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- 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. Agricultural Land Use Source: NASA http://lcluc.umd.edu/images/Science_Themes/Foley1-large.jpg
- 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. 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
- 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. 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. Irrigation • World Water Use: – Agriculture – Domestic – Industry 69% 8% 23% • Irrigated crops provide 40% of food worldwide • Yields with irrigation increase 2-3X
- 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. 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. 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. 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. 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. 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. 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. 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