Chapter 6 - characteristics of soil

Question 1

What is cation exchange

Answer 1

The ability of soil particles to attract retain and release caution
They are positively charged ions

Question 2

What is caution exchange capacity

Answer 2

A soil with a good CEC maintains and holds onto important ions for plant growth

A soil with a poor CEC loses important ions which will effect the growth of plants

Question 3

What factors effect Caution exchange capacity

Answer 3

Humus content
Clay content
PH
Soil texture

Question 4

Soil PH

Answer 4

A measure of the concentration of the hydrogen ions in a solution
In soil ph mainly ranges from 4 to 9

Question 5

What is the optimum PH for crop growth

Answer 5

6.5 and 7.5

Outside these ranges minerals become unavailable to crops

Question 6

What is liming

Answer 6

Speeding ground limestone on the soil
Contains calcium and magnesium
This neutralise acidic ions in the soil by replacing them through caution exchange

Question 7

What is flocculation

Answer 7

The clustering together of soil particles to create larger structures called floccules

Question 8

Characteristics of ground limestone

Answer 8

Moisture content should be no more than 2.5%

Neutralising value should be no less than 90%

Should pass between a 3.5 mm sieve and not less than 35% of it should pass through a 0.15mm sieve

Question 9

Humus content

Clay content

Answer 9

Humus content : collodial humus has the highest CEC as it has a high volume of negative charges on it increasing the amount of cations it can attract

Clay content : soil with a high clay content have a better CEC than soils with a low CEC