382 
MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
and these three grasses made up a large proportion of the total produce. During the 
later years, as on the plot without ammonia, but in a greater degree, Agrostis vulgaris, 
and Holcus lanatus, became very prominent, as also did Anthoxanthum odoratum, and 
Festuca ovina; whilst, on both plots, the Poa trivialis, the Bromus mollis, and the 
Dactylis glomerata, went down very much. Other grasses were represented in less 
number, and generally in less proportion, on the plot with ammonia. 
Of leguminous plants, Lathyrus pratensis is the most prominent on both plots; but, 
whilst without the ammonia the quantity at the last separation was between 5 and 6 
per cent., with the ammonia there has been but a fraction of 1 per cent, of it; and, 
again, without ammonia there was nearly 1 per cent, of Trifolium pratense, but with 
it there was none at all. 
Of miscellaneous species, many more were fairly prominent without than with the 
ammonia ; though with it, Rumex acetosa was not only much more prominent than 
without it, but yielded a very large proportion of the total miscellaneous herbage. 
Finally in reference to the botanical character of the produce—a much greater number 
of species, gramineous, leguminous, and miscellaneous, contribute to the produce 
without, than to that with, the ammonia-salts. 
In Table XX., p. 368, the produce of hay, and its contents of nitrogen and mineral 
matter, are given, for each period, with the farmyard manure and ammonia-salts, side 
by side with those on plot 2 with the farmyard manure alone. 
Over the eight years of the application of the dung, there was an average of 734 lbs., 
over the first six years after the cessation, 520 lbs., over the next six years, 814 lbs., 
and over the whole period of 20 years, 694 lbs., more hay by the dung and ammonia- 
salts, than by the dung alone. Although the increase of produce, due to the ammonia- 
salts, was thus pretty constant, the actual amount of produce per acre w T as nearly 40 
per cent, less over the last six years than over the first eight. Where the farmyard 
manure was used alone, however, the decline was greater still, being nearly 48 per cent. 
The 200 lbs. of ammonia-salts annually applied are estimated to supply about 
41 lbs. of nitrogen, equal to about 50 lbs. ammonia. The increased yield of nitrogen 
in the crop was, however, only 10T lbs. per acre per annum over the first eight years, 
10‘6 lbs. over the next six, 13 5 lbs. over the last six, and 11‘3 lbs. over the 20 years. 
In other words, there was, so reckoned, an average of only about 27| per cent, of the 
nitrogen so supplied recovered as increase in the crop. 
Of mineral matter, there was also an increased amount taken up under the influence 
of the ammonia-salts. But, as without manure, and as with farmyard manure alone, 
the actual amount annually taken up was very much less over each succeeding period; 
indeed, on both plots, 2 and 1, it was considerably less than half as much over the last 
six years as over the eight years of the application of the dung. Still, the ammonia- 
salts undoubtedly had the effect of increasing the amount of mineral matter taken up. 
Over each period there was more lime, magnesia, phosphoric acid, and sulphuric acid, 
