What sphere are soils a part of?
Soils are pedosphere - part of the litosphere
What are soils made up of?
Inorganic components:
Rock fragments
Sand
Silt
Clay
and organic components:
Living organisms
material from decay of organisms
What are the 6 purposes of soil?
Meduim for plant growth
Habitat for organisms
Filters/stores water
Recycles nutrients
Stores carbon/regulates climate
Provides resources for humans
What percentage of world’s carbon dioxide emissions is stored in soil?
10%
What percentage of food production relies on soil?
95%
What does soil texture depend on?
The relative proportions of sand, silt, humus and clay
What is loam?
A soil that contains fairly equal proportions of sand, clay, and silt
What does soil texture determine?
The fertility of the soil
Why are loams ideal for agriculture? (3 reasons)
Good drainage
Good air supply
Retains water
What are 5 inputs of soil?
Solar energy
Organic material (manure, biomass)
Precipitation
Gases
Farming tools like irrigation & fertilizers
What are 5 outputs of soil?
Loss of heat
Diffusion of gases
Evaporation of water
Soil erosion
Loss of dead organic matter
What are 5 transfers of soil?
Erosion
Infiltration
Aeration
Translocation (moving of soil particles)
Biological mixing (movement of soil by animals)
What are 4 transformations of soil?
Decomposition
Weathering
Nutrient cycling
Salinization
Is fertile soil renewable or non renewable and why?
Non renewable because it’s growth rate is 0.05-0.1mm per year
How does farming affect soil?
Topsoil is removed by intensive farming and crop harvesting can leach important nutrients from the soil
How does industrial pollution affect soil?
It causes acidic rain which makes the soil more acid and increases aluminium and iron ions, causing needle death in forestry
What is a crop?
A plant that can be grown and harvested for food production
What is a food staple? (4 examples)
A food that makes up the dominant part of a population’s diet
maize
wheat
potato
rice
What food crop covers the biggest part of the world? (3 examples)
Cereals
Which 3 countries are the top producers of cereal?
USA
India
China
What are food staples in Asia and Africa?
Asia - Rice
Africa - Yams
Why can’t all agricultural land be used to grow crops?
Some of it is too steep or has poor soils
What percentage of the world’s agricultural land is used for raising animals?
77%
Why is our current use of soil for food production unsustainable? (3 reasons)
Food production causes 25% of global GHG emissions
Meat and dairy production have larger carbon prints
70% of global freshwater withdrawals are used for agriculture
What percentage of food goes to waste and why?
14% due to unequal distribution
What is the difference between food waste and food loss?
Food waste: Unnecessary discarding of food
Food loss: Damaged or destroyed food before consumers eat it
What is the 5-step supply chain where food can be lost or wasted?
Production
Handling and storage
Processing and packaging
Distribution and market
Consumption
What is agribusiness?
The business of agriculture - Farming, breeding, processing, etc.
What is the difference between commercial agriculture and subsistance agriculture?
Commercial: Large scale production of crops and livestock
Subsistance: Farming for self-sufficiency (enough for a family or local community)
What are 5 inputs of farms?
Labour
Machinery
Water
Seeds
Livestock
What are 3 outputs of farms?
Crops
Waste
What factors determine what can be grown? (4)
Land aspect
Altitude
Latitude
Slope
Last changed3 months ago