Average Results of Twenty Years. 



91 



The farmyard manure was made in the open yard, and 

 did not contain the dung of animals highly fed on purchased 

 food. The mixed mineral manure was composed per acre- 

 per annum of 



2001b. sulphate of potash (3001b. the first six years). 



lOOlb. sulphate of soda (2001b. the first six years). 



lOOlb. sulphate of magnesia 



2001b. bone ash. ) 



1501b. sulphuric acid, sp.gr. 17. j Su P er P hos P hate of lime - 



The ammonia-salts were formed of an equal mixture of the 

 sulphate and muriate of ammonia of commerce. 



In Table XXI. are recorded the average results of the 

 twenty years : 



TABLE XXI. AVERAGE QUANTITY AND QUALITY OF BARLEY PER ACRE 

 PER ANNUM ON SELECTED PLOTS ; TWENTY YEARS, 1852-1871. 



The significant fact may be noted that, over a period of 

 twenty years in succession, ammonia-salts (1 A) alone gave 

 an average, per acre per annum, of 5 bushels more grain, 

 and of 4cwt. more straw, than the mixed mineral manure 

 (4 0) alone. Again, the ammonia-salts and mixed mineral 

 manure together (4 A) gave an average annual produce of 

 about 19 bushels more grain, and 14cwt. more straw, than 

 the mineral manure (4 0) alone ; but only about 14 bushels 

 more grain, and lOcwt. more straw, than the ammonia- 



