10 



per acre, while the next year the same plot receives no 

 ammonia, but instead superphosphate with potash salts ; in 

 the following year it has ammonia again. On the other plot 

 the same treatment is pursued, but the applications of 

 ammonia fall in alternate years with the applications to the 

 first plot. By comparing the produce of these plots with that 

 of a plot to which only superphosphate and potash salts are 

 applied, we are able to ascertain what is the increase of crop 

 yielded by the ammonia salts in the year of their application, 

 and what after effect, if any, can be recognised in the second 

 year, when no ammonia is applied. At Woburn a similar 

 experiment is carried out both with wheat and barley, and the 

 trial is extended so as to include nitrate of soda as well as 

 ammonia salts. The ammonia salts at Kothamsted supply 

 about 86 Ibs. of nitrogen, and the ammonia salts and nitrate 

 at Woburn about 82 Ibs., per acre. In the following table the 

 average results of eleven years, 1882-92, are given, as in 

 this period we can compare all the results during the same 

 seasons. 



TABLE I. INCREASE OF WHEAT AND BARLEY GIVEN BY AMMONIA SALTS 

 AND NITRATE OF SODA IN THE FIRST YEAR, AND IN THE YEAR 

 FOLLOWING THEIR APPLICATION. AVERAGE KESULTS OF ELEVEN 

 YEARS, 1882-92. 



