Primitive subsistence agriculture can be divided into two types- shifting cultivation and nomadic herding.Shifting CultivationIt is practiced in the forests of the Amazon Basin, tropical Africa, North east India and parts of South east Asia. In these regions, there is heavy rainfall and quick regeneration of vegetation.In this type of farming, the trees are cut and their ashes are collected. The ashes are then mixed with the soil. When the soil becomes infertile, the farmer abandons it and moves to another plot of land.Cassava, yam, maize and potatoes are grown through this method.It is known by different names in different places. It is called Milpa in Mexico, Roca in Brazil, Jhumming in North east India and Ladang in Malaysia.It is also known as slash-and-burn agriculture.Nomadic HerdingIt is practiced in the arid and semi-arid regions of Sahara desert, central Asia, Jammu and Kashmir and Rajasthan.In this type of farming, the herdsmen move from place to place in search of fodder and water along defined routes.This movement arises in response to climatic constraints and terrain.Sheep, yak, camel and goat are commonly reared.They provide milk, meat, wool, hides and other products to the herders and his family.