The first task of the Department was the survey and appraisal of the areas suggested for development. These surveys had of necessity to be brief and directed to essentials only, and they have done no more than establish the main vegetation and soil types of the areas and their probable extent. They have served, however, to site the main areas and to guide later investigations, particu- larly soil fertility studies and more detailed surveys.
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Five criteria have been adopted on which to judge proposed areas. Firstly, the area must be, in general climatic terms, one in which groundnuts and other tropical oilseeds will grow. In particular, rainfall must be adequate in amount and suitably distributed, giving over a number of years an average of not less than 20 in. falling in a five-month period, or longer in the case of larger totals. In many instances vegetation has had to be used as a guide in applying the data from distant stations to the rainfall conditions of a particular area. Secondly, the soils must be medium loams or lighter in texture, since although many other crops than groundnuts are to be grown, the groundnut will be the most important oil producer and its needs must be given first consideration. Thirdly, drainage must be good. These last two considerations do not, of course, rule out the use of heavier and less well-drained soils, within any selected area, for other crops. Fourthly, soils must be such that no harmful chemical condi- tions exist, for example salinity, and any deficiencies in plant foods must be capable of being met by the use of reasonable amounts of fertilisers and of lime. Fifthly, the general topography must be such that large scale mechanical operations will not involve excessive capital expenditure on soil conservation
measures.
Naturally, no area could be selected where communications were inadequate or incapable of improvement at reasonable cost, or where the vegetation was such that clearing operations would be prohibitively expensive. So important is the communications question that in future development of this kind it may well prove best first to select a suitable port with good actual or potential interior communications, and then explore its hinterland for suitable land.
Eight areas have been surveyed from these points of view in the period. They
are:
Tanganyika:
Kenya:
Northern Rhodesia:
Kongwa (Mpwapwa district), Urambo (Tabora district), 'Southern Province Block A (Lindi and Masasi districts), Southern Province Block B (Liwale district),
Korogwe/Handeni area (Korogwe and Handeni districts),
Malindi/Garsen area (Malindi district),
Mackinnon Road (Voi district).
Mumbwa area (Mumbwa and Broken Hill districts).
Kongwa Region, Mpwapwa district, Tanganyika
This was the first area to be developed, and during 1947-48 was the only one in which significant areas of land became available for agriculture. The original trading centre of Kongwa lies a few miles due north of Mpwapwa in the Central Province of Tanganyika, from which it is however separated by the Kiboriani mountain block. The Kongwa Region of the Scheme lies well to the north of Kongwa itself, the nearest boundary of the cleared land being about 7 miles distant, and running roughly east and west parallel with the Kiboriani mountain. The western boundary is roughly parallel with the northwesterly line of the Chinene Hills, again at a few miles distance. The area as a whole forms the southernmost extension of the Masai steppe. Rainfall conditions are not accur- ately known, but at Kongwa mission, four miles from Kongwa towards the
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