Introduction to the Chagga home gardens

The Chagga home gardens are a prime example of a multi-storeyed agroforestry cropping system on Mt Kilimanjaro in Northern Tanzania. The Chagga are Bantu speakers descended from various tribes who migrated into the once-forested foothills of Mt Kilimanjaro. They started changing the native forest by keeping the trees that provided fodder, fuel, and fruit, and replaced less useful ones with new tree and crop species.

Because of the ecological and economic success of the Chagga cropping system, Mt Kilimanjaro is one of the most densely populated areas in Tanzania. These home gardens enable farmers to sustainably grow produce with the minimal input.

However, besides the forest reserve, there is no more land on Mt Kilimanjaro that is suitable for the Chagga gardens to expand. Also, at the present level of management, the existing gardens can no longer be used as intensively, and they are becoming more fragmented due to subdivision. As a result of this land scarcity, some farmers have migrated to Mt Meru, some 70 km south-west of Mt Kilimanjaro, where the ecological conditions are similar.

Geographic location

Mt Kilimanjaro covers a total area of about 3 000 km². The highest peak is 5 895 metres above sea level and the area above the 1 900 m contour is a designated forest reserve and national gardenspark, where no agriculture may take place.

The region has an average annual rainfall of between 1 000 to 1 700 mm which occur during ‘short rains’ from October to December and ‘long rains’ from March to May. More rain falls on the south-eastern and eastern flanks where the Chagga home gardens are than on its northern and western sides, which are sheltered from the wet south-east winds.

The volcanic soils are fertile with a high saturation base and water holding capacity. The steep slopes prevent mechanisation and require substantial erosion control work, and some areas are stony or calcified. Most vegetation is montane rain forest, and the composition and structure vary along altitudinal and rainfall gradients.

On the wetter south-eastern slopes, there is a zone of East-African camphorwood (Ocotea usambarensis) and African
yellow-wood (Podocarpus usambarensis) that occur at an altitude of 1 900 to 2 400 metres above sea level and with a rainfall of 1 500 to 1 800 mm.

Smallholder farms

The south-eastern and eastern slopes are characterised by intensive smallholder production of subsistence and cash crops. The homesteads are densely grouped, and food crops are grown under the canopies of banana and coffee trees. The Chagga’s intensive cropping system integrates several multipurpose trees and shrubs with food and cash crops and livestock on the same unit of land. Several agroforestry practices are found within this cropping system, including the use of multipurpose trees and shrubs to provide shade for coffee, as live fences, for fodder and mulch production, for bee forage, and for anti-pest properties.

Other land uses include various state-owned coffee estates and farms, and the Masai use the drier northern and western slopes for grazing. Major plantation alien species like the Mexican Cypress (Cupressus lusitanica) and Mexican weeping pine (Pinus patula), cover about 3 000 ha in the west and 3 500 ha in north-eastern Kilimanjaro.
The Forestry Department carries out various silvicultural operations in natural forests to encourage the regeneration of root suckers of camphorwood, African fern pine (Podocarpus gracilior) and related Podocarpus milanjianus, as well as Mutarakwa or the African Pencil Cedar (Juniperus procera).

Structure of the system

The Chagga home gardens (vihamba) cover about 1 200 km² (120 000 ha) on the southern and eastern slopes of Mt Kilimanjaro. The southern slopes have a population density of 500 per km² and an annual population growth rate of at least 3%. Moshi town is the nearest major market, which is linked by a good road with Arusha, Tanga, and Dar es Salaam. The home gardens are located mainly between 900 and 1 900 metres  above sea level. In addition to a home on the slopes, each family has another plot or kishamba about 10 to 16 km away in the drier plains below the
southern and eastern slopes.

This area has very few trees and is mainly used for growing annual crops. Components of the home garden include banana (Muse spp.), beans (Phaseolus vulgaris), cabbage (Brassica oleracea), cow pea (Vigna unguiculata), chilli) (Capsicum spp.), eggplant (Solanum melongena), maize (Zea mays), onion (Allium cepa), potato (Solanum tuberosum), sweet potato (Ipomoea batatas), taro (Colocasia spp. and Xanthosoma spp.), tomato (Lycopersicon
esculentum), and yam (Dioscorea spp.).

Typical vertical zonation in a Chagga home garden include coffee (Coffee arabica), cardamom (Elettaria cardamomum), surplus bananas and other food crops that are sold as cash crops. Women market surplus bananas, vegetables and milk, and keep the proceeds. Men get the money from coffee, poultry, and egg sales. At least 15 different types of bananas are grown in the home gardens, including cultivars for food, brewing, and fodder.

Besides the fruit, the stems are used for fodder, and the stem sheaths and dried leaves are used for mulch for coffee bushes. In the lowlands, a little maize is grown and usually intercropped with beans. Finger millet (Eleusine coracanal) is important for brewing and making porridge. The men are responsible for lopping the fuel and fodder trees and shrubs grown in the food gardens, while the women harvest the fodder grasses and herbs.

Cattle are kept for milk and goats and pigs are reared for meat, either for home use or to sell. Some farmers have started keeping improved cattle, including Friesian, Jersey, Ayrshire, and crosses between these and local breeds. On average, a farmer has three cows, two goats, and six chickens, and in some cases also a pig.

Livestock are stall-fed with fodder from shrubs and trees, banana plants and grasses grown on the homestead. Additional fodder is harvested from the kishamba in the plains or bought at Tsh 20 a headload (30 to 50 kg). (Tsh=Tanzanian shilling)

Spatial arrangement or zones

The arrangement of trees, shrubs and food crops seems irregular and looks haphazard.

Vertically, several distinct zones can be distinguished:

• Zone 1 (0 to 1 m): Food crops like taro, beans, and fodder herbs and grasses, as well as regeneration of the overstorey trees and shrubs that provide shade.
• Zone 2 (1 to 2,5 m): Mainly coffee, with a few young trees, shrubs and medicinal plants.
• Zone 3 (2,5 to 5 m): Banana with some fruit and fodder trees.
• Zone 5 (5 to 20 m): Vertical zonation is less distinct with a diffuse zone of the preferred fuel and fodder species; and
• Zone 6 (15 to 30 m+): Valuable timber trees and other fodder and fuelwood species.

Interactions

There is considerable overlap of the storeys as some plants are removed and replaced with others. The close proximity of components results in interactions in both time and space.

The nature of interactions varies and can be:

• Direct: fodder trees and shrubs and livestock; trees and shrubs and bees; cattle manure and crops, trees and shrubs;
• Cyclic: crop residues and cattle; and
• Competitive: bananas and coffee; trees and shrubs and crops.

No data is available to indicate the extent of the direct or cyclic interactions, but trials conducted at the Coffee Research Station, Lyamungu, as well as over a part of the main coffee area on Mt Kilimanjaro, indicated that
bananas interplanted with either young or mature, lightly shaded or unshaded Coffea arabica, reduced coffee yields.

Regarding banana yield, other trials elsewhere showed that, provided farmyard manure was applied to the banana clumps, the yield of bananas planted at 960 stools per ha was not greatly affected by the presence or absence of interplanted coffee. However, reduction of the density of bananas interplanted in coffee from 960 to 480 stools per ha, resulted in a lower total banana production, which was partially offset by the higher rate of fruiting and larger bunches from the more widely spaced plants. This is significant, since bananas, and not coffee, are the Chagga’s primary crop.

Source references

Fernandes, E.C.M., Oktingati, A., Maghembe, J. (1985) The Chagga home gardens: A multi-storeyed agro-forestry cropping system on Mt. Kilimanjaro, Northern Tanzania. Food and Nutrition Bulletin, vol. 7, no. 3 © 1985, The United Nations University. https://journals.sagepub.com/doi/pdf/10.1177/156482658500700311

David & Veronica (2016) Charms of the Chagga People of Tanzania. https://gypsynester.com/charmsof-the-chagga-people-of-tanzania/