EXPERIMENTS ON THE MIXED HERBAGE OF PERMANENT MEADOW. 323 
stunted, and very dark green, leafy growth. This colour indicates a high percentage 
of nitrogen in the dry substance, or more properly speaking a deficient assimilation of 
carbon in proportion to the nitrogen taken up, owing to deficient mineral supply. 
The result was a considerable increase in the amount of nitrogen taken up compared 
with that without manure, but still, less than with the mineral manure alone without 
nitrogen. 
With the mixture of the nitrogenous and mineral manures, on the other hand, the 
produce was still more gramineous than with the ammonia-salts alone ; in fact, the 
weight per acre of gramineous herbage averaged more than twice as much ; the pro¬ 
portion of the produce due to both leguminous and miscellaneous species was also 
less, though the average weight per acre of both was rather more. But here, the still 
more characteristically gramineous herbage was made up in much less degree of a few 
species only. Thus, whilst Festuca ovina and Agrostis vulgaris contributed by far 
the larger proportion of the total herbage grown by ammonia-salts alone, and Anthox- 
anthum ocloratum, IIolcus lanatus, and Dactylis glomerata were only very moderately, 
and every other grass very sparingly, represented, with the ammonia-salts and mineral 
manure together both Festuca ovina and Agrostis were much less prominent, Holcus 
and Dactylis were nearly as much so, and Poa pratensis was the most prominent of 
all. The character of development of the grasses was, moreover, totally different; there 
being, when mineral manures, including potass, as well as ammonia-salts, were used, a 
great tendency to form stem and seed, and to mature. Under these conditions a much 
larger proportion of the supplied nitrogen was taken up than when the ammonia-salts 
were used alone. 
Owing, however, to the totally different proportion of gramineous, leguminous, and 
other species in the herbage without manure, or with mineral manures alone, on the 
one hand, and with ammonia-salts alone, or ammonia-salts with mineral manure on 
the other, it is very difficult to decide on what basis to estimate how much of the 
nitrogen taken up where it was artificially supplied was due to natural sources, and 
how much therefore is to be attributed to the supplies by manure when the ammonia- 
salts were used alone, and how much more when these were used in conjunction with 
the mineral manure? It is probable that, even when used in conjunction with the 
mineral manure, not much more than half the supplied nitrogen was taken up. so that 
the reduction in produce over the second 10 years would not seem to be connected 
with a deficiency of available nitrogen. 
The reduction in the amount of total mineral matter taken up was greater than in 
that of the nitrogen. The falling off in produce would, so far, seem more probably 
connected with a deficiency of available supply of one or more of the mineral 
constituents. Calculation shows, however, that more, and generally much more, of each 
constituent, with the one exception of silica, was applied each year than was removed, 
so that there would be a constantly increasing residue accumulated during the later 
years in all cases in which there was no material loss by drainage. Again, as will be 
2 T 2 
