CEREALS ID/ 



here again we find its distribution limited ; in South Africa 

 it does better on the uplands above 3,000 ft. than at or 

 near sea-level, where the growth of rank weeds which 

 over-top the maize plant interferes with the development 

 of the grain. 



Altitude affects the growth of crops indirectly, as it 

 influences length of season, temperature, precipitation of 

 moisture, depth and richness of -soil, etc. The altitude 

 at which the maize crop can be grown successfully varies 

 from sea-level to 10,000 ft., or possibly more, latitude 

 compensating altitude. In the United States 82 per cent, 

 of the crop is produced between 500 and 1,500 ft. altitude. 



Temperature. Eighty-eight per cent, of the United 

 States crop is grown between the July isotherms 70 and 

 80 F., whilst the actual highest yields have been o'btained 

 between July isotherms 75 and 80 F. The average 

 temperature of the maize belt of Argentina is 62'3 F., 

 and the belt lies between summer isotherms 71 '6 and 

 78-8 F., and annual isotherms 59 and 68 F. 



The average mean monthly temperatures for the four 

 growing months (November to February inclusive) in 

 the Transvaal over a period of seven years are : Pretoria 

 (4,500 ft.), 70-28; Vereeniging (4,7 ft.), 69-29; 

 Bethal (5,580 ft.), 64-68 F. Though we have abundant 

 proof that good maize crops can be grown where the 

 nights are uniformly cool, as in the Transvaal, it is 

 probable that warm nights tend to heavier yields per 

 acre. 



Low soil temperature retards germination and subse- 

 quent growth. Maize lands should be well drained in 

 sub-tropical climates, for wet soils are usually cold. 



Rainfall. As compared with many I think we may 

 safely say, most farm crops maize requires very little 

 moisture, especially when we consider the weight of 

 green material produced by it; King, of Wisconsin, found 

 that it required only about half the rainfall necessary for 

 a crop of oats or clover. But the maize plant requires a 

 considerable amount of water at certain stages of growth, 

 especially up to a height of about 6 in., and again at the 

 time of flower production. 



At the Illinois Experimental Station a rainfall of 13 in. 



