Soil conservation in Kondoa district, Tanzania

This paper describes how overpopula- tion and overgrazing have taken their toll on the sandy loam soils of the lrangi Highlands, Kondoa District, Tanzania. Deforestation, animal husbandry and bush fires have together exacerbated the problem of soil erosion. The paper describes how the rehabilitation aod reclamation programme (HADO) has put into practice a series of soil conservation measures including ridge construction along contours reinforced by trees and grass, construction of diversion banks, animal evacuation and improved agricultural practices. The sometimes detrimental effects of these measures are outlined and the author concludes with an analysis of the les- sons to be learnt from HADO.

Keywords: soil conservation; integrated rural development; Tanzania

Dr Aaron S.M. Mgeni is currently at the Department of Forestry and Wood Scien- ce, University College of North Wales, Bangor, Gwynedd LL57 2UW, UK.

‘TANU, ‘Siasa ni Kilimo’, KIUTA, Dar es Salaam, Tanzania, 1972, 22pp. ‘Aaron SM. Mgeni, ‘Greening of Tanza- nia’s new capital - Dodoma’, in prepara- tion, 1985. 3Aaron S.M. Mgeni, ‘Fuelwood crisis in Tanzania is women’s burden’, Quarter/y Journal of Forestry, Vol 78, No 4, 1984, pp 247-249.

Soil conservation in Kondoa District, Tanzania

A.S.M. Mgeni

Soil erosion has been an issue of growing concern in Tanzania since the 1920s. It has been identified as one of the major causes of the decline of agricultural productivity], and soil conservation measures have been strongly encouraged. Soil erosion is still prevalent, however, particularly in the Dodoma, Shinyanga, Mtwara, Singida, Iringa, Tanga, Mwanza, Mara, Morogoro, Tabora, Kilimanjaro and Arusha Regions. Kondoa District in Dodoma Region in central Tanzania is undoubtedly the worst-hit area.

It is a semi-arid area with an annual rainfall below 800 mm. The unpredictable pattern of rainfall, rather than the small amount, makes planning for rainfed food production and forestry difficult.’

The Irangi Highlands in Kondoa have an undulating topography with sandy loam soils containing little clay and organic matter. Consequently these soils are inevitably susceptible to erosion when deprived of vegetative cover. The Irangi Highlands are inhabited by a mixed peasantry, practising both crop production and animal husbandry. As the human and animal populations have continued growing unabated, the carrying capacity of the highlands has been reached. This has led to serious soil erosion leading to deep gully features over an area of 150000 hectares (Figure 1). The so-called Kondoa Eroded Area now constitutes 12% of the total area of the district.

Reasons for soil erosion in Kondoa District

Deforestation through shifting cultivation

About 50% of Tanzania’s area is covered by some type of forest vegetation. About 30% of the forest land is designated as forest reserves while the remaining 70% is public land. As the forest resources on public land is designated as a ‘collective commodity’ they have not been properly used and managed.” This resource has partly been subjected to ‘shifting cultivation’ - slash-and-burn farming.

In tropical forests, nutrients are stored in the vegetation. Decaying material is eventually transformed into humus which accumulates as a thin layer at the top of the soil profile. The nutrient-rich humus makes the forest topsoil fertile. Shifting cultivation has evolved to take advantage of this nutrient distribution.

0264-8377/8.5/03205-05$03.00 @ Butterworth 8 Co (Publishers) Ltd 205


Figure 1. Deep g&lying caused by

soil erosion.

Shifting cultivation in its prototype form first entailed clearing 1 :he primary forest areas in small patches, burning some of the cleared vegetation, allowing the remainder to decompose. Then the cleared forest areas were tilled for agricultural crop production. Since neither fertilization nor crop rotation were practised, agricultural productivity could be sustained for only two to three years after which the soil became exhausted. The peasant cultivators became itinerants, leaving such plots to lie fallow for at least 10 years. This pattern evolved because it takes 10-20 years for a full secondary forest cover to colonize an area after the deforestation of a primary forest. By then the nutrient status is believed to have been replenished to support agricultural production.

When shifting culti~~ation is practised in its prototype form in conjunction with a Iow-population density of cultivators, reckoned to he 2-3 per square km,’ such land becomes sustainable. Under this form, shifting cultivation alone is not a cause of soil erosion. As the population density of the Irangi Highlands exceeded the threshold of sustainable shifting cultivation, more primary forest area was cleared for farming including marginal areas for agricultural production. As the forest area dwindled, the fallow period was gradually shortened. Eventually cultivation became continuous. This led to accelerated leaching of the nutrients necessary for agricultural crops. As fertilization was not practised, agricultural yields continuously declined. Worse still, soil erosion occurred on a large scale as soil conservation measures were not

“Catherine Caufield, Tropical Moist adopted. This form of farming partly contributed to the environmental

Forests. The Resource, The People, The degradation seen today in the Kondoa Eroded Area. Some areas have Threat, Earthscan, London, 1982, 67~. been gullied to irreversible dimensions.

206 LAND USE POLICY duly 1985


Livestock

When grazing is practised at low intensity, its impact on the environ- ment is minimal. Since the majority of people in Kondoa District were mixed peasants, the animal population grew with the human population. Coupled with the introduction of improved veterinary services, overstocking and overgrazing had disastrous effects in the Irangi Highlands: overgrazing led to land degradation through the trampling of vegetation, compacting the soil and the consumption of the vegetation, leaving the topsoil exposed to erosion by rain and wind. The contribution of overgrazing to land degradation seen today in Kondoa Eroded Area is of equal importance to that caused by cultivation.

Another result of the population increase in the Irangi Highlands has been the transfer of some pasture land to crop production. This reduced the area available for grazing, exerting further pressure on the remaining pastures, causing overgrazing.

The vector of animal trypanosomiasis and human sleeping sickness is the tse-tse fly. As Kondoa District is one of the tse-tse fly infested areas of Tanzania, it was necessary to take action. The method adopted was to eradicate the tse-tse through clearing of forest vegetation, its natural habitat.’ Deforestation in Kondoa District was partly effected to eliminate the tse-tse fly.

Fire, road alignment and fuelwood

The annual bush fires caused by honey collectors, game hunters and peasants preparing agricultrual plots, cattle herders burning pastures to create fresh pastures during the dry season all had an adverse effect on the vegetative cover. When the soil loses its vegetative protective cover, the bare burnt areas deteriorate and become vulnerable to soil erosion.

The Irangi Highlands needed thorough alignment of earth roads. Since this was not observed, road construction caused further soil erosion on the hills.

Collection of firewood for cooking and heating and roundwood procurement for house construction partly contributed to the rate of deforestation.

Conservation measures

Concern over soil erosion in the Dodoma Region began in 1929. The government tried a number of anti-erosion measures including destocking and the introduction of improved farming systems. In 1973-74 a conservation unit under the Forest Divison of the Ministry of Lands, Natural Resources and Tourism named HAD0 (Hifadhi Ardhi Dodo- ma - conserve soil in Dodoma) was established to deal with soil conservation in Dodoma Region. The objectives of HAD0 included conserving soil and water; reclaiming the degraded land; establishing shelterbelts, shade and fruit trees; encouraging communal wood- growing schemes and promoting beekeeping.

The HAD0 method of conserving soil incorporates the construction of bunds or ridges along the contours to reduce the speed and quantity of rainwater run off. Such ridges are stablized by planting trees, shrubs and grass. This technique also involves the construction of the diversion

5A. de Vos, ‘Must Africa suffer the environ- banks at the top of the gullies to prevent them from further

mental consequences of tsetse fly?’ Un- development, followed by banking including the planting of grass and

asyha, Vol 30, no 12, 1978, pp 18-23. shrubs. About 11300 hectares of degraded land have received this

LAND USE POLICY July 1985 207


6Aaron SM. Mgeni, ‘Some thoughts on land use planning in Tanzania’, Tanzania News Review, forthcoming. ‘C.G. Wenner, Soil Conservafion in Tan- zania, The HAD0 Project in Dodoma Region, 1983, 7Opp. ‘Aaron SM. Mgeni, ‘Community forestry in integrated rural development: planning perspectives’, Ceres, May-June 1985.

treatment. The solution to deforestation due to fuelwood demand has been to encourage the rural communities to establish their own woodlots. About 2800 hectares have been established under this programme, providing seedlings to villages, schools and individuals free of charge.

One of the methods outside the scope of HAD0 is animal destocking. This is difficult in Tanzania where the number of animals (irrespective of their quality) is still a symbol of the owner’s affluence. Nor is the pricing of animals effectively based on quality.’ Consequently the response to destocking in Kondoa, as elsewhere, was poor. The Kondoa District Council then had to pass a by-law in 1968 effecting the closure of the Kondoa Eroded Area to animal grazing. About 900~0 animals had to be evacuated as result of this law in 1979.’ The ban has been effective.

Another soil conservation measure outside the scope of HAD0 is the introduction of improved agriculture - ridiing along the contours on cultivated hilly land, terracing, strip farming, intercropping, mulch- ing, manuring, cornposting and agroforestry.

Problems encountered

About 97% of all wood products consumed in Tanzania is fuelwood which constitutes 91% of the total energy consumption. About 90% of Tanzania’s population is rural with 95% of its domestic energy demand met by burning wood. Despite this, fuelwood has been regarded as a ‘minor’ forest product - part of the colonial legacy. Until 196748, forestry in Tanzania was exclusively concerned with the mangement of state-owned forests for the production of industrial wood and regulation of hydrological circles on water catchment areas and conservation of

soil. Forestry for rural development was launched in 196748 under the label, ‘village afforestation’.

The creation of forest reserves, both natural forests and industrial plantations entailed gazetting such land first. Generally this involved evacuating the local people residing in such areas. Furthermore, once such areas had been made into forest reserves, the local people were legally barred from obtaining any forest produce. Foresters had to police their forest reserves to protect them from the local people. This created animosity and suspicion from the rural masses. In retrospect it was a trade-off to assign foresters to undertake the HAD0 project. Although the foresters were technically competent to grow trees and shrubs and to conserve soil, they had limited experience in dealing with projects aimed at rural development where the participation of the beneficiaries was imperative. Inevitably during the initial stages of implementation of the HAD0 project, the local people were uncoop- erative and exhibited strong resistance. This was probably a natural reaction because forestry in rural Tanzania has been viewed as something alien to rural development. Another weakness of HAD0 is that it is planned using the ‘top-downwards’ approach excluding the effective participation of the beneficiaries in the planning process. Solutions to soil conservation in Kondoa Eroded Area are prefabricated from outside the area and then imposed on the communities. The efficiency of such an approach is very limited.”

With the evacuation of animals from Kondoa Eroded Area, there have been certain adverse consequences. Shortages of milk and meat

LAND USE POLICY July 1985


could cause malnutrition, particularly among children. Bearing in mind that the financial resources of the peasants are limited in purchasing agricultural inputs like chemical fertilizers, the lack of manure has an impact on the fertilization of agricultural land.

The main shortcoming of the HAD0 project is that it is almost exclusively carried out by the Forest Division without formal horizontal

coordination or integration with other agencies dealing with the same rural people in Kondoa District. This lack of coordination in rural development is normal in Tanzania. It is imperative, therefore, that an organization dealing with rural development on an integrated basis is formed.' Such an organization should be multidisciplinary including the effective participation of the beneficiaries with planning from the base up. HADO’s main problem has been organizational: because it has

‘FAO, Forestry and Rural Development, been implemented through the Forest Division, it has lacked input for a

FAO Forestry Paper No 26, FAO, Rome, wide range of specializations. Effective rural development is only

1961, 35pp. possible through coordination and cooperation.

LAND USE POLICY July 1985 209

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Soil conservation in Kondoa district, Tanzania