Land Use
Land Use Categories
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Urban
Agricultural
Forests
Parks and protected
Urban
• For the first time, more people live in cities than on
rural land
• Mass urbanization continues
– Movement to cities from rural lands
• Advantages:
– Jobs more plentiful and centrally located
– More efficient use of land per person
• “vertical housing”
• Infrastructure reaches many per given area
Problems with Urbanization
• Unplanned growth results in urban sprawl
• Urban lands spread into arable land
• Growth exceeds capacity of infrastructure
– water, sewer, sanitation, power, roads, schools
• Higher strain on surrounding rural land to
serve urban needs (“ecosystem services”)
• Higher pollution rates
• Heat islands (see p 386)
Urban Heat Island
Atlanta, GA
http://www.law.georgetown.edu/clinics/hi/Cl
imatePolicy.htm
http://earthobservatory.nasa.gov/IOT
D/view.php?id=7205
Sometimes Infrastructure can’t grow
as fast as population, resulting in poor
sanitation, unhealthy living conditions
http://www.mole.my/content/mail-finallyarrives-rio-favela
http://www.laputan.org/mud/
Open sewer in shanty town
http://www.indymedia.ie/article/94825
Agricultural
• Crops
– Arable land = land that can be planted for crops
– Only about 10% of land surface on earth is arable
– Shrinking daily, due to urbanization, topsoil erosion and
desertification
• Range and pasture
– Soil not rich enough for crops, but animals can “turn it into
food”
• Livestock
– Including CAFO’s
• Concentrated Animal Feed Operations
• Aquaculture
– Fish farming (includes shellfish)
– Hydroponics
Crops
• Crops have become more and more efficient
to feed the growing population
– More food produced for each acre of land
• Strain on crops have required more use of
chemical fertilizers, pesticides and herbicides
• Monoculture depletes soil of nutrients,
creating need for inorganic chemical fertilizers
• Pesticides and herbicides create resistant
insects and weeds, creating the need for
increasingly stronger poisons
Topsoil
• surface layer of land that contains lots of
nutritious organics, mixed with inorganic
particles, that holds moisture and that plants
grow well in
• Topsoil erosion – arguably the greatest
environmental problem, next to population
growth
• Created dustbowl of ‘30’s
http://en.wikipedia.org/wiki/Dust_Bowl
http://en.wikipedia.org/wiki/Dust_Bowl
• The Dust Bowl, or the Dirty Thirties, was a period of severe
dust storms causing major ecological and agricultural damage
to American and Canadian prairie lands from 1930 to 1936 (in
some areas until 1940).
The phenomenon was caused by severe
drought coupled with decades of
extensive farming without crop rotation,
fallow fields, cover crops or other
techniques to prevent wind erosion.[1]
Deep plowing of the virgin topsoil of the
Great Plains had displaced the natural
deep-rooted grasses that normally kept
the soil in place and trapped moisture
even during periods of drought and high
winds.
Dust Bowl – topsoil erosion
During the drought of the
1930s, without natural
anchors to keep the soil in
place, it dried, turned to
dust, and blew away
eastward and southward in
large dark clouds. At times
the clouds blackened the sky
reaching all the way to East
Coast cities such as New York
and Washington, D.C. Much
of the soil ended up
deposited in the Atlantic
Ocean, carried by prevailing
winds, which were in part
created by the dry and bare
soil conditions.
These immense dust storms—given
names such as "Black Blizzards" and
"Black Rollers"—often reduced
visibility to a few feet (around a
meter). The Dust Bowl affected
100,000,000 acres (400,000 km2),
centered on the panhandles of Texas
and Oklahoma, and adjacent parts of
New Mexico, Colorado, and Kansas.[2]
Dust Bowl – topsoil loss
http://en.wikipedi
a.org/wiki/The_Gr
apes_of_Wrath
• Millions of acres of farmland became useless,
and hundreds of thousands of people were
forced to leave their homes;
• many of these families (often known as
"Okies", since so many came from Oklahoma)
migrated to California and other states, where
they found economic conditions little better
during the Great Depression than those they
had left.
• Owning no land, many became migrant
workers who traveled from farm to farm to pick
fruit and other crops at starvation wages.
Author John Steinbeck later wrote The Grapes
of Wrath, which won the Pulitzer Prize, and Of
Mice and Men, about such people.
Topsoil erosion
http://www.swac.umn.edu/classes/soil2125/doc/s10chap3.htm
Sheet erosion
http://www.civil.ryerson.ca/stormwater/menu_5/index.htm
Sheet and Rill Erosion
http://www.geo.fu-berlin.de/fb/elearning/geolearning/en/soil_erosion/types/index.html
Topsoil erosion facts
from Cornell University study
The study, which pulls together statistics on soil erosion from more than 125 sources,
reports:
• The United States is losing soil 10 times faster -- and China and India are losing soil 30 to
40 times faster -- than the natural replenishment rate.
• The economic impact of soil erosion in the United States costs the nation about $37.6
billion each year in productivity losses. Damage from soil erosion worldwide is
estimated to be $400 billion per year.
• As a result of erosion over the past 40 years, 30 percent of the world's arable land has
become unproductive.
• About 60 percent of soil that is washed away ends up in rivers, streams and lakes,
making waterways more prone to flooding and to contamination from soil's fertilizers
and pesticides.
• Soil erosion also reduces the ability of soil to store water and support plant growth,
thereby reducing its ability to support biodiversity.
• Erosion promotes critical losses of water, nutrients, soil organic matter and soil biota,
harming forests, rangeland and natural ecosystems.
• Erosion increases the amount of dust carried by wind, which not only acts as an
abrasive and air pollutant but also carries about 20 human infectious disease organisms,
including anthrax and tuberculosis.
http://www.news.cornell.edu/stories/march06/soil.erosion.threat.ssl.html
desertification
Loss of topsoil results in land drying and desert
expanding into it.
Desertification: dust storm over
Mediterranean Sea
http://amazingdata.com/world-day-to-combat-desertificationand-drought-special/
Desertification
Most vulnerable areas are in red
http://en.wikipedia.org/wiki/File:Desertification_map.png
Solutions include:
Planting tree lines to try to break up the wind
http://amazingdata.com/world-day-to-combat-desertificationand-drought-special/
Topsoil solutions
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Contour farming and strip cropping
Crop rotation, including legumes
Letting fields “lie fallow”
No-till farming
Cover crops
Drip irrigation systems
http://kids.britannica.com/comptons/art56029/An-aerial-view-of-farmland-inMinnesota-shows-the-unique
Range and Pasture Land
• Topsoil too thin to
support crops
• Cattle and other
livestock can graze
and turn “inedible
plants” into food
• Overgrazing becoming
a problem
– Plants cannot recover
fast enough
http://www.kkl.org.il/kkl/english/main_subject/curb%20global%20warmi
ng/livestock%20grazing-combats%20or%20spreads%20desertification.x
CAFO’s
• Remember?
• Concentrated Animal Feed Operations
• Most livestock are raised this way in US and other
developed countries
• Pollute water ways and concentrated wastes can
seep into groundwater
• Mistreatment of animals
• Animals eat only corn and grains – no free range
CAFO chickens
• http://www.jehovahjirehfarm.com/chicken.php
Non-CAFO
CAFO cows
http://oklahomafarmreport.com/wire/cattlenews/5279988_
TCFAReactCAFORegs_202519.php
CAFO pigs
• Notice the cage is not large enough for them
to lie down
http://www.enlightenamsterdam.com/veganism.html
CAFO manure management
Note that manure
must be carefully
managed to avoid
leaching into nearby
waterways or
groundwater
http://www.enlightenamsterdam.com/veganism.html
Forests
http://jerryd
greer.wordpr
ess.com/200
8/04/19/joyc
e-kilmermemorialforestnantahalanational-
Three types:
• Virgin – never been cut
/
• Native – forest that is planted and managed
• Tree farms – areas where trees are planted in
rows and harvested like crops
forest-nc
– Georgia has a huge industry of tree farms
http://www.kynd.com/~finest/retail.htm
Loblolly tree farm in Georgia
Notice:
•Monoculture
•No growth on forest floor
•No biodiversity
http://www.flickr.com/photos/41460075@N08/4147750657/si
zes/o/in/photostream/
Used for pulp and paper industry
Forests: Deforestation
Clear cutting
• removing ALL the trees in
an area
• Cheaper
• More erosion
http://www.thecroc.org/crocblog/2
009/10/clearcut-for-the-climate/
Selective cutting
• cutting only middle-aged or
mature trees
– More eco-friendly
– Preserves biodiversity
– Decrease erosion and fire
danger
http://pdsblogs.org/pdsapes812/2012/01/0
6/responsible-forest-management/
Forests: Deforestation
• Much deforestation of virgin forests is done to
clear for agricultural uses – grazing and
croplands
Forests
• Reforestation
– Planting trees where they have been recently
removed
• “Afforestation”
– Planting trees where they haven’t been for over
50 years
• New England now contains more forest than it
did a century ago
Forests
Benefits:
• Carbon sink – trees take up and store carbon
dioxide from the atmosphere
• When trees are burned in clear cutting, all the
Carbon stored in trees is released at once as
CO2 (combustion)
Parks and Preserves