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, gra.s.s-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 a.s.similable 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 Sta.s.sfurt mineral manures, which contain large quant.i.ties 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 quant.i.ties 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 a.n.a.lysis, 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 s.p.a.cing 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 cla.s.sed 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 sh.e.l.led 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 a.n.a.logy 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 a.n.a.logy 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 a.n.a.lysis 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 const.i.tuent 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 a.n.a.lysis, 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 quant.i.ty 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 subst.i.tution 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 appet.i.te 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 algae 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 Caja.n.u.s indicus, or of c.l.i.torea 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 s.p.a.ce 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 subst.i.tuted. 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.