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Soil is the growing medium for our foodWithout it we could not survive

Soil purifies our waste

Soil is home to plants and animalsIt may take up to 100 years to form one inch of topsoil

We are losing so much soil to erosion each year that the

lost soil if loaded into dump trucks parked back to back

would extend to the moon and back.

An earthworm can work a ton of soil a year

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Sandy particlesare the only particleswhich may be large enough to beseen with the naked eye.

Predominantly sandy soil has a grittyfeel (coarse-textured) when rubbedbetween the fingers.

Silt particlesare smaller than sandparticles. Predominantly silty soils feel

powdery (like flour) and do not holdtogether well when wet, though theyare more cohesive than sandy soils.

Clayey soilhas the smallest soilparticles, and many small porespaces. Soils with a high number ofclay particles have a very high waterholding capacity and are very fine-textured, making them feel smoothand sticky (like soap) when wet.

Loam is the best soil texture forgrowing things. It is a mixturethat has useful amounts of clayand silt in a base of sand.

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SOIL FORMATION

The formation of soil happens over a very

long period of time. It can take 1000 years or

more. Soil is formed from the weathering of

rocks and minerals. The surface rocks breakdown into smaller pieces through a process

of weathering and is then mixed with moss

and organic matter

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Weatheringis the breaking downof rocks, soilsand mineralsas well as artificialmaterials through contact with the Earth'satmosphere, biotaand waters. Weathering are of threetypes

Physical weathering

Chemical weathering

Biological weathering

http://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Biota_(ecology)http://en.wikipedia.org/wiki/Biota_(ecology)http://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Mineralhttp://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Rock_(geology)

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TIME

CLIMATE

PARENT MATERIAL

TOPOGRAPHY AND RELIEF

ORGANISM

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A newly exposedsurface will have verylittle if any soil whileold surfaces will oftenhave much deepersoils

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Climate, particularly temperature, precipitationand frost action have a profound influence onthe soil forming processes which occur within a

region

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Parent material is the

unconsolidated mineral and

organic deposits in which soilsare developing. It determines

the mineralogical composition

and contributes largely to thephysical and chemicalcharacteristics of the soil.

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The up and down changes in hills andmountains of a particular location is referredto by scientists as topography. Topographyhas an important influence in how soils

form.

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TOPOGRAPHY &RELIEF

1. The first topographic factor is steepness of

hill and mountain slopes.

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2. The second topographic factor effecting

soil formation is drainage, or in other

words, how well is the soil able to get ridof extra water via draining it.

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All living organisms activelyinfluence the soil forming process.

These organisms include bacteria,fungi, vegetation and animals.Their major influence is the effect

on the chemical and physicalenvironment of the soils.

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SOIL TEXTURE IS A QUALITATIVECLASSIFICATION TOOL USED INBOTH THE FIELD ANDLABORATORY TO DETERMINECLASSES FOR AGRICULTURE SOILS

BASED ON THEIR PHYSICALTEXTURE

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Soil textures are classified by the

fractions of each soil separate (sand,

silt, and clay) present in a soil.Classifications are typically named for

the primary constituent particle size or

a combination of the most abundantparticles sizes, e.g. "sandy clay" or

"silty clay."

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Soil texture graph is classified accordingto its composition, and the three basic

materials that comprise soil are clay,sand, and silt. The proportions of each ofthese components determines whether

soil is classified as "sandy clay," "siltyclay," "loam," or another term.

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