Session 2 Uses

Session Papers

Faidherbia albida in the Traditional Farming Systems of Central Ethiopia

A. Laike¹

Abstract

Faidherbia albida is a component of the traditional farming system (teff, mixed cereal, and livestock) of the southeastern Shewa region of Ethiopia. In this high-potential cereal zone, it is found on seasonally waterlogged ground, along riverbanks, and in woodland areas. The tree produces more leaves during the dry season than in the wet season and normally bears fruit once a year (November-January), with an average of 3-5 kg seed per tree. Generally farmers severely prune the species every 3-4 years for fencing and fuelwood. In coffee-growing areas, the trees serve as shade. They also provide feed and shade for animals and medicine for some diseases. F. albida is also revered as a holy tree. Farmers have different views on the beneficial effects of F. albida on crop yields. Those using commercial fertilizer do not appreciate its traditional role as soil-improver. Current research, especially on the regeneration and management off. albida is inadequate. More studies should be undertaken to enhance germination, improve establishment techniques and management systems, and promote the organization of a research network on F. albida.

Introduction

Faidherbia albida, an indigenous tree species in Ethiopia, is widely distributed throughout the country, except in the wet humid southwestern region. It is normally dominant and codominant in riparian forests and woodlands on floodplains where the water table is near the surface (Breitenbach 1963). Because of its wide range of distribution, the species is known by a variety of local names: garbi in Orominga, grar in Amharic, garsha in Tigringa, qeretor in Gamonga, and bura in Sidaminga.

The species is managed and utilized by the farmers in different ways, depending on the farming system. The value attached to the species by different groups of farmers also varies accordingly. This paper presents the cultural practices and mode of utilization of F. albida in the southeastern Shewa region of central Ethiopia. The discussion is based on the author's personal observations and findings from informal interviews with some farmers of the region.

Ecology of the Region and Characteristics of the Tree

According to Ethiopia's agroecological zoning, the southeastern Shewa region is within the high-potential cereal zone (HPC), with mean annual rainfall 700-1200 mm; mean annual temperature, 16-21°C; and altitude, 1500-2000 m above sea level. The topography is mostly flat, with extensive bottom lands where Vertisols predominate. The seasonal rainfall pattern is weakly to strongly bimodal. The small rains (April-May) are generally too unreliable to allow a second crop to be grown prior to the main rains (June-September). The main farming system of the region is teff (Eragrostis tef (Zucc.) Trotter) with other cereals in combination with livestock.

F. albida in this region is found scattered on the seasonally waterlogged ground along riverbanks and in woodland and grassland areas. It forms pure stands only in farmlands where farmers deliberately maintain it to the exclusion of other tree species. Usually, in its natural habitat, F. albida is associated with Acacia tortilis, Acacia sieberiana, Acacia etbaica, Acacia seyal, and Balanites aegyptiaca.

The phenology of the species in this area follows the same general pattern in Sahelian countries. Normally, the trees produce the greatest amount of leaves in the dry season and very few during the rainy season. The trees bear fruit once a year, between November and January, with an average seed production of 3-5 kg tree^-1.

Some trees, however, produce pods during other months, although not consistently.

The regeneration of F. albida in the region is normally achieved by seed propagation, although some root suckering does occur on older trees. In spite of the large amount of seed produced, seedlings can seldom be found, even under mature F. albida trees. We have found an average of only 2-4 seedlings or young saplings on a hectare bearing 20 or more mature trees. Germinating seedlings are usually browsed by animals or plowed under unnoticed during cultivation of the land for crop production. Those that remain are encouraged to develop and mature.

Cultural Practices and Utilization of F. albida

Natural stands of F. albida in Ethiopia are generally managed in two ways, depending on the type of farming system and area where it grows. In the coffee-growing region of Hararghe (eastern Ethiopia), particularly in the Gelemso area, farmers usually maintain and protect F. albida in their coffee plantations for shade. Pods of the trees are collected and fed to livestock. On the other hand, mature trees found in cereal-based farming systems (southeastern Shewa region and the Fedis area of Hararghe) are regularly pollarded at intervals of 3-4 years. Whole canopies are cut right back to the trunk, leaving the trees completely bare. Farmers use the branches for fuelwood and for fencing their compounds and barns. Except for very old trees, which no longer pollard properly, F. albida trees are not normally felled. In this region, F. albida generally is not used for construction because it is prone to termite attack and does not last more than 3 years. However, farmers living in Fedis, Hararghe region, prefer F. albida branches for constructing their houses, and have no serious problems.

F. albida is also used in the region as a source of shade for animals during the dry season. Its pods are widely preferred by animals. Leaves are usually browsed only by goats. Extracts from the bark are said to be used for treating toothache and sore throat in humans and eye disease in animals.

Besides the economic value attached to the species, F. albida is also revered as a holy tree, and is therefore protected by all members of the community. In the absence of F. albida, either A. tortilis or some Ficus spp are revered.

An informal survey to assess the impact of social forestry in some parts of the central region (Modjo area), showed that 74% of the respondents maintain trees on their farmland for different uses. The most protected species is F. albida, followed by A. etbaica and A. tortilis (Kahurananga 1990). In this locality, most of the farmers recognize the beneficial effects of F. albida to crops. The survey also showed that 54% of the respondents claim that where F. albida exists on the farm, crops perform better than in areas without the trees. This has been confirmed by research done in the same area by the Forestry Research Center (FRC), where an increase of 43% in wheat yields was obtained near an F. albida tree (FRC, unpublished data). Similar results were also reported earlier in Gelemso, Hararghe region (Poschen 1986).

In the neighboring localities, however, farmers do not necessarily appreciate the attributes of F. albida and its effect on crop yield. They simply protect the trees on the farm for wood production. In fact, these groups consider F. albida as only the third most important species in their area. According to some farmers who were interviewed, the reason why F. albida is the only species now found in the farms is because it was not favored by the farmers even for firewood in past years. In spite of the different values attached to F. albida, no attempt has been made so far to plant the species on any reasonable scale, either by farmers or by government or private institutions. The survey disclosed that only 2% of the respondents were planting any trees on farmland, and those were mostly Eucalyptus spp. It is interesting to note, however, that very recently some non-governmental organizations and state farms have started planting F. albida as an agroforestry species On farmlands as well as on some abandoned farms. For this and other purposes, a total of 308 kg of F. albida seed has been distributed by the seed center of the FRC in 1990 alone (Getahun et al. 1990a).

Ongoing and Completed Research

So far, there have been only a few investigations done on F. albida in Ethiopia. The beneficial effects of the species in improving crop yield have been evaluated in Hararghe region with different crops (Poschen 1986), and increased yields of maize and sorghum grown within the vicinity of F. albida have been observed.

F. albida was also tried in an alley-cropping trial in Hirna, Hararghe region. It was found too slow-growing to give the expected minimum biomass to be used as green manure. In addition, its lateral growth and its thorns, which make it unworkable for the bare hands of the farmers, made its use in alley cropping problematic (Getahun et al. 1990b). Bekele (1990b), in his study of the impact of F. albida on soil properties and undergrowth, found more plant species (17 species) under the tree canopies than on open land (8). Another study to investigate the germination behavior of F. albida seeds was conducted by Bekele (1990a), who reported that of the different treatments used to break seed dormancy, mechanical scarification and acid treatment (HNo₃, H₂SO₄) were found effective. Other treatments using ethanol, locally made alcohol, and boiling water were not effective.

The response of F. albida seedlings to Rhizobium inoculation was evaluated by Laike (1988), who found that F. albida responds positively if proper Rhizobium strains are used. Performance of 3.5-month old seedlings inoculated with a Rhizobium strain isolated from the nodules of A. mangium grown in Nueva Ecija, the Philippines, was comparable with the performance of seedlings treated with chemical nitrogen (400 mg kg^-1 of soil). Total biomass obtained was 2.9 g and 3.1 g. respectively.

At present, the FRC is conducting a national comparative provenance trial of F. albida in the eastern Shewa region. Seeds of F. albida have been collected from representative stands in six regions. The seedlings are being raised in the FRC nursery for out-planting in Jun 1991. Data on survival and growth rate will be collected over the 10-year period of the experiment.

Conclusion and Recommendations

It has been proved by different researchers in many countries that F. albida improves the yield of crops grown under its canopy; this also holds true in the Ethiopian situation. Yet, most farmers of the central region do not necessarily appreciate this quality of the species. This is perhaps due to the inherently high level of fertility of the soil and the regular use of chemical fertilizers. In areas where the natural fertility is relatively lower, however, farmers do appreciate the role of the species in cropping systems. This appreciation and protection of the species is mainly limited to naturally grown trees; not much attention is paid to young seedlings.

Existing stands of F. albida are mostly dominated by mature trees of more or less similar age. The number of seedlings and saplings observed are too few to guarantee the sustainability of the species in the area. Older trees are also cut for fuelwood and construction purposes. This situation, coupled with the lack of interest by farmers in planting the species or protecting the naturally growing seedlings, foreshadows the gradual disappearance of the species from the region. Such a consequence may be aggravated by the existing fuelwood crisis, where more and more F. albida trees may be cut.

References

Bekele T. 1990a. Investigation of germination behaviour of Acacia albida seeds using various treatment procedures. B.Sc. thesis, Biology Department, Addis Ababa University, Addis Ababa, Ethiopia.

Bekele T. 1990b. Impact of Acacia albida on soil properties and undergrowth in Awass, Southern Central Ethiopia. Thesis, Swedish University of Agricultural Sciences, Wondo Genet, Switzerland.

Breitenbach F. 1963. The indigenous trees of Ethiopia. (2nd edn.) Ethiopian Forestry Association. Addis Ababa, Ethiopia. 305 pp.

Getahun A., Abate, F., and Gebre, B. 1990a. A brief history of FRC and Forestry Research in Ethiopia. Information bulletin. Addis Ababa, Ethiopia: Forestry Research Center. 45 pp.

Getahun A., Alemayehu, Y., Bekele, Z., and Bogalle, W. 1990b. Research into multi-purpose tree species in Ethiopia. Addis Ababa, Ethiopia: Forestry Research Center. (Limited distribution.)

Kahurananga, J. 1990. Informal surveys to assess social forestry at Dibandiba and Aleta Wendo, Ethiopia. Rome, Italy: Food and Agriculture Organization of the United Nations. (Limited distribution.)

Laike, A. 1988. The response of Acacia albida (Del.) to different Rhizobial isolates in two soil types. M.Sc. thesis, University of Philippines, Los Banos, Laguna, Philippines. 65 pp.

Poschen, P. 1986. An evaluation of the Acacia albida-based agroforestry practices in the Hararghe highlands of eastern Ethiopia. Agroforestry Systems 4:129-143.

Footnote__________

1. Forestry Research Centre, P.O. Box 30708, Addis Ababa, Ethiopia. Laike, A. 1992. Faidherbia albida in the traditional farming systems of central Ethiopia. Pages 39-41 in Faidherbia albida in the West African semi-arid tropics: proceedings of a workshop, 22-26 Apr 1991, Niamey, Niger (Vandenbeldt, R.J., ed.). Patancheru, A.P. 502 324, India: International Crops Research Institute for the Semi-Arid Tropics; and Nairobi, Kenya: International Centre for Research in Agroforestry.