EXPERIMENTS ON THE MIXED HERBAGE OF PERMANENT MEADOW. 305 
We will first refer to the results on plot 15, receiving 550 lbs. of nitrate of soda 
per acre per annum, estimated to contain the same amount of nitrogen as the 400 lbs. 
ammonia-salts applied to plot 5, namely, 82 lbs. It is remarkable that, whilst with a 
given amount of nitrogen applied as ammonia-salts there was an average annual 
increase of produce over the 18 years of only 489 lbs., there was with the same amount 
applied as nitrate of soda 1618 lbs., or 1129 lbs. more. Or, to put it in another 
way, whilst the ammonia-salts gave an average annual increase of little more than 
one-fifth over the unmanured produce, the nitrate of soda gave more than one-and- 
two-thirds as much. Further, whilst over the second period compared with the first 
the produce declined 10’3 per cent, without manure, and 251 per cent, with ammonia- 
salts, it only fell off 31 per cent, with the nitrate of soda. 
The yield of nitrogen, again, was one-fifth more under the influence of the nitrate 
than of the ammonia-salts ; and whilst, over the second period compared with the first, 
it declined nearly 9 per cent, without manure, and more than 17 per cent, with 
ammonia-salts, the reduction was only per cent, with the nitrate of soda. 
But it was in the amounts of mineral matter taken up that the difference in the 
effects of the ammonia-salts and the nitrate of soda was the most marked. Thus, 
whilst over the 18 years the quantities of mineral matter removed in the crops were 
almost identical without manure and with ammonia-salts, with the nitrate of soda 
more than one-and-a-half time as much was taken up; and the increase, which 
amounted to an average of nearly 80 lbs. per acre per annum, was more than two-and- 
a-half times as much as is accounted for by the increased amount of soda taken up, 
due to the nitrate of soda used. It is remarkable, too, that whilst the decline in the 
amount of mineral matter taken up over the second period compared with the first was 
13'5 per cent, without manure, and 35‘3 per cent, with the ammonia-salts, it was only 
91 per cent, with the nitrate of soda. Of individual mineral constituents, not 
supplied in either manure, more lime, more magnesia, and considerably more of potass, 
phosphoric acid, and silica, were removed in the produce by the nitrate than in that by 
the ammonia-salts. 
To attempt to explain these results, even as fully as the data at command will 
allow, would be to go beyond the facts more special to this section, and to trench upon 
those specially belonging to the botanical and chemical sections, and would, indeed, 
involve a long discussion. It must suffice in this place briefly to indicate the main 
points. Under the influence of the nitrate of soda a greater total number of species 
maintained a place than under that of the ammonia-salts. Among the grasses a 
greater variety contributed to the bulk of the herbage, and they showed a greater 
tendency to form stem and seed. There was also somewhat more leguminous herbage, 
and considerably more referable to miscellaneous species, of which, moreover, a greater 
number were fairly prominent. 
It will be readily conceived that, under the conditions here described, there would 
be a greater variety, and better development, and consequently a wider and deeper 
MDCCCLXXX. 2 R 
