THE ROTATION OF CROPS. 71 



comparatively cheap, the necessity for rotative cropping is not 

 so apparent, and, indeed, in some localities it is questionable 

 whether a change would be economically sound at present. 

 However, these areas are limited, and the capacity of all 

 soils to yield productive crops must sooner or later diminish. 

 As a system in maintaining permanent agriculture, there can 

 be no question of the advisability of rotative cropping all over 

 South Africa. Even the " maize rancher " — growing from 

 500 to 1,500 acres and more of maize on rich soils — will find 

 it profitable to use a green manure on a third or fourth of his 

 land each year. However, the rotation to be followed will be 

 governed by considerations, such as transportation, market 

 requirements, labour, locality, the individual farm and kind of 

 farming practised, whether grain or stock farming, and, 

 further, the kind of stock. 



In general, the rotation must be built on the main crop 

 to be grown, e.g., maize in the Transvaal, Orange Free State 

 and Natal. Where the crops are fed to stock and the manure 

 returned to the land, green-manuring is less necessary than on 

 those farms where the bulk of the crops grown are sold; 

 Further, the dairy farmer requires a greater variety of crops 

 than does the sheep farmer. The former wants silage, grain 

 for concentrates, hay and pasture; the latter in South Africa 

 is concerned chiefly with pasture and hay. 



The nature of the soil, too, will determine to a certain 

 extent, the crops to be grown. Potatoes prefer loose open 

 soils, while wheat will grow better than most crops on 

 relatively heavy soils. Mangels are a much more successful 

 crop on alkali soils than maize. Lucerne cannot be grown 

 profitably on acid soils, where rye, potatoes and cowpeas might 

 yield quite good crops. Sandy soils require more frequent 

 green-manuring and fertilising than clay loams. Bulky crops, 

 like potatoes, require good transport facilities, a consideration 

 not so important to the cotton grower. Obviously, too, the 

 climatic requirements of crops will play an important part 

 in planning a rotation. Cotton must have a longer growing 

 season than teff , millets, and most varieties of maize ; the 

 winter cereals have completed their growth shortly after, or 

 even before, maize has been planted; millets and sorghums 

 give good crops in regions having a rainfall too low for success- 

 ful maize farming; and whether the precipitation is chiefly 

 in winter or summer will, naturally, have a very material 

 bearing on the choice of crops. 



