Soil aggregate stability and consistency

Question 1

Factors that affect aggregate formation

Answer 1

1) wetting and drying
2) freezing and thawing
3) root activity
4) decaying organic matter
5) adsorbed cations
6) soil tillage

Question 2

What is the major agent in soil aggregation?

Answer 2

organic matter

Question 3

What is liquid limit?

Answer 3

water content at which soil becomes semi-fluid

Question 4

How do you determine liquid limit?

Answer 4

Casagrande’s apparatus

Question 5

What is Maximum Water Holding Capacity? (soil moisture constant)

Answer 5

amount of soil moisture that can be held by the soil when all the pore spaces are filled up with water

Question 6

What is field capacity? (soil moisture constant)

Answer 6

amount of water held by soil when a previously saturated soil is allowed to drain until that point when drainage has stopped

Question 7

What is permanent wilting point? (soil moisture constant)

Answer 7

amount of water held by soil when vegetation starts to wilt

Question 8

what is hygroscopic coefficient? (soil moisture constant)

Answer 8

moisture content when water mostly exists in vapor phase

Question 9

What is the downward movement of soil referred to as?

Answer 9

percolation

Question 10

What is the upward movement of soil referred to as?

Answer 10

capillary movement