The Soils Around Us
Soils and Ecosystems in Crisis
•
“The coming 50 years are likely to be the final period of rapidly
expanding, global human environmental impacts. Future agricultural
practices will shape, perhaps irreversibly, the surface of the Earth,
including its species, biogeochemistry and utility to society”
•
Agricultural use of soil systems faces challenges:
– Need for increased production per hectare
– Need to reduce environmental footprint
• Fertilizer use and loss
• energy
– Resist land loss by erosion, urbanization, etc.
World Food Production
•
Maintained pace due to
inputs of energy and
mass
World Food Production
•
Pace and efficiency are
declining with time
World Food Production
•
Pace and
efficiency are
declining with
time
•
The fundamental
resource (soils)
are declining
with time
Functions of soils in ecosystems
Biologically Essential Elements
Soils as an Environmental Interface
The Soil System
•
3d component of Earth surface
•
Dimensions a human construct
•
System allows us to quantify
inputs, outputs, and changes
•
Soil system is a component of
eocsystems
The Soil System
•
Dynamic with time
•
Properties depend on
state factors
The Soil System
•
Result of combination
of factors is unique soil
•
Horizons and other
properties depend on
state factors
BIOTA
CLIMATE
TOPOGRAPHY
PARENT
TIME
MATERIAL
Soil Horizons/Profile
Importance of Knowledge of Whole Soil
Soil Composition
• solids
• gases
• water
• life
Soil pH
Soil Particle Sizes
Nutrient Sources in Soils