340 



THE AGRICULTURAL NEWS. 



OCTOBEE 30, 1909. 



INDIAN FRUIT. 



THE MANURING OF CACAO. 



The following is taken from the seventh of a series 

 of articles bv J. PI. Hart, F.L.S., on Caean, which 

 are appearing in the West India, Coininitt.ee Circulur. 

 Reference lo these articles has been made already cm 

 pages 260 and 292 of the present voUiine of the Af/ri- 

 cidtural News: — 



The application of manure is a .suliject upon which 

 chemists and vegetable physiologists difl'er in many respects. 

 The chemist is apt to insist upon the manure being buried 

 beneath the .soil, or, he says, inuch nf its value will be lost 

 owing to the dispersion of its volatile properties by moving 

 air ; but the cultivator may easily ascertain the best method 

 of applying manures of all kinds, if he studies the life history 

 and character of the plant, and the nature and morphology 

 of its organs of assimilation; and moreover, the frequent 

 showers of the tropics prevent any great waste of the volatile 

 constituents, unless they come -so heavy as to wa.sh them away. 



The destruction of roots which the operation of burying 

 manure occasions, would, in most instances, completely nullify 

 the action of the manure applied, as the broken roots would 

 not have the power, or the same amount of surface for 

 absorbing food, as when uninjured; and the manure applied, 

 through its coming into direct contact with injured tissue, 

 would tend to destroy the roots by its caustic character, 

 rather than to be absorbed by them. That beneficial results 

 follow the application of manure when buried beneath the 

 surface, is, of course, patent to the novice, but in the case of 

 surface-feeding plants, it is only afti-r the roots have recovered 

 from the injuries done by the digging, that they arc able to 

 take up any manure which has been applied when these 

 organs are again in a condition to pciform their proper 

 functions. Even granting that no s[)ecial harm is done to the 

 trees, there is inevitable delay in the economy of growth, the 

 hazard of losing a flowering season, and consequent loss of 

 crop. 



With dccp-rooting plants tin- burial nf manure is the 

 most economical method of application, as there can then be 

 no loss of volatile constituents. ., 



If we think over for a while the course which Nature 

 ha^ pursued for ages in supplying plants with their food, we 

 shall find that the method adopted is purely surface maiuu'ing, 

 and this method, with not a few modifications, is generally 

 being adopted in what are called Orchard Cultures. h;ven 

 the ground the plant grows on, has been almost entirely 

 formed, by additions to its surface, by detritus from .surround- 

 ing lands, by deposits made by Hood waters, or by decay 

 induced by the How of water over its surface carrying with it 

 solvents which are able to disintegrate the materials of whicli 



it is coiiipn.sed. For tree cultivation, surface manuring is tlie 

 only method in wliich the manure can be fully utilized, and 

 \ve can easily take steps to guard against evaporation or 

 dispersion of volatile principles, by covering the manure with 

 inateiial which will act as an absorbent and thus retain the 

 constituents likely to escape. 



In practice, the covering of the ground with fresh or 

 decaying vegetable material is known as ' mulching ', and it 

 has been proved that for cacao the practice is of the greatest 

 value. 



iJr. Francis Watts, L'.M.G., Imperial Commissioner of 

 Agriculture for the West Indies, in reporting on experiments 

 in Dominica, has the following, with reference to five experi- 

 ment plots of cacao : ' The most interesting plot is the one 

 mulched with grass and leave.s, tlie sweepings of the lawn 

 at the Botanic Station. In the first period, this plot, though 

 giving a greater yield than the no-manure plot, fell far behind 

 the plot receiving dried blood, or the plot receiving conqilete 

 nianuie, viz. dried blood, i)hosphate and potash (2 A) and 

 that receiving dried blood with [ihosphate and potash (-1 E). 

 The yield was practically identical with that from the plot 

 receiving dried blood alone (3 B). In the third year, this 

 plot far surpassed all the others, giving yields G6 per cent, 

 greater than that obtained from the no-manure plot.' 



In the Botanical Depaitment, Trinidad, for many past 

 years, mulching has been taught as a valuable method for 

 orchard culture of cacaO and other produi-ts, and in Vol. V, 

 Jlot-Diicfil llidletiti, Trinidad, 190l'-.j, the following beneficial 

 etfects are recorded, viz., that mulching: — 



( 1 ) Kee])s down weed.s. 



(2) IVevents evai)oration, and keeps ground moist. 



(3) Furnishes suitable manure in gradual sup[ilics. 



(4) Attracts earth worms to the surface, and cau.scs them 

 to cut numerous burrows, which aerate and cultivate the soil ; 

 in fact the worms actually manure it by carrying down into 

 the tunnels the decomposed organic matter. 



T>y the u.so of ' mulching,' it is certain that cacao can be 

 grown successfully on lands that could not produce it otherwise; 

 and on some of the large estates the practice is lieing adopted, 

 especially on those fields which suffer during tlu' dry se.uson. 



The cacao tree, although it likes a deep, rii li soil, is also 

 a surface-feeding plant, and the grinind round the trees 

 cannot lie dug or forked witli impunity, for, although the 

 tree will stand considerable hardship, it is neviTtheless 

 materially injured when the roots are mutilated. There are 

 conditions, however, such as when the surface soil lias been 

 thoroughly baked by drought, when it would be benclicial 

 to lightly prick it up with a fork, taking care not to break 

 the roots (vertical forking). A slight forking is, liowever, 

 permissible at times, previous to applying farmyard manure 



