Lesson 6: soil problems Flashcards
Where is soil erosion common?
Western European countries- China, USA
What is soil erosion?
relocation/ loss of topsoil through natural forces
name 2 natural causes for soil erosion and 2 human causes
natural- wind/rain
human- deforestation/tilage
What are the problems that soil erosion brings?
- 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)
Give an example of a country where waterlogging is prevalent
egypt/ places with high water tables
What is waterlogging?
an excess of water within the soil- a natural problem
give 3 natural causes for waterlogging
heavy rainfall, high runoff, impermeable subsoils
What problems does waterlogging bring? name a country that experienced this:
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
Give an example where salinisation is prevalent
the middle east
What is salinisation?
the accumulation of salt within soil- human and physical causes
What is a human and a physical cause of salinisation?
human= over abstraction of groundwater-> saltwater intrusion
physical= low precipitation or high temps-> high levels of evaporation
What are the problems that salinisation can bring?
- 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
How could soil be managed more effectively?- 2 ways
- better farming techniques
- not covering soil up with impermeable soils
Name 3 strategies to manage soil:
- lower density grazing
- Irrigation management
- Rotational farming
How is low density grazing used as a strategy to manage soil problems?
not as many animals on the field, fewer will trample on soil, allowing crops to grow more
How is irrigation management used as a strategy to manage soil problems?
do not overwater the soil- especially in hot climates (otherwise it will travel to the bedrock)
How is rotational farming used as a strategy to manage soil problems?
planting something different in the field each year prevents diseases continuing onwards
what are solutions to soil erosion? give an example of a case study:
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
