land classification and use chapter 8 land is more than soil n natural and artificial...
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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
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
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
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