Agricultural Land and Water - PowerPoint Presentation

Slide1

Agricultural Land and Water

Text extracted fromThe World Food ProblemLeathers & Foster, 2004

ttp://www.amazon.com/World-Food-Problem-Toward-Undernutrition/dp/1588266389Slide2

Agricultural Land Use

http://lcluc.umd.edu/images/Science_Themes/Foley1-large.jpg

Source: NASASlide3

Land Availability

Ag land has increased slowly2.8% 1960s2.3% 1970s

3.7% 1980s2.1% 1990sMost increases in pasture land

Grazing cattle, Brazil

http://www.ypte.org.uk/docs/factsheets/env_facts/env_images/brazil_cattle.jpgSlide4

Land with Crop Potential

2.57 billion hectares of land with crop potentialExcluding chinaOnly using < 1 billion

Problems with most unused potential landHillyPoor soilPoor drainageCould increase ag land

30%

China

http://www.agapetea.com/store/images/common/about_blacktea3.jpgSlide5

Potential arable landSlide6

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.jpgSlide7

Land lost to Ag production

Urban expansionSmall effect worldwideGlobal warming may flood coastal areas

Soil degradation1/3 cropland worldwide abandoned due to erosion

http://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/Erosion.jpg/397px-Erosion.jpgSlide8

Irrigation

World Water Use:Agriculture 69%Domestic 8%

Industry 23%Irrigated crops provide 40% of food worldwideYields with irrigation increase 2-3XSlide9

Irrigated land

http://upload.wikimedia.org/wikipedia/commons/4/4a/Irrigated_land_world_map.pngSlide10

Water withdrawals for irrigation

http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/04/sci_nat_feeding_the_world/img/3.jpgSlide11

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 andcritical life-supporting ecosystems”

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http://www.globalwaterpolicy.org/images/sandrapostel1_19.jpgSlide12

Conserving Ag water

Water harvesting Collecting and saving runoffDrip irrigation

Drought tolerant varieties

Drip irrigation

http://static.howstuffworks.com/gif/irrigation-drip.jpgSlide13

Colorado River

River is drained dry

before it reaches the oceanHeavy irrigation useColoradoArizona

California

Mexico

City water supply

Las VegasPhoenixTucson

http://aquafornia.com/wordpress/wp-content/uploads/2008/02/irrigation-_2-by-bor-pfs.jpg

California irrigation from the Colorado RiverSlide14

Irrigation in China

Yellow river used for irrigationRiver ran dry in 1972For 15 days

Since 1986 runs dry every yearIn 1997, dry for 227 days

Yellow RiverSlide15

India River Interlink Plan

$200 billion plan to bring water to south India

Will link 36 rivers with canalsCompleted in 2016Potential benefitsReduce floodingHydroelectric power

Irrigation

http://www.ben-center.org/riverMaps/RiverLinkingMainMap.jpgSlide16

Vandana Shiva

Industrial ag requires 5x water of indigenous ag

wheat and ricePumping groundwater not the solutionAquifers depleted

Big dams not the solution

benefit cities, investors

Ecologically destructive

Displaces poor farmersMany small dams better

Small dam, India

http://www.netradiomeeting.it/public/foto/SHIVA_VANDANA.jpg

http://farm4.static.flickr.com/3018/2397775485_c4fce43d8d_m.jpgSlide17

Aswan Dam, Egypt

BenefitsControls flooding of Nile RiverHydroelectric power

ProblemsFertile silt not depositedFarmers must use fertilizerSchistosomiasis increase

Nile delta receding

Increased salinity

http://www.2travel2egypt.com/sightseeing/images/aswandam.jpg