The Chagga tribe are Bantu speakers. They moved to the slopes of Kilimanjaro about 300 years ago. During the 17th and 18th centuries, they were nomadic pastoralists. In between the 18th and 19th centuries the Chagga began permanent settlements and they slowly developed modern agriculture. With their long term experience in farming, the Chagga have a unique style that helps conserve the land. They use terrace farming on steep slopes, growing tall tress and under them, planting Arabic coffee, bananas and many small crops like maize, beans and garden vegetables. Thus they can grom a cash and a food crop on the same plot of land. The Chagga have developed an extensive irrigation system using the large amounts of rainfall high on the mountain to irrigate their extensive farms.