100 



CULTUEE OF THE SUGAR BEET. 



Jonlie gives the following as the composition of French stable-manures 

 of average quality, estimated in pounds per ton of 2,000 pounds : 



A comparison of this table with that given before will show that in 

 order to supply in stable manure the required nitrogen and phosphoric 

 acid for the production of an average crop of 20 tons per acre, it will 

 be necessary to apply at least 20 tons of stable manure to the same area. 

 But this quantity will contain a considerable excess of alkaline matters 

 over the quantity demanded by the crop, and will only tend to increase 

 the saline constituents of the root at the expense of the sugar. This 

 excess of mineral matters is often used to explain the production of roots 

 of low saccharine value. Let us bring together the figures for the con- 

 stituents of plant-food mentioned, as found in 20 tons of stable manure 

 from cows and as found in the yield of an acre giving 20 tons of beets : 



In practical work, therefore, it is found better to reduce the quantity 

 of stable manures applied, and to supplement them with the other sub- 

 stances mentioned above. A comparison of the productive influences 

 exerted by stable manures and by the artificial compounds usually em- 

 ployed to supplement it, or as substitutes for it, will be found in the fol- 

 lowing table, showing the results of the experiments made by Professor 

 Deherain at the Grignon agricultural school, working with the Vilmorin 

 improved race of beets. These results are interesting as showing the 



