1394 
MESSES. J. B. LAWES, J. H. GILBEET, AND M. T. MASTEES, 
been obtained from tbe previously accumulated stores within the soil. It would seem, 
too, more than probable that the source of the continued large yield of nitrogen on 
plot 6, after the discontinuance of the application of the ammonia-salts, is also to be 
attributed, mainly at any rate, to a supply rendered available from earlier accumula¬ 
tions, rather than to the unrecovered residue of the previously applied ammonia-salts. 
The mineral composition of the herbage as remarkably illustrates the difference in 
the character of growth as do the facts in regard to the nitrogen. Leaving fuller 
details on both points for the third or chemical part of our report, it may be stated 
that, even in the first year after the change, very much more total mineral matter, 
and especially very much more potass, and phosphoric acid also, was taken up on 
plot 6 than on plot 5. Indeed, over the 12 years since the change of manuring, 
nearly twice as much total mineral matter has been taken up in the first and second 
crops of plot 6 as in those of plot 5; but even on plot 6 less has been taken up than 
on plot 7 during the same period. Analytical details which are at command relating 
to the produce of the first seven of the last 12 years, show that it is of potass and 
phosphoric acid especially, that there has been a greatly increased accumulation by 
the growing plants; and it is these which, other things being equal, favour the 
tendency to stem- and seed-formation. 
Thus, evidence of very various kinds concurs in showing that the effect of the 
change of manuring was not very strikingly to affect the distribution of species on 
the plot, and especially not to bring into prominence plants of free and luxuriant 
habit; but it was, on the other hand, very greatly to alter the character of develop¬ 
ment of the plants of meagre habit which had already possession of the soil. This 
remark applies especially to the grasses and to the Miscellanese, the effect on the 
Leguminosae being, in a marked degree, to increase their predominance as well as to 
favour their maturing tendency. 
15 . Equal nitrogen and equal potass, in nitrate of soda and sulphate of potass, and in 
nitrate of potass; in each case with superphosphate of lime; Plots 19 and 20. 
Having regard to the very marked effects of nitrate of soda, and of salts of potass, 
whether used separately or in conjunction, on the botanical composition, the luxuriance, 
and the character of development, of the mixed herbage, it seemed desirable to 
determine the comparative effects of a given amount of nitrate of potass, and of a 
mixture of nitrate of soda and sulphate of potass, containing the same amount 
of nitrogen and the same amount of potass. Accordingly, in 1872, plots 19 and 20 
were set apart for experimenting on this point. The area appropriated had from 
the commencement been enclosed with the other experimental ground, and so pro¬ 
tected from grazing by animals. It had been entirely unmanured for a number of 
years, and every year one crop of hay had been removed from it. To plot 19, 275 lbs. 
of nitrate of soda (the same amount as applied to plot 16) was applied; and to plot 20, 
