90 The Rothamsted Barley Experiments. 



into sulphate and soluble superphosphate of lime ; sulphuric- 

 acid, in the phosphatic mixture just mentioned, in sulphates 

 of potash, soda, and magnesia, in sulphate of ammonia, &c. ; 

 chlorine, in muriate of ammonia ; silica, as artificial silicate 

 of soda. Of other constituents, the nitrogen has been 

 supplied as sulphate and muriate of ammonia ; as nitrate 

 of soda ; in farmyard manure ; in rape-cake. The non- 

 nitrogenous organic matter, yielding by decomposition 

 carbonic acid and other products, was supplied in farmyard 

 manure, and in rape-cake. The artificial manure or mixture 

 for each plot is ground up, or otherwise mixed, with a 

 sufficient quantity of soil and turf-ashes to make it up to a 

 convenient measure for uniform distribution over the land. 

 The mixtures so prepared are, with proper precautions, sown 

 broadcast by hand, it having been found that the application 

 of an exact amount of manure, to a limited area of land, 

 can be best accomplished in that way. 



Passing now to the field results, the investigators have 

 constructed tables showing the quantity and quality of the 

 produce obtained in each one of the twenty seasons. It will 

 suffice here, however, to reproduce only those tables showing 

 the average results of the entire period, the results in the 

 best season, and the results in the worst. The following are 

 the numbers of the selected plots, with an account of the 

 manures supplied, per acre, per annum : 

 Plots. 



1 O. Unmanured. 



7. 14 tons farmyard manure. 



4 0. Mixed mineral manure alone. 



1 A. 2001b. ammonia-salts alone. 



4 A. Mixed mineral manure and 2001b. ammonia-salts. 



4 A A. Mixed mineral manure and 4001b. ammonia-salts 

 first six years, 2001b. ammonia-salts next ten years, 

 2751b. nitrate of soda last four years. 



4 C. Mixed mineral manure and 20001b. rape-cake first 

 six years, lOOOlb. rape-cake last fourteen years. 



