AGRO-GEOGRAPHICAL CONDITIONS IN SOUTH AFRICA. 



In some areas, fortunately, the fluctuations are less, and 

 in these crop-growing is more assured, e.g. : — 



Bethal, Transvaal (average 30.39 ins.). 

 Year. Inches. 



1906 

 1907 

 1908 

 1909 

 1910 

 1911 

 1912 

 1913 

 1914 

 1915 



'26.69 



35.3 



22.6 



39.81 



30.36 



33.83 



26.44 



22.84 



42.60 



32.88 



Bethal is situated in one of the largest and most certain 

 maize and potato producing districts in the Union. That it is 

 so is attributable not only to the high average rainfall, but to 

 the small yearly fluctuation. In the period taken, only once 

 (in 1908) was the precipitation as low as 74 per cent, of the 

 average annual rainfall, whereas at Griquatown, Bethulie and 

 Zeerust, during several of the bad years, the rainfall was 

 between 42 and 45 per cent, of the average annual rainfall. 



In parts of Natal, too much rain occurs in some years ;, 

 resulting in crop failures, because of the water-logged condition 

 of the soil in those seasons. 



Evaporation, Character, Distribution and Eun-off. — 

 In considering the dissipation of the rainfall, these factors are 

 intimately connected. Generally speaking, in a country like 

 South Africa, where the evaporation is usually three to four 

 times as large as the precipitation, a precipitation of half an 

 inch or less is of very doubtful utility, since the penetration of 

 the rain is so small that the evaporation of the whole would 

 take place probably before capillary connection with the lower 

 soil moisture has been accomplished, and before succeeding 

 showers have taken the penetration to an effective depth. Over 

 the greater part of South Africa 20 to 30 per cent, of the annual 

 rainfall occurs in light showers of this nature, which on the 

 whole is of very little advantage in crop production. With the 

 exception of a few localities, to be mentioned later, the rainfall 

 in the Union is mainly of a pelting, torrential character which 

 soon deflocculates the surface soil particles into a relatively 

 impervious layer. The air is imprisoned in the interstices of 



