oil Permanent Meadoio Land. 
527 
of ammonia-salts was used ; in fact, it was then higher than in 
any other case where mineral manures were used in conjunction 
vf\\\\ ammonia-salts. The Table records the results of only one 
year (1862) in which, to this mixture of 800 lbs. of ammonia- 
salts and the " mixed mineral manure," silicates (so much exhausted 
by the hay crop) were added (13^), and the figures show almost 
exactly the same proportion of nitrogen recovered as in the same 
year without the silicates (13a). 
Lastly, when ammonia-salts were added, in comparatively 
small or moderate amount, to a quantity of farmyard-manure 
itself containing a very large amount of nitrogen, the increased 
yield of nitrogen beyond that in the produce by farmyard-manure 
alone amounted, over the seven years, to only 21*9 per cent., and 
over the last four years to only 13'8 per cent, of that supplied 
in the ammonia-salts. It may be further remarked that, if the 
farmyard-manure employed be assumed to have been of fair 
average composition, the proportion of its nitrogen reckoned as 
recovered in the increased yield (beyond that without manure), 
reaches to even a still lower amount. 
To sum up on this point, the average results taken over the 
seven years are, that, when the nitrogenous manures (ammonia- 
salts or nitrate) were used alone 29*9, and when in conjunction 
with the mixed mineral manure 45'1 per cent, of the supplied 
nitrogen were reckoned as recovered as increased yield of it in 
the crop. In our former Report, +hen taking the results of 
three years only, the amounts were 26"1 per cent, without, 
and 46 6 per cent, with the mineral manure. The result 
over the more extended period is, therefore, somewhat higher 
Avithout, and somewhat lower with, the mineral manure. When 
ammonia-salts were superadded to an amount of farmyard- 
manure doubtless containing nitrogen, carbon, and every mineral 
constituent, in larger quantity than the crop it yielded (though in 
comparatively slowly available condition), the increased yield of 
nitrogen due to the ammonia-salts was then less than in any of the 
other conditions of their use ; and it was considerably less over 
the later than over the earlier years. It may be remarked that 
nitrate of soda containing the same amount of nitrogen as that 
in the ammonia-salts added to the farmyard-manure, but used in 
conjunction with the mixed mineral manure, was reckoned 
to return nearly three times as much of the supplied nitrogen. 
Before leaving the question of the amount of nitrogen esti- 
mated as recovered in the increase for a given amount sup- 
plied in manure, it should be observed that, inasmuch as 
the whole of the nitrogen of the after-grass is not returned 
to the land by the animals fed upon it, the amount will be 
VOL. XXIV, 2 M 
