292 Report of Experiments on the Growth of Barley, 
phosphoric acid and potass applied in the first year, but which 
gave no increase in that year, were sufficient, if still present and 
available, to supply those constituents for more than the excess of 
corn and straw obtained on the nitrate, as compared with the 
ammonia-plot. Further, the experiments with wheat have 
afforded abundant evidence, that phosphates and potass-salts 
previously applied, have been effective for 20 years or more, when 
nitrogenous manures have been afterwards supplied, to work 
them out, so to speak. There can be little doubt, indeed, that part, 
at any rate, of the greater effect of the nitrate in the experiment 
in question, was really due to the supply of mineral constituents 
in the first year. 
The results next to be considered show the effects of double 
the above amounts of ammonia-salts alone, or nitrate of soda alone, 
but applied for a few years only as under : — 
Plot 1. A. A :— 
6 years, 1852-1857, 400 lbs. ammonia-salts, per acre, per 
annum. 
Plot 2. N :— 
1 year, 1852, 3J cvvts. superphosphate, 300 lbs. sulphate 
potass ; 
5 years, 1853-1857, 550 lbs. nitrate of soda. 
Thus, as in the previous comparison, the two plots received 
corresponding amounts of nitrogen as ammonia-salts, and as 
nitrate of soda, respectively, for a series of years ; but whilst the 
ammonia plot received the double dressing of ammonia-salts, in 
the first as well as the succeeding 5 years, the nitrate plot received 
phosphates and potass without nitrate in the first year, and the 
double quantity of nitrate in the succeeding 5 years. 
Table XXXII. (See next page) shows the produce obtained, 
and also the increase, both over the unmanured produce, and over 
that by the smaller amounts of ammonia -salts, or nitrate, in the 
corresponding years. 
Thus, there is an average annual produce of 46 bushels of 
corn, and 28J cwts. of straw, by the application of 400 lbs. of 
ammonia-salts alone for 6 years ; also of 48 bushels of corn, and 
31J cwts. of straw, by the same amount of nitrogen as nitrate of 
soda alone for 5 years (but succeeding a dressing of superphos- 
phate and sulphate of potass). The produce by the double 
amount of ammonia-salts alone represents an average annual 
increase over the unmanured produce of 17 J bushels of corn, and 
12;^ cwts. of straw ; and of 7| bushels of corn, and cwts. of 
straw over that by half the quantity of ammonia-salts for the same 
period. In like manner the produce by the double amount of 
nitrate of soda alone, represents an annual total increase of 19| 
