CULTURE OF THE SUGAR BEET. 105 



singault, conclude that wheat scarcely admits of a change in the com- 

 position of its ashes, whatever may be the composition of the fertilizers 

 applied ; the same is true of potatoes. 



But Pellet finds that the beet, on the contrary, may grow with equiv- 

 alent substitutions of the alkaliles necessary to the formation of sugar, 

 so that, as shown by the experiments of Joulie, soda may be found in 

 the ash of some beets in the same quantity as potash, while in others 

 the quantity of potash is seven times that of soda. This substitution 

 may also be noticed between lime and potash, but experience shows that 

 though the alkalies may thus substitute each other, and lime, by equiv- 

 alents, certain other bodies, such as phosphoric acid, will not admit of 

 being replaced. The experiments of Champion and Pellet also show 

 that in all plants we may observe a relation between the total weight of 

 ashes and the special organic matters for which the plant is cultivated. 

 Thus, in wheat between the starch and total ash, and in the beet between 

 the sugar and total ash. They construct the following table, showing 

 in general that for the formation of 100 pounds of sugar in beets, the 

 roots and leaves in their development must consume — 

 1 to 1.20 pounds of phosphoric acid. 

 5 to 6 pounds of potash. 

 1.5 to 2 pounds of soda. 

 1.5 to 1.6 pounds of lime. 

 1.2 to 1.4 pounds of magnesia. 

 2.7 to 3.5 pounds of nitrogen. 



Excess of all may be present in the soil, but if phosphoric acid be 

 wanting sugar will not be produced, while if lime is wanting it will be 

 replaced by potash or soda or magnesia, and this rule holds good for the 

 other alkalies. The author therefore concludes that 1 of phosphoric acid 

 corresponds to 100 of sugar, while 5 to G of potash corresponds to the 

 same amount, and consequently phosphoric is worth 5 or 6 times more 

 than potash in the formation of sugar, if potash replaces no other alka- 

 lies ; in other words, if a soil be wanting in 60 pounds of assimilable 

 potash per acre, there will be a deficit of 1,000 pounds of sugar, while 

 for the same deficit only 10 pounds of assimilable phosphoric acid need 

 be wanting. Phosphoric acid he considers a non-dominant but indis- 

 pensable element or base for the formation of sugar in the beet. 



Eeasoning from these data, they conclude that without experiment, but 

 by examination of the average composition of the ashes and of the quan- 

 tity of nitrogen in the plant, and comparing the total weight of the dif- 

 ferent constituents with that of the given proximate principle to be pro- 

 duced, for instance, sugar in the beet and starch in wheat and potatoes, 

 it is possible, they say, to determine the order in which the elements of 

 plant -food are indispensable for each plant. Thus, for the beet they 

 range: 1, phosphoric acid; 2, lime or magnesia; 3, nitrogen; 4, potash 

 or soda. On the other hand, the order for wheat is : 1, lime or magnesia; 

 2, potash ; 3, phosphoric acid, &c. These are facts of great importance 



