Fundamentals of Soil Science (1+1)

Introduction

• The term soil structure refers to the arrangement of primary and secondary particles in to a certain structural pattern.
• The primary particles are sand, silt and clay whereas the secondary particles are the cluster of the primary particles which are called aggregates and peds.

• Soil structure greatly influences the amount and nature of porosity and thus influences much soil physical process such as water retention and movement, porosity and aeration, transport of heat etc.
• Structure can be modified by cultivation and tillage operations while texture is an inherent property of soil and cannot be modified within short period of time.

 

• Soil structure is most usefully described in terms of

1. Type of aggregates (form),
2. Class (average size) and
3. Grade (degree of aggregation)

For naming a soil structure the sequence followed is grade, class and type.