In sedentary pastoralism, or pastoral farming, pastoralists grow crops and improve pastures for their livestock. Most herders in Mongolia follow a pattern of nomadic or semi-nomadic pastoralism. Transhumance is a "form of pastoralism or nomadism". Nomadic pastoralism developed in the Pontic-Caspian steppe beginning in the Chalcolithic. The heartland of pastoralism is the Eurasian steppe. Traditional modes of subsistence like pastoralism and fishing are now supplemented by the cash-based economy. The Tsonga traditional economy is based on mixed agriculture and pastoralism. The traditional occupation of Ahirs are pastoralism and agriculture. Economy in the Vedic period was sustained by a combination of pastoralism and agriculture. Similarly, food acquisition was by pastoralism, agriculture, and hunting. Specialization occurred as a result of the increasing importance of both intensive agriculture and pastoralism. The economy focused on local agricultural production and sheep-and-goat pastoralism. The importation Bantu pastoralism reshaped the continent's economy. Land uses include broad-acre pastoralism, bauxite and silica sand mining, nature reserves, tourism and fishing. The number employed outside small-scale agriculture and pastoralism was about 6 million.