ON THE MIXED HERBAGE OE PERMANENT MEADOW. 
1311 
regard to the distribution of species would revert to its former condition. Thus, the 
fourth separation-year (1877) is the second year of the application of the mineral 
manure instead of the nitrate on plot 15. On plot 17, however, where the smaller 
quantity of nitrate was employed from the commencement, no change has been made 
in the manuring up to the present time. 
As in the case of plot 5, the following table (Table LXVI., pp. 1312-13) gives for plot 15 
the particulars of the per cent., and of the actual amount yielded, of each species among 
the grasses and the .Miscellanese, which contributed in any one year more than 1 per 
cent, to the produce, the results for those species yielding less than this being given 
collectively; whilst those occurring on the unmanured plot, but not on the manured 
one at all, are again enumerated and bracketed together. As before, for the few species 
of Leguminosse, the full details are given. But, as there was a fundamental change of 
manure between the third and fourth separation-years, the mean for the first three 
separation-years is given, and the results for the fourth (1877) separately, instead of 
the mean for the four years. 
It should be observed that much more increase of produce was obtained on plot 15 
by nitrate of soda than on plot 5 by ammonia-salts containing the same amount of 
nitrogen. The reduction in produce was much less in the later years by the nitrate 
alone than by the ammonia-salts alone; much .more nitrogen was yielded in the pro¬ 
duce by the nitrate, and the decline in the yield of it was much less; one and a-half 
time as much mineral matter was taken up by the herbage on the nitrate plot, includ- 
mg, besides soda which was supplied in the manure, more lime, more magnesia, and 
much more potass, phosphoric acid, and silica; all of which must have been derived 
from the stores of the soil itself. Lastly, the decline in the amount of mineral matter 
taken up in the later years was less than with the ammonia-salts. 
For an explanation of the much greater result in almost every particular of produc¬ 
tion with the nitrate of soda than with ammonia-salts containing the same quantity 
of nitrogen, we must look to the difference in the condition and distribution of the 
nitrogen within the soil, and to the coincident great difference in the flora in the two 
cases. The nitrogen of the nitrate distributes much more rapidly than does that of 
the ammonia-salts ; much of the ammonia being probably in the first instance retained 
as such in the upper layers of the soil, and only gradually oxidating and distri¬ 
buting as nitrites or nitrates. The result is that many more species are favoured by 
the nitrate; a greater variety of grasses contribute to the bulk of the produce; and 
leguminous, and especially miscellaneous species, are more favoured. Accordingly, 
there is a much greater variety of “habit ” developed under the influence of the 
nitrate, and a much more extended range of soil is commanded by the roots of the 
more varied herbage. Hence much more mineral matter is derived from the stores 
of the soil, and the different plants, especially the grasses, yield much more stem and 
mature much better. Indeed, as will be seen, some of the most deeply-penetrating 
grasses flourish under these conditions. 
8 E 2 
