Lecture 16

Soil Quality and Desertification

Today's objectives -

• To learn how soils develop
• To learn what the basic soil structures are
• To learn what the importance of soil is to agriculture
• To learn some of the major problems facing agriculture from soil degradation
• To learn how to reduce these problems

Vocabulary -

weathering –
frost wedging –
erosion –
gullying –
leaching –
soil –
soil horizon –
humus –
A horizon –
O horizon –
B horizon –
C horizon –
caliche -
regolith –
laterite –
trace elements –
permafrost –
salinization –
terracing –
crop rotation –

Lecture Outline -

Weathering of rocks
Development of soils
What are the soil horizons
Agricultural use of soils
Replenishment of soils
Soil degradation
Causes and effects of erosion
Mitigating erosion