VARIATION IN COMPOSITION OF PLANTS 85 



from the soil. The crop grows rank and sappy, conse- 

 quently the nitrogenous matter is largely present in the 

 form of amides. Heavy nitrogenous manuring would 

 tend to increase considerably the proportion of water and 

 probably double the protein in the plant, while phos- 

 phatic and potassic manures would tend to increase the 

 proportion of carbohydrates, and, by causing the plant to 

 mature earlier, the proportion of albuminoid nitrogen. 



Small mangels may contain 2 to 3 per cent, less 

 water than large mangels, and the carbohydrates be 

 increased by the same amount; hence, ton for ton, 

 small roots have a greater feeding value than large ones. 

 This does not mean a small crop is better than a large 

 one, but simply emphasises the fact that in a 30 or 

 40 ton crop (per acre) it is better to have the roots 

 of medium rather than of very large size; hence it 

 is generally wise to leave the plants fairly close together 

 at singling time. 



In Ireland, it appears from a Report of the Depart- 

 ment of Agriculture that "complete" mixtures 1 of 

 artificials increased the bushel weight of oats. 



At Garforth (1899 and 1900), Herbert Hunter 

 carried out experiments to test the effect of various 

 artificial manures on the composition and quality of 

 barley. The report shows that a nitrogenous manure 

 alone, or even with phosphatic manure in addition, 

 adversely affected the quality, which was only improved 

 when " complete " mixtures were used. A nitrogenous 

 manure in incomplete mixtures appeared to increase the 

 percentage of nitrogen in the grain, but when applied in 

 conjunction with phosphates and potash, the proportion 

 was hardly affected. 



1 A "complete mixture " of artificials refers to those artificial 

 manures which supply Nitrogen, Phosphates, and Potash. 



