MANGOLDS 



15 



Thus, towards the end of OrtohtT, the ph)ts receiving the excess of 

 nitro'^on present a very unhealthy api)eiirance ; a lar<;e proportion of tlie 

 plants seem scorched and withered as regards the outer leaves, and only 

 show a cluster of small dark green active leaves at the heart. 



WITU COMPLETE MINERALS. 



(riots 4.) 



WITH DUNG. 

 (Plots 1.) 



Fig. 3. — Mangolds. Effect of increasing amounts of Nitrogen. Aveiage 

 Produce of Roots per acre, 1876-1902. 

 O = No Nitrogenous Manure. I N = 86 lb. Nitrogen as Nitrate of Soda. 



A = 86 lb. Nitrogen as .\mraonium-salts. | C = 98 lb. Nitrogen as Rape Cake. 

 AC - 98 lb. Nitrogen as Rape Cake, and 86 lb. Nitrogen as Amraonium-salts. 



Effect of Mineral Manures. 



The effect of the different mineral constituents of a manure upon the 

 mangold crop can be seen by an examination of Plots 4, 5, and 6. 



'i'he great increase of crop comes as a rule when potash is added to 

 the superphosphate, and is to be correlated with the fact that the 

 mangold is essentially a sugar-producing plant, and that large supplies of 

 potash seem to be essential to the processes in the plant which result in 

 the formation of sugar and similar carbohydrates. 



The effect of potash and of the other saline manures is plainly visible 

 in the appearance of the plants themselves. On the plots receiving potash 

 the plant begins to ripen early, the leaves turn yellow and become Haccid, 

 so that in October these plots may be seen outlined from the rest by their 

 liffhter tint. 



