Agricultural Land and Water
Text extracted from
The World Food Problem
Leathers & Foster, 2004

ttp://www.amazon.com/World...
Agricultural Land Use

Source: NASA

http://lcluc.umd.edu/images/Science_Themes/Foley1-large.jpg
Land Availability
• Ag land has increased
slowly
–
–
–
–

2.8% 1960s
2.3% 1970s
3.7% 1980s
2.1% 1990s

• Most increases in...
Land with Crop Potential
• 2.57 billion hectares of
land with crop potential
– Excluding china

• Only using < 1 billion
•...
Potential arable land
Agricultural Intensity

HANPP: Human Appropriation of Net Primary Production
http://www.eoearth.org/upload/thumb/4/45/HANP...
Land lost to Ag production
• Urban expansion
– Small effect worldwide

• Global warming may
flood coastal areas
• Soil deg...
Irrigation
• World Water Use:
– Agriculture
– Domestic
– Industry

69%
8%
23%

• Irrigated crops provide
40% of food world...
Irrigated land

http://upload.wikimedia.org/wikipedia/commons/4/4a/Irrigated_land_world_map.png
Water withdrawals for irrigation

http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/04/sci_nat_feeding_the_world/img/3.jpg
Sandra Postel
• “Water use tripled

between 1950 and 1990
– as world population soared
by some 2.7 billion…

• Worldwide d...
Conserving Ag water
• Water harvesting
– Collecting and
saving runoff

• Drip irrigation
• Drought tolerant
varieties
Drip...
Colorado River
• River is drained dry
– before it reaches the ocean

• Heavy irrigation use
–
–
–
–

Colorado
Arizona
Cali...
Irrigation in China
• Yellow river used for
irrigation
• River ran dry in 1972
– For 15 days

• Since 1986 runs dry

Yello...
India River Interlink Plan
• $200 billion plan
– to bring water to south India

• Will link 36 rivers with
canals

– Compl...
Vandana Shiva
• Industrial ag requires 5x
water of indigenous ag
– wheat and rice

• Pumping groundwater
not the solution
...
Aswan Dam, Egypt
• Benefits
– Controls flooding of
Nile River
– Hydroelectric power

• Problems
– Fertile silt not
deposit...
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Agricultural landandwaterf09

  1. 1. Agricultural Land and Water Text extracted from The World Food Problem Leathers & Foster, 2004 ttp://www.amazon.com/World-Food-ProblemToward-Undernutrition/dp/1588266389
  2. 2. Agricultural Land Use Source: NASA http://lcluc.umd.edu/images/Science_Themes/Foley1-large.jpg
  3. 3. Land Availability • Ag land has increased slowly – – – – 2.8% 1960s 2.3% 1970s 3.7% 1980s 2.1% 1990s • Most increases in Grazing cattle, Brazil http://www.ypte.org.uk/docs/factsheets/env_facts/env_images/brazil_cattle.jpg pasture land
  4. 4. Land with Crop Potential • 2.57 billion hectares of land with crop potential – Excluding china • Only using < 1 billion • Problems with most unused potential land – Hilly – Poor soil – Poor drainage • Could increase ag land – 30% China http://www.agapetea.com/store/images/common/about_blacktea3.jpg
  5. 5. Potential arable land
  6. 6. Agricultural Intensity HANPP: Human Appropriation of Net Primary Production http://www.eoearth.org/upload/thumb/4/45/HANPP_Figure_3.jpg/625px-HANPP_Figure_3.jpg
  7. 7. Land lost to Ag production • Urban expansion – Small effect worldwide • Global warming may flood coastal areas • Soil degradation – 1/3 cropland worldwide abandoned due to erosion http://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Erosion.jpg/397px-Erosion.jpg
  8. 8. Irrigation • World Water Use: – Agriculture – Domestic – Industry 69% 8% 23% • Irrigated crops provide 40% of food worldwide • Yields with irrigation increase 2-3X
  9. 9. Irrigated land http://upload.wikimedia.org/wikipedia/commons/4/4a/Irrigated_land_world_map.png
  10. 10. Water withdrawals for irrigation http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/04/sci_nat_feeding_the_world/img/3.jpg
  11. 11. Sandra Postel • “Water use tripled between 1950 and 1990 – as world population soared by some 2.7 billion… • Worldwide demand for water cannot triple again – without causing severe shortages for • crop irrigation, • industrial use, • basic household needs http://www.hipco-ne.com/images/gated.gif http://www.globalwaterpolicy.org/images/sandrapostel1_19.jpg and • critical life-supporting ecosystems”
  12. 12. Conserving Ag water • Water harvesting – Collecting and saving runoff • Drip irrigation • Drought tolerant varieties Drip irrigation http://static.howstuffworks.com/gif/irrigation-drip.jpg
  13. 13. Colorado River • River is drained dry – before it reaches the ocean • Heavy irrigation use – – – – Colorado Arizona California Mexico • City water supply California irrigation from the Colorado River http://aquafornia.com/wordpress/wp-content/uploads/2008/02/irrigation-_2-by-bor-pfs.jpg – Las Vegas – Phoenix – Tucson
  14. 14. Irrigation in China • Yellow river used for irrigation • River ran dry in 1972 – For 15 days • Since 1986 runs dry Yellow River every year • In 1997, dry for 227 days
  15. 15. India River Interlink Plan • $200 billion plan – to bring water to south India • Will link 36 rivers with canals – Completed in 2016 • Potential benefits – Reduce flooding – Hydroelectric power – Irrigation http://www.ben-center.org/riverMaps/RiverLinkingMainMap.jpg
  16. 16. Vandana Shiva • Industrial ag requires 5x water of indigenous ag – wheat and rice • Pumping groundwater not the solution – Aquifers depleted • Big dams not the Small dam, India http://farm4.static.flickr.com/3018/2397775485_c4fce43d8d_m.jpg http://www.netradiomeeting.it/public/foto/SHIVA_VANDANA.jpg solution – – – – benefit cities, investors Ecologically destructive Displaces poor farmers Many small dams better
  17. 17. Aswan Dam, Egypt • Benefits – Controls flooding of Nile River – Hydroelectric power • Problems – Fertile silt not deposited • Farmers must use fertilizer http://www.2travel2egypt.com/sightseeing/images/aswandam.jpg – Schistosomiasis increase – Nile delta receding – Increased salinity

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