on Permanemt Meadow Land. 
529 
be advantageously compensated by a judicious use of some of 
the more active artificial or purchased manures. 
" In the experiments which form the subject of this paper, 
the amount of farmvard-manure armually employed was 14 tons 
per acre, which would doubtless contain very much more of every 
constituent of the hay-crop than the produce yielded. Under 
these circumstances, although the superaddition of ammonia-salts 
considerablv increased the crop, they gave a less result than under 
anv of the other conditions of experiment. If the same amount 
of farmvard-manure, or even less of well-rotted dung, were 
emploved once in four or five years, this would supply sufficient 
of most of the mineral constituents for a larger amount of in- 
crease than would be obtained in several years by its use alone ; 
and. imder such circumstances, the additional application of 
moderate quantities of the more rapidly active manures, such as 
Peruvian-guano, or ammonia-salts or nitrate of soda and super- 
phosphate of lime, would not only serve to bring into more rapid 
use the constituents of the dung, but the increase of crop would be 
obtained without injury to the permanent condition of the land, 
and with little detriment to the character of the herbage deve- 
loped. 
Under some circumstances ammonia-salts, and under others 
nitrates, seem to be the more active in proportion to the nitro- 
gen they contain. But, as the mixed herbage of grass-land 
includes plants of very different habits of growth, seeking their 
nutriment at very different ranges within the soil, and as the 
nitrogen of nitrate of soda becomes distributed much more 
rapidly than that of ammonia-salts, it is desirable to employ a 
mixture of these two manures. Bv this means the growth of 
a greater variety of plants is favoured, and very probably a 
greater amount of increase will be obtained within a given time 
for a given amount of nitrogen applied. 
Assuming the dung to be employed in quantity sufficient for 
the due restoration of the alkalies, alkaline earths, and silica, it 
would, of course, at the same time supplv a considerable amount 
of phosphoric acid also. But experience shows that, even when 
this is done, activity of growth is frequently considerably in- 
creased if direct phosphatic manures be also employed. The 
phosphoric acid may be advantageouslv and economically applied 
either in the form of Peruvian guano, which at the same time 
supplies a large quantity of ammonia or ammonia-yielding matter 
and a little potass also, or as superphosphate of lime. 
2 M 2 
