EXPERIMENTS ON THE MIXED HERBAGE OF PERMANENT MEADOW. 331 
irregularly and imperfectly, yielding hay of low quality. Though, if the grass were 
fed off young, or cut green for feeding, it would probably be fairly good food. 
Coincidently with these botanical and other characteristics of the herbage grown by 
mineral manures and ammonia-salts, we have, as already stated, an abnormally high 
percentage of nitrogen in the produce when an excessive amount of it is supplied in 
the manure. There is also a somewhat high percentage of mineral matter in the dry 
substance of these large, coarse, unevenly ripened, and almost exclusively gramineous 
crops. 
Further, the results of the ash-analyses, which will be fully considered subsequently, 
show some striking differences in the mineral composition of the produce. Thus, 
there is a strikingly lower percentage of lime, a lower percentage of magnesia, and, 
notwithstanding the produce is so prominently gramineous, a lower percentage of 
silica, in the dry substance of the hay, than where the growth is less forced, and the 
herbage is at the same time more mixed. Of potass and phosphoric acid, but espe¬ 
cially of potass, there is, on the other hand, a considerably higher percentage in the 
dry substance of these coarse gramineous crops, as also there is of chlorine. Again, 
whilst the percentage in the dry substance, of lime, magnesia, soda, sulphuric acid, 
and silica, has decreased over the later compared with the earlier years, that of the 
potass and phosphoric acid (and also that of chlorine) has increased over the later 
years. The percentage of lime especially has decreased the more, but that of the soda, 
sulphuric acid, and silica, the less, the greater the amount of the ammonia-salts applied, 
and the coarser the herbage. 
Comparing plots 11-1 and 11-2, both with the mixed mineral manure and the 
large amount of ammonia-salts, but 11-1 without, and 11-2 with silicates, the only 
noticeable difference in the percentage mineral composition of the herbage is, that 
there is a slightly higher percentage of silica in that where it was applied, and with 
this there is a less percentage of potass, and a less increased percentage of it over the 
later years. There is, at the same time, a somewhat less excessive percentage of 
nitrogen where the silicates were used. The increased actual amount per acre of 
mineral matter removed where the silicates were applied was, however, much greater 
than is represented by the increased amount of silica taken up. (which was only about 
7 lbs. per acre per annum out of the 400 lbs. of crude silicates used). Nor is this 
result to be explained by supposing that there was a deficiency of available soda and 
lime where the silicates were not applied, since but a small proportion of that otherwise 
supplied of either had been utilised ; and there was, therefore, unless lost by drainage, 
an annually increasing residue of them accumulating within the soil. There can, 
indeed, be little doubt that, in the presence of the excessive supply of nitrogen, and 
the increased activity of growth induced by it, the silicates of soda and lime employed 
were effective in other ways than merely as supplies of either silica, soda, or lime, to 
the plant. The effect w r as probably due in part to reactions of the alkaline silicates 
within the soil; for, under their influence there was more nitrogen, magnesia, potass, 
2 u 2 
