SOIL

Silty Soils

This kind is finer, smoother in texture and holds water better than sandy soils. It also holds up nutrients and makes it better for crop cultivation.

Loamy

This soil is a mixture of sand, clay and silt particles and has the ability to retain water. It is high in calcium, aeration and ideal for most crops and vegetables.

Soil

a mixture of organic matter, minerals, gases, liquids, and organisms that together support life.

Specific Pollution

accounted for by particular causes, occurring in small areas the reasons for which can be easily identified. Land pollution such as this is normally found in cities, old factory sites, around roadways, illegal dumps and sewage treatment stations

Peaty

are acidic and as a result, does not support decomposition very well. It is dark in color, rich in organic material, although contains less nutrients than loamy soils. It retains water very well.

Pedogenesis

is the process of soil formation as regulated by the effects of place, environment, and history.

Clay

it has very little air spaces. are very sticky when wet, and can be molded into any shape and form. When they dry, they are rock hard.

14

number of pH units

25%

percentage of air in soil

45%

percentage of minerals in soil

5%

percentage of organic matter in soil

25%

percentage of water in soil

1. Rainfall and Leaching 2. Acidic Parent Material 3. Organic Matter Decay 4. Harvest of High Yielding Crops 5. Nitrification of Ammonium

reasons why soils are becoming more acidic

Soil Alkalinity / Alkaline Soil

referred to by some gardeners as "sweet soil."

alkaline or "sweet"

soils with pH values above 7

acid or "sour"

soils with pH values below 7

Base

substance that releases hydroxyl ions (OH-)

Acid

substance that tends to release hydrogen ions (H+)

Soil Chemistry

the branch of soil science that deals with the chemical composition, chemical properties, and chemical reactions of soils.

Biological Weathering

the breakdown of rocks by living things.

Horizon R

(bedrock) A mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils - if the bedrock is close enough to the surface to weather. This is not soil and is located under the C horizon.

Horizon E

(eluviated) Leached of clay, minerals, and organic matter, leaving a concentration of sand and silt particles of quartz or other resistant materials - missing in some soils but often found in older soils and forest soils.

Horizon O

(humus or organic). Mostly organic matter such as decomposing leaves. is thin in some soils, thick in others, and not present at all in others.

Horizon C

(parent material) The deposit at Earth's surface from which the soil developed

Horizon B

(subsoil) Rich in minerals that leached (moved down) from the A or E horizons and accumulated here

Horizon A

(topsoil) Mostly minerals from parent material with organic matter incorporated. A good material for plants and other organisms to live

Pedosphere

Earth's body of soil that has four important functions

Neutral

Soils with pH of 7

Sandy Soils

are free draining, with the largest, but fine and hard particles. It has a gritty feel. It does not bind very well. It is poor in holding water and easily warms up in the spring season.

Physical Weathering

breakdown of rocks from the result of a mechanical action.

Chemical Weathering

breakdown of rocks through a change in their chemical makeup.

Widespread Pollution

covers extensive areas and has several causes the reasons for which are difficult to identify. Cases such as these involve the spreading of pollutants by air-ground water systems and seriously affect human health and the environment

Soil pH

describes the concentration of hydrogen ions in the soil solution

Chalky

e alkaline with a pH of about 7.5. It is not acidic and often stony with chalk or limestone bedrock. It is free draining because of its coarse and stony nature.

Parent Material, Living Organisms, Climate, Topography, Time

five main factors that affects formation of soil

Weathering of Rocks

how soil is formed

Soil Acidity

involves intensity and quantity aspects. The intensity aspect is universally characterized by the measurements of H+ ion activity, expressed as pH

Environmental Soil Chemistry

the study of chemical reactions between soils and environmentally important plant nutrients, radionuclides, metals, metalloids, and organic chemicals.