, 1908-08-01
SEA-WEED AS A MANURE.

At the Conference of cotton growers which
was held at Barbados in May last, reference
was made to the q estion of utilizing sea-
weed as a manure. This material is IN most
countries used for manurial purposes by
agriculturists whose land is near the sea-
coast, although the large content OF water
(65 to 80 per cent. in the fresh state) makes
transport nm expensive item for those LIVING
any distance inland. Sea-weed is used on q
very large scale by farmers in many OF the
coast States Of America, and q bnlletln of
the United States Department Of AgElcul-
ture mentions that in Rhode Island, the an
nual value Of the manure from this source
has been estimated to be as high as $4,000
Sea-weeds of different kinds naturally
differ, in their content of fertilizing coustitu-
ents. Some Of them contain a relatively
high proportion of nitrogen, and others Of
potash, but as a general rule they are def
cient in phosphoric acid.
tn a publication issued by the Department
of Agriculture of the Dominion of Caaada,
an anall sis is given OF sea- weed from the
Canadian coast. This col ain d 27.93 p
cent, of organic matter Gncinding O463
%nitrogen), O'1O8 phosphorus acid, ald POPS
potash. In other words the amount Of fer
tilizing constituents present was al the rats
Of 936 fb of nitrogen, 2.1S ID. of phosphor-
ic acid, and 400 ID. OF potash per ton. The
must be- considered q valuable mtnure, on
account Of the large amount Of potash and
nitrogen contained, more particularly the
former. For general agricultural purposes.
however, aud in order to make it . complete
fertilizer, it might, with profit, be supple
mented by bone meal, which would supply
phoaphoric acid. AS a green manure, the
application Of sea-weed would add largely to
the humus in the soil, and uudoubted y I'M
prove the filth or mechanical! con Hilton of
the latter, more especially on very heavy or
very light lands. 1t may be applied at the
rate of 20 or 80 tons per acre.
If the sea- weed is spread in thin layers
on the shore, and allowed to dry for a day
or two, it may with economy be carted much
longer distances than when in the perfectly
fresh state.
When sea-weed is burnt, the nitrogen is
lost, but the potash and phosphoric acid
remain behind in the ash. Analysis of the
ash of the Canadian sea-weed showed that
it contained 1.27 per cent. of phosphoric acid,
and 1851 per cent. of potash, together with
1863 per cent. of lime. The proportion Of
potash is considerably higher than that in
ordinary wood ashes, usually valued on &C.
count Of their content of this fertilizing con-
s~tituent.
In the case of land at some distance from
she shore, therefore, which 1t is though,
would especially benefit by the application
Of potash, it would probably be found eco
nomical to forego the organic matter, and
reduce the sea-weed to ash, a ton of which,
on the basis of the above analysis, would
contain over 500 fb. OF potash, and about
% b. of p~hosphoric acid.
In reference to the use of saa-weed by
estate owners in the West Indies, Professor
Albuquerque mentioned, at the Cotton
Growers Conference above referred 10, that
q sample of West Indian sea-weed, partially
dried in the sun, analysed by him contained
49.5 per cent. organic matter, 0.78 per cent.
nitrogen, OBJ per cent. phosphoric acid, and
of this material, according to the scale OF
the Barbados Agricultural Society, would
work out ut about So per ton.-I6id.