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 TIME CLIMATE TOPOGRAPHY PARENT 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