Topic 5 - Soil systems and society Flashcards
Soil systems storage
Include organic matter, organisms, nutrients, minerals, air and water
Transfers in the soil system
Include biological mixing and leaching (minerals dissolved in water moved through soil)
Inputs to the soil system
Leaf litter and inorganic matter from parent rock, precipitation and energy
Outputs from the soil system
Include uptake by plants and soil erosion
Transformations in the soil system
Include decomposition, weathering and nutrient cycling
Soil
A complex ecosystem made up of minerals, organic matter, gases and liquid, which forms the habitat for many animals and plants
Horizons in soil
Different layers of the soil
O Horizon - leaf litter
A Horizon - mineral horizon at the surface showing organic matter enrichment
E Horizon - Subsurface horizon showing depletion of organic matter, clay, iron and aluminium compounds
B Horizon - subsoil horizon showing enrichment of clay material, iron, aluminium or organic compounds
C Horizon - loosened or unconsolidated material
R Horizon - bedrock
Translocation
Materials in the soil are sorted and layers are formed by water carrying particles either up or down
Soil porosity
The amount of space between particles
Soil permeability
The ease at which gases and liquids can pass through the soil
Subsistence farming
Growing food for own families and communities
Cash cropping
Growing crops for the market
Commercial farming
Takes place on a large, profit-making scale, maximising yields per hectare
Extensive farming
Uses more land, low inputs, low outputs (hill sheep farming)
Intensive farming
Uses lots of energy and inputs for high outputs (rice farming, battery chicken farming)
Pastoral farming
Raising of animals
Arable farming
Cultivation of crops
Mixed farming
Both animals raised and crops cultivated (animal waste can be used to fertilise the crops)
Undernourishment
Almost 1bln worldwide did not get enough energy from their food
Unbalanced diet
Enough energy from food but lacking essential vitamins, protein and minerals
FAO
Food and Agricultural Organisation
Monoculture
Farming one type of crop (may apply to forestry too)
Yield
An amount produced of an agricultural product
GM crops
Genetically modified crops - have DNA of one species inserted into a crop species to form a transgenic plant. Controversial
Processes leading to soil degradation
1) Soil erosion (by wind or water) usually occurs when the land is bare and no vegetation on it (perhaps due to deforestation)
2) Processes which make the soil less suitable for use - various chemicals may end up in the soil and make it useless in the long run
Human activities which may lead to soil degradation
- overgrazing
- deforestation
- unsustainable agriculture
Ways to improve the soil
Addition of soil conditioners
Soil conservation
- Grow cover crops
- Terrace hillsides
- Ploughing
- Contour farming
Wind reduction - plant trees or bushes between fields
Improve irrigation techniques
Stop ploughing marginal lands
Crop rotation
