View
221
Download
1
Category
Tags:
Preview:
Citation preview
Total land used for agriculture ~ 12.4 billion acres
3.8 billion acres~ 10 % of earth’s land surface
8.6 billion acres~ 23 % of earth’s land surface
Science July 22 2005: Vol. 309. no. 5734, pp. 570 - 574
Most of the earth’s land surface is not well suited for agriculture
Green areas have few constraints
http://soils.usda.gov/use/worldsoils/mapindex/stresses.html
US Midwest is mostly green !
Quantifying Biodiversity
Group Known Species
Estimated Total Species
Percentage Known
Vascular plants
220,000 270,000 81%
Algae 40,000 60,000 67%
Fungi 69,000 1,500,000 5%
Bacteria 3,000 30,000 10%
(Hawksworth, 1991)
Most live in soil
The soil matrix presents its inhabitants with many challenges
Structural rigidity
Tortuous, loosely connected and highly constricted porosity
Low quality nutritional resources
Moisture fluctuations
Soil participates in the hydrologic cycle
water
water
SPRING
Tile drain
Runoff
Leaching
Gulf of Mexicohttp://www.greenlandsbluewaters.org/04_Glover.ppt
~40% of agricultural soils in IL have been tiled
Agricultural drainage short-circuits the soil
http://www.grida.no/climate/vital/graphics/large/12.jpg
Soil participates
in the C cycle
Gt = 109 t = Pg = 1015 g
C sequestration
Coal underlies 37,000 square miles of Illinois -- about 65 percent of the state's surface.
Illinois' coal reserves contain more Btu's than the oil reserves of Saudi Arabia and Kuwait.
Arguably the largest reserves of all US states
~ half of the coal in the eastern US
~ 1/5 of the coal in the US
IL has enormous coal reserves
Recommended