PART IV. J
per tree above the control. Moreover it was found that the complete
manure was essential; if the ntirogen or potash was omitted there was
only a very slight gain in the crop.
In the Annual Report of the Director of Agriculture for Ceylon
for 1915 there is an account of some experiments in manuring coconuts.
In Ceylon the soil is deficient in phosphoric acid, also the ratio of
phosphoric acid to nitrogen is low.
It was found that complete manure raised the yield of nuts from
29 to 57 per tree per annum (969%) and a complete soluble manure
every six months raised the yield from 23.4 to 54 per tree per annum
(13195). A leguminous mulch with basic slag and kainet in equal
parts, 400 lbs. per acre raised the nuts from 80.7 to 56 per tree per
annum. It was also found that manure increases the power of the
tree to retain its nuts.
Working from the results obtained in Ceylon and Porto Rico a
small series of experiments was begun a year ago to test the effect of
certain manures on excessive nut fall and gummosis.
Expt. 1. Effect of a complete manure consisting of :
11 Ibs. muriate of potash;
5 lbs. basic slag;
3% lbs. nitrate of lime per tree per annum.
Expt. 2. Effect of above with the nitrate of lime omitted.
Expt. 3. Effect of 10 lbs. of poonac per tree per annum. This
is a composite but not complete manure which is
available at a low price in Zanzibar, whether it is cheap
as a manure remains to be tested.
Expt. 4. Effect of 40 lbs. of lime per tree every three years.
Expt. 5. Effect of 3 Ibs. of coconut husk ash per tree per annum.
Expt. 6. Effect of 6 Ibs. of coconut husk ash per tree per annum.
In accordance with the results obtained in other countries and
already described, no increase has been found in the crop during the
first year.
In June, 1925, the D. of A. with another purpose In view manured
three plots respectively with muriate of potash, sulphate of potash and
superphosphate; these plots are also under observation to see what
effect if any, these single manures have on excessive nut fall and
guMmMmosis.
It will be another two years at least before the experiments yield
conclusive evidence that starvation is, or is not, the chief cause of
excessive bud fall. The balance of the evidence from this and other
countries is that there is at least some connection between them.
MecHANICAL INJURY AS CAUSE OF DISEASE.
Mechanical injury may check the flow of sap and so cause the
starvation of certain buds and inflorescences. In Ceylon, Gadd
considers that mechanical injury such as the fracture of the peduncle
is the cause of excessive bud fall. An examination of a large number
of inflorescences bearing aborted flowers or diseased nuts, did not
reveal the presence of any such injuries; similarly the examination
of a number of unopened spathes did not result in the finding of
caterpillars or other insects damaging the stalks or flowers. In Malay
both Batrachedra arenosella and Tirathaba damage many of the
female flowers within the spathe

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