The St. Lucie County tribune. (Fort Pierce, St. Lucie County, Fla.) 1905-1920, 1910-03-11
FERTILIZER IN
THEP|NEAPPLE:
Discarded Old Plants Worth $50
Per Acre If Returned to Soil.
VALUABLE PLANT FOOD
Nearly Two Tons of High Grade Fertiliz-
ing Material Found in Old Pineapple
Plants from Single Acre

AS the pineapple fields on the East
Coast become old and give way to new
paintings, the grower is confronted
with the problem of disposing of the old
plants. In the past they have usually
been disposed of in the way that seem
ed easiest, without much thought of
their value. Some haye hauled them
out to tho river bank or other out-of-
the-way place; some have burned them:
few have dug trenches and buried
them at depth of IL inches or more;
while others have put them in piles to
decay, and then spread the residue over
their fields.
To know the value of the old plants
we must know the amount of material
per acre and its pant-food content.
The average green weight of several
whole plants from four-year.old field,
was found to be l2a pounds. There
would be about l4,O00 such plants to
the acre, since this is the average num-
Der that is usually set. This will give
87a tons of green plants. Since about
l5a per cent.of this is dry matter. there
would be approximately l3b tins Of
water-free material to the acre. From
the average of many analyses we find
that this Water-free material contains
the following amounts of fertllizing
constituents: nitrogen OLA per cent,
equivalent to 0.9 per cent. ammonia),
phosphoric acid 0. SO per cent, and pot
ash "a per cent.
From these figures we find that l3A
tons of dry material will contain 200
pounds of nitrogen CAB pounds Of
ammonia) equivalent to 1923 pounds Of
high-grade dried blood; 224 pounds of
phosphoric acid equivalent to 1924
pounds of Stag phosphate. and 648
pounds of potash equivalent to 1896
pounds of high-grade sulphate of pot
ash. At the present price of fertilizers
these materials would be worth $8l. SO
1884 cents per ton for the green ma
teral, $6.04 per ton for dry materially.
If the plants from an acre of ground
are thrown on the river bank or in some
other waste place, all of this is lost. If
they are burned, the nitrogen (ammonia)
is lost, the value of which would be
$40.7O. In either case the land is de-
prived of ITS rlghtful heritage, the
humus.
1t would certainly be better to bury
the plants than to throw them away
or burn them but to bury them COM
pletely requires the digging of trenches
at least twelve inches deep, and in do
ing this, much of the surface soil which
is the richest analyses have shown
that there is much more nitrogen just
at the surface in the pineapple fields
than there is at depth of IL inches or
more) is placed entirely out o. the reach
of the roots of the young plants that
are to follow. In course sandy soil like
the pineapple soil, the plant-food tends
to leach away, especially when it is
once beyond the network of roots, and
on this account it does not seem wise
to cover up rich surface soil deeply.
The method of pilng the plants into
heaps like compost heaps has been sue
cessful and would seem to be the least
Wasteful of any. One grower who dis
pose of his old plants in this way cut off
the tops and grubs them into the soil
to the depth of four to six inches, and
also dig up the stubs with the lower
leaves and puts them in large piles to
the condition of well-rotted stable
manure, and when spread over the
ground are grubbed into the depth of
two or three inches. If this should
seem an expensive method, we need
only remind ourselves that the old plants
must he disposed of in some way, and
in throwing them away or burning
them we lose much plant-food. and in
have to bear the expense of
moving them.
In addition to furnishing nitrogen.
acid, and potash, the decay
ed plants furnish the humus which is
greatly needed. This is especially the
case on the East Coast where the eli
matte conditions favor the rapid disap-
of humus. The humus fur
ishes food for the bacteria which are
at work converting inert nitrogen into
available nitrogen, its acts as sponge
to hold moisture and plant-fOod, and it
causes better circulation of the air
tn)lgh the soil.
This decaying organic matter will
gradually bring about an acid condition
of the soil, which can readily be cor
rected by the use of Stag phosphate,
finely ground limestone, crashes. Only
when the plants are diseased should
they be burnt, and this should be done
in such way that the ashes can be re-
turned to the soil. Florida Agrcultur-
al Experiment Station, bulletin by A.
w. Blair.
Charles EdasOn and c.. +. DeMouth.