CAB129-37 — Page 312

This area is bounded, about 35 miles west of Lusaka, by the Mwembeshi river, and continues in a long, narrow strip, somewhat broken by the drainage, for about 70 miles between the vast seasonally flooded flats of the Kafue river to the south and the boundary of the heavy miombo on grey-white plateau soils 15 to 20 miles to the north. Rainfall is from 25 to 35 in. in a single season from December to April. Apart from the limestone hills and granite ridges of the northern edge, and scattered outliers of the same formations in the area, the topography is extremely level. The soils are distinctly sub-tropical in type, varying from silty, light grey to heavy red loams on the higher ground to heavy grey and black clay loams in the valleys. The area of red soil is relatively small, grey and brown loams being more typical. The vegetation is very varied, but mostly light, consisting of a number of types of light open woodland and parkland or savannah with Combretum, Peltophorum, Afromosia and other species, and with tall grass. On the more broken ground and in a few areas on level ground out- liers of miombo stretch from the northern boundary.

Although the soils are somewhat heavier than those of the Tanganyika areas, excellent yields were obtained on trial plots conducted by the Northern Rhodesian Department of Agriculture. The heavier types seem likely to be well suited to sunflowers and maize. The area is not likely to be developed until the future of the transport situation in the Rhodesias can be more confidently foreseen.

3. CLIMATE AND METEOROLOGY

Although little formal meteorological work has been possible, mainly due to lack of equipment, some general observations may be of value in amplifying the description of the areas in Section 2.

All of the areas in which the scheme is operating are semi-arid, in that their climates are all marked by a practically rainless season of at least six months. The rainy seasons are in general more or less continuous from December to the end of April, but there is a tendency to the development of a double rainfall maximum in the Central and Western Provinces, and there is a distinct period of scattered rain in October, in the Southern and Western Provinces.

Kongwa

The 1947-48 season was a relatively dry one throughout the Central Province. Failures of maize and bulrush millet, due to the drought, were common. The midseason gap was a very long one, lasting at Kongwa from about January 20 to the beginning of March, and this was a factor of great importance in con- sidering the results of the agricultural operations, since it covered the early growth period of many of the plantings. Rainfall was recorded during the season at Kongwa headquarters, and at Units 1 and 2. The results were as follows, in inches:

Kongwa H.Q. Kongwa, Unit 1 ... Kongwa, Unit 2...

Nov. Dec. Jan.

Season

Feb. Mar. Apr. May June July total

trace 3.45 5.88 1.05 4.76 0.50 0.08 Nil Nil 15.72 0.23 5.74 5.31 2.39 7-18 1.71 0.41 0.06 Nil 23.03 no 0.51 4.85 0.75 5.47 2.62 0.13 0.08 Nil *14-41

record

December to June

These figures illustrate the wide spatial variation which appears to be charac- teristic of the Kongwa rainfall. Individual storms are frequently confined to an area only a mile wide, although their path may run for several miles. Rain reaches the units at Kongwa very largely from the north and north-east. Some comes in from the west, due to orographic precipitation started on the Chinene hills. Kongwa itself receives a certain amount of rain from clouds which move along Kiboriani mountain from the east or cross it from the south-east, but such rain has not been observed to reach the plains to the north. It appears, therefore, that the rain shadow of the Kiboriani block in respect of rain coming from the south-east is practically complete.

Page 312

103

Page 312

165

', '