SOIL POLLUTION
Loamy
It is the soil all farmers dream of, as it is full of nutrients from decomposed organic material.
Peaty
It retains water very well.
Nitrification
The use of fertilizers, especially those supplying nitrogen, has often been blamed as a cause of soil acidity.
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
Specific Pollution and Widespread Pollution
Two types of Soil Pollution:
Soil
a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Earth's body of soil, called the pedosphere,
Specific Pollution
accounted for by particular causes, occurring in small areas the reasons for which can be easily identified.
Climate
affecting the rate of weathering and organic decomposition
Peaty
are acidic and as a result, do not support decomposition very well.
Chalky
are alkaline with a pH of about 7.5.
Rainfall and Leaching Excessive rainfall
is an effective agent for removing basic cations over a long time period (thousand of years).
The more ammoniacal nitrogen fertilizer
is applied, the more acidic the soil gets.
Clay
is believed to form in places where the rock is in contact with water, air or steam. Example, sediments on sea or lake bottoms may become clay soils with time.
base
is defined as a substance that releases hydroxyl ions (OH-)
acid
is defined as a substance that tends to release hydrogen ions (H+)
silt
is deposited and cemented with time, it forms siltstone.
The pH scale
is divided into 14 divisions or pH units numbered from 1 to 14.
Soil formation
is influenced by organisms (such as plants), micro-organisms (such as bacteria or fungi), burrowing insects, animals and humans.
Rainfalls
is most effective in causing soils to become acidic if a lot of water moves through the soil rapidly.
Acidity
is produced when ammonium-containing materials are transformed to nitrate in the soil.
Soil chemistry
is the branch of soil science that deals with the chemical composition, chemical properties, and chemical reactions of soils.
Soil pH
is the measure of acidity or alkalinity of a soil.
Pedogenesis
is the process of soil formation as regulated by the effects of place, environment, and history. Biogeochemical processes act to both create and destroy order within soils.
Soil
is the thin layer of material covering the earth's surface and is formed from the weathering of rocks.
Horizon O
is thin in some soils, thick in others, and not present at all in others.
Erosion
loss of organic carbon, increased salt content, compacting, acidification and chemical pollution
Parent Material
minerals forming the basis of soil
oil forms
plants begin to grow in it. The plants mature, die and new ones take their place. Their leaves and roots are added to the soil.
Alkaline or "sweet"
soils with pH values above 7
Environmental soil chemistry
study of chemical reactions between soils and environmentally important plant nutrients, radionuclides, metals, metalloids, and organic chemicals.
Land pollution
such as this is normally found in cities, old factory sites, around roadways, illegal dumps and sewage treatment stations.
biological weathering
the breakdown of rocks by living things. Burrowing animals help water and air get into rock, and plant roots can grow into cracks in the rock, making it split.
Topography
The shape, length and grade of a slope affects drainage.
colluvial
(gravity transported)
Horizon O
(humus or organic) Mostly organic matter such as decomposing leaves.
alluvial
(water transported)
aeolian
(wind transported) soils
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.
Organic Matter Decay
Decaying organic matter produces H+ which is responsible for acidity.
Acidic Parent Material
Due to differences in chemical composition of parent materials, soils will become acidic after different lengths of time.
Crop Production
Harvesting of crops has its effect on soil acidity development because crops absorb the lime- like elements, as cations, for their nutrition.
Soil alkalinity/Alkaline soil
Is referred to by some gardeners as "sweet soil." The pH level of alkaline soil is above 7, and it usually contains a great deal of sodium, calcium and magnesium.
Soil pH
It describes the concentration of hydrogen ions in the soil solution.
Peaty
It is dark in color, rich in organic material, although contains less nutrients than loamy soils.
Chalky
It is free draining because of its coarse and stony nature.
Loamy
It is high in calcium, aeration and ideal for most crops and vegetables.
Chalky
It is not acidic and often stony with chalk or limestone bedrock.
Horizon E - (eluviated)
Leaching 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 A - (topsoil)
Mostly minerals from parent material with organic matter incorporated. A good material for plants and other organisms to live.
Chalky
Not the best for crops to grow in as they lack manganese and iron.
The major causes for soils to become acidic are listed below
Rainfall and Leaching
Horizon B - (subsoil)
Rich in minerals that leached (moved down) from the A or E horizons and accumulated here.
Parent Materials
Soil minerals form the basis of soil. They are produced from rocks (parent material) through the processes of weathering and natural erosion. Water, wind, temperature change, gravity, chemical interaction, living organisms and pressure differences all help break down parent material.
Time
Soil properties may vary depending on how long the soil has been weathered.
Neutral
Soils with a pH of 7
Acid or "sour"
Soils with pH values below 7
Climate
Temperature affects the rate of weathering and organic decomposition. With a colder and drier climate, these processes can be slow but, with heat and moisture, they are relatively rapid.
Factors Affecting Soil Formation
The accumulation of material through the action of water, wind and gravity also contributes to soil formation. These processes can be very slow, taking many tens of thousands of years.
Horizon C - (parent material)
The deposit at Earth's surface from which the soil developed.
Clay
The particles that make up clay are the finest and they bind very well.
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.
Silty Soils
are heavier than sandy soils, and almost midway between the properties of sandy and clay.
Sandy soils
are often the first to become more acidic because water percolates rapidly, and sandy soils: contain only a small reservoir of bases (buffer capacity) due to low clay and organic matter contents.
Soil materials
are progressively moved within the natural landscape by the action of water, gravity and wind The soils left on steep hills are usually shallower. Transported soils include:
Silt particles
are so small and not easily seen by the eyes. It leaves a bit of residue after you touch them.
Sandy soils
are very low in nutrients, as they are usually washed away. Its degree of aeration depends on the sizes of the particles, which vary a lot in size. It is usually formed from the weathering or disintegration of bedrock such as shale, limestone, granite and quartz.
physical weathering
breakdown of rocks from the result of a mechanical action. Temperature changes, abrasion (when rocks collide with each other) or frost can all cause rocks to break down.
chemical weathering
breakdown of rocks through a change in their chemical makeup. This can happen when the minerals within rocks react with water, air or other chemicals.
Widespread Pollution
covers extensive areas and has several causes, the reasons for which are difficult to identify.
Soil chemistry, as a discipline
embracing all chemical and mineralogical compounds and reactions occurring in soils and soil- forming processes.
Soil
forms continuously, but slowly, from the gradual breakdown of rocks through weathering. Weathering can be a physical, chemical or biological process:
Topography
grade of slope affecting drainage, erosion and deposition
Living Organisms
influencing soil formation
Time
influencing soil properties.
Soil degradation
is a complex problem that requires governments, institutions, communities and individuals to take joint measures.
Queensland (and Australia)
is a very old weathered landscape with many ancient soils.