Lesson 6: soil problems

Question 1

Where is soil erosion common?

Answer 1

Western European countries- China, USA

Question 2

What is soil erosion?

Answer 2

relocation/ loss of topsoil through natural forces

Question 3

name 2 natural causes for soil erosion and 2 human causes

Answer 3

natural- wind/rain
human- deforestation/tilage

Question 4

What are the problems that soil erosion brings?

Answer 4

• less soil to absorb rainwater-> floods are more intense, bare slopes more prone to landslides
• water pollution- sediment from eroded soil clogs water ways= harms aquatic life, water treatment is more difficult
• reduces crop yields and increases the cost of growing foods (reduction of water capacity in the soil-> washing away plant nutrients)

Question 5

Give an example of a country where waterlogging is prevalent

Answer 5

egypt/ places with high water tables

Question 6

What is waterlogging?

Answer 6

an excess of water within the soil- a natural problem

Question 7

give 3 natural causes for waterlogging

Answer 7

heavy rainfall, high runoff, impermeable subsoils

Question 8

What problems does waterlogging bring? name a country that experienced this:

Answer 8

inhibits agricultural productivity (airspaces become filled with water-> preventing plant roots from respiring-> crop disease, stunted growth)
WL soils lose nutrients- less fertile over time
e.g. bangladesh- low lying, monsoons

Question 9

Give an example where salinisation is prevalent

Answer 9

the middle east

Question 10

What is salinisation?

Answer 10

the accumulation of salt within soil- human and physical causes

Question 11

What is a human and a physical cause of salinisation?

Answer 11

human= over abstraction of groundwater-> saltwater intrusion
physical= low precipitation or high temps-> high levels of evaporation

Question 12

What are the problems that salinisation can bring?

Answer 12

• reduction of agricultural productivity- irrigation salts are leached out in top soil- affects roots (intolerant to salt- over time kills crops)
• inhibits osmosis- difficult for plants to absorb soil water

Question 13

How could soil be managed more effectively?- 2 ways

Answer 13

1. better farming techniques
2. not covering soil up with impermeable soils

Question 14

Name 3 strategies to manage soil:

Answer 14

1. lower density grazing
2. Irrigation management
3. Rotational farming

Question 15

How is low density grazing used as a strategy to manage soil problems?

Answer 15

not as many animals on the field, fewer will trample on soil, allowing crops to grow more

Question 16

How is irrigation management used as a strategy to manage soil problems?

Answer 16

do not overwater the soil- especially in hot climates (otherwise it will travel to the bedrock)

Question 17

How is rotational farming used as a strategy to manage soil problems?

Answer 17

planting something different in the field each year prevents diseases continuing onwards

Question 18

what are solutions to soil erosion? give an example of a case study:

Answer 18

afforestation-> binds roots
terracing techniques
reducing deforestation

New South Wales- landholders reduced soil erosion through techniques e.g. gully management, tree planting, and water diversion = stabilize landscapes and prevent further degradation