8^38 
THE TROPICAL 
AaBIOULTURIST, [Nov. 1, 1902. 
ARTIFICIAL MANURING FOR TEA. 
[Paper read, September 2dth by Chairman 
Dimbula P. A. at General Meeting.] 
It may be within tlie recollection of some 
you that 15 or 16 years ac(o, I published the result 
of a series or manuring experiments on coffee as 
carried out on Yoxford estate. With the adviot 
of green hup;, coffee was wiped out and those 
experiments came to an end. Eight years ago I 
was able to commence a series of experiments 
on tea which have been in progress since, and 
winch have given me some insight into the 
principles Avhich should guide us in dea'ing with 
tea. This is my juslitication for addressing you to- 
day on the subject of manuring tea, which i^i I judge 
of interest to most of you, though probably soma 
already know as much as I do myself and perhaps 
more. I must commence by makina the admis- 
sion that I cannot give accurate scientific proofs 
of all my deductions. With coffee it was a com- 
paratively simple matter as the object was solely 
to find out how to produce the largest crop with 
the least injury to the tree, wliereas with tea 
it is, at least; as important to find out how far 
the quality is affected by the manure. Oa ihis 
latter point I have only been able to draw my 
conclusions from my general experience. Mr 
Alleyn says, I understand, that he lias been able 
to get to the bottom of the subject and has 
patented his information, which you wi'^l be able 
to buy from him shortly. He has been more 
fortunate than myself in being able to expend 
money on a large scale which is necessary for 
discovering how quality is best maintained or 
increased, along with the increase of leaf. We 
see fiequent references to manuring in the papers. 
Many seem to think that all manures should be 
suppressed by legislation as tending to over- 
production which is not only impracticable, but 
shows how little the true principles of manuring 
have been grasped. It is quite impossib'e to 
distinguish between manures which are sustaining 
and manures which are forcing, the difference is 
one of degree and not of kind. There are two 
systems of manuring in vogiie : the one is, mainly 
sustaining the object being to restore tlie 
natural fertility of the soil; the ofher 
is forcing, in that it teods to raise 
the production of an estate beyond what would 
have been its normal yield under the most 
favourable conditions. I regret to see the latter 
system has found its way into Dimbula, because 
this district has undoubtedly a flavor, and quality 
which I would wish to see it maintain and which, 
I believe, will be lost by the adoption of the 
forcing system. I believe it is quite possible t© 
manure in such a way as to keep the tea at a 
normal level of production combined with good 
quality and that it will pay better in the long 
run to work on this system. Such at any rate are 
tl»e conclusions I have arrived at after ten years' 
of experience of manuring tea and eight years of 
careful experiment. My first experiments were 
conducted with the object of finding out the 
most important element required in a manure for 
tea and were so arranged as to compare the results 
of adjoining plots of the size of one-sixth of an acre, 
by leaving out one element in each plot on the 
plan of M Ville. The important elements removed 
from the soil by the tea crop are nitrogen, 
phosphpric acid and potash, 1,000 lb. of tea re- 
moving 45 lb. of nitrogen, 8 lb. of phosphoric acid, 
and 22 lb. of potash. My plots were laid out, 
therefore, as follows: — 
No. 1 in manure ; No. 2 nitroEjeu alone ; No. ,3 
phosphate and potash ; No. 4 nitrogen, phosphate 
aad potash ; No. 5 nitrogen aad phosph ita ; No. '6 
nitrogen in excess, phosphate and pot'ash. ' : 
I was very soon convinced tliac the dominatiiig 
element was nitrogen. That is to say that without 
nitrogen phospheric acid and potash were almost 
inert. That for the best effect all 3 elements were 
required and more especially potash. That addi- 
tional nitrogen meant an increased yieLI, but did 
not invariably pay owing to the great cost of 
nitrogen. My further experiments have been 
directed more to finding out the most profitable 
mixture to supply and have not been carried 
very far as yet. The great cost involved has 
prevented my experimenting in the direction of 
finding out the effect of different manures upon 
quality and I have to fall back upon general 
conclusions from the obseivations of manur- 
ing on estates under niy own direction 
and that of others. My conclusions may not be 
considered at all convincing, but I give you them 
for what they are worth. The sources of nitroqen 
best known tons are sulphate of ammonia, nitrate 
of potash, castor cake, blood meal and fish manure 
of p/iosjiheric acid, bones ground or steamed, ba le 
slag and fish manure (super-phosphates are seldom 
used) of potash. Nitrate and sulphate of potash and 
kainit which contains about 25 per cent of sulphaie 
of potash. I have used my combinations of these 
manures, but for figures as to results I would com- 
mend to your notice Mr Joseph Eraser's published 
experiments which are by far the most complete of 
any I have heard of. As regards tlieir effect upon 
quality I give the preference to castor cake or a 
mixture of castor cake and blood meal as the 
source of nitrogen, for the reason as it 
seems to me that the effect is lasting and not too 
forcing ; blood meal alone is too forcing and 
quickly used up. Sulphate of ammonia has in- 
variably appeared to me to be accompanied by a 
loss of quality, whether iised by itself or in com- 
bination, though it may be only a coincidence. Fhb 
manure I have only used once, and I confess that I 
have a dislike to it as being too stimiilating in 
its effect and its use has seemed to me usually 
accompanied by a loss of quality. I imagine that 
its nitrogen comes into action inore speedily than 
its phosphoric acid, though it is very rich in both 
elements. Nitrate of potash is, I think, useful as 
a source of nitrogen and potash, the nitrogen 
coming into action very quickly but being speedily 
washed out in wet ^Veather. B isic dag I look 
upon as a very valuable source of phosphoric aeid 
and I .am inclined to endorse Messrs Freudenberg 
and Go's., statement that it tends to maintain 
quality in the tea owing to the two oxides of iroh 
which it contains. Bones either steamed or ground 
should, I think, form part of every manure mixture 
as the phosphoric acid contained in them comes into 
action gradually and is not too speedily used up. 
I give the preference to sulphate of potash as the 
source of potasli as being retained in the soil better 
than the nitrate. Potash, I consider, is a most 
important constituent in a manure if quality is 
to be maintained. Potash is known to have great 
effect upon the carbo-hydrates of plants, that is 
to say upon their main structure and ever since 
the time when I commenced my coffee experi- 
ments I have noticed that potash improved the 
health of the trees to which it was applied, . .! 
