8i 
THE TROPICAL AGRICULTURIST. 
[Aud. 1, 1902. 
■were compared with an nnmanured plot. Dried blood 
gave the largest yield and ihe best financial returns as 
a source of nitrogen. The tobacco grown without 
fertilisers ripened ten days to two weelis later than that 
.grown with fertilisers. 
Influence of Time of Harvesting. — These experiments 
were underdaken at the Wisconsin Station to deter- 
mine whether the tobacco leaf increased in size and 
thickness, and whether the loss in curing diminishes, 
when th,i plants are allowed to stand a considerable 
time after topping. 
The results showed that when the plants were per- 
mitted to stand 32 days, as against others allowed to 
stand only 18 days, the thickness and dry matter 
of the leaf tended to increase, and the yield has 
a like tendency, i.e., after curing, a greater weight 
of the leaf was obtained, but the area per pound of 
leaf wxs less. 
It was thus possible to vary the commercial grade, and 
influence the price considerably, by harvesting the crop 
at different stages of maturity. This w.i s one of the 
methods by which the quality of tobacco might be sen- 
sibly cotrolled. 
Effect of Priminc) Tobacco Pteis.— Priming, which 
consists in removing the leaves from the stalk of tlie 
plant aa. thev mature, has a marked effect on the erowth 
and chemical composition of the upper leaves. Tbe re- 
moval of the lower leaves causes an increase of growth 
in the upper, and also a hieher percentage of nitrogen- 
ous matter and nicotine. Priming is believed by many 
practical growers to be the proper method of harvest- 
ing the cigar-and cigarette-types, for in this way the 
leaves are uniformly matured and the subsequent pro- 
duct is consequently of a more uniform character. 
The priming of tobacco is more expensive than 
cutting the stalk, as more labour is required, but 
the improvement in quality fully warrants this addi- 
tional cost. 
Experiments in Topping Tobacco were conducted at 
the Central Experimental Farm at Ottawa, Canada, 
in order to det^mine how the time of topping, 
and the number of leaves left on the plants, affect 
the yield. The plants were topped July 20th and 26th 
and August 2ad, and on each, date one plot was cut 
back to nine leaves and another to eleven leaves per 
plant. The larger yields were obtiuned from the latest 
topping, and the greater number of leaves per 
plant. The time and manner of topping has a great 
influence upon the character of the leaf produce. As a 
ru"e the earlier a plant is topped and the lower it is 
cut, the heavier, richer and darker-coloured the leaves 
become. This is a decided advantage for some crops, 
but a disadvantage to others. 
Disease of Tobacco.— Ihe disease to which most at- 
tention has been given manifest themselves during the 
curing process, and are commonly known as 'stem 
rot" and " pole burn " or "pole sweat." The latter 
makes its appearance as small dark spots on the sur- 
face of the leaf near the veins and midrib, where mois- 
ture is most abundant. The disease is supposed to be 
primarily due to a fungoid growth which attacks the 
leaf on the surface and gives access to a bacterial pro- 
cess of decay by disintegrating and partially destroy- 
ing the leaf tissue. It has been ascertained that mois- 
ture and temperature have a marked effect on the 
activity of these organisms. Decreasing the omount 
of moisture lowered their vitality, and a temperature 
up to 70°F. or even 90° F. favoured their development, 
while a temperature of over 100° or 110 °F. and below 
35° or 40° F. temporarily or permanently checked their 
vitality. 
From investigations it was concluded that nnder the 
atmospheric conditions most favourable to the deve- 
lopment of " pole sweat " the temperature and mois- 
ture in the interior of a closed barn could be regu- 
lated by artifiicial heat so as to reduce to a minimum 
the liability of tobacco to damage from fungi or other 
like organisms. 
" Stem rot " is a fungoid disease which frequently 
(tStpsts the stems of tfae plants iu the laat stage of 
curing. No special experiments were made upon this 
disease, but as a remedial measure it was suggested that 
when the crop is cureri all stems and refuse attacked 
by stem rot be burned before the fungus has matured, 
and the barn furcated with sulphur immediately after 
curing, and agam before the harvesting of the next 
season's crop. 
Experiments m curiiig Tobacco.— loha.'ico goes through 
certain processes of fermentation from the time it is 
cut until it is ready for the manufacturer. During this 
time it is said to be curing and ageing, After the 
harvest the leaves are speared upon laths and huug in 
a barn to dry. Artificial heat is often employed for 
this purpose. Experiments with different methods of 
curing tobacco have been conducted at several experi- 
mental stations. At the lN'or^■h Carolina station, the 
ordinary method of cutting down the plant and curing 
it with tlie leaves on the sta'k proved less profitable 
than curing by the Snow process, in which the leaves 
are cut from the stalk as they ripen, and cured sepa- 
rately. A greater yield was obtained with the tobacco 
cured by the leaf process and the quality was better. 
This effect is ascribed to harvesting the leaves as they 
became mature, while, by the stalk process, many of 
the lower leaves were over-ripe, and the upper leaves 
still green at the time of cutting. It was found that 
the time and temperature required for curing leaves 
from different parts of ihe plant varied accord'ng to 
their ripeness, and for this reason the leaf-curing 
provided the most desirable method, as the leaves were 
all of the same degree of maturity. At Wisconsin it 
was found that the loss of water in curing was about 
71 per cent, of the weight of green leaf. 
It is stated that the chai^ges in the colour of the leaf 
during the curing process were not directly due to the 
loss of moisture, but depended largely upon the degree 
of ripeness — the riper the leaf, the lighter in colour it 
would be when cured. 
Prom data obtained in this work it was concluded 
that tobacco should be cured in as moist an atmos- 
phere as possible, without incurring damage from 
" pole burn." A temperature within the curing house 
not exceeding 75° F., and a degree of humidity 
among the plants represented by a wet bulb depres- 
sion of 2 ° , were regarded as suitable conditions. In 
order to maintain these requirements, the plants 
should be evenly distributed in the curing-house, in 
order to equalise the humidity of the building, and 
the ventilation should be under perfect control, with a 
provision to regulate the humidity of the air by the use 
of artificial heat. 
Fermentation of Tobacco. — The fermentation or 
sweating of tobacco is carried out in several ways. To 
give a general idea of the method of procedure, that 
followed in Florida may be cited. After the tobacco is 
cured, tbe leaves are stripped from the stalk and 
made up into hands, i.e., bundles tied together at the 
base. These hands are either piled on the floor or put 
into bins, and the fermentation allowed to proceed 
gradually. The temperature of the pile gradually rises, 
until it roaches its maximum, which is sometimes aa 
high as 180 ° F. From this point the temperature 
gradually subsides, and finally attains the normal 
temperature of the room. 
In connection with the changes which take place 
during the process of fermentation, most attention has 
hieherto been given to the loss in weight of the leaves 
and to the chemical changes which occur. At Con- 
necticut State station the weight and chemical com- 
position of cured and fermented leaves was compared. 
The loss in the fermentation of upper leaves, short 
seconds, and first wrappers was 9 7, 12"3 and 9"1 per 
cent, respectively. About three-fourths of the loss in 
the short seconds consisted of water, the upper leaves, 
lost almost the same proportion in dry matter, and in 
the first warppers the loss of dry matter was a little 
less than that of water. 
The nitric acid, ammonia, fibre and starch contents 
of the leaves were affected very little by the process 
of fermentation, and the chief loss of dry matter was 
foand to have ocQucred in the nicotine, atbuminoicls, 
