THE CULTURE OF TOBACCO.—-NO. I. 
169 
nitrogen, and the larger the supply of vegetable 
mould, the richer the plant becomes in these bod¬ 
ies, as well as the oil to which it owes its odor and 
flavor, which is also nitrogenized. 
But the supply of an increased amount of nitro¬ 
gen is not the only office that vegetable matter 
performs in the soil. Those writers who have 
treated of the subject have omitted the most im¬ 
portant function. It is notorious that in our coun¬ 
try no tract of drained land which is rich in vegeta¬ 
ble mould is sterile. Yet the same fields when 
impoverished lose their fertility, and may be re¬ 
claimed by a new addition of vegetable matter. 
This is true of most lands in new countries, the min¬ 
eral basis of which has not been much altered by 
cultivation. 
What then are the changes produced by the 
presence of vegetable matter in the soil that it 
should be so suited to fertilize lands ? The min¬ 
eral or bare soil consists of many chemical bodies 
insoluble in pure water, and yet essential to plants; 
such are bone-earth, earbonate of lime, and pot¬ 
ash, which is present as a silicate. No insoluble 
substances can pass through the roots of a plant, 
they must therefore become soluble. As long as 
the earth is naked this takes place with extreme 
slowness, and only by reason of the carbonic acid 
present in rain-water, which gives it the property 
of dissolving a small quantity of bone-earth, (phos¬ 
phate of lime,) and carbonate of lime, and changes 
the silicate into soluble pearlash, (carbonate of pot¬ 
ash.) These changes are essential to the growth 
of plants; but on bare lands they take plaee to so 
limited an extent, that only slow-growing vegeta¬ 
bles can appear thereon. But in soils rich in 
mould, there is constantly produced by its decay 
large quantities of carbonic acid, which acting in the 
same way as that present in rain, causes a very 
much larger proportion of the same minerals to be¬ 
come soluble, and fit to sustain the growth of plants 
by supplying them as fast as they are required. All 
American soils are rich in these insoluble mineral 
substances, although their quantity varies; it is, 
therefore, not surprising that the addition of vege¬ 
table matter, by rendering them capable of entering 
the roots of plants, should confer fertility. 
The presence of vegetable matter in tobacco- 
lands has a two-fold influence in supplying the ne¬ 
cessary amount of ammonia and nitric acid, as 
well as rendering potash, &c., soluble with suf¬ 
ficient rapidity, and this last property is much the 
most important Tobacco planted out in June ri¬ 
pens by the middle of September; in less than 
three months it has taken up from the soil its min¬ 
eral matters. The commercial specimens contain 
about 17 per cent, of ash, and an acre may yield 
about one thousand pounds, it therefore contains 
170 lbs. of ashes, drawn from the soil in that short 
time, all of which must have become soluble. 
But before I leave the subject of vegetable mould, 
it is necessary to remark, that the term humus ap¬ 
plied to it by speculative agriculturists, has intro¬ 
duced a great deal of confusion into the science. 
Humus, regarded in a chemical sense, does not 
exist in the soil, for it is pure vegetable matter in 
a certain stage of decay ; whereas, every particle 
of mould contains mineral matter, such as potash, 
bone-earth, gypsum, &c., which are by no means 
to be overlooked in treating of its action on plants. 
The property of forming carbonic acid, and 
thereby rendering the insoluble bone-earth, silicate 
of potash, and carbonate of lime of the soil soluble, 
belong to humus ; but as the vegetable matter de¬ 
cays, the mineral substances belonging to the leaves 
or roots from which it has been produced are also 
liberated and become food for the crop. 
When tobacco is planted in newly cleared land, 
it is furnished most liberally by the dead leaves 
with ammonia, nitric acid, and the mineral sub¬ 
stances present in them, independently of the soil; 
but in addition to this supply, the insoluble sub¬ 
stances of the earth are rapidly rendered soluble 
to give it a further quantity of food. So long as 
the forest stood, it showered in every autumn its 
leaves as a top-dressing to the land. They con¬ 
sisted of vegetable matter, in the texture of which 
mineral substances were closely imprisoned, and 
liberated only with the slow decay of the leaf. 
The decay was slow, because during the warm 
months the ground was sheltered by new foliage; 
but as soon as this covering is removed, the hoe 
used to loosen the soil, plants with little shade in¬ 
troduced, the decay is rapid, and the supply of 
food keeps pace with it. These are the conditions 
which are requisite in poor lands for a tobacco 
crop, and as soon as they have ceased, its culture 
is arrested. In rich loams, where the solution of 
the minerals of the soil is much more rapid, and 
where 10 to 20 per cent, of vegetable matter is in¬ 
corporated in the earth, tobacco may be obtained 
for many years, but it is always an exhausting 
crop. 
It has been stated that 170 lbs. of mineral mat¬ 
ter are removed in less than three months by a 
crop of tobacco from one acre of land. This is 
very much more than wheat or other grains carry 
off in eight or nine months. Thus wheat planted 
in October and cut in June, takes from the soil of 
the same mineral substances 22 in a crop of 20 
bushels with straw. In these estimates the sand 
or silica is omitted, inasmuch as its supply is too 
great in all soils to cause any fear from exhaustion. 
The important mineral substances present in 
Havana tobacco examined by Hertwig, (Liebig’s 
annealon for April, 1843,) are: 
Salts of potash.34.15 
(£ lime.51.38 
te magnesia.... 4.09 
Phosphates. 9.04 in 100 parts ashes. 
These substances were for the most part insoluble 
in the earth, and must have been dissolved during 
the growth of the crop. 
We have now arrived at a clear view of the 
cause of sterility in lands as respects tobacco — 
saline substances and ammonia are not rendered 
fit for food icith sufficient rapidity. We also see 
why a large amount of dead leaves, or other 
vegetable rubbish will yield a crop, by giving 
up to the roots a sufficient quantity of these 
bodies. 
The great question is, whether there are* eco¬ 
nomical means by which land which has lost the 
power of sustaining tobacco, can be rendered fer- 
