Population and Land Use in Developing Countries Report of a Workshop (1993) / Chapter Skim
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5 Northern Nigeria: Land Transformation Under Agricultural Intensification
5 Northern Nigeria: Land Transformation Under Agricultural Intensification
Pages 42-69
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From page 42... ...
in: · soillwater conservation structures, · irrigationldrainage structures, · management structures (especially enclosures) , Much more needs to be done before the data and methods can be considered to be satisfactory.
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From page 43... ...
The evidence reported here supports the hypothesis that under conditions of land scarcity, population growth on smallholdings drives agricultural intensification, land investments, and productivity enhancement, which are together consistent with an objective of sustainable resource management. The Study Area In the semiarid zone of northern Nigeria (Figure 1)
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From page 45... ...
The Central Nigeria Project (Land Resources Development Centre, 1979) carried out extensive soil investigations in the Kano Close-Settled Zone in 1977.
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46 MICHAEL MORTIMORE Act]
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The air photo work was supplemented with ground surveys in randomly located quadrats, which included species identification, height estimations, and girth measurements of all woody plants above 10 cm in girth at breast height. POPULATION CHANGEs The High-Density Case The censuses of 1952 and 1962 suggested a net rate of increase of 2.62.9 percent a year (Green, 1970; Mortimore, 1974~.
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From page 48... ...
If the rate of natural increase after 1962 were assumed to be 2.9 percent (as in Malumfashi in 1973) , and migration were zero, the average density in Ungogo District in 1988 would have been 495 persons/km2 an increase that is improbable on the basis of field observation.
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From page 49... ...
A comparison between the two areas, whose present densities differ by a factor of 4, provides an opportunity to test the hypothesis that population density is a predictor of agricultural intensification. Such an investigation is, however, complicated by ecological and historical differences no two areas can be strictly comparable.
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From page 50... ...
Fieldwork in 1990 suggests that small areas of shrubland, notwithstanding their poor quality, had been added to the cultivated upland. Multicropping is still restricted to lowland sites (though pumps have increased the lift available)
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, field boundaries are usually unmarked, and farm trees are extremely sparse. Fallows are occupied by regenerating dum palm bush and grasses.
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Field studies indicate that the most visible change to occur since 1969 was an increase in the extent of mobile sand, which by 1986 had come to occupy up to 20 percent of one or two badly affected localities. This increase is attributed to the effects of drought and reduced rainfall more than to management, since the evidence available on livestock numbers does not indicate a substantial increase, and cultivation is not generally associated with dune remobilization (Mortimore, 1 989a)
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From page 53... ...
that the upland subsystem is unsuitable for rainfed cultivation in most years and that cultivable land is restricted largely to the lowland subsystem; or (2) that net population increase was brought to a stop by out-migration and that the subsequent labor shortage impeded further expansion of cultivation.
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From page 54... ...
Nevertheless, deep cultivable soil horizons, along with little government interest in controlling soil erosion (even in colonial times compared with East Africa) , gave a low profile to soil and water conservation in smallholder perceptions.
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Oriented in a rectangular grid facing Mecca, they define the characteristic visible structure of the landscape. Intensive livestock production is now creating a new need, on farms belonging to wealthy individuals, for purchased wire fences.
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In the low-density area, trees (especially date palms) are found on lowland farms in considerable numbers, but on cultivated upland sites, where the water table is deep, only occasional volunteers from the natural flora are found.
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From page 57... ...
With regard to particle size distribution, the overall results suggest a small diminution in the coarse sand fraction, an increase in the predominant fine sand fraction, a small increase in very fine sand, and no significant changes in the silt and clay fractions, each being less than 7 percent. The cultivation technologies are not known, but except for one land system, the soils show little evidence of physical deterioration under long-term annual cultivation.
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From page 58... ...
To test this possibility, two catenas sampled in the earlier study, one inside a forest reserve and one outside it on cultivated farmland, were resampled. Comparing these soils with one another, and those of the forest reserve with those on farmland in the Close-Settled Zone, does not support the hypothesis that the properties of cultivated upland soils are of a lower order of magnitude than those of uncultivated soils in a comparable ecological zone.
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From page 59... ...
Soil Management and Population Density Evidence has been presented that the topsoils on cultivated upland in the high-density area are stable with respect to most of the standard diagnostic physical and chemical soil properties. Although the values tend to accord with low levels of fertility, a comparison with uncultivated soils suggests that the soils are by no means degraded.
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From page 60... ...
FARM TREES Under a regime of annual cultivation, natural woodland is gradually transformed, by the clearance, selection, protection, and planting of trees, into farmed parkland. The trees provide, among their many functions, browse for small ruminants in an integrated system of crop, livestock, and tree husbandry.
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From page 61... ...
Farm Trees and Population Density In northern Nigeria (and elsewhere in West Africa) , the transition from bush fallowing to annual cultivation (normally associated with increasing population density)
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From page 62... ...
DEMOGRAPHIC VERSUS NONDEMOGRAPHIC FACTORS The evidence reviewed so far leads to the conclusion that population growth, and high population density, are compatible with sustainable resource management by smallholders. A relationship between population growth and agricultural intensification in northern Nigeria could be inferred long before Ester Boserup's elegant statement of her hypothesis in 1965.12 A review of the farming system of the high-density case (the Kano Close-Settled Zone)
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From page 63... ...
Actual family labor inputs are also influenced by their opportunity costs in alternative income earning activities, at home or away; by the sexual division of labor; by labor withdrawal for education; and by random indisposition. Among these, the opportunity costs seem to be crucial.
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From page 64... ...
The extent to which it correlates with changing population density (apparently independent of market influence) is attributable to the continuing priority accorded by peasant smallholders to household subsistence production.
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From page 65... ...
The farm tree component of the high-density system well integrated with crops and livestock is also being managed sustainably, whereas farm trees do not play a significant part in the low-density system, except on lowland sites. It is concluded that population growth, and high population density, are compatible with sustainable resource management under smallholder conditions.
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From page 66... ...
crops. Agricultural incomes may be used to finance education or employment while offfarm earnings may be invested in agriculture or land improvements 13 There are interesting parallels between the experience in the Kano farming system and in the Machakos District, Kenya, where rapid population growth has accompanied a transition from extensive to intensive farming and very substantial investments in land and water conservation during the last three decades (the preliminary output from this study is available in a series of working papers published by the Overseas Development Institute, London)
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From page 67... ...
1961 Population densities and agriculture in Northern Nigeria.
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From page 68... ...
McTainsh, G., and S Stokes 1980 Environmental Data Bank for Central Northern Nigeria.
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From page 69... ...
Turner, B 1977 The Fadama Lands of Central Northern Nigeria: Their Classification, Spatial Variation, Present and Potential Use.
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