9 
12. Mulching with leguminous weeds and twigs plus 
complete fertilizer (Biogine Truffaut). 
13. Control plot. 
In these experiments all costly manures have been excluded 
even stable manure which, after all, it is difficult to obtain on 
a large scale except at prohibitive prices. Concentrated com¬ 
plete and soluble manures are alone used especially the complete 
fertilizers of the firm Truffaut of fixed composition, which are 
already known to most planters. All chemical manures cannot 
be employed in vanilla culture, those full of organic matters 
may by fermentation cause the decay of the roots or from their 
bulk be considered too expensive for transport reasons. Three 
other sets of experimental plots are being prepared and as soon 
as the war is over it is hoped that more money will be devoted 
to them. Until now no extra expenditure has been incurred. 
This is not so easy to care for as most planters imagine. 
A series of experiments were outlined and started by this 
Department 12 years ago. A few promising results were 
obtained and recorded. Some of these were reproduced in the 
Bulletin of the Imperial Institute for 1909 and in a standard 
book on Spices by II. H. Ridley, F. R. S. But from want of funds 
the experiments were stopped and at various times I was asked 
to lesumethem. As the yanilla vines under experiment have 
to be planted in homogenous soil properly walled in and even 
in cemented basins one can imagine that they must be attended 
to continually and that the experiments when once started 
should on no account be altered or discontinued. 
The necessity of growing vines of equal strength, in 
walled in plots where the soil is rendered homogenous, pre¬ 
cludes the experimental plots being too large and for this 
reason a scheme had to be adopted which provides for their 
duplication and even triplication without which no scientific 
experiment is possible. Furthermore the manuring experiments 
must preferably be made in cemented basins, as stated the first 
time they were started in 1903. Yanilla culture is not possible 
without shade, shelter and live props of some sort. Those 
employed for that purpose, when once the manure is spread 
very soon produce an abnormally high number of rootlets 
which find their way to the fertilizers. The poor orchid is 
thus deprived of a great part of the manure upon which the 
experiments are based, and it also suffers from the effect of 
the network of rootlets hindering its growth. 
A separate experiment has also been made in a bed mea¬ 
suring 22 feet long in which 22 vines have been set out at the 
same time. In this plot the props used were cuttings of 
Gliricidia maculata and in the other plots the usual Pignon 
dTnde (Jatropha curcas) props. The experiment was tried to 
determine the influence of the newly introduced shrub as a 
vanilla prop. The rapid growth of this leguminous shrub, its 
resistance to diseases and to adverse conditions of soil and 
climate and the ease with which the cuttings strike roots in all 
classes of soil render it an ideal one for vanilla culture. So far 
it has been successful, its abundant foliage being at least 10 
times more vigorous than that of the Pigeon d’ln le without 
being either too heavy. After 2 month.? growth it has been 
possible to set the vanilla vines on the props and at the time 
of writing, i.e., 8 months after the cuttings were pl mted out, it 
becomes necessary to prune the shrub and thus obtain with the 
primings an excellent mulch on the spot for the orchid. It 
remains to be seen to what extent its rapid growth will dry up 
the soil in absorbing too much moisture in time of drought. 
However there is no indication so far that the vanilla vines are 
suffering in the least from deficiency of moisture although 
the plot is fully exposed to the sun. In comparing this shrub 
with all the others used as vanilla props in the low country one 
is struck at once by the possibility of making in a short time 
a vanilla plantation in fully exposed situations without having 
to plant any trees to shade the vines beforehand. I do not 
think any other shrub used hitherto can benefit a shade 
loving orchid in the same way, especially when one considers 
that it is a leguminous plant capable of fixing atmospheric 
nitrogen and improving the soil itself. 
The following props were uprooted after nine months 
growth to examine the root system of each and consider 
their suitability as props for vanilla. 
