1. Agricultural Land and Water
Text extracted from
The World Food Problem
Leathers & Foster, 2004
ttp://

2. Agricultural Land Use Source: NASA

3. Land Availability Ag land has increased slowly
Most increases in pasture land
Grazing cattle, Brazil

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

5. Potential arable land

6. Agricultural Intensity
HANPP: Human Appropriation of Net Primary Production

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

8. Irrigation World Water Use:
Agriculture 69%
Domestic 8%
Industry 23%
Irrigated crops provide 40% of food worldwide
Yields with irrigation increase 2-3X

9. Irrigated land

10. Water withdrawals for irrigation

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 and
critical life-supporting ecosystems”

12. Conserving Ag water Water harvesting Drip irrigation
Collecting and saving runoff
Drip irrigation
Drought tolerant varieties
Drip irrigation

13. Colorado River River is drained dry Heavy irrigation use
before it reaches the ocean
Heavy irrigation use
Colorado
Arizona
California
Mexico
City water supply
Las Vegas
Phoenix
Tucson
California irrigation from the Colorado River

14. Irrigation in China Yellow river used for irrigation
River ran dry in 1972
For 15 days
Since 1986 runs dry every year
In 1997, dry for 227 days
Yellow River

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

16. Vandana Shiva Industrial ag requires 5x water of indigenous ag
                                     
Vandana Shiva
Industrial ag requires 5x water of indigenous ag
wheat and rice
Pumping groundwater not the solution
Aquifers depleted
Big dams not the solution
benefit cities, investors
Ecologically destructive
Displaces poor farmers
Many small dams better
Small dam, India

17. Aswan Dam, Egypt Benefits Problems Controls flooding of Nile River
Hydroelectric power
Problems
Fertile silt not deposited
Farmers must use fertilizer
Schistosomiasis increase
Nile delta receding
Increased salinity