764 
THE TROPICAL 
ArTRICULTTJRIST. 
[May 1, 1900. 
COCONUTS AND CHEMISTRY : 
A SHORT CONTBIBUriON TO THE 
CHEMISTRY OF COCONUT CULTIVATION. 
(By M. Cochran.) 
It eaunofc fail to be of some service towards 
tlie perfecting of the art of manuring the coco- 
nut tree, if we compare, in respect of the more 
important constituents (fiom an agricultural 
point of view,) what the crop removes from the 
soil with what is added in manures by ex- 
perienced |)!anters. 
There are several considerations which lead 
one to expect considerable diversity in the re- 
commendations of experienced ))lanters for the 
inanuring of coconuttrees, one of these is tlie great 
capability for incre ased yield which may legiti- 
mately be inferred from the great differences in 
the amounts of crop obtained from average trees 
grown under average conditions, and from trees 
grown under the most favourable conditions, 
thus, while the average crop all over the island 
is set down by some writers as between 14 and 
20 nuts per tree per annum, there are trees to 
be found growing under very favourable con- 
ditions of soil, &c, which are said to yield 
for years in succession at the rate of 400 nuts 
per tree per aniiuni. One writer in 1896, dat- 
ing from Dombawinne estate, Mirigama, stated 
the maximum yield of a cijconut tree as 900 
nuts in one year. Another reason for the diver- 
sity in manurial recommendations is the t.iet 
that, in some cases, only the oil and part of 
the poonac, in others only the copra, is sent from the 
estate, while in other cases the whole nuts and 
some ot the leaves are removed. 
One system of manuring has for its object to 
return to the soil an amount of fertilising 
material equivalent to that removed \ty the 
copra. Taking 170 lb. of poonac as the produce 
of 1,000 nuts, and reckoning the poonac to 
contain 3-3 per cent of nitrogen, 1'35 per cent 
of phos[>lioric acid, and two per cent of potash, 
there would be removed in the poonac from 1,000 
nuts 5 61 lb- of nitrogen, 2 295 lb of phosphoric 
acid, and 3 4 lb. of potash. Planters wlio manure 
expect to get as least 40 nuts per tree pei 
annum. One )>lanter informs me that he gets 
13 nut? per picking per tree, and there are six 
pickings per annum, so that he gets 90 nuts 
per tree per annum, I shall suppose that, while 
.'jome planters who manure get 40 nuts per tree, 
others get as many as SO. Each tree will at 
tiiese rates of production remove from the soil 
in co))ra (as estimated from the poonac) in two 
years respectivelj''. 
Trees Trees 
yielding yielding 
40 ijut9 per 80 nuts per 
annum. annum, 
lb. lb. 
Nitrogtn .. -4488 -3376 
Potash .. -272 -5440 
Phosphoric Acid .. ■1876 -3672 
It is necessary, however, to take into account the 
fertilising int-icdients removed from the soil in the 
husk, tlie ;-iiell and the "milk" of the rii>e nut. 
From analyses I have made I find that 
1,000 husks each weighing VlA'^ lb. 
1,00IJ shtils e:<.Lh weit;hiiig "GGG ,, 
.tJO lb. '"milk" or 4 lb. per nut remove from 
the soil. 
Nitrogen ., .. •2-6618 lb. 
Potash .. .. i:V4706 „ 
I'hoflpheric acid,. •6420 „ 
From these data, it is easy to calculate wliab is re- 
moved in two years by the husks shells and milk 
of 40 and 80 nuts respectively, and, adding the 
same to the quantities found in the poonac, we 
get : — 
Amounts of nitrogen phosphoric acid and potash 
removed from the soil in two years by crops of 40 
and 80 nuts per annum re.'^pectivelj'. 
Nitrogen .. .. -6007 lb. 1-3214 lb. 
Potash .. .. 1-3497 „ 2-6984 „ 
Phosphoric acid . . -2350 ,, -4700 ,, 
I shall now compare with these amounts of im- 
portant ingredients removed liy crop the amounts 
added to the soil by the different systems of 
manuring coconut trees as practised by experienced 
planters. First, vie niay consider the system of 
using the manure of cattle fed on the grass only 
of the coconut estate. This system, of course, adds 
nothing to the mineral ingredients of plant food of 
the estate ; but it should increase the amount of 
nitrogen available for the tree, and even the 
mineral ingredients are rendered more available for 
plant food by being assimilated, first by the herbage, 
and afterwards by the cattle. It will be interest- 
ing, therefore, to calculate the amounts of the 
fertilising materials that are clrawn from the soil 
by the grass, and converted into still more avail- 
able forms of plant-food by the cattle grazing cu 
the estate. For piactical purposes, the amounts of 
fertilising material in the grass may be taken as 
the same as that supplied in the manure seeing 
the cattle are not being fed with a view to being 
fatteneil. I have no exact data as to the quantity 
of grass produced on an acre of coconut field ; but 
I am informed by the well-known coconut planter 
Mr. Francis Beven, of Franklands estate, that 100 
acres of coconut land can grow grass for fiO to 70 
head of cattle. I also understand thac he con- 
siders 50 lb. weight of grass, per head per day, as 
good average grazing, when there is no <lrought, 
but drought must be taken into the calcula- 
tion, so I shall allow in this calculation 40 lb. 
of grass per head of cattle per diem. At this 
rate of consumption 65 cittle (the average 
per hundred acres) would require 2,609 lb of grass 
per day; and, to supply this, each acre would 
have to yield a little less than A\ tons of grass 
per annum. 
A sample of the grass on which the cattle on 
Frankl.ands estate graze was analysed. In tlie 
anhydrous state it contained nitrogen 1"740 per 
cent, potash 2 375 per cent, and plio.sphoric acid 
•487 per cent. If these results aie calculated 
into fresh grass containing 75 per cent, of mois- 
ture we get: — 
Fertilising ingredients in fodder Rraaa. 
per cent. 
Nitrogen .. .. 435 
Potash .. .. -594 
Phosphoric Acid . . "122 
An acre of the grass furnishing tons per 
annum would supply in the form of cattle 
manure in one year : — 
Nitrogen .. .. 41412 lb. 
Potash . . . . ae-.i.oO ., 
Phosphoric Acid . . 11 t>j.4 ., 
Taking 75 trees per acre each tree ge's per 
annum, and dniing three years respectiveiy : — 
perantuim. rlr.ucf; 3 jeai'S 
Nitrogen . . -552 lb. 1 6.5ij !b. 
Potash .. •7'>4 ., 2 2o2 ,, 
Phosphoric Acid -15.5 ,, •4W ,, 
Passing now to cattle shed nianare, we find 
that Mr. W B Lamont recommended, as the 
