Background information on Karatu
Karatu district is one of the ﬁve districts in the Arusha Region, located in the northern part of Tanzania (Figure 1) between latitudes 38 10′ and 48 00′S and at longitude 348 47′E. The district measures 3,300km2. Land use is classiﬁed as follows: arable land 102,573ha, pasture land 155,808ha, forest, bush and tree cover 61,218ha and Lake Eyasi 1,060ha; Karatu district has four administrative divisions, 13 wards and 45 registered villages, Rhotia being one of them. The administrative headquarters is in Karatu town, approximately 150km west of Arusha town. It is an important stopover formost tourists heading forNgorongoro and Serengeti national parks. The ofﬁcial population is 178,434 people (92,895 men and 85,539 women), growing at an annual rate of 3.2 per cent and aggregated into 33,000 households. The average population density is 52people/km2 with low population in the western zone along Lake Eyasi (7-10/ km2) and higher densities (100/km2) in Karatu and Mbulumbulu divisions (URT, 2004b). The district has three physiographic zones, uplands,
midlands and lowlands, with altitude ranging from 1,000 to 1,900m asl (above sea level). Rainfall in the district is bimodal; short rains fall between October and December and long rains between March and June (KDC, 2001). Rainfall ranges from less than 400mm in the Eyasi basin to over 1,000mm in the highlands with rainfall zones classiﬁed as semi-arid (300700mm/year) and sub-humid (700-1,200mm/year), respectively (Meindertsman and Kessler, 1997). Soils vary depending on their origin and location in the
landscape. Shallow degraded soils with low fertility are found on uplands of the inland valleys and on the slopes. Clay soils of moderate fertility are found in the valleys with gently rounded summits and on slopes overlying soft gneiss rocks. Arable farming and pastoralism are the two kinds of
land use. Farming is largely rainfed.