on PeTmanent Meadow Land. 
521 
compounds ; but when it is tlie result of excessive nitrogenous 
manuring, the produce is then ahnost exclusively Graminaceous 
and comparatively im matured ; and, under such circumstances, a 
certain portion of the nitrogen may exist in a low condition of 
elaboration, and a high proportion may, in fact, represent a 
deficient accumulation of other matters rather than a favourable 
development of nutritive nitrogenous substance. A percentage 
of nitroeren in raeadow-hav bevond that obtained without manure 
or by means of farmyard-manure is, therefore, under such con- 
ditions, not to be taken as evidence of higher feeding value. 
The value of the manure voided by the animals feeding on the 
hay, will, however, be the higher the higher the proportion of 
nitrogen it contains — especially as it so happens that there is 
generally with a high percentage of nitrogen a high percentage 
of mineral matter also. 
Produce of Constituents per Acre. 
As pointed out in our former report, particular interest 
attaches to the question of the amount of constituents taken from 
an acre of land in the hay-crop, because very frequently the 
system of restoration adopted in the case of the meadow-land 
of a farm is even less satisfactory than in that of the land under 
rotation ; hence it becomes necessary to impress upon the farmer 
how great is the exhaustion to which his meadow-land may be 
subject. 
Tables VL, VII., and VHI. (pp. 535-6-7) show, respectively, 
the amounts of dry substance, of mineral matter, and of nitrogen, 
removed per acre from each of the experimental plots, in each 
of the last four years ; also the average amounts per annum, both 
in the produce and in the increase by manure, over the four years, 
and oyer the whole seven years of the experiments. 
Over the seven year-s, there has been removed per acre annually 
from the unmanured land an average of 2358 lbs. (about 
21 cwts.) of dry substance, containing 167^ lbs. (1^ cwts.) of 
mineral matter, and nearly 40 lbs. of nitrogen. This amount 
of dry substance is somewhat higher than the average of the first 
three years of the experiments ; but it agrees very closely with, 
though it somewhat exceeds, the amounts annually taken from 
the land in wheat or barley grown year after year without 
manure. The above amounts of mineral matter and nitrogen 
are, however, each fully one-half more than are removed in 
wheat or barley grown under such circumstances. 
The unmanured produce of hay would contain between 900 
and 1000 lbs. of carbon. By the use of ammonia-salts alone, or 
