Report of Experiments on the Growth of Wheat. 475 
Average Annual Produce hy Mineral Manure and Ammonia' 
Salts. 
The plots included in this series are Nos. 21, 22, 6, 7, 8, 
and 1G, to each of which exactly the same mixed mineral manure 
(consisting of superphosphate of lime and the sulphates of potass, 
soda, and magnesia) was applied as that which was used alone 
on plot 5, and then gave less than 18J bushels produce, and less 
than 3 bushels' increase of dressed corn ; but it was now em- 
ployed in conjunction with ammonia-salts, in amounts varying 
from 100 lbs. to 800 lbs. per acre per annum. 
On plot 21 the mixed mineral manure was used with 100 lbs. 
of the muriate, and on plot 22 with 100 lbs. of the sulphate of 
ammonia of commerce. The muriate contained rather more 
ammonia than the sulphate, and gave rather more than 22 bushels, 
whilst the latter gave rather less, and also rather less straw. The 
increase over the produce by the mixed mineral manure alone, 
was 3f bushels of corn and 4 cwts. of straw with the muriate, 
and 3|- bushels of corn and rather less than 3f cwts. of straw 
with the sulphate. In each case, therefore, the addition of 
100 lbs. of ammonia-salt to the mixed mineral manure, gave 
more increase over the produce by the mineral manure alone, 
than was obtained over the unmanured produce by the use of the 
mineral manure itself, though it supplied annually an abundance 
of potass, soda, magnesia, lime, phosphoric acid, and sulphuric 
acid. 
Yet the proportion of increase obtained for a given amount of 
ammonia in these two experiments was less than is usual when 
such moderate quantities are used. Indeed, the results which 
follow will show that it was considerably less than when twice, 
and even four times as much ammonia was employed with the 
same mineral manure. The fact is, plots 21 and 22 were com- 
paratively short lengths of land, so near to the hedge-green as to 
be to some extent affected by trees (especially 21), and they were 
only brought under exact experiment in the ninth and succeeding 
years as being the most eligible of the remaining unallotted por- 
tions of the experimental field. Their results are, therefore, not 
so trustworthy as those obtained on the other and larger areas. 
On plots 6, 200 lbs. of ammonia-salts (equal parts sulphate 
and muriate) were used with the mineral manure, and the mixture 
gave an average annual produce of 28J bushels of dressed corn, 
and 3012 lbs. = nearly 27 cwts. of straw, or an increase over the 
produce by the mixed mineral manure alone of 9g bushels of corn, 
and 1115 lbs. = nearly 10 cwts. of straw, which is much more for 
a given amount of ammonia than was obtained on plots 21 and 22, 
where the smaller amounts of ammonia-salts were employed. 
