SORGHUMS. 115 



ditions may vary considerably in size, care should be taken 

 not to discard a variety on that account. This may necessitate 

 the adjustment of the planting plates accordingly, in order to 

 obtain a correct spacing. 



EoTATiONS. — While it may pay a maize farmer to have 

 a third or fourth of his land down to cowpeas, it may be un- 

 profitable for a farmer growing grain sorghums to do the same 

 unless his farming is also largely devoted to stock-farming. 

 Green-manuring in arid parts, while extremely important, has 

 been found to be very costly. The yield per acre is small, con- 

 sequently extensive methods are more profitable. However, if 

 cowpeas or similar crops can be fed on or off the land, and the 

 manure returned to the soil, as a policy of permanent agricul- 

 ture it will pay to do so. On very sandv soils the effect of 

 green-manuring in binding the soil will often compensate the 

 farmer for his extra expenditure. Fertilisers should be em- 

 ployed very cautiously and not until experimented with on a 

 small scale. These soils are often extremely poor in phos- 

 phates and, where deficient, small dressings of 100 to 200 

 pounds of superphosphate per acre may pay. Phosphorus has a 

 tendency to promote vigorous root-growth, and in doing so 

 enables the plant to feed over wider areas. Thus a better use 

 of the available moisture and plant food is afforded. In com- 

 parison with most soils, those in sorghum areas are compara- 

 tively rich in plant food, and the necessity for applying 

 fertilisers is not so urgent as in more humid parts. 



Planting. 



Date of Planting. — Their early growth is very tardy, 

 particularly in cool weather, consequently they are usually 

 planted somewhat later than maize. In South Africa the date 

 of planting is usually governed by the seasonal rainfall. The 

 Kaffir corns may be planted from the latter part of October to 

 the end of December, while Milo, Feterita, and Kowliang 

 Negari may be planted up to the middle of January. Sor- 

 ghums for forage or ensilage may be sown up to the latter part 

 of January. Late sown sorghums are often badly attacked by 

 aphids. 



As in all crops, the rate of planting depends on the fer- 

 tility of the soil, the climatic conditions, the vitality of the 

 seed, and the purpose for which the crop is grown. 



For forage, planting must be much thicker than for grain 

 or silage. For grain, the rows should be 3 to 3 feet 6 inches 



