510 
Report of Experiments icith different Manures 
a notable diminution in the proportion of Leguminous herbage, 
though the total yield of hay per acre was not diminished. 
The addition of 400 lbs. of ammonia-salts (equal parts sulphate 
and muriate) to the mixed mineral manure of Plot 8 (Plot 10) 
increased the average annual produce over the last four years 
from 36^ cwts. to 53f cwts. of hay, that is, by about 18|^ cwts; 
and the average annual increase obtained by this mixture, above 
the produce without manure, was nearly 28f cwts. over the last 
four, and rather more than 31^ cwts. over the whole seven years. 
There is, therefore, when this large amount of ammonia-salt is 
used in conjunction with the mixed mineral manure, an indica- 
tion of a slight falling off in the annual yield. In reference to 
this point it should be particularly borne in mind, that whilst 
the produce by the mixed mineral manure alone contained Legu- 
minous herbage in amount equal to nearly one-fourth of its 
total weight, that grown by the mixed mineral manure and 
ammonia-salts contained scarcely a trace of such herbage. The 
produce in the latter case consisted (with the exception of a few 
luxuriant weeds), almost entirely of Graminaceous plants, or 
grasses, properly so called, which require a large amount of 
silica for their development ; and as the manure employed con- 
tained none, the large amount of increase must have caused a 
considerable drain of the available silica of the soil, the limita- 
tion of the supply of which probably set a limit to the amount 
of increase obtained by this otherwise heavj- manuring. 
The addition of 2000 lbs. of sawdust per acre per annum to 
the mixed mineral manure and ammonia-salts [(Plot 11) very 
little affected either the amount or the character of the produce, 
which was, however, rather less than without the sawdust. On 
this Plot 11, as on Plot 9, the potass-salt was omitted from the 
manure in 1862, but the amount of soda-salt increased, and 
about 2 cwts. less hay were obtained than on Plot 10 with the 
potass and without the sawdust. This difference is, however, but 
small ; and although (not having at present at command cither 
the analytical details relating to the first crop, or the results 
relating to the after-grass) we do not record the amounts of the 
first crop of the present season (18G3), it may be mentioned in 
passing that Plot 11, without potass, has this year given a some- 
what larger amount of Graminaceous hay than Plot 10 with it. 
The general result in regard to the effects of these mixtures 
of mineral constituents and ammonia-salts (Plots 10 and 11) is, 
that, by their means, we have obtained for seven or eight years 
consecutively, an average produce of about 2f tons of hay per 
acre, and an average increase of about 1^ ton. 
Adding to the same mixture of mineral constituents and 
ammonia-salts 2000 lbs. of cut wheat-straw annually, scarcely 
