326 Report of Experiments on the Growth of Barley, 
years ; and, practically speaking, nearly the whole of the result 
was obtained during the first -1 years of the 7. It is true that 
the mixed mineral manure was not applied on Plot 16 as on 
Plot 5 during the last 7 years ; but with the liberal appli- 
cation during the 13 years and previously, there could be 
no want of available mineral constituents within the soil ; and 
even if the produce during the 7 years were compared with 
that without any manure, instead of with that with mineral 
manure, the annual increase from the residue would appear but 
little more, and the general result would remain substantially the 
same. 
Again, Plots 5, and 17 and 18, particulars of which are given in 
Table XLIII., received during the first 8 years (1844-'51) 
various, but, upon the whole, very similar mixtures of mineral 
manures, ammonia-salts, and rape-cake ; and, as the Table 
shows, they yielded very similar average annual amounts of 
produce during that period. In 1852, therefore, the plots were, 
'practically, in very similar condition. For the produce of that 
year, and each vear since, up to the present time, Plot 5 has 
received a mixture of superphosphate of lime, and sulphates of 
potass, soda, and magnesia. Over the same period. Plots 17 
and 18 have received the same mineral manure, or ammonia- 
salts, alternately. For example, for the crop of 1852, Plot 17 
received 400 lbs. ammonia-salts, and Plot 18 the mineral 
manure ; for that of 1853, Plot 17 received the mineral manure, 
and Plot 18 the ammonia-salts ; and so on, alternately, for the 
20 years. Thus, in each year, the one or the other plot 
was manured with mineral manure, succeeding a dressing of 
ammonia-salts. These were conditions obviously very favour- 
able for turning to account any residue of the nitrogenous 
manure of the previous year which might still remain in the 
soil in a state of combination, and distribution, such as to be 
available for the plant. The Table shows the produce obtained 
each year on Plot 5 by mineral manure year after year, and 
also that obtained each year by mineral manures after ammonia- 
salts, on Plot 17, or 18, as the case may be. 
It is seen that the mineral manure on Plot 17, or 18, each 
year succeeding a liberal dressing of ammonia-salts for the crop 
of the previous year, gave, in 20 years, only 16^ bushels of 
corn and 22^ cwts. of straw, or annually only | bushel of corn 
and 1^ cwt. of straw, more than Plot 5, which received the 
same mineral manure every year without the interposition of any 
ammonia-salts. 
The result is, then, that when 400 lbs. of ammonia-salts per 
acre were used for wheat, the unexhausted residue of nitrogen, if 
any, gave very little increase of produce in succeeding years ; 
