on Permanent Meadoio Land. 
245 
and nitrogen in some form evaporated? — that a portion remains in 
the soil in some fixed and unavailable state of combination ? — that 
ammonia, or some other compoimd of nitroijcn, or free nitrogen 
itself, is given off during the growth of the plant? — or, it may be, 
that the range of distribution of the supplied nitrogen, and its 
state of combination within the soil, are alone sufficient obstacles 
to its being taken up in larger proportion by the immediate crop? 
Should the last supposition afford a sufiicient explanation of the 
facts observed, the assumed loss would be one but in appearance 
merely. Tlie farmer might then still hope to reap the whole 
benefit of his costly nitrogenous manures, in the course of time, 
in succeeding crops. Be this as it may, the facts that have been 
recorded afford additional confirmation of the opinion so fre- 
quently insisted upon, that, in the case of the Graminaceous 
plants which we cultivate, a full crop is obtained only when 
there is a liberal provision of available nitrogen within the soil ; 
and, further, that when this provision is made by means of 
direct nitrogenous manures, a large proportion of the so-supplied 
nitrogen will remain unrecovered in the increase of crop, at least 
for a considerable period of time. 
The main facts elicited on a consideration of the acreage yield 
in the Iiajj-crop, of some of its important constituents, or classes 
of constituents, according to the condition of manuring, may 
be summed up as follow: — 
1. The average annual prodtice of Total Dry Substance, in the 
unmanured rneadow-hay-crop, was about 1 ton per acre, which 
would contain about 900 lbs. of carbon. These amounts are 
somewhat less than were annually obtained icithout manure in 
either vheat or barleij. 
2. Purely carbonaceous manures did not appear to increase the 
assimilation by the Graminaceous herbage of either carbon or 
nitrogen. 
3. Purely mineral manures induced little or no increased assi- 
milation of either carbon or nitrogen by the Gi-aminaceous, but a 
considerable amount by the Leguminous herbage. 
4. Specially nitrogenous manures, such as ammoniacal salts, even 
when used alone, notably increased the assimilation of carbon 
and nitrogen by the Graminaceous, but not by the Leguminous 
herbage. 
5. By means of manures supplying Loth mineral constituents and 
nitrogen, but no carbon, there was an annual increase of Grami- 
naceous produce, equal to about 1^ ton of dry substance per 
acre, which would contain about 12 cwts. of carbon. 
6. The annual vield of mineral constituents in the unmanured 
