Shifting cultivation

Shifting cultivation is an agricultural system in which areas of land are cultivated for a short time. Shifting cultivation is also known as slash and burn agriculture.
Shifting cultivation is practised in the thickly forested areas of Amazon basin, tropical Africa, parts of southeast Asia and northeast India. These are areas of heavy rainfall and quick regenerating of vegetation. Then they are left to grow back their natural vegetation, while the farmer moves to another area. It is practised in forested areas of the Amazon basin.It is one of the rudimentary forms of cultivation.
After cultivation a plot of land is cleared by felling the trees and burning them. The ashes are then mixed with the soil and crops like maize, yam, potatoes and cassava are grown. After the soil looses its fertility, the land is abandoned and the cultivator moves to a new plot. 
Because the soil is no longer protected by the large trees in the rainforest system, it can be ruined easily by thick rain and too much sun. One of the main problems with shifting cultivation is that the land is ruined after being used 3 or 4 times. Areas of land are abandoned and not prepared to grow again, and the rainforest becomes smaller with each preparation for a new piece of land. The land loses its fertility and so this is not a reliable form of cultivation.