LO 1.0 - Explain the Origin of Soils

Question 1

Question

What is soil?

Answer 1

• Surface layer of earth’s crust. (Except eg bare rock or shifting sand.)
• Loose material consisting of fragments of rock and organic matter (OM). Also contains air, water and living organisms.

Question 2

Name the 4 main components of soil.

Give the ideal percentages if you can.

Answer 2

4 main components of soil and ‘ideal’ amounts of each.

• Organic Matter (OM) 5%
• Air 25%
• Minerals particles 45%
• Water 25%

Question 3

Informational

Some properties of Soil.

Answer 3

It supports Plant growth.

It varies, consider

• geology, topography, climate, vegetation, time, influence of man.

It can be deep or shallow, water logged or well drained, acid, alkaline or neutral.

Question 4

Consider this…

for a moment, the importance of soil to us.

All civilisations have depended on soil for many purposes, making soil one of the most important natural resources.

Answer 4

Importance of Soil.

• food
• fodder
• fresh water
• fibres
• fuel
• fabrications
• furniture
• farmaceuticals.

Question 5

Question

What is the functions of soil as a medium for plant growth?

Answer 5

Soil: As a medium for plant growth

• Provides anchorage
• Supplies nutrients and water
• Allows for exchange of gases
• Allows for associations with other organisms

Question 6

How does soil make Organic Matter?

Answer 6

Soil: Breakdown of Organic Matter

Micro-organisms within the soil breakdown animal and plant matter to make the nutrients.

Question 7

Consider this.

Soil and Human Engineering.

Answer 7

An understanding of the physical nature of soils is important in the design and construction of roads and buildings.

Question 8

Question

How is water effected by soil regarding purification?

Answer 8

Water is modified as it passes over or through soil by various processes like microbial activity and the trapping of particles.

Clean water passing over or through contaminated soil can become polluted.

Question 9

Name some organisms that inhabit soil and consider their roles.

Answer 9

Habitat for organisms

• Earthworms
• Grubs and larvae
• Centipedes
• Millipedes
• Nematodes
• Bacteria
• Fungi . . .

Some are beneficial to plants, others harmful.

Many play a role in the ongoing development of soil.

Soil organisms are used in the improvement of polluted soils, in the production of antibiotics, and in the production of biological controls for plant pests.