(par 5.1.2) Soil salinity (taken from wikipedia)
http://en.wikipedia.org/wiki/Soil_salination From Wikipedia, the free encyclopedia Visibly salt-affected soils on rangeland in Colorado. Salts dissolved from the soil accumulate at the soil surface and are deposited on the ground and at the base of the fence post. Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization.[1] Salts occur naturally […]
(par 5.1.2) Slash-and-burn (taken from wikipedia)
http://en.wikipedia.org/wiki/Slash-and-burn From Wikipedia, the free encyclopedia Not to be confused with scorched earth. “Occupational burning” redirects here. It is not to be confused with occupational burnout. Slash-and-burn practices in Eno, Finland, 1893 This astronaut photograph illustrates slash-and-burn forest clearing along the Rio Xingu (Xingu River) in the state of MatoGrosso, Brazil. Slash-and-burn is an agricultural technique that involves the cutting […]
(par 5.1.2) Agricultural revolution (taken from wikipedia)
http://en.wikipedia.org/wiki/Agricultural_revolution From Wikipedia, the free encyclopedia “Agrarian Revolution” redirects here. For the Agrarian Revolution in China between 1927-–1937, see Chinese Civil War. An agricultural revolution or agrarian revolution is a period of transition from the pre-agricultural period characterized by a Paleolithic diet, into an agricultural period characterized by a diet of cultivated foods; or a further transition from a living […]