Deserts and desertification glossary

Arable Land fit for crop production.   Arid Climatic conditions marked by low rainfall (less than 200 mm per year) and often in combination with high temperatures resulting in high evaporation rates.   Biome Community of living things, plants and animals, best adapted to the physical environment, climate, and soils.   Bund An embankment or dam built to carry water across the surface for a particular purpose.   Deforestation The permanent clearing of forests for agricultural use and for settlements. It can contribute to climate change and lead to soil erosion.   Desert A landscape form or region that receives little precipitation - less than 250 mm per year.   Desertification Degradation of the land in arid or semi-arid areas leading to it become desert. This can be caused by climate change or poor land management practices.   Drought The naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious water shortages.   Erosion The removal of topsoil and the breakdown of rocks due to the action of the wind or water.   Evaporation The transformation of liquid water into water vapour in the atmosphere.   Groundwater Water which flows underground between layers of rock. It may come to the surface at springs or seepage to form oases or swamps. Humans may draw this water from wells or bores for agricultural, household and industrial use. It is replenished through surface seepage, but this may take many years depending on the depth of the aquifer. Irrigation The collection and distribution of water in drylands   Marginal land Land that is on the verge of being suitable or unsuitable for farming, usually due to sparse vegetation and low rainfall.   Silt Fine particles of sand which cover land surfaces or fill up water courses.   Subsistence Production methods that barely produce enough to meet the basic needs of the farmer or worker. There is no surplus if disaster strikes or that can be sold for profits.