About the Potato Atlas Archives...
The first World Potato Atlas was developed at the International Potato Center (Centro Internacional de la Papa, or CIP) in the 1980s and maintained for several years -- primarily by Robert Rhoades, Robert Hijmans, and Luisa Huaccho -- to provide country-specific information about potato production, constraints, and uses. A newer version of the atlas, providing updated and more detailed information of a limited selection of countries, was initiated in 2006.
The "atlas archives" included here are based on chapters of the original effort which so far have not been substantially updated. Although some of this information is clearly obsolete, some remains relevant, at least for historical background.
HISTORY AND OVERVIEW
Potatoes were introduced in the 1920s by German mission stations in the Southern Highlands of Tanzania (then the German colony of Tanganyika), where local farmers began cultivation in small scale gardens. Other variety introductions likely arrived via Kenya and Malawi as farmers designate older local varieties by the names of these countries (Mallya and Jackobsen, 1976). After the First World War, Great Britain assumed control of the region. In 1928, 84 tons of potatoes were exported to Shamboa District. The potato made it possible for farmers to move their cultivation to higher altitudes. Detailed information on the subsequent development of potato production until the 1960's in Tanzania is unavailable.
GEOGRAPHY AND PRODUCTION ZONES
Potatoes are generally grown in areas between 1,800 and 2,700 meters above sea level (masl), the most important area being the Southern Highlands, particularly the Iringa and Mbeya regions (Macha et. al., 1982). Estimates for 1980 show these regions accounting for approximately 90 percent of total production or 550,000 tons out of a total national production of less than 600,000 tons (Macha et al., 1982).
Representative growing areas are found in Njombe and Makete districts of the Iringa Region (Uyole Agricultural Center, 1980). These districts lie at 2,000-2,500 masl. Topographically, they include the Ubena Plateau, an undulating plain in the eastern and central portions of the region, and Ukinga highlands in the west which is characterized by steep mountains and narrow valleys with a few high plateaus.
In addition to the southern highlands, potatoes are also grown in suitable areas to the west of Mt. Kilamanjaro, notably in Arusha region, and in Kagera Region west of Lake Nyanza near the Ugandan border. Minor production occurs in Mara, Tanga, Kigoma, Rukwa, and Ruvuma Regions and possibly elsewhere (Macha et al., 1982).
Average annual precipitation in the production area ranges from 600 mm to over 1,600 millimeters (mm). The bulk of this falls between December and April, with some areas receiving up to 100 mm or more in October and November. Frost occurs occasionally on the plateaus and commonly in the highlands during March and April (UAC, 1980; Jakobsen, 1982). Major soil types include relatively fertile soils derived from volcanic ash and pumice, occupying ridge crests and gentle slopes; well to poorly drained soils of alluvial origin and moderate to high fertility on flood plains; and shallow, acid soils derived from bedrock on steep slopes (UAC, 1980).
PRODUCTION SYSTEMS AND CONSTRAINTS
In Njombe and Makete districts of the southern highlands, the major planting season begins in early September and lasts until the beginning of the rains in November and December. Planting is generally earlier in the higher areas. Varieties with proven resistance to late blight may be planted relatively late in the season and harvested three to four months later. A second planting peak takes place on the plateaus in March/April, but is subject to increased risk of frost and late blight. A third planting takes place in small plots along valley bottoms in June/July (Jakobsen, 1980).
After grass fallow, turf is turned over to form ridges 30-50 centimters (cm) high, spaced 120-150 cm apart along contours. The dry grass is then burned. Planting occurs as soon as possible after burning, and in any case, before the onset of the rains. Plant densities of one plant per square meter or less are common. This system is especially practiced with some of the older cultivars, notably loti, which developed many long stolons and often gave good yields (Jakobsen, 1980). With the introduction of high yielding, disease tolerant, short stoloned cultivars such as Baraka and Sasuma, some farmers are using smaller, more closely spaced ridges. These are made with hoes on flat land after planting (in rows) and germination. Cultivation occurs simultaneously with the hoeing up of the ridges, and burning is dispensed with (Jakobsen, 1980). The hand hoe is the most important tillage tool (Lutende, nd).
In the second and third plantings (March/April and June/July, respectively), potatoes are commonly intercropped with maize, peas, cabbages, and other crops. Potatoes are commonly rotated with maize, wheat, and peas as well as grass fallows, although individual farmers vary considerably in rotations practices. Fertilizers and other purchased inputs are rare except for the largest farmers and those living in the vicinity of agricultural research stations (Jakobsen, 1980).
Harvesting is generally done manually, typically after the haulms have died. Potatoes may be left in the ground until nearly a year after planting (Jakobsen, 1980). In some cases, however, farmers harvest early to fetch higher prices in the market (Lutende, nd). Most of the harvesting and transporting of potatoes on the farm is performed by women. Men may assist the women, but according to Makete and Njombe, almost never perform these tasks alone (Jakobsen, 1980).
Mallys and Jakobsen (1976) report that in some cases a proportion of the crop is not harvested at all, but left in the ground to sprout of its own accord. Such volunteer crops may persist for five years without replanting. While yields are very low, this in-ground system avoids seed storage problems as well as labor costs associated with land preparation, planting, and transportation of seed. Yields vary considerably ranging from less than one ton per hectare (t/ha) for volunteer crops (Mallys and Jakobsen, 1976) to over 40 t/ha under experimental conditions (Macha et al., 1982). Typical yields for main season crops under farm conditions are probably on the order of 5-10 t/ha (Macha et. al., 1982).
Anonymous, no date. The Marketing of Potatoes in Dar es Salaam. International Potato Center, Region III.
FAO 1986. Basic Data Unit, Production Account. Unpublished May 1986.
Jakobsen, H. 1980. Potatoes in Njombe and Makete Districts in 1979 (Working Paper). Uyole Agricultural Center.
Jakobsen, H. 1976. Potato Production in Tanzania. Paper Presented to the Regional Workshop on Potato Seed Production and Marketing, Nairobi, October 1976. International Potato Center, Region III. 4 pp.
Lutende, D.D.K., no date. Potato Production and Post Harvest Technology in Tanzania. Uyole Agricultural Center.
Macha, C.A. 1976. Report on Potato Production in Tanzania. International Potato Course: Production, Storage, and Seed Technology. Report of Participants. International Agricultural Center, Wageningen, The Netherlands.
Sumugurka, G. and R. Mwambene 1982. Potato (Solanum tuberosum) Improvement in Tanzania. Paper Presented to the Regional Workshop on Potato Development and Transfer of Technology in Tropical Africa, Addis Ababa, August 22 to September 1, 1982. International Potato Center, Region III.