April i, 1889] THE TROPICAL AGRICULTURIST. 
Henaratgoda and Ambepussa ? Has he travelled 1 
through the length aud brendth of these districts and 
examined their soil and found everywhere slab rock 
underlying the surface soil ? I venture to think he 
has not, and because he perhaps has seen an occa- 
sional slab rock peep out of the soil, therefore he 
indulges in hasty generalizations aDd says that slab 
rock underlies all these districts. What authority is 
there for the statement that slab rock underlies the 
whole of the late Mr. Wilson's estate at Jaela ? 
What is the meaning of the statement that the 
soil of the above estate is so hard that it " will not 
take in manure"? What is done by it to the manure 
applied to the soil? Sent back to Colombo? Mr. 
Jardiue or Dr. Trimen said nothing about " feeding 
up" trees. Indeed, Dr. Trimen recommended nothing. 
Ke only threw out the suggestion that perhaps a 
basket or two of manure to the affected trees 
may do good. About working up soils during 
the " heavy monsoons " I have a very decided 
opinion, but I do not feel called upon to dis- 
cuss it just now. Why I wonder is it a "wastage 
of money and labour to apply manure during 
dry weather," and why will it not have effect on the 
trees ? What I wonder becomes of manure applied 
during dry weather ? Spirited away ? I suppose your 
correspondent meant to say the effect of such appli- 
cation will not be immediate. Well, if he did, it per- 
haps would have been better if he said it instead of 
leaving it to be guessed. 
It is no new discovery that the drought affects 
coconut trees in the upland districts more than those on 
low-lying lands on the sea-borde. The cause is not far to 
seek. Water is within easy reach of the roots of trees 
in the latter localities. A coconut tree is a huge pump- 
ing machine. It requires a large lot of water to mature 
its fruit and to make good the loss by evaporation 
from its leaves. When the supply is unequal to the 
demand, as a natural consequence the leaves droop 
As to the cause of the bunches requiring to be propped 
I have a theory. It is owing to an insufficiency of 
salt in the soil, for propping becomes necessary in 
inland districts even when trees grow in moist situa- 
tions, while on the sea-borde the stems are strong 
enough to support the fruit without the aid of a prop. 
It is very kind of " Planter " to give his opinion 
without being asked for it that " trees in the higher 
districts will not thrive for long," and that " after 20 
years they go down." On the contrary my observation 
goes to show that the older the tree grows the higher 
will it go up. If he refers to the roots it is true ; they 
are constantly going down, and my observation goes to 
show that the lower they {the roots mind you) go down, 
the better the chance for the tree resisting the effects 
of drought and being more fruitful. In the district 
from which I write the oldest trees are the best. No 
district suffers more from drought than the Mahaoya 
valley, and yet it is the district with the best soil 
among upland districts. I hope your correspondent 
will excuse my presuming to place the opinion of so 
inexperienced a man as Mr. Jardine against his. Mr. 
Jardine thinks we can go on for years without 
manure if we only unlock the vast stores of manure 
present in the soil. 
Let it not be noised abroad that all the proprietors 
of coconut estates in the condemned districts are in 
hot haste to part with their properties for what they 
will fetch. There is to be a general exodus and all 
are going to invest in coconut properties in the 
district from which your correspondent dates his letter. 
— Truly yours, B. 
SALT FOE COCONUTS. 
Veyangoda, 22nd March 1889. 
Dear Sir, — A grand mistake is made by those 
who say that because authorities rate low the 
manurial value of salt therefore the benefits of its 
application to coconut trees are problematical. The 
fact is lost sight of that every available authority 
speaks of salt only in relation to the cultivation of 
cereals, roots and grasses. Now all the salt these crops 
require (a very Bmall quantity) is fouud in the soil, 
be log carried to it by natural agencies. The case is 
different with the coconut, the home of which is the 
sea-shore, the soil of which is impregnated with salt and 
where the atmosphere must be heavily charged with 
saline particles. When extending the cultivation of 
this palm inland, none of the natural conditions under 
which it grows aud flourishes is present. In the 
place of the free sandy soil of the seashore we grow 
it iu a hard stiff soil, often with a hard gravelly 
bottom. On the seacoast the vertical roots have 
free access to water — an element that plays a no un- 
important part in its growth and development. In- 
land though the vertical roots are in a permanently 
damp soil, yet it is only the roots of the older trees 
that have access to sufficient water to mature their 
nuts and to replace what is lost by the leaves by 
evaporation. Last though not least the soil inland 
has perhaps about a hundreth part of the salt pre- 
sent in the soil on which the palm naturally grows. 
Actual analysis does not show I admit that a large 
quantity of salt is present in the ashes of the tree, 
but, as the late Mr. Davidson of Jaffna says, a pro- 
perty belongs to salt which chemical analysis cannot 
take cognizance of. I do not say that the soil in the 
inland districts is devoid of salt, for that would be 
nonsense in the face of the monsoon storms that sweep 
across the island. All I say is that perhaps it does 
not exist in quantities sufficient for the requirements 
of the tree, not only to be taken up as food, but also to 
play another important part, to which I shall pre- 
sently advert. Now agricultural chemistry teaches us 
that if the soil is deficient in one constituent of the 
food of a certain tribe of plants, that tribe of plants 
cannot flourish on that particular soil. I have given 
the habit of coconut trees in the inland districts, unlike 
those on the sea-coast, being unable uDaided to sup- 
port their bunches of fruit, a good deal of anxious 
thought. I am of opinion that this want of stamina 
is entirely due to an insufficiency of salt in the soil. 
In addition to salt being a direct fertilizer, it pos- 
sesses two very valuable attributes : one is its action 
as a solvent, the other its hygrosorptive properties. 
Salt, we read, sets free in the soil its inherent store 
of phosphoric acid, nitrogen and potash. In addition to 
this it renders silica soluble. So much for its great 
chemical value. It exerts as I said a great me- 
chanical influence as well. Its affinity for moisture 
is well known. Its application to a soil keeps it free 
and moist, and salt-saturated soil will absorb much 
moisture at night. This will be condensed during the 
day, and the vapour moving' in the soil will naturally 
be condensed on the coolest substance it will come 
in contact with — the roots. Experiments have proved 
that roots absorb moisture in dry weather in the form 
of tiny drops of dew deposited on their surface. 
Now as to the proper dose of salt per acre, a cor- 
respondent in your columns spoke of having applied 
£ bushel per tree to a few trees with wonderful 
results. At 70 lb. per bushel this will be 52 lb. 
per tree or 1 ton 14 cwt. 92 lb. per acre of 
75 trees. This seems an enormous dose — does n't 
it ? But I have an entry in my notebook that from 
one to two tons of salt per acre is injurious to 
vegetation. This refers presumably to cereals, root 
crops and grasses; but no sane man is likely to ex- 
periment with too large doses of salt and kill his trees. 
Half a ton per acre scattered broadcast over the 
wh< le surface of the soil after ploughing or working 
with the mamoty will, I am sure, not be considered 
an overdose. One difficulty in the way of asking that 
Mr. Drieberg, the Superintendent of the School of 
Agriculture, experiment with salt, is that the School 
is situate within the full influence of salt-laden breezes. 
If there be any effect on the trees then it will not be 
so marked as inland and on soils inclined to be stiff 
and clayey. I would apply salt not exclusively with 
other manures, but also as a top dressing to the soil 
to ameliorate its mechanical condition. Salt is said to 
act as a prophylactic against cattle disease. Why not 
kill two birds with one stone by applying it to laud and 
thus give it to them in the herbage ? B. 
[We, of course, never meant that Mr. Drieberg 
should oontine his experiments to the seashore. 
-Ed.] 
