A3 Self Check

Question 1

Self-Check A3-1

1. The simple definition of soil has three main characteristics. Name them.

Answer 1

Self-Check A3-1

Answers soil must be unconsolidated, occur naturally and have distinct layers when viewed from the side.

Question 2

2. Explain the difference between primary and secondary minerals.

Answer 2

2. primary minerals are relatively unchanged since they were cooled from lava.

Secondary minerals are new minerals that have formed over time from the weathering products of primary minerals. Secondary mineral crystals are usually much smaller in size and provide more in the way of fertility and water holding. minerals will effervesce Carbonate

Question 3

3. What simple test can be used to determine the carbonate content of soils?

Answer 3

Carbonate minerals will effervesce (bubble) when they come in contact with dilute HCl acid.

Question 4

4. How is humus different from regular organic matter?

Answer 4

Humus is the fraction of soil organic

matter that remains after the more

easily decomposable organic matter

has been broken down.

Question 5

5. Explain the term “unavailable water”.

Answer 5

Soils with high clay and humus moisture

that is held too tightly by soil particles

to be available for plant growth.

Question 6

6. Which soil components have the most impact on water holding capacity?

Answer 6

6. Soils with large interconnected contents

store larger amounts of soil water.

Question 7

Which soil conditions promote free exchange of air between the atmosphere and the soil?

Answer 7

Soils with large interconnected

pore spaces and low water content

promote free exchange of air

between the soil and atmosphere.

Question 8

Answer 8

Compacted soils can affect crop root growth and the soil water-holding capacity, reduce nutrient uptake and make the growing crops more prone to pests and diseases. All these effects can lower final crop yields.

Poorly structured soil waterlogged in wet conditions, restricts the development of the plant root system.