280 Fertilizers 



phone acid and potash. The nitrogen demands for the 

 two crops are practically identical. In the case of both 

 kinds of crops, these fertility constituents are obtained 

 entirely through the roots from soil sources. 



In respect to fertilization, however, the root crops 

 may be divided into two groups, very similar in their 

 demands for plant-food, the first to include mangel- 

 wurzels, fodder-beets, sugar-beets and carrots, and the 

 second turnips, swedes (rutabagas) and rape. 



Fertilizers for fodder-beets, sugar-beets and carrots. 



The first group requires that the fertilization with 

 nitrogen and phosphoric acid shall be liberal, and that 

 these constituents shall be applied in readily soluble 

 forms, in order to meet the large and early demands of 

 the plant for them. Potash is also a very essential 

 constituent, particularly upon soils of a light, sandy 

 character; upon clay loams the plant is better able to 

 obtain this element. 



In order to obtain a large amount of actual food by 

 the growth of these crops, a large tonnage must be secured, 

 and a large yield cannot be obtained unless provision is 

 made for a continuous and rapid growth, and this again 

 cannot be accomplished without an abundant supply of 

 nitrogen and phosphoric acid, which, as already stated, 

 are the elements which, more than any others, seem to 

 rule the crop. 



In the case of sugar-beets, the suggestion for fertiliza- 

 tion when grown for sugar (Chapter XVII) may be fol- 

 lowed in large part. That is, particular attention should 

 be given to the supply of nitrogen and phosphoric acid, 

 though when grown for forage it is important not only to 

 secure sugar, which constitutes a large proportion of the 



