456 THE farmers' handbook. 



and plants of smaller stature, or those differing in any marked respect from 

 the type, should be hoed out before they flower. If neighbouring farmers 

 are growing sorghums or other allied plants, the seed should be harvested 

 only from the centre of the paddock, and the outside rows neglected. 



There should be a ready demand for sorghum seed true to type, as most of 

 the seed sold at present produces crops notorious for unevenness, and some- 

 times containing Planter, Amber cane, and broom millet types. Such crops 

 are not only unsightly, but they are often inferior in sap content and more 

 difficult to harvest. 



Sorghum Poisoning. 



Cases of death have occurred frequently amongst cattle feeding upon 

 sorghum. The deaths have been attributed by some to the presence of a 

 poisonous substance in the plant, whilst others hold that they are caused by 

 hoven, and the crop is not more likely to cause death than any other 

 green food. The suddenness of death, however, amongst stock after eating 

 only small quantities of the plant seems to indicate that some other cause 

 than the one which results in hoven is at work. 



Sorghum poisoning is of fairly common occurrence in Australia, and has 

 also been reported from America and Egypt. The latest investigations in the 

 prussic acid content of sorghum have led to the following conclusions : — 



(1) When sorghum is grown on poor, infertile soil, added nitrosen may 

 slightly increase the amount of hydrocyanic acid in the plant. With 

 a fertile soil and abundant nitrogen, this effect may not be produced. 



( 2) During the first three or four weeks of the plant's life the prussic 

 acid is concentrated in the stalks. Then it rapidly decreases and 

 disappears there, but apparently persists in the leaves in decreasiig 

 percentages until maturity. 



(3)- Climate and variety may be more important factors than soil 

 nitrogen in determining the amount of the acid in the plant. 



(4) Complete hydrolysis of the giucosid is obtained by digesting the 

 macerated tissue for two hours at 40 to 45 deg. Cent. ; that is, the 

 steaming of the crushed tissue as stated will remove the effects of 

 the poison. 



In feeding sorghum to stock it is only necessary to adopt certain pre- 

 cautions to avoid loss. Experience shows that it is only under some circum- 

 stances that it is poisonous. In some cases stock, after feeding on young 

 sorghum, suffer no ill-effects, whilst in others death results. The poisonous 

 substance gradually lessens as the plants get old, and entirely disappears by 

 the time seed is formed. Stock should not be allowed to eat young sorghum, 

 especially if it is wilted through dry, hot weather. Stunted sorghum may 

 also cause death, and immature sorghum which has been frosted is dangerous. 

 The mature sorghum is harmless, and can be fed with perfect safety. 

 Apparently the poisonous properties in immature sorghum are destroyed 

 when it is made into silage. 



THE GRAIN SORGHUMS. 



In early times the grain sorghums were those principally cultivated. This 

 was probably due to the fact that the seed was one of the chief sources of 

 diet of mankind, just as it is at present among many of the native tribes 

 of Africa. As civilization progressed and social conditions changed, the 

 use of the grain as an article of man's diet diminished, and for a considerable 

 period the cultivation of the grain sorghums was not encouraged. Especially 



