EXPERIMENTS OX THE MIXED HERBAGE OF PERMANENT MEADOW. 313 
leguminous herbage of plot 7. The details will be fully considered further on. 
But, in the meantime, a clue to the source of the increased yield of nitrogen in the 
mixed herbage would seem to be obtained. It would appear that, under the influence 
of the mixed mineral manure, both the powers of collection, assimilation, and transfor¬ 
mation, of the plants themselves, have been considerably augmented, and the accu¬ 
mulated stores of nitrogen within the soil have been rendered more available. They 
have, in fact, served, either directly or indirectly, as manure for both the Graminese 
and the Leguminosse. We have, too, in the facts, an addition to the previously 
existing evidence in favour of the supposition that the Leguminosse derive the large 
amounts of nitrogen they assimilate from the stores of the soil itself. 
Turning to the amounts of mineral matter taken up under the influence of the 
liberal supply of it by manure, Table V., page 308, shows that, over the first period 
nearly one-and-two-thirds as much, over the second period more than twice as much, 
and over the 20 years nearly twice as much, was taken up on plot 7 as without 
manure. The analytical data further show that, whilst of lime and silica only about 
one-fourth more, of magnesia about one-half more, and of sulphuric acid and chlorine 
about twice as much, was taken up as without manure, of phosphoric acid there was 
nearly three times, and of potass nearly three-and-a-half times as much ; and, with 
the liberal supply, and the greatly increased assimilation, of potass, there was, of soda 
alone less taken up and retained in the manured than in the unmanured produce ; 
indeed, there was less than half as much, notwithstanding that soda was annually 
applied in the manure. Again, whilst the percentages of lime, of magnesia, and of 
silica, were considerably less in the dry substance of the manured than of the un¬ 
manured produce, those of the sulphuric acid and chlorine were rather higher, that of 
the phosphoric acid was nearly twice, and that of the potass more than twice as high ; 
the percentage of soda, on the other hand, was little more than one-fourth as much in 
the dry substance of the manured as of the unmanured produce. 
The general result is, that a mixed mineral manure alone has, in a very marked 
degree, influenced the description of plants developed, and the character of their 
development, greatly favouring the tendency to form stem and seed-—that is, to mature; 
it has also much increased the amount of total produce grown, and of nitrogen as well 
as mineral matter taken up. The evidence, so far, points to the potass of the manure 
as mainly conducive to these effects, the phosphoric acid probably coming second in 
order of importance. A comparison of the results obtained by superphosphate of lime 
alone, and by superphosphate of lime and sulphates of soda and magnesia without 
potass, with those by the “ mixed mineral manure ” which, besides these, contained 
potass, will throw further light on these points. 
5. Superphosphate of Lime alone ; Plot 4-1. 
Plot 4—1 has been manured with superphosphate of lime alone every year from 
1859 up to the present time, or for a period of 21 years. In each of the three 
mdccclxxx. 2 s 
