1352 
MESSRS. J. B. LAWES, J. H. GILBERT, AND M. T. MASTERS, 
that the result was the establishment of a few freer-growing, and the retardation of 
more meagrely-developing species, we have obviously, in the fact of the predominance 
of plants of greater feeding and growing capacities, conditions suited to the gathering 
up of more food, even with the same supplies; whilst, this being the case, the compara¬ 
tively small increased supply would not be without its influence. In other words, the 
increased produce on the plot, and the increased accumulation of nitrogen, silica, and 
mineral constituents generally, is not to be referred exclusively to the increased supply 
of constituents from without, but largely to the special conditions favouring the develop¬ 
ment of species having a greater power of food collection, and therefore a greater power 
of growth. 
9. Ammonia-salts (800 lbs. jper acre), and mixed mineral manure, including potass; 
Plots 11-1 and 11-2. 
It has been shown that on plots 9 and 13, with the mixed mineral manure (in¬ 
cluding potass), and 400 lbs. of ammonia-salts per acre per annum, the herbage became 
extremely prominently gramineous, and was, upon the whole, coarse and stemmy. 
Still, it seemed desirable to determine whether or not the limit of growth attainable 
with the soil in question, and with average seasons, was reached, and to ensure that 
this limit should be secured. Accordingly, on plot 11, with the same mineral manure 
as on plot 9, double the quantity of ammonia-salts, that is 800 lbs. per acre per annum, 
supplying on the average about 172 lbs. of nitrogen (see p. 1305), was applied. 
During the first three years, however, this appearing from the results to be excessive, 
the quantity of ammonia-salts was reduced to one-half, that is, to the same as on 
plot 9 ; but the results obtained indicating that the limit of possible growth was not 
reached, the quantity was again doubled, and the double application has been continued 
up to the present time. * After the first six years, three with the double, and three with 
the single amount of ammonia-salts, and when it was decided again to use the double 
quantity, the plot was divided, one half, 11-1, having besides the ammonia-salts the 
same mineral manure as before; and the other, 11-2, the same, with the addition of 
artificial silicates of soda and lime for nine years, and afterwards of silicate of soda alone. 
Compared with plot 9, there was a considerable increase of hay produced, and of 
nitrogen taken up, on the plots 11, with increased. amount of ammonia salts ; and in 
each item there was more increase on 11-2 with the silicates than on 11-1 without. 
There was, too, with the silicates, a less falling off in hay, and in mineral matter taken 
up, and a greater increase in the nitrogen gathered, over the later than over the earlier 
years. And, although there was less increase of herbage produced for the second 
increment of ammonia-salts applied than for the first, yet there was a greater pro¬ 
portion of the nitrogen supplied recovered in the increase. That is to say, the 
* Note, January, 1883.—The above was written in 1881; for the crop of 1882 the quantity of ammonia- 
salts was reduced from 800 to 600 lbs. 
