1344 
MESSRS. J. B. LAWES, J. H. GILBERT, AND M. T. MASTERS, 
more nitrogen, and more mineral matter removed, than with either description of 
manure used separately; but whilst with the mineral manure alone there was, in the 
later years, an increase rather than a diminution in all three items of yield, there was 
with the combination, at any rate within the first 20 years, a diminution in all, but in 
a much less degree than with the nitrogenous manure alone. An adequate conception 
of these differences can, however, only be attained on a detailed comparison of the 
botany of the respective plots as affected by the very characteristically different 
descriptions of manures. 
The first point to remark is the very great reduction in the number of species under 
the influence of this mixed nitrogenous and mineral manure (Table L XXL, pp. 1342-3). 
Compared with plot 3 without manure, and taking the four separation-years, there is an 
average of three fewer species of grasses, two fewer of Leguminosse, and as many as 16 
fewer of miscellaneous plants; or of 21 less total number of species found in the samples. 
The number only varied from 27 to 30 in the four separation-years, and averaged only 
28 ; whilst, without manure, there was an average of 49. Compared with plot 5 with 
ammonia-salts alone, there was on the average, and almost in every individual instance, 
a slight reduction in the number of species of each description of herbage; and there 
were, on the average of the four separation-years, five fewer species with the mixture 
than with the ammonia-salts alone. Compared with the results on plot 7 with the 
mixed mineral manure alone, there was, with one exception, a reduced number of 
species of each description of herbage in each separation-year. The average reduction 
was of grasses three, of Leguminosse two, and of miscellaneous species 10; or, in all, an 
average of 15 fewer species by the addition of the ammonia-salts to the mineral 
manure. 
A glance at the lines of totals in the table will show that the herbage became 
almost exclusively gramineous under the influence of the luxuriance induced by the 
nitrogenous manure, and the tendency to stem-formation and maturation favoured by 
the associated mineral constituents. Thus, in the last separation-year nearly 95 per 
cent, of the mixed herbage was referable to gramineous species, not half a per cent, to 
Leguminosse, and not 5 per cent, to Miscellanese. 
Taking the average of the four separation-years there was, in fact, nearly three times 
as much gramineous herbage per acre as without manure, nearly twice as much as by 
the ammonia-salts alone, and not far from twice as much as with the mineral manure 
alone. Reckoned in the same way, there was, on the average, not much more than 
one-twentieth as much legumineous herbage as without manure, rather more than 
with ammonia-salts alone, and only about one-hundredth as much as with the mineral 
manure alone. Turning to the total miscellaneous species a little more is yielded on 
the average by the mixed nitrogenous and mineral manure than without manure, 
about one-third more than by the ammonia-salts alone, but even less than by the 
mineral manure alone. 
Looking to the record of the percentage of the individual gramineous species in the 
