EXPERIMENTS ON THE MIXED HERBAGE OF PERMANENT MEADOW. 385 
point it may be observed that, even if progressing favourably, they would probably 
retain not more than from 5 to 10 per cent, of the nitrogen of such food. 
The object was, indeed, to secure that the treatment of the second crops should 
interfere as little as possible with the balance of constituents of the respective plots, as 
affected, on the one hand by the application of manure of known composition, and on 
the other by the removal of the first crops only, the quantity and composition of which 
were determined. In 15 out of the 20 years the second crops were so fed off by 
sheep ; but, as the animals frequently suffered so much from change from better food, 
bad weather, or both, the plan was not always adopted in the later years of the 20, and 
has now been finally abandoned altogether. Thus, in the eleventh, fifteenth, eighteenth, 
and nineteenth seasons (1866, 1870, 1873, and 1874), the produce of aftergrass was cut, 
carefully spread on its own plot, and left to decay; whilst, in 1875, after the twentieth 
first crop had been removed, the second was cut, made into hay, removed, and weighed. 
In the four years in which the aftergrass was cut and spread on the land, we need 
not, perhaps, assume any loss of either nitrogen or mineral matter by the treatment. 
In the 15 seasons in which the second crops were fed off by sheep, there may have 
been some slight removal of those constituents ; but, on the other hand, the nearly 
total amount returned to the land would be in a much more active manurial condition 
than in the cases when the produce was cut and spread on the land. Upon the whole, 
therefore, it is doubtless nearer the truth to assume the balance of constituents on the 
different plots to depend on the amounts supplied in manure, and those taken off in 
the first crops only, than to attempt any numerical estimate of the quantities lost by 
the feeding of the sheep on the plots. At the same time, it may be considered that 
the estimates of constituents removed in the first crojDS probably somewhat understate, 
especially in some seasons, the actual loss to the land. 
Although it may thus be assumed that the chemical condition of the respective 
plots, so far as the actual amount of manurial constituents is concerned, would be little 
affected by the treatment of the second crops, it cannot be doubted that the character 
of the complex herbage would be influenced thereby, and differently according to the 
character of the manures, and of the seasons. As a means of forming some judgment 
on the point, botanical notes w r ere generally made on the growing second crops ; and, 
in order to arrive at some estimate of the actual and relative amounts of aftergrass, 
whenever the second crops were fed off by sheep, a given number of animals was 
allotted to each plot, according to its produce, penned on a portion of it, and the fold 
extended day by day as the grass was eaten down. In this way data were obtained for 
calculating how T many sheep would be maintained per acre, for one week, on each plot; 
and, assuming that they would, on an average, consume grass equal to 16 lbs. of hay 
per head per week, the quantity of aftergrass, reckoned as hay, was estimated. The 
results so obtained are, of course, only approximations to the truth ; but such they 
are ; and they may be taken as at any rate giving some idea of the actual and relative 
3 D 
MDCC'CLXXX. 
