Land Classification and Land Classification and UseUse

Chapter 8Chapter 8

Land is more than soilLand is more than soil

Natural and Natural and artificial artificial characteristics of characteristics of an area to be used an area to be used for agricultural or for agricultural or other purposesother purposes

Includes renewable Includes renewable and nonrenewable and nonrenewable resources plus resources plus improvementsimprovements

LandLand

The surface of the earth not The surface of the earth not covered with watercovered with water

Maybe temporarily or permenently Maybe temporarily or permenently covered with watercovered with water

A pond for aquaculture is A pond for aquaculture is considered landconsidered land

CroplandCropland

Used for Used for growing cropsgrowing crops

Crops grown Crops grown typically typically improve the improve the tilth of the tilth of the landland

Major Characteristics of Major Characteristics of CroplandCropland

Soil - Large impact on productivity. Soil Soil - Large impact on productivity. Soil texture, nutrients and internal structuretexture, nutrients and internal structure

Climate - average of water conditions Climate - average of water conditions over a long timeover a long time

Topography - form or outline of the Topography - form or outline of the surface of the earthsurface of the earth

Water supply - amount of water Water supply - amount of water available for cropsavailable for crops

Subsurface conditions - Soil Subsurface conditions - Soil textures, hardpanstextures, hardpans

Pollution - can prevent plant Pollution - can prevent plant growthgrowth

Alternative UsesAlternative Uses Best land use is Best land use is

determined by determined by how the land will how the land will give the most give the most benefits to people.benefits to people.

Which use will give Which use will give the highest returnsthe highest returns

What will happen What will happen if productive if productive cropland is used cropland is used for other for other purposes?purposes?

Land CapabilityLand Capability

Suitability of land Suitability of land for agricultural for agricultural uses.uses.

Usage should not Usage should not cause damage to cause damage to the land although the land although nutients maybe nutients maybe removedremoved

Arable landArable land

Land that can Land that can be used for row be used for row cropscrops

Can be tilledCan be tilled Alternatives Alternatives

include pasture include pasture and forest and forest cropscrops

Land ImprovementLand Improvement

Four common practices to improve Four common practices to improve arable landarable land– IrrigationIrrigation– Erosion ControlErosion Control– DrainageDrainage– Forming (land forming)- surface is Forming (land forming)- surface is

smoothed or reshaped.smoothed or reshaped.

Soil TilthSoil Tilth

Physical condition Physical condition of the soil that of the soil that makes it easy or makes it easy or difficult to workdifficult to work– Poor tilth has hard Poor tilth has hard

clodclod– Maybe very wet or Maybe very wet or

very dryvery dry

Capability FactorsCapability Factors

Characteristics of land that Characteristics of land that determine its best usedetermine its best use– Surface textureSurface texture

proportion of sand, silt, clay down to proportion of sand, silt, clay down to about 7 inchesabout 7 inches

three major classificationsthree major classifications– sandysandy– loamyloamy– clayeyclayey

Internal drainageInternal drainage

Permeability- movement of water Permeability- movement of water and air through soiland air through soil

Directly related to nutrient contentDirectly related to nutrient content Classified as very slow, slow, Classified as very slow, slow,

moderate and rapidmoderate and rapid– water quickly soaks into sandy soil water quickly soaks into sandy soil

with high permeabilitywith high permeability– soils with clay have slow permeability soils with clay have slow permeability

Soil DepthSoil Depth Thickness of the soil layers Thickness of the soil layers Requirement depends upon type of Requirement depends upon type of

crop to be producedcrop to be produced Four soil depths are usedFour soil depths are used

– very shallow - less than 10 inchesvery shallow - less than 10 inches– shallow - 10 to 20 inchesshallow - 10 to 20 inches– moderately deep - 20 to 36 inchesmoderately deep - 20 to 36 inches– deep - over 36 inchesdeep - over 36 inches

Shallow soils are often the result of Shallow soils are often the result of erosionerosion

ErosionErosion Loss of topsoil by wind or other forcesLoss of topsoil by wind or other forces Four categoriesFour categories

– very severe erosion- 75% or more and very severe erosion- 75% or more and large gullies are presentlarge gullies are present

– severe erosion - 75% of soil has eroded severe erosion - 75% of soil has eroded but no large gullies presentbut no large gullies present

– moderate erosion- 25 to 75% of soil has moderate erosion- 25 to 75% of soil has eroded with small gullies presenteroded with small gullies present

– none to slight erosion - less than 25% of none to slight erosion - less than 25% of soil has eroded and no gullies are soil has eroded and no gullies are presentpresent

SlopeSlope

The rise and fall of the The rise and fall of the elevation of the landelevation of the land

Measured in percentsMeasured in percents Important in determining the Important in determining the

best use of the landbest use of the land

Surface RunoffSurface Runoff

Water from rain, snow, or other Water from rain, snow, or other precipitation that does not soak precipitation that does not soak into the groundinto the ground

Can be reduced by conservation Can be reduced by conservation practicespractices– chopping stalkschopping stalks– terracesterraces– ground coverground cover

Land Capability ClassesLand Capability Classes Assigning a Assigning a

number to landnumber to land Eight classes usedEight classes used I to VIII with I I to VIII with I

being the best being the best arabilityarability

Class I to IV can be Class I to IV can be cultivatedcultivated

V to VIII tend to V to VIII tend to have high slope or have high slope or low and wetlow and wet

ClassesClasses

Class I - Very good landClass I - Very good land– Very few limitationsVery few limitations– deep soil and nearly leveldeep soil and nearly level– can be cropped every year as long as can be cropped every year as long as

land is taken care of land is taken care of Class II - Good landClass II - Good land

– has deep soilhas deep soil– may require moderate attention to may require moderate attention to

conservation practicesconservation practices

Class III - moderately good landClass III - moderately good land– crops must be more carefully selectedcrops must be more carefully selected– often gently sloping hillsoften gently sloping hills– terraces and stripcropping are more terraces and stripcropping are more

often usedoften used Class IV - fairly good landClass IV - fairly good land

– lowest class cultivatedlowest class cultivated– on hills with more slope than class IIIon hills with more slope than class III

Class V - Unsuited for cultivationClass V - Unsuited for cultivation– can be used for pasture crops and can be used for pasture crops and

cattle grazing, hay crops or tree cattle grazing, hay crops or tree farmingfarming

– often used for wildlife or recreation often used for wildlife or recreation areasareas

Class VI - Not suited for row cropsClass VI - Not suited for row crops– too much slopetoo much slope– usually damaged by erosion with gulliesusually damaged by erosion with gullies– can be used for trees, wildlife habitat, can be used for trees, wildlife habitat,

and recreationand recreation Class VII - Highly unsuited for Class VII - Highly unsuited for

cultivationcultivation– has severe limitationshas severe limitations– permanent pastures, forestry, wildlifepermanent pastures, forestry, wildlife– slope is usually over 12 percentslope is usually over 12 percent– large rock surfaces and boulders may be large rock surfaces and boulders may be

foundfound– very little soil presentvery little soil present

Class VIIIClass VIII Cannot be used for Cannot be used for

row crops or other row crops or other cropscrops

often lowland often lowland covered with watercovered with water

soil maybe wet or soil maybe wet or high in clayhigh in clay

aquatic crops aquatic crops maybe grown theremaybe grown there

used for waterfowl used for waterfowl habitathabitat