EXPERIMENTS ON THE MIXED HERBAGE OP PERMANENT MEADOW. 389 
but, as without manure, the herbage is complex, and the command by the roots, 
especially of the upper layers of the soil, will be very varied. 
With the same mineral manure as on plot 7, and 400 lbs. ammonia-salts per acre 
per annum in addition (plot 9), the first crops average about one-and-a-half time as 
much as with the mineral manure alone, but the estimated average of the second crops 
is very nearly the same in the two cases. Accordingly, under the influence of the 
addition of the ammonia-salts, the proportion of the second crop to the first is much 
less than with the mineral manure alone, and in a still greater degree less than without 
manure. Thus, with the much more luxuriant growth of first crops under the influ¬ 
ence of the ammonia-salts, and the much more simple, and almost exclusively grami¬ 
neous herbage, the actual quantity of the second crop is small, and its proportion to 
the first little more than half as much as without manure, and only about two-thirds 
as much as with the mineral manure alone. 
With, besides the mineral manure, nitrate of soda containing approximately the 
same amount of nitrogen as the 400 lbs. of ammonia-salts, the first crops averaged 
more still ; they, also, consisted almost exclusively of free-growing (though chiefly 
other) grasses ; and they comprised but few species. With these characters, the 
second crops averaged even rather less than with the ammonia-salts, and bore a smaller 
proportion to the first. 
In the cases of plot 9 with the mixed mineral manure and ammonia-salts, and of 
plot 14 with the mixed mineral manure and nitrate of soda, the amount of nitrogen 
applied was sufficient to give nearly the maximum growth of first crops, but not so 
excessive as to give a percentage of nitrogen in the produce much higher than is 
normal in the almost exclusively gramineous hay ; indicating, therefore, that the 
unrecovered amount of supplied nitrogen did not remain within the soil in a readily 
available condition ; and hence, probably, in part, the comparatively little increase of 
growth of second crop. In the case of plot 11, however, with double the amount of 
ammonia-salts of plot 9, we have upon the whole still larger first crops, and almost 
exclusively gramineous herbage, which contained, however, a very abnormally high 
percentage of nitrogen ; and, with the obvious excess available, there is here more 
second crop, and a higher proportion of second crop to first, than with the smaller 
amount of nitrogenous manure. There is, moreover, a tendency to a greater amount, 
and proportion, of second crop in the later years. 
The general result is that, when (with mineral manure) active nitrogenous manures 
are used, but not in excessive amount, the increase of the first crop will, in favourable 
seasons, be such as to leave comparatively little available nitrogenous residue for the 
second crop; whilst, the produce under such circumstances being characteristically 
gramineous, and comprising comparatively few species, the condition of the herbage is 
not very favourable for subsequent growth. It will be seen further on, however, that 
the percentage of both mineral matter and nitrogen is generally much higher in the 
