166 



HOPS. 



Whatever manure is applied, the amount of materials 

 taken up from the soil by the plants must always be taken 

 as the basis for estimating the substances to be replaced, 

 and on this point accurate information is afforded by 

 analysing the plant, or rather its ash — see following 

 table : — 



Assuming that, as reported by Hirzel, the following quan- 

 tities are produced per acre : — 



Leaves 

 Bine 



Cones 



Total 



Lb. 

 3,235 

 3,824 

 662 



7,721 lb.. 



then, on the basis of the foregoing figures, the amount of 

 materials removed from an acre of soil every year will be as 

 follows : — 



'Dr. E. Wolff's Aschenanalysen, Part ii., 1870-1880 (Berlin, 1880). 



