Soil is made of loose, weathered rock and organic material.

5 factors of Soil Formation

Soil is formed by…

• Parent Material: the original “Mom & Pop” soil transported from elsewhere, usually by wind or water, at different speeds

• Climate: the amount, intensity, timing, and kind of precipitation that breaks down parts of ecosystem (i.e. rocks, trees) into soil

• Topography: Slope and Aspect affect the angle of the land and position toward/away from the sun that soil will be exposed to

• Biological: Plants, animals, microscopic organisms, and humans interact with soil in different ways

• Time: the amount of time it takes for the four factors (above) to interact with each other

SOIL CONSERVATION

• Did you know …

It takes 200-400 years to form 1 cm of sustainable soil.

• There are 1,000 – 500,000 bacteria and 1M- 20M actonomycetes

There are thousands of different soils

throughout the world.

Five important factors influence the specific

soil that develops.

• The main types of soil on earth are:

– - Loess (pronounced “luss”): fertile soils developed on wind-blown glacial silt deposited during the Ice Ages.

– - Laterites: red, iron oxide-rich soils of wet, hot tropical areas, created by intense chemical weathering of parent rock material.

– - Pedalfers: rich soils with brown color, high in aluminum and iron; typical of cooler, wet temperate climates world-wide.

– - Pedocals: soils typical of warm, arid regions; high in calcium and commonly contain caliche (white deposits of calcium carbonate)

– - Tundra soils: soils forming in polar climates of permafrost (permanently frozen ground).

Soil Profile

• A Soil Profile is a vertical cross-section of layers of soil found in a given area.

Soil Horizon

• Soil horizons are the layers in a soil profile used to classify soil types.

• Horizons based on color, texture, structure, rock fragments, and any unique characteristic worth noting.

• Major Soil Horizons are depicted by a capital letter in the order (from top down): O, A, B, C, and R

O Horizon: Organic Layer “Organic Matter” Horizon• Surface-layer, at depths of 0-2

feet• Dark in color, soft in texture• Humus - rich organic material of

plant and animal origin in a stage of decomposition

• Leaf litter – leaves, needles, twigs, moss, lichens that are not decomposing

• Several O-layers can occur in some soils, consisting only of O-horizons

A Horizon: Topsoil“Topsoil” or “Biomantle”

Horizon• Topmost layer of mineral soil,

at depths of 2-10 feet • Some humus present, darker in

color than layers below• Biomantle - most biological

productive layer; earthworms, fungi, and bacteria live this layer

• Smallest and finest soil particles

A Horizon: Topsoil This is generally

the most productive layer

of the soil.

Conservation efforts are

focused here!

B Horizon: SubsoilsThe “Subsoil” Horizon• At depths of 10-30 feet• Rich in clay and minerals

like Fe & Al• Some organic material

may reach here through leaching

• Plant roots can extend into this layer

• Red/brown in color due to oxides of Fe & clay

C Horizon: TransitionThe “Regolith”

Horizon• At depths of 30-48 feet• Made up of large rocks or

lumps of partially broken bedrock

• Least affected by weathering and have changed the least since their origin

C Horizon: Transition This layer of

transition is almost completely void of organic mater and

is made up of partially weathered

parent material.

Bedrock“Bedrock” Horizon• At depths of 48+ feet

• Deepest soil horizon in the soil profile

• No rocks or boulders, only a continuous mass of bedrock

• Colors are those of the original rock of the area

USES OF SOIL

Uses of Soil 1. Soil is used in agriculture.2. Soil is used in constructions and arts.3. Soil is used in Waste Management.4. Soil is significant to the Environment.5. Soil plays an important role in filtrating and purifying water. 

SOIL CONSERVATION STRATEGIES

• Planting Vegetation

• Soil Organisms

• Terracing

• Crop Rotation/ multi-cropping

• Watering the Soil

MISUSE OF SOIL

• Inappropriate Infrastructure - bad site layout• Occasional toxic exposure – producing the

necrosis and decline of microorganisms• Soil Loss – extraction, removal of topsoil; • Wrong Cultivation methods – inadequate

organic matter, humus should be 5% by volume

• Extended monocropping

• Citations:• 1. http://ngm.nationalgeographic.com/2008/09/soil/mann-text• 2. http://ngm.nationalgeographic.com/geopedia/Soil• 3. http://books.google.com/books?

id=XjfyWjxEZioC&printsec=frontcover&dq=Sara+Scherr+Soil+Degradation&source=bl&ots=L7CtmuDB5c&sig=RxMDT2H3khTjw40RG5D16VBV8vY&hl=en&ei=CqdgS9fVOY_OsQP-5sjBCw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAwQ6AEwAA#v=onepage&q=&f=false

• 4. http://www.dpi.vic.gov.au/dpi/nreninf.nsf/646e9b4bba1afb2bca256c420053b5ce/d1ce10f1b7687d94ca256f0000053199/$FILE/LC0063.pdf

• 5. http://www.fao.org/DOCREP/004/Y1796E/y1796e02.htm#P4_0•

Read more: http://greenanswers.com/q/124177/nature-recreation/land-soil/how-do-humans-cause-soil-degradation-and-how-does-impact-food-s#ixzz2HvBkThMG