on Permanent Meadow Land. 
511 
increased the average produce of hay, notwithstanding that 
the straw was calculated to furnish, by gradual decompo- 
sition, besides other mineral constituents, the silicates in 
which the artificial mixture was deficient, and to contribute a 
supply of carbonic acid for the solution of the mineral consti- 
tuents of the soil, and a small amount of available nitrogen also. 
The after-grass has, however, generally been slightly more 
luxuriant ; and, as shown in the last number of the Journal, 
the description of herbage developed was somewhat different, 
and, perhaps, rather superior. 
On Plot 13 (divided in 1862 into 13a and 13Z»), in addition 
to the mixed mineral manure, there was applied a double or 
very excessive amount of ammonia-salts (800 lbs.) in the first, 
second, third, and seventh years of the experiments, but only 
400 lbs. in each of the three intermediate years, 1859, I860, 
and 1861. The result of this very heavy dressing was an 
average over the seven years of above 3 tons of hay per acre 
per annum. It was somewhat less during the last four years, 
in three of which the single amount only of ammonia-salts was 
used ; but in 1862 (and in the present year also) the produce 
was again increased with the increased supply of ammonia-salts, 
though by no means in proportion to that increased supply. As 
shown in the last number of the Journal, the heavy crops grown 
on this plot contained not a trace of Leguminous plants ; but, 
with the exception of a few very luxuriant weeds, they consisted 
almost entirely of comparatively few species of very free-growing 
grasses, in an over-luxuriant and very stemmy condition. 
As just alluded to, in 1862, that is, after the experiments had 
been continued for six seasons, this Plot 13 was divided into 
two equal portions ; and to one of these (13i) 200 lbs. of a silicate 
of soda, and 200 lbs. of a silicate of lime, were applied per acre, 
in addition to the manures of Plot 13a. This led to scarcely 
any appreciable increase in the first year of the application, but 
the results of the present or second season show an increased 
produce of about 6 cwts. of hay per acre where^ the silicates 
were used ; and it was obvious to the e^ e that some of the 
grasses were more luxuriant. It remains to be seen what will 
be the effects of this addition in future years. There is no doubt 
that the heavy dressing of 13a, without silicates, forcing, as it 
does to such a degree, the luxuriant growth of Graminaceous 
plants, which require more silica than herbage of any other 
description, must tax very severely the store of available 
silicates within the soil. Additional evidence will be given 
on the point further on ; but it may be here remarked in 
passing, that the forcing of very heavy crops of hay by the 
use of artificial manures alone is by no means recommended. 
VOL. XXIV. 2 L 
