Cacao, relatively to the size of the tree, may be planted very
closely. We have stated that it rejoices in a close, moisture-laden
atmosphere, and this permits of a closer planting than would be
admissible with any other orchard crop.
In very rich soil the strong-growing Forastero variety may be planted
3.7 meters apart each way, or 745 trees to the hectare, and on lighter
lands this, or the more dwarf-growing forms of Criollo, may be set
as close as 3 meters or rather more than 1,000 trees to the hectare.
The rows should be very carefully lined out in one direction and
staked where the young plants are to be set, and then (a year before
the final planting) between each row of cacao a line of temporary
shelter plants are to be planted. These should be planted in quincunx
order, i. e., at the intersecting point of two lines drawn between
the diagonal corners of the square made by four cacaos set equidistant
each way. This temporary shelter is indispensable for the protection
of the young plantation from wind and sun.
The almost universal custom is to plant, for temporary shelter, suckers
of fruiting bananas, but throughout the Visayas and in Southern Luzon
I think abacá could be advantageously substituted. It is true that,
as commonly grown, abacá does not make so rank a growth as some
of the plantains, but if given the perfect tillage which the cacao
plantation should receive, and moderately rich soils, abacá ought to
furnish all necessary shade. This temporary shade may be maintained
till the fourth or fifth year, when it is to be grubbed out and the
stalks and stumps, which are rich in nitrogen, may be left to decay
upon the ground. At present prices, the four or five crops which
may be secured from the temporary shelter plants ought to meet the
expenses of the entire plantation until it comes into bearing.
In the next step, every fourth tree in the fourth or fifth row
of cacao may be omitted and its place filled by a permanent shade
tree. The planting of shade trees or "madre de cacao" among the cacao
has been observed from time immemorial in all countries where the crop
is grown, and the primary purpose of the planting has been for shade
alone. Observing that these trees were almost invariably of the pulse
or legume family, the writer, in the year 1892, raised the question,
in the Proceedings of the Southern California Horticultural Society,
that the probable benefits derived were directly attributable to the
abundant fertilizing microörganisms developed in the soil by these
leguminous plants, rather than the mechanical protection they afforded
from the sun's rays.
To Mr. O. F. Cook, of the United States Department of Agriculture,
however, belongs the credit of publishing, in 1901, [4] a résumé of
his inquiries into the subject of the shades used for both the coffee
and the cacao, and which fully confirmed the previous opinions that
the main benefit derived from these trees was their influence in
maintaining a constant supply of available nitrogen in the soil.
That cacao and its wild congenors naturally seek the shelter of
well-shaded forests is well established; but having seen trees in these
Islands that were fully exposed at all times showing no evidences of
either scald, burn, or sun spot, and in every respect the embodiment
of vigor and health, we are fully justified in assuming that here the
climatic conditions are such as will permit of taking some reasonable
liberties with this time-honored practice and supply needed nitrogen
to the soil by the use of cheap and effective "catch crops," such us
cowpeas or soy beans.
Here, as elsewhere, an Erythrina, known as "dap-dap," is a favorite
shade tree among native planters; the rain tree (Pithecolobium saman)
is also occasionally used, and in one instance only have I seen a
departure from the use of the Leguminosæ, and that in western Mindanao,
there is a shade plantation composed exclusively of Cananga odorata,
locally known as ilang-ilang.
While not yet prepared to advocate the total exclusion of all shade
trees, I am prepared to recommend a shade tree, if shade trees there
must be, whose utility and unquestioned value has singularly escaped
notice. The tree in question, the Royal Poinciana (Poinciana regia),
embodies all of the virtues that are ascribed to the best of the
pulse family, is easily procured, grows freely and rapidly from seed
or cutting, furnishes a minimum of shade at all times, and, in these
Islands, becomes almost leafless, at the season of maturity of the
largest cacao crop when the greatest sun exposure is desired.
The remaining preparatory work consists in the planting of intersecting
wind breaks at intervals throughout the grove, and upon sides exposed
to winds, or where a natural forest growth does not furnish such a
shelter belt. Unless the plantation lies in a particularly protected
valley, no plantation, however large in the aggregate, should cover
more than 4 or 5 hectares unbroken by at least one row of wind-break
trees. Nothing that I know of can approach the mango for this
purpose. It will hold in check the fiercest gale and give assurance
to the grower that after any storm his cacao crop is still on the
trees and not on the ground, a prey to ants, mice, and other vermin.