Land Classification and Use

Chapter 8

Land is more than soil

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

Includes renewable and nonrenewable resources plus improvements

Land

The surface of the earth not covered with water

Maybe temporarily or permenently covered with water

A pond for aquaculture is considered land

Cropland

Used for growing crops

Crops grown typically improve the tilth of the land

Major Characteristics of Cropland

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

Climate - average of water conditions over a long time

Topography - form or outline of the surface of the earth

Water supply - amount of water available for crops

Subsurface conditions - Soil textures, hardpans

Pollution - can prevent plant growth

Alternative Uses Best land use is

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

Which use will give the highest returns

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

Land Capability

Suitability of land for agricultural uses.

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

Arable land

Land that can be used for row crops

Can be tilled Alternatives

include pasture and forest crops

Land Improvement

Four common practices to improve arable land– Irrigation– Erosion Control– Drainage– Forming (land forming)- surface is

smoothed or reshaped.

Soil Tilth

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

clod– Maybe very wet or

very dry

Capability Factors

Characteristics of land that determine its best use– Surface texture

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

three major classifications– sandy– loamy– clayey

Internal drainage

Permeability- movement of water and air through soil

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

moderate and rapid– water quickly soaks into sandy soil

with high permeability– soils with clay have slow permeability

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

crop to be produced Four soil depths are used

– very shallow - less than 10 inches– shallow - 10 to 20 inches– moderately deep - 20 to 36 inches– deep - over 36 inches

Shallow soils are often the result of erosion

Erosion Loss of topsoil by wind or other

forces Four categories

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

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

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

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

Slope

The rise and fall of the elevation of the land

Measured in percents Important in determining the

best use of the land

Surface Runoff

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

Can be reduced by conservation practices– chopping stalks– terraces– ground cover

Land Capability Classes Assigning a

number to land Eight classes used I to VIII with I

being the best arability

Class I to IV can be cultivated

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

Classes

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

land is taken care of Class II - Good land

– has deep soil– may require moderate attention to

conservation practices

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

often used Class IV - fairly good land

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

Class V - Unsuited for cultivation

– can be used for pasture crops and cattle grazing, hay crops or tree farming

– often used for wildlife or recreation areas

Class VI - Not suited for row crops– too much slope– usually damaged by erosion with

gullies– can be used for trees, wildlife habitat,

and recreation Class VII - Highly unsuited for

cultivation– has severe limitations– permanent pastures, forestry, wildlife– slope is usually over 12 percent– large rock surfaces and boulders may

be found– very little soil present

Class VIII Cannot be used

for row crops or other crops

often lowland covered with water

soil maybe wet or high in clay

aquatic crops maybe grown there

used for waterfowl habitat