330 Report of Experiments on the Groioth of Bai-ley, 
manure per acre per annum for 20 years ; those with mixed 
mineral manure and 200 lbs., 400 lbs., 600 lbs., and 800 lbs., of 
ammonia-salts, per acre per annum ; and that with the same 
mineral manure and 550 lbs. nitrate of soda per acre per annum. 
For barley, the plots are — that with 14 tons farmyard manure 
per acre per annum for 20 years ; that with the same mixed 
mineral manure as for the wheat, and 200 lbs. ammonia-salts 
per acre per annum for 20 years ; that with the same mineral 
manure for 20 years, 400 lbs. ammonia-salts for the first 
6 years, 200 lbs. for the next 10 years, and 275 lbs. nitrate 
of soda for the last 4 years of the 20 ; and that with the same 
mineral manure and 2000 lbs. rape-cake for the first 6 years, 
and 1000 lbs. for the next 14 years. 
For oats — the plot with the same mixed mineral manure as for 
wheat and for barley, and 400 lbs. ammonia-salts ; also that with 
the same mineral manure and 550 lbs. nitrate of soda per acre 
per annum, but for three years only. 
The increase in the amount of nitrogen in the produce by the 
use of it in manure is, in the cases of the artificial mixtures of 
nitrogenous and mineral manure, calculated over the amount 
determined in the produce by the corresponding mineral manure 
without ammonia. The increase in the produce of nitrog<?n 
by farmyard manure is also calculated over that by the purely 
mineral manure. 
According to the figures, there was, with the same mixed 
mineral manure and 200 lbs. of ammonia-salts per acre per 
annum for 20 years in succession, rather less than one- third 
of the supplied nitrogen recovered in the increase of the wheat, 
but nearly one-half in that of the barley. 
With the same mineral manure, and 400 lbs. ammonia-salts 
applied for 20 years for wheat, and 400 lbs. for 6 years, 200 
lbs. for 10 years, and 275 lbs. nitrate for 4 years — in all 20 
years — for barley, there was recovered in the increase of the 
wheat, again scarcely one-third, but in that of the barley again 
nearly one-half. With the same mineral manure and 400 j^lbs. 
ammonia-salts applied to oats, but for 3 years only, there was 
even rather more than one-half of the supplied nitrogen reckoned 
to be recovered in the increase of crop. 
When the more excessive amounts of ammonia-salts were 
applied for wheat, notably less than one-third of the supplied 
nitrogen was recovered, and the less the greater the excess. 
On the other hand, when 550 lbs. of nitrate of soda (contain- 
ing nitrogen = 400 lbs. ammonia-salts) were applied, there was, 
even with wheat, not much less than half, and with oats rather 
more than half of the nitrogen recovered in the increase of crop. 
With rape-cake applied for barley, a considerably less pro- 
portion of the nitrogen was recovered than with ammonia-salts. 
