Soil aggregation

Question 1

What is soil aggregation?

Answer 1

binding together of soil primary particles to form aggregate units or peds

Question 2

Importance of soil aggregation

Answer 2

1) Modifies soil texture effect
2) Facilitates root growth
3) Increases soil porosity = higher infiltration
4) Decreases soil transportability

Question 3

What factors of affect aggregate formation?

Answer 3

• Physical processes
• Organism & organic matter
• Absorbed cations

Question 4

Physical processes that affect aggregate formation

Answer 4

1) Alternate wetting and drying
2) Freezing and thawing
3) Root extension
4) Tillage operation
5) Action of soil organisms

Question 5

Organisms and organic matter that affect aggregate formation

Answer 5

1) Viscous microbial products
2) Associated bacteria and fungi
3) Organic exudates from plant roots

Question 6

Factors affecting aggregate stability

Answer 6

1) temporary mechanical binding action of microorganisms
2) cementing action of the intermediate products of microbial synthesis and decay
3) cementing action of the more resistant and stable humus components

Question 7

What is soil structure?

Answer 7

grouping or arrangement of soil particles

Question 8

List of different soil structures

Answer 8

1) Spherodial
2) Plate-like
3) Block-like
4) Prism-like
5) Massive
6) Single grained

Question 9

What factors affect BD and Porosity?

Answer 9

• Soil texture
• Organic Matter content
• Land use