25. The most commonly mentioned constraints to the adoption of animal draft power are: trypanosomiasis; lack of animal husbandry skills; and the lack of mechanical skills. We will critically examine these constraints in this section. In addition to these, we will examine the constraints to animal traction in the tropical highlands and the humid tropical zone.
i) Trypanosomiasis
26. The tsetse fly is "shade loving" and can only survive under forest and bush cover. A recession in this vegetative cover leads to a recession in the tsetse fly infestation, and therefore to a change in disease incidence. Increases in population densities lead to a reduction in forest cover as larger areas are brought under cultivation and this acts as a natural control mechanism against the fly. This correlation between population density, land use intensity, and tsetse fly abatement has been observed in several parts of sub-Saharan Africa (Jahnke, 1976; Ford, 1971; Tiffen, 1976; Bourn, 1983; Jerve, 1982 among others). Low population densities rather than tsetse fly infestation can be considered the reason for low intensities of land use. If the tsetse fly were indeed the major constraint and if tillage was profitable, then one would expect to see tractor use being prevalent in these areas, but one does not.
27. Nevertheless, at the forest margin the tsetse fly is an important constraint to the use of animal traction. Where population densities increase farming intensities at the forest margin, N'dama and other trypanotolerant cattle breeds could be used for providing traction power.
ii) Lack of animals and animal husbandry skills
28. Sub-Saharan Africa is often characterized as having a historic dichotomy between crop production and livestock rearing. This supposed polarization between farmers and herders has been given as the reason for the slow spread of animal traction. The argument goes as follows: since the cultivators do not have any animals they lack livestock husbandry skills and hence are not in a position to maintain the animals required for traction purposes. Although it is easy to find examples of tribes that have historically been exclusively cattle herders (such as the Fulani, Maasai, etc.), it is hard to find crop farmers (outside the forest zone) who do not keep any livestock. By the time the farming system reaches a stage where it is appropriate to introduce the plow, the society has in general already acquired livestock husbandry skills. The question then is why some groups who own cattle and who cultivate crops do not use the animals for working their land. The general answer is that these farmers face other constraints to the use of animals (low intensities of farming, light sandy soils, extremely short growing season, etc).
iii) Lack of mechanical skills and repair services.
29. A frequent assertion among specialists studying agricultural mechanization in Africa is that the farmers lack mechanical skills required for the operation of animal traction equipment and that they do not have access to services for the timely repair and maintenance of equipment. These assertions are in general misleading.
30. The use of bicycles and mechanical mills has become very common all over sub-Saharan Africa, even in areas where animal traction is not used. The mechanical skills required for the use and maintenance of this equipment is as high if not higher than that for the use of animal traction equipment. In our survey villages there was not one village where handhoe tillage is practiced which did not have bicycles and/or mechanical mills. Also, almost all our survey villages had a resident blacksmith capable of doing minor repairs on handhoes, plows and other animal traction equipment. As for major repairs and welding, we found that 8096 of the survey villages had access to these facilities within a distance of 20 kilometers (see Table 4).
Table 4. Distance from repair facilities
|
|
0-5 km |
6-10 km |
11-15 km |
16-20 km |
>20 km |
Total | |
|
Animal Traction | |||||||
|
|
Number of cases |
10 |
3 |
6 |
1 |
5 |
25 |
|
|
Percent of total |
40 |
12 |
24 |
4 |
20 |
100 |
|
Tractors | |||||||
|
|
Number of cases |
0 |
1 |
3 |
5 |
5 |
14 |
|
|
Percent of total |
0 |
7.2 |
21.4 |
35.7 |
35.7 |
100 |
|
Bicycles | |||||||
|
|
Number of cases |
7 |
4 |
4 |
2 |
7 |
24 |
|
|
Percent of total |
29.2 |
16.7 |
16.7 |
8.2 |
29.2 |
100 |
Source: Pingali et. al (1987)
iv) Tropical highland areas that persist in handhoe use
31. Mountainous tropical highland areas are a primary example of intensively cultivated areas that persist in the use of handhoes. There are two reasons for the continued use of the hoe in the mountainous highlands, a) a steep terrain is often a constraint to the use of animal or tractor power, and b) many tropical highland areas have a comparative advantage in the production of tree crops and/or milk rather than field crops and therefore the opportunities for using mechanical tillage equipment is limited. Field crops such as maize are grown on small plots mainly for home consumption, handhoes are used to till these plots because the power requirements are relatively low and the period available for land preparation is very long. Rwanda, Burundi and the Kikuyu districts of Kenya, are examples of highland areas that have persisted in the use of handhoes.
v) Constraints to animal traction in the humid tropics
32. Most soils in the humid tropical zones are extremely fragile and intensive field crop production of the type observed in sub-humid and semi-arid zones leads to high levels of leaching, soil acidification and/or soil erosion (Kang and Juo, 1981). Several attempts have been made at establishing permanent field crop production in this zone with mechanized clearing and land preparation, but these attempts have generally run into problems after a few years.
33. In the humid tropical zones where population densities are high, the upland areas are planted with a dense mixture of crops of varying durations. For instance, a system of intercropping short - and medium-term crops such as manioc, yams, cassava, maize and beans under a protective cover of trees is very common in southeastern Nigeria. This system of farming closely mimics the natural vegetation and is viable over the long-run, since the soil would be covered most of the year and therefore the detrimental effects on the soil are minimized. Where market opportunities exist, the humid tropical areas specialize in tree crop production such as cocoa, oil palm-southern Cote d'Ivoire is an example. Where population densities are small and market infrastructure is not well developed, agriculture in the humid tropics continues to be characterized by long fallow cultivation systems. Clearly, the role of animal drawn plows is limited in these systems. The only place where animal traction has a potential in the humid zone is in the cultivation of the bottom lands usually planted with rice-Philippines and other southeast Asian countries are examples where hand cultivation persists in the upland areas.
