EXPERIMENTS ON THE MIXED HERBAGE OF PERMANENT MEADOW. 357 
phosphate of lime) when used alone, and how comparatively little was its effect when 
used in conjunction with ammonia-salts, but without potass ; and we have here again 
strikingly brought out the influence of a liberal available supply of potass within the 
soil, both upon the quantity and the quality of the produce, Lastly, such evidence 
as is at command on the point does not favour the supposition that any considerable 
proportion of the nitrogen of the ammonia-salts applied during the 13 years, and not 
recovered in the crops during the period of the application, remained in an available 
condition in the soil, and was reclaimed in the succeeding seven years under the influ¬ 
ences of the mixed mineral manure. 
In connexion with these results showing the effects of a pretty complete mineral 
manure, used after the continuous application of an excess of ammonia-salts alone for 
a number of years, brief reference may be made to a somewhat parallel experiment. 
When considering the results obtained on plot 15, manured for 18 years in succes¬ 
sion with 550 lbs. per acre of nitrate of soda alone, containing 82 lbs. of nitrogen, or 
approximately the same amount as the 400 lbs. of ammonia-salts employed on plots 
5 and 6, attention was called to the fact that the nitrate alone gave considerably more 
produce, containing more nitrogen, much more mineral matter, and falling off much 
less in the later years, than where the ammonia-salts were applied. The herbage, too, 
was both more mixed and better developed under the influence of the nitrate. It 
was pointed out that these better results were doubtless in great part due to the more 
rapid, wider, and deeper, disti’ibution of the nitrogen of the nitrate, than that of the 
ammonia-salts. Plants of a more varied root-range were thus encouraged ; possession 
of a greater range of soil was thus acquired; and probably the reactions within the 
soil and subsoil liberated more of their mineral constituents. But, as the 550 lbs. of 
nitrate had come, in the later years, to yield only about the same amount of produce 
as half the quantity used on another plot (17), and it was estimated that only a com¬ 
paratively small proportion of the nitrogen applied was recovered in the increased 
crop, it was decided, as in the case of plot 6 with the ammonia-salts, to stop the 
further supply of the nitrate, and to apply the mixed mineral manure instead. 
The change has thus far extended only over three years, 1876-77-78 ; but the field, 
the botanical, and the chemical, results already obtained are of marked character, and 
of much interest, and may fitly be referred to in general terms in this jflace. 
Under the influence of the nitrate, not only was the herbage more complex than 
with the ammonia-salts, but the grasses were less patchy and tufty, not of so dark a green 
colour, and yielded more stem, much of which, however, bleached rather than ripened, 
apparently from mineral exhaustion. There was scarcely any leguminous herbage; 
but species of other orders contributed about one-fifth of the produce; Rumex acetosa 
was prominent, but decreased in the later years; but the most prominent, and increas¬ 
ing as the experiment proceeded, was the Cerastium triviale, Achillea millefolium 
coming next, 
