survey of the irrigation potential of the lower tana river basin kenya

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2.4 Costs of Irrigation and Agronomio Considerations (see Chapters VII, VIII and IX)
During the project studies, two levels of possible irrigation development were
considered, namely 250,000 acres, and 300,000 acres. The estimated direct capital
expenditure necessary worked out at 53 million and 60 million East Africa pounds
respectively (see details in section 2.5 below). Direct investments in institutional
and social infrastructure were estimated to cost an additional £E.A. 400 per net acre,
and processing facilities a further £E.A. 200 per net acre. The foregoing did not
include the costs of supporting productive activities such as forestry and fisheries,
nor the external infrastructure related to project development.
Since the cost of irrigation development per acre seemed to be so high, attention
was concentrated on cash crops which could offer fair to good returns.
Agronomic trials at Galole covered cotton, sugar cane, kenaf, groundnuts, castor,
beans, maize, sorghum, rice, and fodder crops. Except for cotton, already well
established at Galole, the tests made could not be sufficiently comprehensive in the
time available, and more testing remains to be done. However, on the studies made
and information available, a cropping pattern was evolved which included cotton,
sugar cane, kenaf and groundnuts as major crops.
Table 9-2 shows that,of 8 crop-acres in 6 years, 6 crop-acres would be devoted
to the cash crops cotton, sugar cane, and kenaf and only 2 crop-acres to groundnuts
and beans. No staple food crop is included at all. The adoption of such a rotation
would involve the assumption that supplies of staple foods for the whole population
of the area could always be imported from elsewhere, at reasonable prices and with
sufficient certainty. Considering the location and circumstances of the projeot,
in a somewhat remote and semi-arid part of the country, this is quite unrealistic.
Few prospective cultivators would be attracted by an economy consisting essentially
of cash cropsj a man's first ooncern is to secure hie food supply, and it is essential
to grow sufficient basic foodstuffs every year, within the rotation.
The efficient production and handling of sugar cane calls for higly organized
plantation methods, rather than cultivation by individual tenants. Further, a
factory is essential, under skilled direction; to justify its heavy cost, there must
also be grown from the start a sufficiently large area of cane.
The cutting, retting, and processing of kenaf requires much labour which, for
efficiency, must be well organized, and even mechanized methods of decortication
need further development. As was brought out in the studies made, casual labour
does not exist in the area, nor is it likely to be easily attracted there in future,
unless it is well organized and continually employed, at fair rates.
It is considered that the whole question of the oropping plan to be adopted
requires more and very careful investigation, including trials and tests on a field
scale of varieties and yields of crops over a sufficient period to establish what
benefits may be expected. Such investigations are matters of some urgency.
Meantime, data are not yet available on which to make specific suggestions
as to potential cropping patterns which might be further considered. It does,
however, appear possible to envisage a pattern which omits sugar cane and kenaf,
but maintains cotton as the main cash crop, with groundnuts and maize or sorghums
as food crops. Cropping intensity would be slightly less than that envisaged in
the pattern originally suggested, but it might nevertheless provide a rate of net
farm revenue oomparable with the figure of E.A. Sh 950 per acre of holding, forecast
in Table 9-2 for the original cropping pattern.