Soil and Plant Analysis

Grades of structure

Grades indicate the degree of distinctness of the individual peds. It is determined by the stability of the aggregates. Grade of structure is influenced by the moisture content of the soil. Grade also depends on organic matter content, texture etc. Four terms commonly used to describe the grade of soil structure are:

Structure-less

• There is no noticeable aggregation, such as conditions exhibited by loose sand.
Weak structure

• Poorly formed, indistinct formation of peds, which are not durable and much UN-aggregated material.
Moderate structure

• Moderately well-developed peds, which are fairly durable and distinct.
• Strong structure: Very well formed peds, which are quite durable and distinct.

Structure naming
For naming a soil structure the sequence followed is grade, class and type; for example strong coarse angular blocky, moderate thin platy, weak fine prismatic.