dried clover-roots,
consequently an acre yielded 3,622 lbs. of roots, or more than twice the
weight of roots obtained from the soil of the same field where the
clover was twice mown for hay.

"In round numbers, the 3,622 lbs. of clover-roots from the land mown
once, and afterwards left for seed, contained 51-1/2 lbs. of nitrogen.

"The roots from the soil after clover-seed, it will be noticed, were not
so clean as the preceding sample, nevertheless, they yielded more
nitrogen. In 64.76 of organic matter, we have here 1.702 of nitrogen,
whereas, in the case of the roots from the part of the field where the
clover was twice mown for hay, we have in 81.33 parts, that is, much
more organic matter, and 1.635, or rather less of nitrogen. It is
evident, therefore, that the organic matter in the soil after
clover-seed, occurs in a more advanced stage of decomposition, than
found in the clover-roots from the part of the field twice mown. In the
manure, in which the decay of such and similar organic remains proceeds,
much of the non-nitrogenous, or carbonaceous matters, of which these
remains chiefly, though not entirely, consist, is transformed into
gaseous carbonic acid, and what remains behind, becomes richer in
nitrogen and mineral matters. A parallel case, showing the dissipation
of carbonaceous matter, and the increase in the percentage of nitrogen
and mineral matter in what is left behind, is presented to us in fresh
and rotten dung; in long or fresh dung, the percentage of organic
matter, consisting chiefly of very imperfectly decomposed straw, being
larger, and that of nitrogen and mineral matter smaller, than in
well-rotted dung.

"The roots from the field after clover-seed, it will be borne in mind,
were dug up in November, whilst those obtained from the land twice mown,
were dug up in September; the former, therefore, may be expected to be
in a more advanced state of decay than the latter, and richer in
nitrogen.

"In an acre of soil, after clover-seed, we have:

Lbs.
Nitrogen in first six inches of soil 4,725
Nitrogen in roots 51-1/2
Nitrogen in second six inches of soil 3,350
-------
Total amount of nitrogen, per acre, in
twelve inches of soil 8,126-1/2
=======

"Equal to ammonia,