306 SCIENCE IN AFRICA 



an arable country'. T. D. Hall (1934) in his presidential address 

 (on pastures) to section C of the association, pointed out that more 

 than thirty years ago several experts who were at work on stock 

 range investigations, were diverted to arable problems. Dr. Burtt 

 Davy, for instance, was gathering data on the stock-carrying capa- 

 city of land and indigenous grasses 'when he was told to devote his 

 time to the maize industry which was considered of greater impor- 

 tance — a decision that has cost South Africa a great deal'. 



In certain settled areas in East Africa the same principle may 

 apply. The country now devoted to coffee, tea, and sisal is on the 

 whole unsuited to stock raising, but land now used for maize, and 

 perhaps the wheat lands also, would probably be more valuable 

 for mixed farming. The problem is, of course, largely an economic 

 one, dependent on demands of the moment and the capacity of 

 each area to produce exports in competition with the world's 

 cheapest producers. 



In native agriculture the relative merits of land for crops or 

 stock are equally if not more important. Here agricultural develop- 

 ments are closely bound up with measures for the control of disease. 

 It is known by the natives themselves that many insect-borne dis- 

 eases of plants, animals and man may be avoided or reduced by 

 fairly close settlement, leading even to the verge of soil erosion. It 

 is not yet known to them, however, that by their own efforts a 

 reasonable standard of fertility can be maintained together with 

 close settlement, through the adoption of methods such as mixed 

 farming. 



When attempting to foresee Africa's future the example of other 

 countries in warm latitudes may well be of assistance. When land 

 is available in large blocks the first settlers are generally stock men 

 like the early Australian farmers, the ranchers of the United States 

 and the farmers in South Africa. Even the earliest settlers in 

 Kenya went there in the hope of its becoming a stock country. Later, 

 as land values rise, pastoral holdings are broken up and a cultiva- 

 tion phase sets in, to be succeeded in its turn by mixed farming. 

 Such a sequence of events has taken place in many parts of Australia 

 and America. At the present time in parts of the United States of 

 America it appears that too much concentration of crops has led to 

 serious soil exhaustion and erosion, so that the recent commission 



