Land Classification and Use
description
Transcript of Land Classification and Use
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