Agricultural Land and Water

1
Agricultural Land and Water

• Text extracted from
• The World Food Problem
• Leathers Foster, 2004

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2
Land Availability

• Ag land has increased slowly
• 2.8 1960s
• 2.3 1970s
• 3.7 1980s
• 2.1 1990s
• Most increases in pasture land

3
Land with Crop Potential

• 2.57 billion hectares of land with crop potential
• Excluding china
• Only using lt 1 billion
• Problems with most unused potential land
• Hilly
• Poor soil
• Poor drainage
• Could increase ag land 30

China
4
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

5
Irrigation

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

6
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

7
Conserving Ag water

• Water harvesting
• Collecting and saving runoff
• Drip irrigation
• Drought tolerant varieties

8
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
9
India River Interlink Plan

• 200 billion plan to bring water to south India
• Will link 36 rivers with canals
• Potential benefits
• Reduce flooding
• Hydroelectric power
• Irrigation

10
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

Vandana Shiva Research Foundation for Science
Technology and Ecology

11
Aswan Dam, Egypt

• Benefits
• Controls flooding of Nile River
• Hydroelectric power
• Problems
• Fertile silt not deposited
• Farmers must use fertilizer
• Schistosomiasis increase
• Nile delta receding
• Increased salinity