The manuring problem must be met and solved by the best resources at
our command. The writer has had pointed out hundred of trees that,
wholly guiltless of any direct application of manure, have borne
excellent crops for many successive years; but he has also seen
hundreds of others in their very prime, at thirty years, which once
produced a hundred select nuts per year, now producing fluctuating
and uncertain crops of fifteen to thirty inferior fruits.
Time and again native growers have told me of the large and uniformly
continuous crops of nuts from the trees immediately overshadowing their
dwellings and, although some have attributed this to a sentimental
appreciation and gratitude on the part of the palm at being made one
of the family of the owner, a few were sensible enough to realize
that it came of the opportunity that those particular trees had to
get the manurial benefit of the household sewage and waste.
Yet, the lesson is still unlearned and, after much diligent inquiry,
I have yet to find a nut grower in the Philippines who at any time
(except at planting) makes direct and systematic application of manure
to his trees.
In India, Ceylon, the Penang Peninsula, and Cochin China, where the
tree has been cultivated for generations, the most that was ever
attempted until very recently was to throw a little manure in the
hole where the tree was planted, and for all future time to depend
on the inferior, grass-made droppings of a few cattle tethered among
the trees, to compensate for the half million or more nuts that a
hectare of fairly productive trees should yield during their normal
bearing life.
Upon suitable cocoanut soils--i. e., those that are light and
permeable--common salt is positively injurious. In support of this
contention, I will state that salt in solution will break up and
freely combine with lime, making equally soluble chlorids of lime
which, of course, freely leach out in such a soil and carry down
to unavailable depths these salts, invaluable as necessary bases
to render assimilable most plant foods; and that, on this account,
commercial manures containing large amounts of salt, are always to
be used with much discretion, owing to the danger of impoverishing
the supply of necessary lime in the soil.
Finally, so injurious is the direct application of salt to the roots
of most plants that the invariable custom of trained planters (who,
for the sake of the potash contained, are compelled to use crude
Stassfurt mineral manures, which contain large quantities of common
salt) is to apply it a very considerable time before the crop is
planted, in order that this deleterious agent should be well leached
and washed away from the immediate field of root activity.
That the cocoanut is able to take up large quantities of salt may not
be disputed. That the character of its root is such as to enable it to
do so without the injury that would occur to most cultivated plants
I have previously shown, while the history of the cocoanut's inland
career, and the records of agricultural chemistry, both conclusively
point to the fact that its presence is an incident that in no way
contributes to the health, vigor, or fruitfulness of the tree.
Mr. Cochran's analysis, based upon the unit of 1,000 average nuts,
weighing in the aggregate 3,125 pounds, discloses a drain upon soil
fertility for that number, amounting in round numbers to--
Pounds.
Nitrogen 8 1/4
Potash 17
Phosphoric acid 3
Reducing this to crop and area, and taking 60 fruits per annum per tree
as a fair mean for the bearing groves in our cocoanut districts and
on those rare estates where a systematic spacing of about 173 trees
to the hectare has been made, we should have an annual harvest of
10,300 nuts, or, stated in round numbers, 10,000, which will exhaust
each year from the soil a total of--
Pounds.
Nitrogen 82 1/2
Potash 170
Phosphoric acid 30
The cocoanut, therefore, while a good feeder, may not be classed with
the most depleting of field crops.
To make this clear I exhibit, by way of contrast, the drafts made
by a relatively good crop of two notoriously soil-impoverishing
crops--tobacco and corn--and, on the other hand, the drafts made by
an equivalent average cotton crop--a product considered to make but
light drains upon sources of soil fertility.
A proportionate tobacco crop of 1,000 kilos per hectare will withdraw
from the soil (reduced to the same standard of weights adopted by
Mr. Cochran)--
Pounds.
Nitrogen 168
Potash 213
Phosphoric acid 23
An equivalent crop of shelled corn, say, of 125 bushels per hectare,
will withdraw--
Pounds.
Nitrogen 200
Potash 135
Phosphoric acid 75
while a relative crop of lint cotton of 237 kilos (700 pounds) per
hectare [6] will only exhaust, in round numbers--
Pounds.
Nitrogen 114
Potash 70
Phosphoric acid 30
There is an analogy between these four products that makes them
all comparable, in so far as all are largely surface feeders, and,
as experience shows that there can be no continuing success with
the last three that does not include both cultivation and manuring,
we may use the analogy to infer a like indispensable necessity for
the successful issue of the first.
Cultivation as a manurial factor should, therefore, not be overlooked,
and all the more strongly does it become emphasized by the very
difficulties that for some years to come must beset the Philippine
planter in the way of procuring direct manures.
When it comes to the specific application of manures and how to make
the most of our resources, we shall have to turn back to the analysis
of the nut and note that, relatively to other crops, it makes small
demands for nitrogen. At the same time it must not be forgotten that
these chemical determinations only refer to the fruit and that,
with the present incomplete data and lack of investigation of the
constituent parts of root, stem, leaf, and branch, we have nothing
to guide us but what we may infer from the behavior of the plant and
its relationship to plants of long-deferred fruition, whose manurial
wants are well understood.
It is now the most approved orchard practice to encourage an early
development of leaf and branch by the liberal application of nitrogen,
whose stimulant actions upon growth are conceded as the best.
In temperate regions, the exigencies of climate exact that this be
done with discretion and care, in order that the unduly stimulated
growths may be fully ripened and matured against the approach of an
inclement season. In the Tropics no such limitations exist, and the
early growth of the tree may be profitably stimulated to the highest
pitch. That this general treatment, as applied to young fruit trees,
is specifically the one indicated in the early life of the cocoanut,
may be quickly learned by him who will observe the avidity with
which the fleshy roots of a young cocoanut will invade, embrace,
and disintegrate a piece of stable manure.
Notwithstanding lack of chemical analysis, we may not question the
fact that considerable supplies of both potash and phosphoric acid
are withdrawn in the building up of leaf and stem; but these are
found in sufficient quantity in soils of average quality to meet
the early requirements of the plant. It is only when the fruiting
age is reached that demands are made, especially upon the potash,
which the planter is called upon to make good.
Good cultivation, the application of a generous supply of stimulating
nitrogen during its early career, and the gradual substitution in
later life of manures in which potash and phosphoric acid, particularly
the former, predominate, are necessary.
How, then, may we best apply the nitrogen requirements of its early
life? Undoubtedly through the application of abundant supplies of
stable manures, press cakes, tankage, or of such fertilizers as furnish
nitrogen in combination with the large volume of humus necessary to
minister to the gross appetite of the plant under consideration. But
the chances are that none of these are available, and the planter
must have recourse to some of the green, nitrogen-gathering manures
that are always at his command.
He must sow and plow under crops of pease, beans, or other legumes
that will furnish both humus and nitrogen in excess of what they
remove. Incidentally, they will draw heavily upon the potash deposits
of the soil, and they must all be turned back, or, if fed, every
kilo of the resulting manure must be scrupulously returned. He must
pay for the cultivation of the land, for the growing of crops that
he turns back as manure (and that involves further expense for their
growing and plowing under), and, in addition, he must be subject to
such outlay for about seven years before he can begin to realize for
the time and labor expended.
But there are expedients to which the planter may have recourse
which, if utilized, may return every dollar of cultural outlay. By
the use of a wise rotation he can not only maintain his land in a good
productive condition but realize a good biennial crop that will keep
the plantation from being a financial drag. The rotation that occurs
to me as most promising on the average cocoanut lands of these Islands
would be, first, a green manure crop, followed by corn and legumes,
succeeded by cotton, and then back to green manures.
To make the first green crop effective as a manure, both lime and
potash are essential--the former to make available the nitrogen we
hope to gather, and the potash in order to secure the largest and
quickest growth of the pulse we are to raise for manurial purposes.
Both these elements are generally in good supply in our cocoanut lands;
but, if there is uncertainty upon this point, both should be supplied,
in some form. Fortunately, the former is cheap and abundant in most
parts of the Archipelago, and, when well slaked, may be freely applied
with benefit, at the rate of a ton or even more to the hectare.
In default of the mineral potash salts, the grower must seek unleached
wood ashes, either by burning his own unused jungle land to procure
them or by purchasing them from the neighbor who has such land to
burn over. If located on the littoral, he will carefully collect
all the seaweed that is blown in, although in our tropical waters
the huge and abundant marine algæ are mostly lacking. Such as are
found, however, furnish a not inconsiderable amount of potash, and,
in the extremities to which planters remote from commercial centers
are driven, no source is too inconsiderable to be overlooked.
The first green crop selected will be one known to be of tropical
origin which, with fair soil conditions, will not fail to give a good
yield. He may with safety try any of the native rank-growing beans,
or cowpeas, soja, or velvet beans; or, if these are not procurable, he
has at command everywhere an unstinted seed supply of Cajanus indicus,
or of Clitorea ternatea, which will as well effect the desired end--to
wit, a great volume of humus and a new soil supply of nitrogen. It
remains for the planter to determine if the crop thus grown is to
be plowed under, or if he will use it to still better advantage by
partially feeding it, subject, as previously stated, to an honest
return to the land of all the manure resulting therefrom.
He may utilize it in any way, even to selling the resulting seed
crop, provided all the remaining brush is turned back to the land
and a portion of the money he receives for the seed be reinvested in
high-grade potash and phosphatic manures. The plantation should now
be in fair condition for a corn crop, and, as a very slight shading
is not prejudicial to the young palms, the corn can be planted close
enough to the trees, leaving only sufficient space to admit of the
free cultivation that both require.
It must not be forgotten that corn makes the most serious inroads
upon our soil fertility of any of the crops in our rotation, and,
unless by this time the planter is prepared to feed all the grain
produced to fatten swine or cattle, it had better be eliminated from
the rotation and peanuts substituted. In addition to this, he must
still make good whatever drains the corn will have made upon this
element of soil fertility.
Cropping to corn attacks the cocoanut at a new and vulnerable point,
against which the careful grower must make provision. It will be
remembered that an average corn crop makes very considerable drafts
upon the soil supply of phosphoric acid; but, if the grain is used
for fattening swine, whose manure is much richer in phosphates than
most farm manures, and the latter is restored to the land, serious
soil impoverishment may be averted.
The next step in our suggested rotation is the cotton crop. Here,
too, limitations are imposed upon the planter who is without abundant
manurial resources to maintain the future integrity of his grove. He
may sell the lint from his cotton, but he can not dispose of it
(as is frequently done here) in the seed.
If the enterprise be not upon a scale that will justify the equipment
of a mill and the manufacture of the oil, he has no alternative but
to return the seed in lieu of the seed cake, wasteful and extravagant
though such a process be.
The oil so returned is without manurial value and, if left in the
seed, is so much money wasted. The rational process, of course,
calls for the return of the press cake, either direct or in the form
of manure after it has been fed. With this is also secured the hull,
rich in both the potash and the phosphoric acid [7] which we now know
is so essential to the future welfare of the grove.
The above rotation is simply suggested as a tentative expedient.
The ground will now be so shaded that we can not hope to raise more
catch crops for harvesting, although it may be possible during the
dry season to raise a partial stand of pulses, of manure value only;
but, from the fruiting stage on, this becomes a minor consideration.
This stage of the cultural story brings us once more face to face
with the principle contended for at the beginning of this paper,
namely, that there can be no permanent prosperity in this branch of
horticulture until the crop is so worked up into its ultimate products
that none of the residue of manufacture goes to waste.
At best the return of these side products is insufficient, and, despite
their careful husbandry, we can not ultimately evade a greater or less
resort to inorganic manures of high cost and difficult procurement.
The residue from the press cake is rich in nitrogen and humus, which,
in the ever-increasing shade of the grove, will become more and more
difficult to produce there through nitrogen-making agencies; but the
waste from the manufacture of coir and the ashes from the woody shell
will go far toward supplying the needed potash.
Such a system would, if closely followed, practically restrict the
farmer's ultimate purchases to a small quantity of acid phosphates,
or of bone dust, which, in conjunction with good tillage, should
serve to maintain the grove in a highly productive condition for an
indefinite term of years.