soil
a complex ecosystem made up of minerals, organic material, gases and liquids which forms the habitat for many animals and plants
translocation
when water carries particles either up or down in the soil, forming layers
salinisation
when water evaporates from soil, leaving minerals behind. This occurs when Precipitation < Evaporation
leaching
when water moves down through the soil, carrying dissolved minerals with it. This occurs when Precipitation > Evaporation
O horizon
uppermost layer of newly added organic material
A horizon
upper layer where humus builds up
humus
when the decomposition of organic material is incomplete, forming layer of dark brown or black organic material
B horizon
the layer where soluble minerals and organic matter are deposited from the layer above. In particular, clay and iron salts can be deposited here
C horizon
a layer of mainly weathered rock from which soil forms
R horizon
parent material (bedrock or other medium)
porosity
the amount of space between soil particles
permeability
the ease at which gases and liquids can pass through the soil
subsistence farming
the provision of food by farmers for their own families or the local community - no surplus
cash cropping
growing crops for the market, not to eat yourself
commercial farming
large-scale production of crops or livestock for sale
LEDC - less economically developed country
a country with low to moderate industrialisation and low to moderate average GNP per capita
MEDC - more economically developed country
a highly industrialised country with a high average GNP per capita
agribusiness
the business of agricultural production including farming, seed supply, breeding, chemicals for agriculture, machinery, food harvesting, distribution, processing and storage
extensive farming
uses more land with a lower density of stocking or planting and lower inputs and outputs
intensive farming
uses land more intensively with high levels or input and output per unit area
pastoral farming
raising animals usually on grass and on land that is not suitable for crops
arable farming
growing crops on good soils to eat directly or to feed to animals
mixed farming
has both animals and crops and is a system where animal waste is used to fertilise crops and improve soil structure and some crops are fed to animals
soil degradation
when soil is either taken away of is made less suitable for use
overgrazing
when too many animals graze in the same area
overcropping
when land is overused for growing crops, leading to a depletion of nutrients in the soil
cover crops
fast growing crops to cover the soil
terracing
a method to reduce the steepness of slopes by replacing the slope with a series of horizontal terraces, separated by walls
ploughing
breaking up the soil structure, temporarily increasing drainage
contour farming
plowing and cultivating along the contour lines of the land
crop rotation
planting different crops in a rotation to help replenish nutrients in the soil