The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1899-11-21

Wy DE calCulateC Tor any crop, large or
small. This he calls fertilixing ~ res
tiiution. The idea seems rational
enough that II we return to the soil
what we have taken out. and In the
same condition. the soil would be as
good as II was before II produced n
crop. II IL an old advice and In some
cases coed one. that We return TO
the soil the begasse and the leaves and
allow the bulky mass a sufficient time
to decompose and become absorbed by
the soil. This requires much labor and
plenty OF land, 80 that the rotation Of
planting In a good many years in COM
ing again to the same field
In ratooning field ! have In many
Instances plowed under the leaves and
added nitrates and lime, and had good
results from them, more, think, from
the mechanical effect than from their
chemical properties; but we have been
informed from some of our own plant
crs. IA well as from those In other
countries, that a surer
way does not exist Of propagating bor-
ers. and other injurious insects, while
others urge the destruction Of all
leaves and decayed cane in order 20
keep out the many obscure sicknesses
and diseases usually found about cane
fields. II It could be done, a better way
would be to compost all such matters
until 1t was At as rotted manure. to be
transported and placed on our fields, as
We do now with stable manure.
Burning the leaves In the fields de-
stroys all the nitrogen, while the ash
which remains is invariably swept
away by the wind. the little that re b.
mains Is generally very insignificant.
even in those parts where there are no
constant winds. Leaves brought from
the field to generate steam in the mill
give some ash which Is recovered
the nitrogen, of course. in this case is
lost just as well as IL they were burned
in the field. When newly cut, the
weight OF the top, green leaves and all
the leaves either stripped of or which
fall on during growth, Is said by Bas-
set to be 81 per cent Of the weight of
the cane ready for the mill. and con-
tains 20 per cent Of all the nitrogen and
about 72 per cent of the mineral mat
ter used by the entire plant. Could IT.
be possible to return to the soil the ele-
nents taken up by the cane and the
leaves, we would have for every 1900
pounds of cane 420 grammes Of nitro
gen and 1866 Kilograms of mineral mat.
tel. and from the leaves which came
from these 1900 pounds Of cane $50
grammes nitrogen and 9.5 grammes OF
mineral matter, a total for cane and
leaves. 1877 kilos nitrogen and 1925 XII
los mineral matter.
II We multiply all these figures by
612 we will have a little over seven
tons cane per ton Of sugar, which might
nearly represent our requirements;
then the nitrogen and the mineral mat
ter would be for every ton Of sugar
made, as follows, viz: 1.37x6h equals
S.9 kilos nitrogen, equals 1858 pounds;
1S.25x6h equals S6.12 kilOs mineral
matter. equals 1896 pounds. But as
nearly all plantations burn the cane
leaves in the field or elsewhere, they
lose, according to these figures which !
have taken from Basset's work, page
Cos, about IA pounds nitrogen for ev-
cry ton Of sugar made-from the burn
ins of the leaves only.
DR.. Kruger, in one OF his Java re-
ports, page 107. says the value Of 100
kilos, or 220 pounds, OF the dried sub
stance. In leaves. would be worth 43
,entimes for its contained nitrogen. and
In his work. Sugar Cane and Its Gull
page 21S. referring to cane
leaves, says their worth Is very small
as mature. even taking their nitrogen
and the mineral ash into considera-
ton. In 100 kilos dry substance, he
puts their value at IL pfennig. II
green leaves are dried in the sun for
three or four weeks they lose four
liiths of their weight and they lose
in their value as a fertili-
Ger; and 1t Is only in the possible ap-
rlication Of the first strippings, which
usually contain notable proportion OF
green. undecayed leaves, where any
benefit from their nitrogen
and their mineral substances might be
taken into consideration.
Boname says. "The ash from a given
OF green leaves may contain
as much as II per cent or % per cent OF
potash, but from the ash of withered,
dry leaves only as much as 2.63 per
tent to EFT per cent of potash, both ex.
pressed, Of course, on the ash of the
dry substance. It Is therefore In the
period when the leaves are In
perfect vigor that they are richest in
nitrogen and potash. and when their
functions are performed. their cle-
ments grow less and less, while the
pi oportion OF silica augments as they
grow Of less value to the cane, and
eventually they fall of altogether. The
greater portion of the alkaline salts
have either returned to the cane stick,
or by rains or dew been diffused out
and returned to the SOIL"
The use OF commercial fertilizers is
very much over the Islands.
Lime is now recommended where for
nerly its place was taken up by large
loses of superphosphate, q useless ex-
penditure, In many cases. From my
1wn experience ! can trace but little
benefit In our land from the use OF
phosphates. either soluble or not, and
associated with other elements or ap-
FLIED alone. Potash alone, or w.lh
yuanO. gave no marked effect, but II
followed by an application OF nitrate
)f soda or sulphate of ammonia, rem
Tered much assistance to the growing
,rop. and In adding nitrate soda have
'Ollnd best reati1ta n acco8 M nied with