Management aspects of the Chagga home gardens

The Chagga home gardens are an excellent example of a multi-storeyed agroforestry cropping system on Mt Kilimanjaro in Northern Tanzania.

These home gardens belong to the Chagga, Bantu speakers descended from various tribes, who create these multi-storey gardens on the once forested foothills of Tanzania’s iconic Mt Kilimanjaro. They started changing the native forest by keeping the trees that provided fodder, fuel, and fruit, and replacing less useful ones with new tree and crop species.

Indigenous knowledge

The Chagga have an intimate knowledge of the various crops and plants and their ecological requirements, as their management techniques were handed down from one generation to the next. Using indigenous knowledge is one of the cornerstones of successful agroforestry systems. When the farmers think it is time, they carry out different operations. These include opening up the canopy of the towering trees to allow more sunlight in to enhance fruiting of the coffee trees, spacing out the banana stools or clumps, and feeding the soil with animal manure to ensure better crop yields.

They also maintain plant species like Datura arborea and Rauwolfia caffra or quinine tree, that repel or eradicate various pests. They also know the best fodder trees and shrubs and when and how to lop them. Every home garden has a network of irrigation and drainage ditches that are linked to the home gardens in the area. These ditches carry runoff water from the slopes above the home gardens and can be tapped by each farmer to water his crops.

The number of coffee bushes and banana clumps in a home garden depends on the owner’s preferences and management abilities, as well as the altitude and aspect or compass direction of the land. Home gardens contain on average 330 to 1 200 banana clumps per hectare and 500 to 1 400 coffee trees per hectare.

On average, about 39 other trees and shrubs are maintained and managed in the home garden. Plants that can tolerate shade, including beans, yams, an edible tuber, and taro, a root vegetable, are planted between the bananas and coffee plants. Crops that need more sunlight are grown in a part of the home garden where the canopy has been trimmed to provide minimum shade.

Most coffee trees have one stem, and extension services provide advice on pruning and spraying against leaf rust and coffee-berry disease. Banana clumps are maintained with three to five pseudostems (suckers grown from rhizomes) of different ages to encourage an ongoing banana harvest.

Most farmers allow natural regeneration or plant new trees to regenerate valuable timber species. Young trees grow in the shade, which encourages straight stems with few branches. When it is time, the overhead canopy is thinned to allow the young trees to grow into the upper storeys to 0,6 to 1 m³, which takes about 60 to 80 years. A large Elgon teak tree (Olea welwitschli) of about 1 m³ can fetch a price of Tsh 10 000. (Tsh = Tanzania shilling)

If the present owner fells such a tree during his lifetime, he plants a new one in turn so that the next owner also inherits a valuable tree.

Although most of the home gardens are intensely cultivated and well managed, there are some neglected, overgrown and even abandoned home gardens. The different species have different uses, including providing shade for crops, as live fences and boundary markers, fuelwood and charcoal, timber for building materials and tool handles, storage constructions and roof thatch, fodder and fruit, medicine and pest repellents, grass planted as soil erosion prevention, and grave markers.

The functioning of the home garden system

Land

Home gardens vary in size from 0,2 to 1,3 hectares, with an average size of 0,68 ha. Traditionally, the land was divided only between the sons, but daughters can now also inherit all or part of the home garden. Interestingly, land tenure is based on a strongly held traditional belief that there is a close spiritual link between one’s ancestors and the soil, hence the need for grave markers. Once a member of the immediate family has been buried in the home garden, tenure is assured for the current owner and his descendants. Such a plot may even be abandoned for several years without the danger of someone else taking ownership.

However, as the lowland kishamba is allocated by the state and according to the size of the family, tenure is on an annual and usufructuary basis, as long as the land is not destroyed or laid to waste. If this land is not used for up to two years, another person may claim it.

Workforce

An average household size of 9,9 people provides a workforce of four family members to plant, tend, and harvest as needed, and in the case of bananas, taro and yams, this is required throughout the year.

Coffee harvesting

Coffee harvesting normally begins in August and continues until January, with the peak harvesting period between January and March. Coffee harvesting coincides with land preparation and planting of crops in the home gardens and, on the lowland, kishamba.

April to June is a quiet time before harvesting of maize, beans, and finger millet from the lowlands starts in all earnest. All operations on the slopes are performed by human labour, while tractors are sometimes used for ploughing in the kishamba.

Farm implements

Each farmer has on average farm implements, including axes, hoes and pangas valued at Tsh 560. Few farmers own tractors, which they lease to others for ploughing.

Seeds

Seeds are mostly obtained from previous crops, but it can also be bought from the Tanzania Farmers’ Association.

Fertilizer

Chemical fertilizers are generally not used. Instead, dung from the stall-fed livestock and other household wastes are spread around the banana clumps and coffee bushes to replace nutrients in the soil.

Yield

An average home garden of 0,68 ha produces about 125 kg of beans at about 184 kg per ha, 280 kg of parchment coffee with the skin on until beans are roasted (412 kg per ha) and  275 bunches of bananas (404 per ha) per year.

Maize

The maize harvest from the each kishamba plot averages 360 kg per year. Most of the coffee is sold, but poorer quality coffee beans harvested at the end of the harvesting season are retained for own use.

Crop failure

No total failure of bananas and other fruits, root crops and livestock has ever occurred. While no production data is available for taro, yams, cardamom, and onions, local sources indicate that crop failure involving coffee and or maize, and beans occurs once every three or four years.

Each farmer keeps between three and five traditional beehives, from which at least 5 kg of honey is harvested per year.

Milk production

Traditional cattle breeds under stall-fed conditions produce between one and four litres of milk per day, but improved cattle provide up to between eight and sixteen litres a day. Pigs are fattened up and sold within six to twelve months.

Fodder

Although it is difficult to estimate the quantity of fodder produced in the home garden, most of the Chagga farmers are almost self-sufficient in fodder production for their livestock.

Fuelwood

Fuelwood production in home gardens is estimated at 1 to 2 m³ per year (1,5 to 3 m³ per ha per year). Assuming a minimum consumption of 1 m³ per adult per year, each family requires 4 to 6 m³ per year. A home garden supplies a quarter to a third of their fuelwood requirements, and the rest is obtained from the forest reserve or the kishamba in the form of Acacia spp. and Combretum spp.

Marketing and credit

The Kilimanjaro Uremi Co-operation (KUCl is a co-operative concerned with the production and marketing of coffee, that also supply free pesticides for use against coffee-berry disease and leaf rust. In addition, the Chagga use a variety of plant species with pest-resistant properties. The KUC offers credit facilities, while the Tanzania Rural Development Bank (TRDB) also offers soft loans for dairy cattle and pig production.

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

Indigenous Knowledge: Preserving Traditional Wisdom in Agroforestry (n.d) FasterCapital
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