[52] I regret that I am unable to give the botanical name of this tree, and of some others subsequently mentioned. I have drawn up a list of trees, some of which may be retained till better trees can be grown to supply their places, and also of other trees which are positively injurious to coffee, but do not publish them, partly in order to save space, and partly because I have not been able to ascertain the botanical names of all the trees in question.
[53] My manager last year weighed and counted the Jack fruits from a single tree. There were forty fruits which weighed 572 lbs. The largest fruit weighed 30 lbs.
CHAPTER XII.
MANURE.
The question of shade is, as we have seen, a highly complicated one, and is also, as we shall see, a cause of complication in the subject we are now about to consider; for, were no shade required, the subject of manuring the land for coffee would, comparatively speaking, be a simple one. And it is very important to call attention to this point, because hitherto planters have not in any way allowed shade to disturb their manurial practices, but have applied their manures equally to land under the direct shade of the trees, and to the open spaces between them, which are only under the influence of lateral shade, or, in other words, have manured their land as if there were no shade trees on it whatever. A little consideration, however, will show that the kinds and qualities of the manures applied should be quite different under the shade of trees, from what they ought to be in the open spaces between them. For, close around the stems of the shade trees we have a large leaf deposit, which manures the soil and maintains its physical condition, and, at the same time, comparatively speaking, small crops of coffee, while in the open spaces between the shade trees we have a small amount of leaf deposit, and much heavier crops of coffee. If, then, we further take into consideration the fact that the soil between the shade trees is liable to be deteriorated by a greater exposure to wash and to baking from the sun after the soil has been thoroughly soaked, it is evident that manuring should be largely varied both in quality and quantity, if we are at once to manure efficiently and economically. And I desire the more particularly to call attention to this matter, because no planter, as far as I am aware, has at all studied the subject. And it is principally of very great importance because what we call bulk manures, i.e., farmyard manures, pulp, composts, and top soil, are difficult to procure in large quantities, and cost much to apply, as they have to be carried on coolies' heads, and often for considerable distances, down the rows of coffee trees. The more, then, we can limit our applications of bulk manure to such lands as urgently require them, the better shall we be able to devote a full supply to the soil which most requires such manures. Now if we apply our bulk manures to the land directly under the shade trees, we shall certainly be injudiciously using our mammal resources, because the leaf deposit under the shade trees supplies exactly that kind of padding which gives its chief value to bulk manures, and, if these opinions are sound, it therefore follows that we should, as a rule, apply all our bulk manures to the spaces between the shade trees, and only apply them to the land under the shade trees, when, from the soil being of a clayey character, an occasional application of bulk manure may be required to improve the texture of the soil, or, in other words, make it more easily workable. And it also follows that we should only apply bones, lime, and ashes, fish and oil-cake to the coffee under the direct influence of the shade trees.
But there is another question as regards manuring under the shade trees that requires careful consideration, and that is, whether we can, by heavy manuring, produce in such situations a larger crop than we could by a small application of manure, and from an experiment made by the late Mr. Pringle, formerly chemist on Messrs. Matheson and Co.'s estates in Coorg, it would seem to be a waste of money to supply more than a very moderate amount to the coffee directly under the shade trees, for he found that a considerable increase in the quantity of manure gave no increase in the crop. But I do not, of course, accept this experiment as conclusive, as it was made with bones alone, and it is possible that a more favourable result might have been obtained had an application of foliage stimulating manure been used as well, for the growth of new wood under shade is extremely slow, and it is probable that this slow growth, by giving an insufficient supply of young wood, is really the main cause of the yield under the shade trees being so much less than that from the coffee in the spaces between them. But the whole of this branch of my subject requires further careful experiment and observation before we can arrive at any definite conclusion. In the meanwhile, and till it can be shown that, with the aid of foliage stimulating manures, we can increase the yield under the direct shade of the trees, it is evident that as coffee under direct shade produces less than coffee in the spaces between the shade trees, the coffee that produces more should have a larger supply of manure.
It is hardly necessary to add here that, in order to prevent confusion, the whole field of coffee to be operated on should first of all be manured evenly all over with the quantity and quality of manure which it is advisable to use under the shade trees. After that, additional manure should be applied to the spaces between the shade trees. It is quite clear to me that a great economy of manure would be effected by this practice, and that from not applying bulk manures to the coffee under the shade trees, the physical condition of the land in the spaces between them could be maintained in a much more satisfactory degree than it is at present.
Then there is another question which, I believe, has hitherto escaped notice, and that is, as to whether we should not make some alteration in the kinds of manure so as to suit them better to the various aspects we have to deal with, for even in land of the same quality, and treated in precisely the same way, there is a considerable difference in the appearance of the coffee when we pass from an eastern or southern aspect to a western one, and a very great and marked difference is at once perceptible when you enter the coffee on a northern aspect. In the last-named case the coffee is nearly always green, and steadily but slowly growing, while on the southern and eastern aspects the coffee in the hot weather is apt to present a dried-up and sickly appearance. Then on these two last-named aspects there is commonly an over supply of suddenly grown wood. We should therefore, I think, increase foliage-stimulating manures on northern aspects, and diminish them on the southern and eastern, while we should have a medium degree of such manure in the case of western aspects. It seems to me that the reasoning in favour of foliage-stimulating manures on northern aspects is the same as in the case of coffee trees under direct tree shade, which always prevents the rapid growth of new wood. But on this point, as well as on that in the previous section, experiments must be made before any definite conclusion can be arrived at.
The quantity of manure that should be annually supplied is evidently a matter of the greatest importance, and here the first thing to be borne in mind is that of the four manures we require, namely, lime, nitrogen, phosphoric acid, and potash, the first two are somewhat easily removed from the soil, while the last two are firmly retained by it. It is evident, then, that lime and nitrogen should be applied little and often, while phosphoric acid and potash may be applied either little and often, or in large quantities at longer intervals, whichever may be found most convenient. But in the opinion of an eminent agricultural chemist whom I have specially consulted on the subject, nitrogen, if applied in slowly decomposing form, as for instance, in the shape of oil-cake, would only be lost in an infinitesimal degree, but still he admits that there would be a loss, and as we cannot tell what that loss may amount to under the influence of our tropical climate and deluges of rain, it would be safe to assume that nitrogen, as well as lime, should be put down at short intervals and, in order to make up for the escape of these manures from the soil, in larger proportions than either phosphoric acid or potash.