on Ferinanent Meadow Land. 
239 
that the mineral constituents of the hay will, in anything like a 
corresponding: degree, find their way back from whence they came. 
It will be obvious, therefore, that, according to current practice, 
the meadow-land will be much more liable than the arable to 
become deficient in a due provision of the necessary mineral con- 
stituents. These considerations show that both the wheat and 
the barley-crops may, with comparative impunity, be kept up 
to a high point of productiveness by means of forcing portable 
manures, provided only that the crops of the course, as a whole, 
receive their due share of the home manures. It will, at the same 
time, be equally obvious, that similar means are not applicable 
for the production of full crops of hay, unless similar conditions 
be provided ; that is to say, unless the meadow, in its turn, receive 
a due proportion of the home manures. 
Where, however, grass is grown for hay by those holding little 
or no arable land, it is generally for the supply of a neighbouring 
town ; and in such cases a liberal amount of stable and other 
town-manures is generally brought upon the land. Under these 
circumstances, the additional use ot the more active portable 
manures, will not, as a rule, be advantageous. 
3. The Nitrogen per Acre. 
Attention must now be directed to the acreage yield in the hay 
of the important constituent nitrogen. In the experiments under 
consideration, the annual yield of nitrogen per acre, taking the 
average result of 3 years, was, without manure, 39-8 lbs. (see 
Table VI.). By the side of this amount it may be mentioned, 
that the average of 14 consecutive years of unmanured wlieat gave 
30"7 lbs. ; and that of G consecutive years of iinmanurcd barley, 
26 5 lbs. of nitrogen. 
r'rom these figures it appears, that the haj'-crop (so far as the 
experiment has yet extended) has given from one-third to one- 
half more nitrogen per acre per annum, without manure, than 
either wheat or barley. Part of this excess of nitrogen in the 
h<iy-crop, though probably not the whole of it, is due to the fact, 
that the mixed herbage of the hay comprised a number of 
Leguminous plants, which contain a higher per-centage of nitro- 
gen, and have apparently greater powers of assimilating it from 
natural sources, than the Graminaceou.t ones. Indeed, where 
mineral manures alone were employed (Plot 8), under the influ- 
ence of which the development of Lrgnminons plants was ercater 
than on any of the other plots, there was an average of 5G'6 lbs. 
per acre per annum of nitrogen, without the supply of it in 
manure, instead of only 39 8 lbs. without manure of any kind. 
Thus, without the addition of any nitrogenous manure, there was 
