Unexhausted Residue of Manures. 



179 



The objects sought in discontinuing the application of 

 ammonia- salts on plot 6, and substituting therefor the 

 mixed mineral manure, were to determine the effects of the 

 latter, not only on the amount of produce, but on the character 

 of the herbage and of its chemical composition ; and especially 

 to acquire data in reference to the question whether any, or 

 how much, of the nitrogen of the previous applications, which 

 had not been already recovered in the increase of crop, would 

 be so under the influence of liberal manuring. 



TABLE XLIV. AVERAGE PER ACRE PER ANNUM, BY MIXED MINERAL 

 MANURE ALONE 7 YEARS, AFTER AMMONIA-SALTS ALONE 13 YEARS ; 

 PLOT 6. 



A consideration of the facts shows it is probable that, after 

 the thirteen years' application of ammonia-salts to plot 6, 



N 2 



