364 MAIZE 



CHAP. 322. Artificial Manures or Commercial Fertilisers. — The 



VIIL scarcity of farmyard manure has led to the manufacture and 

 use of the so-called Commercial Fertilizers or Chemical Manures. 

 Their principal function in the economy of the farm is to 

 increase fertility, not to maintain it. They are obtained from 

 natural deposits, such as the nitrate beds of Chile and guano 

 from the Guano Islands or from caves, or are manufactured 

 from bones, blood, and refuse of various sorts. Artificial 

 manures are of two sorts, " general " or complete, and 

 " special " or incomplete. 



323. Method of Applying Fertilizers. — Experiments con- 

 ducted on a large scale have clearly shown that the best 

 method of applying the fertilizer to the maize crop is through 

 the planter with the seed ; this is usually done by means of 

 the fertilizer attachment which can be bought with every good 

 planter. Some commercial fertilizers are not so well dried as 

 others and are apt to stick in the box of the machine unless 

 watched ; the result is that the machine may run for the 

 greater part of a row without dropping any manure, and an 

 uneven stand and growth will result. 



One of the great advantages derived from the application 

 of these fertilizers in the climate of South Africa is the 

 stimulus which they give to the young seedling, enabling it 

 to get a good start in life. Broadcast sowing of artificial 

 manure generally benefits the weeds rather than the maize 

 plants, for in the often dry spring of the South African Maize- 

 belt it rarely gets washed down to their roots. 



324. Influence of Season on the Efficacy of Fertilizers. — It 

 has been found that fertilizers produce different effects on the 

 crop in different years, and this has been traced to seasonal 

 variations, such as difference in rainfall. In the United States 

 it has been found that in dry seasons land manured with stable 

 manure may give poorer returns than land which has had no 

 manure at all. Also that the best results from the use of either 

 stable manure or commercial fertilizers are obtained in seasons 

 of good rainfall. 



325. Use of Lime. — Lime is an essential constituent of 

 good soils and is extensively used for the improvement of agri- 

 cultural land. It is absorbed by the crop, being found in the 

 ash of plants, but its specific action in promoting plant growth is 



