202 AGRICULTUEAL EXPERIMENT STATION. [Jan. 



Iiesult.t per Hectare. 



I Percentage 

 Kilos. j Iiicn-asc over 

 Unmanurcd. 



Unmanured, ....... 



Soluble phosphoric acid, .... 



Water and citrate soluble i^hosphoric acid, 



Citrate soluble phosphoric acid, . 



Unmanured, ....... 



Leather -J- soluble phosphoric acid, 



Leather -|- -water soluble -)- citrate soluble phos- 

 phoric acid 

 Leather -|- citrate soluble j^hosphoric acid, . 



Unmanured, ........ 



Nitrate of soda -j- soluble phosphoric acid, . 



Xitrate of soda -\- water -|-citi-ate soluble phos- 

 phoric acid. 

 Nitrate of soda -|- citrate soluble phosphoric acid. 



34,830 

 34,380 

 34,290 

 34,380 

 33,840 

 37,890 

 37,180 

 35,910 

 32,940 

 43,380 

 42,070 

 43,830 



-1.5 

 -1.2 

 -1.5 



11.9 



10.7 



6.0 



28.1 

 24.2 

 29.4 



AVhile the leather has shown its effect, it runs far behind 

 the nitrate of soda. Petermann says that from a financial 

 stand-point the leather sliows a loss and the nitrate of soda a 

 gain. Of his results the experimenter makes the following 

 resume : " "With horse Ijean the leather shows practically no 

 influence the first year ; with oats and sugar beets an increase 

 is noted, but this is slight when compared with that from 

 blood and nitrate of soda." In a later publication Peter- 

 mann says that in his experiments from 1880 to 1885 the 

 various forms of nitrogen have shown the following relative 

 worth: 1, nitrate of soda; 2, blood; 3, dissolved wool; 4, 

 ground bone ; 5, raw wool ; G, leather. 



Deherain * gives the results of the following experiments 

 conducted in the field at Grignon with ground leather. The 

 results with wheat in 1880 and 1881 show the residual effect 

 of the leather applied to potatoes in 1879 : — 



Chimie Agricole (1892), 619. 



