and handsome pastures, with

good grass for cattle, and it strikes me the soil would be

very fertile were the country inhabited and improved by

reasonable people.

Alvar N. C. de Vaca

As in the rankest soil the most beautiful flowers are

grown, so in the dark soil of poverty the choicest flowers

of humanity have developed and bloomed.

James Allen

At an unprecedented time with the worst attack ever on

our soil, our President displayed extraordinary

determination, leadership and resolve when history was

thrust upon him and the United States.

Olympia Snowed

At the age of nineteen and a half, I went to the Land of

Israel to till its soil and live by the labour of my hands. As

I did not find work, I sought my livelihood elsewhere.

Samuel Y. Agnon

SOURCE:

- “ The Physical Universe”

K. Krauskopf and A. Beiser.

Mc Graw Hill. 2008.

-Google

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Made by: Colleen Guzman Lorza