The number and size of the drains will depend upon the amount of rainfall, the contour of the land, and the natural absorbent character of the soil. In no case should the ditches be less than 1 meter wide and 60 cm. deep, and if loose stones are at hand the sloping sides may be laid with them, which will materially protect them from washing by torrential rains.
These main drains should all be completed prior to planting. Connecting laterals may be opened subsequently, as the necessities of further drainage or future irrigation may demand; shallow furrows will generally answer for these laterals, and as their obliteration will practically follow every time cultivation is given, their construction may be of the cheapest and most temporary nature. Owing to the necessity of main drainage canals and the needful interplanting of shade plants between the rows of cacao, nothing is gained by laying off the land for planting in what is called “two ways,” and all subsequent working of the orchard will consequently be in one direction.
The Plantation.
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,[1] 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.