The Rothamsted Wheat Experiments. 



salts in 1848, and ammonia-salts alone (like 10a) in 1845, 

 1847, 1849, 1851, and in each of the last thirty -two years ; 

 10a received mineral manure alone in 1844, and ammonia- 

 salts alone in each of the last thirty-nine years. 



TABLE VI. AMMONIA-SALTS ALONE. 



Of the period preceding 1852, in the season of 1848, lOb 

 received mineral manures, as well as ammonia-salts, and 

 yielded 25J bushels per acre, as against 19| bushels on 100., 

 which received the same ammonia- salts without minerals. 

 On the other hand, when 106, in 1850, received minerals 

 alone, the produce was only 18 bushels per acre, as 

 against 27 bushels obtained on 10a, manured with ammonia- 

 salts only. Though, in the periods of eight years, the 

 produce of 10& is always in excess of that of 10a, the 

 difference is nevertheless seen to be a declining one. As 

 the drainage water from cultivated fields is known to contain 

 but a very small amount of potash, and frequently no 



