CHAPTEE II 



AGRO-GEOGRAPHICAL CONDITIONS IN RELATION 

 TO CROP DISTRIBUTION IN SOUTH AFRICA 



Agronomic production is, of course, directly correlated with 

 the natural factors of production. It is necessary, therefore, 

 to discuss these somewhat in detail : 



Eainfall. — Too often the capacity of a region to produce 

 crops is estimated on the average annual precipitation. That 

 this, especially in South Africa, is misleading will be shown 

 in the following discussion, in which the very important modi- 

 fying influence of yearly fluctuation, seasonal distribution, 

 character, evaporation and run-off of rainfall are taken into 

 account. 



The average annual rainfall on the east coast of England is 

 only 26 inches ; in Lincolnshire and Essex the averages are as 

 low as 18 and 20 inches respectively, yet the lack of moisture 

 is never so acute there as in parts of South Africa where the 

 average is nearly 30 inches per annum. The reasons for this 

 are as follow : — 



(1) In this part of England the seasonal rainfall is more 

 evenly distributed throughout the year ; 20 per cent, of rain 

 falls in spring, 23 per cent, in summer, 31 per cent, in autumn 

 and 26 per cent, in winter. 



In the Transvaal approximately 90 per cent, falls in the 

 six hottest months. 



(2) The evaporation from a free water surface near London 

 is only 20.6 inches per annum, whereas in South Africa it 

 ranges from 65 inches to 75 inches. 



(3) The rain is of a soft, misty character in England, while 

 in South Africa it is precipitated generally in heavy 

 torrential downpours. Consequently the loss from run- 



