2. WHAT IS A RESOURCE
A resource is a source or supply from which benefit is produced.
Typically resources are materials, energy, services, staff, knowledge,
or other assets that are transformed to produce benefit and in the
process may be consumed or made unavailable. Benefits of
resource utilization may include increased wealth, meeting needs or
wants, proper functioning of a system, or enhanced well being.
From a human perspective a natural resource is anything obtained
from the environment to satisfy human needs and wants.
3. LAND
Land, sometimes referred to as dry land, is the solid surface of
the Earth that is not permanently covered by water.[1] The vast
majority of human activity occurs in land areas that
support agriculture, habitat, and various natural resources.
Some life forms (including terrestrial plants and terrestrial animals)
have developed from predecessor species that lived in bodies of
water.
4. LAND MASS
"Land mass" refers to the total surface area of the land of a
geographical region or country (which may include discontinuous
pieces of land such as islands). It is written as two words to distinguish
it from the usage "landmass", the contiguous area of land
surrounded by ocean.
The Earth's total land mass is
148,939,063.133 km2 (57,505,693.767 sq mi) which is about 29.2% of its
total surface. Water covers approximately 70.8% of the Earth's
surface, mostly in the form of oceans and ice formations.
12. Soil Erosion
What causes soil erosion?
How serious of a problem is it?
Good news and bad news from the U.S.
What is desertification?
How do salts degrade the soil?
14. Impacts of Soil Erosion
Loss of soil fertility
Sediment runoff causes problems in surface
water (pollution, clog ditches, boat channels,
reservoirs)
#1 source of U.S. water pollution
Renewable only on LONG timeframes (200-
1,000yrs. for 1 inch)
22. Reducing and Cleaning Up
Salinization
Reduce irrigation
Switch to salt-tolerant crops
Flush soils
Not growing crops for 2-5 years
Install underground drainage
23. Soil Degradation on Irrigated Land
1. Precipitation and
irrigation water
percolate
downward
2. Water table rises
3. Bad for roots
Evaporation
Transpiration
Evaporation
Waterlogging
Less permeable
clay layer
Fig. 14-11 p. 283
24.
25.
26. What controls soil productivity?
Water -infiltration, drainage, storage
Nutrients/toxins (12/17)
Gas Exchange -CO2 out, O2 in
Strength/rooting volume
Waste Disposal
Seed/seedling nursery
28. Where are the productive soils?
We see what we know. The more we know,
the more options we realize we have with
the world’s soils.
29. What are some threats?
Finite arable land: 1.1 billion hectares
1961 0.32 ha/p; today 0.15 ha/p; 2050 0.12 ha/p
Erosion – today 12-40 Mg/ha 30% agricultural lands irreversibly
damaged.
Desertification – e.g., 27% China affected w/ new 2500 km2/yr.
Salinization- affects 20% of world’s 250+ million hectares of irrigated
lands.
Contamination w/ heavy metals.
Urbanization and other competing uses.
Problematic off-site issues & competing uses.
30. Soil Conservation
What is soil conservation and how does it work?
What are some methods for reducing soil
erosion?
Inorganic versus organic fertilizers
32. Conventional Tillage
Farmers plow the land and then
break up and smoothes soil to
make a planting surface
Leaves soil vulnerable to erosion
Midwest tillage often down in fall
(winter bare)
33. Conservation Tillage
Disturbing the soil as little as possible
while planting crop
Not tilling over winter
Planting without disturbing soil
Special equipment “inject” soil with
seed, fertilizer etc.
In 2003 45% of U.S. farms
41. Organic Fertilizer
Has decreased in the
U.S. due in part
because most
farmers no longer
raise livestock and it
costs too much to
transport
Poop Factory and
Phillies Soil
Inorganic fertilizers
have taken off
42. Inorganic Fertilizers
Nitrogen, Phosphorous,
Potassium
Grown in usage
worldwide
Credited with
increasing crop yields
(1/4 of world crops)
W/o could only feed 2-
3 billion people
Many problems
associated (see next
slide)
44. Energy Resources
Supplementing free solar energy
99% of heat comes from the sun
Without the sun, the earth would be –240 0C (-400 0F)
We supplement the other 1% with primarily non-renewable
energy sources
45. Energy Resources
Renewable (16%)
Solar
Wind
Falling, flowing
water
Biomass
Non-renewable
(84%)
Oil
Natural gas
Coal
Nuclear power
46. Energy sources and uses
Energy uses in developed countries
industrial
domestic
transportation
Note: Electricity is not an energy source,
converted from another source (coal,
hydro, nuclear, etc.).
47. Evaluating Energy Resources
Renewable
Future availability
Net energy yield
• It takes energy to get energy
Habitat degradation
Cost (initial and ongoing)
Community disruption
Political or international issues
Suitability in different locations
Polluting (air, water, noise, visual)
48. Each type of power project needs to be evaluated
for the benefits and costs
51. OIL and NATURAL GAS
Accumulations of dead marine organisms on the ocean
floor were covered by sediments.
Muddy rock gradually formed rock (shale) containing
dispersed oil.
Sandstone formed on top of shale, thus oil pools began
to form.
Natural gas often forms on top of oil.
• Primary component of natural gas is methane
52.
53. Natural Gas
50-90% methane
Cleanest of fossil fuels
Approximate 200 year
supply
Advantages and
disadvantages
54. Coal – What is it?
Solid fossil fuel formed in several stages
Land plants that lived 300-400 million
years ago
Subjected to intense heat and pressure
over many millions of years
Mostly carbon, small amounts of sulfur
56. Coal – what do we use it for?
Stages of coal formation
• 300 million year old forests
• peat > lignite > bituminous > anthracite
• Primarily strip-mined
Used mostly for generating electricity
• Used to generate 62% of the world’s electricity
• Used to generate 52% of the U.S. electricity
Enough coal for about 200-1000 years
• U.S. has 25% of world’s reserves
High environmental impact
Coal gasification and liquefaction
57. Nuclear Energy
Fission reactors
Uranium-235
Fission
• Resulting heat
used to produce
steam that spins
turbines to
generate
electricity
• Produces
radioactive
fission fragments
Light water generator – used in
all U.S. and 85% world wide.
Great danger of
losing coolant!
58. The Nuclear Fuel Cycle
Produces highly radioactive
materials that must be stored
safely for 10,000-240,000 years.
59. Energy Efficiency and Renewable
Energy
84% of energy is wasted
41% degradation
43% unnecessary
Fuel wasting vehicles
Furnaces
Poorly insulated buildings
60. Energy Efficiency and Renewable
Energy
Four primary energy wasters:
Incandescent light bulb 95%
Nuclear Power – 86%
Cars – 75-80%
Coal – 66%