Dec. 1, 1899.1 THE TROPICAL AGRICULTURIST. 
383 
previously considered identical with it. Vanillin often 
crystallises out on the pods in the foi^m of tine needle- 
shaped crystals — someumes only years after picking. 
The crystals notori.iusly influence the value of 
the article; they are regarded as a measure of quality. 
This measure is occasioaally misleading, as is de- 
monstrated by the fact that the finest Mexican 
Vanilla contains only 1-70 per cent. ; Vanillin. 
Mauritius Vanilla, 2'45 per cent.; Java Vanilla, 2-75 
per cent, and yet the first is by far the most 
valned. The explanation lies in the volatile oil which 
gives the special aroma, the products of Java and 
Bourbon being accomponied by another oil of pleasant 
odour. The percentage of Vanillin varies from 1 to 
2.75, with but few exceptions. 
Vanilla is usually packed in air-tight tin boxes 
in which it will retain its aroma for years. 
The quality may be estimated from the following 
points of view : — The longer and darker the pod, and 
the greater the quantity of crystals formed, so much 
the better are the goods. They should feel oily, and 
should emit a fresh, strong and pleasant odour. The 
pods in a box should be equal in length, not broken 
or in any way damaged. It must be preserved in air- 
tight vessels, as the aruma rapiJiy volatilises. Thfise 
conditions are not always compiled with in the retail 
trade; one result thereof is a regretably frequent 
adulteration of old odourless Vanilla with benzoic 
oil, which is said to restore the odour and oil of 
almonds to give the the suppleness. The most hard- 
ened deceivers go so far as to strew Vanilla witii salt 
to imitate the Vanillin crystals. 
A product of the plant, unknown in Europe, but 
prized in South America, is a juice which trickles 
from the fully ripe fruit, and is caught in vessels 
huug beneath. 
MANURING OF TROPICAL PLANTS -RICE. 
The two varieties of this plant— viz., water rice 
and upland rice— require different, soils and different 
climates. The first variety is more generally culti- 
vated, and requires a moist, clay, soil, that tan stand 
the necessary wateiing. Lighter soils should at least 
have a loamiy, impermeable subsoil. Upland rice, 
on the other hand, can be grown on a soil not quite 
so rich ; it stands dryness much better, and thrives 
also in less warm climates. 
The following quantities of plant-food ingredients 
are removed from one acre*: — 
By an average crop of Phosphoric Nitrogen 
Acid. 
16 3 lb. 
21-9 lb. 
26'2 lb. 
39-2 lb. 
2,676 lb. grains . . ) 
2,676 „ straw .. 128-1 lb. 
446 „ chaff .. ) 
By a good crop of 
4,014 lb. grains . . ^ 
4,460 ,, straw .. V45-7 lb. 
624 „ chaff .. j 
Very thorough investigations have been conducted 
by Prof. Kelluerf and others in Japan, as the ferti- 
liser requirements of water rice. In order to deter- 
mine the exhaustion of nitrogen, phosporic acid, and 
potash in the soil, a fertiliser trial was inaugurated, 
in which each plot received the following quantities 
of fertilisers to the acre . — ■ 
Plot 1 No fertiliser. 
,, 2 89 lb. phosphoric acid 89 lb. po'iish — lb. nit, 
3 — „ „ „ 89 ,, „ §9 „ „ 
4 S9 „ „ „ — „ „ 89 „ „ 
.. 5 89 n „ „ 89 „ „ 89 „ „ 
Nitrogen was applied in the form of snlphate of 
ammonia, phosphoric acid in the form of double 
superphosphate, and potash in the form of carbonate. 
The development of the plants corresponded to that 
of the previous years; the plants which had received 
a complete fertiliser grew best of all, showing a nor- 
* Lierke, praktische Diingetafeln, Berlin, Parey. 
t Imp. University of Agricultiue Komaba, Tokio, 
Japan, Bull. II, &c. 
mal green colour; next came the plants to which no 
pocash had been applied. The plants to which no 
nitrogen had been given were of a light-green colour. 
Phosphoric acid seems to have a very beneficial eiiect 
npon the growth of the plant, for the plants which 
had not received phosphoric acid differed but little 
form the nnfertilised plants ; they were of a dark 
green colour, but very small. The average yields 
from three check plots (the size of the plots is 
unfortunately not given) were as follows* : — 
fYields given in ounces.) 
Straw. Full grns. Empty grns. Total. 
No fertiliser ... 10-2 7 5 O'l 17-8 
Without nitrogen \&8 12 0 0 2 29-0 
Withont phos- 
phoric acid ... 13-1 9-5 0 2 22'8 
Without potash 22-2 14-6 0 4 37-2 
Complete fertiliser 27-5 20 3 0-3 . 48-1 
Investigations were also conducted, to determine 
the quantity of nitrogen available by the rice-plant 
when green manuring with a lagume {Astmc/alus 
lotoides, Lam. j is resorted to.f Astragalus was sowu 
in the autumn, and fertilised with different quan- 
tities of lime. In the beginning of May, when the 
plant was in full bloom, it was cut, weighed, and 
then turned under. The yield of green material was 
as follows : — 
Quantity of lime 
applied per acre 01b. 891b. 1781b. ,3561b. 
yield of astraga- 
lus per acre 8,99ilb. 16, 5731b. 16,3411b. IS.iSll-b. 
The conclusion can thus safely be drawn, that as- 
tragalus responds well to lime fertilisation, though 
89 lb. per acre were sufhoieut for the soil in ques- 
tion. The leguminous plauts analysed 12'23 per cent, 
dry matter and 0'3()9 per cent, nitrogen ; the pla'nta 
from the plots fertilised with lime contained 2,266 lb. 
dry matter and 69 lb. nitrogen per acre. In addi- 
tion to the green manuring, 98 lb. of phosphoric acid 
in ihe form of phosphate of soda and 89 lb. of potashin 
the form of carbonate were applied. The yields from 
the separate plots were as follows : — 
Fertilisers Applied Yields per Acre in lb. 
per Acre. 
Straw, p^"" Empty. TotaK 
Grains. Grains. Yield. 
Potash and phosphoric 
acid without nitrogen 0-478 3-631 0 029 0-849 
Potash and phosphoric 
acid, green manuring 
without lime ... 0 556 5-141 0-037 0-973 
Potash and phosphoric 
acid, green manuring 
with 89 lb. lime ... 0-747 5-653 0 047 1-315 
Potash and phosphoric 
acid, gieen manuring 
with 1781b. lime ... 0-736 5'497 0 049 1-291 
Potash and phosphoric 
acid, green manuring 
with 356 lb. lime ... 0-767 5-764 0 041 1-348 
Potash and phosphoric 
acid, complete fertili- 
ser with 473 lb. sul- 
phate of ammonia ... 0 870 5-692 0-068 1-416 
Gieen manuring increased the yield considerably 
especially on the plots that had received lime. The 
complete mixture of artificial fertilisers produced 
just as good yields as the' green manuring; as in 
green manuring the nitrogen in the atmosphere can 
be utilised, this method is naturally less expensive 
and hence more profitable. 
A similar experiment with green manuring was 
conducted with another nitrogen-gatherer — viz., indigo 
{JiitJigoJeia tivctoria) — in the botanical garden at 
Biiitenzorg, Java.| 
* "Jahresberioht fiir Agriculturchemie." 1892, p. 250. 
t "Jahresberioht fiir Agriculturchemie," 189Ii p. 172, 
J " Verslag omtrerit den 'Staat von "Stands plauten- 
tuin" te Buiteuzoig ofer het Jaar 1894, Batavia 
1895, page 42. . 1 ,1 
