434 SCIENCE IN AFRICA 



OVERSTOCKING 



The following discussion applies to those areas where stock have 

 increased in numbers either generally or locally to a point where 

 the natural food supply is insufficient. It is intended to be con- 

 sidered in conjunction with the sections of Chapter V on soil 

 erosion, Chapter VI on pasture research, and Chapter XIII on 

 shifting cultivation. 



There has been a certain confusion over the meaning of the 

 term 'overstocking', but the definition given by Hornby (1936) 

 makes it clear: 'Overstocking is defined as the maintenance of 

 animals on a piece of land to the detriment of its carrying capacity'; 

 it is not synonymous with soil erosion, which, as pointed out in 

 Chapter V, may result from several causes, of which overstocking 

 is one. 



In many parts of the continent especially in East and South 

 Africa, the effects of overgrazing on the vegetation and soils of the 

 country are more serious than are those of shifting cultivation. It 

 is generally assumed that the evil is the result of great increases 

 in stock in recent years, and that the causes have been the cessa- 

 tion of inter-tribal warfare and the persistence of the lobola or 

 bride-price custom. 



It is important to recognize that the areas where overstocking is 

 noticeable are not as a rule very large in extent; it is essentially the 

 result of local congestion. An important contributory factor to 

 this local congestion is water-supply. All cattle have to remain 

 within reach of permanent water during the dry seasons, when the 

 pasture is least capable of withstanding continual grazing and 

 trampling. Some experts, among them Major McCall (Tangan- 

 yika, Veterinary, 1929, D.R.), lately Director of the Department 

 of Veterinary Science and Animal Husbandry in Tanganyika, 

 went so far as to suggest that the problems of that territory should 

 be ascribed entirely to uneconomic distribution, local congestion 

 and bad husbandry rather than to overstocking in an absolute 

 sense. Captain Hornby, the present Director of the department, 

 has surveyed the general situation in Tanganyika in several pub- 

 lications (Hornby 1934 and 1936). In his view about 40,000 

 square miles of the territory are stocked to saturation, and of these 



