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acid.

It is well known that the external tissues of all growing
plants become more or less charged with earthy salts, espe-
cially carbonates of lime and magnesia with some phosphates,
which have been carried from the soil to their surfaces in solu-
tion in water containing carbonic acid (which is in all the water
of the soil) and left there in a form insoluble in water upon
the escape of that acid and the evaporation of the water which
brought them up. As all the moisture of the fertile earth
contains this solution, which is drawn up and evaporated from
the general surfaces of the plants exposed to the air, it can
readily be seen, that because of the greater evaporation and
the more concentrated nature of the soil solution, in the dry
season, there must necessarily be a larger accumulation of this
surface deposit in the dry than in the moist or wet season, when
evaporation is measurably checked. For the same reason the
ash per centage of the leaves and bark of plants is greater than
that of the interior parts, and that of the leaves of deciduous
plants greater than that of the leaves of evergreens, which
give off less water by evaporation.

The effect of this evaporation has very justly been com-
pared to the deposit of the limestone crust in the steam-
boiler and the formation of stalactites in caves ; and this
irregular increase of the ash per centage causes many appa-
rent discrepancies in the mineral ingredients of plants, and
increases the difficulties in the chemical study of plant nourish-
ment; for while it is generally admitted as fully demonstrated,
that certain mineral ingredients, to be found in the ashes of all
vegetables, are essentially necessary to their growth, it must
be acknowledged that some or some portion of these ingredi-
448



THE HEMP AND BUCKWHEAT PLANTS, &C. I I

ents are of no more significance than the incrustation in the
steam-boiler; being mere accidental deposits on the surface,
the result of the escape and evaporation of the agents, water
and carbonic acid, which held them in solution in the sap of
the plants and in the water of the soil.

In the same manner may we explain the influence of a dry
season in increasing the fertility of the surface of the soil ;
the soil solution, on the evaporation of the water, leaving its
dissolved salts and other ingredients upon the surface ; so
that seasons of long drought are usually followed by others
of great productiveness when there is sufficient moisture.

The larger ash per centage of sample C is mainly due to
this cause; the leaves not having fallen, which yield a very
large proportion of ash.

The ashes of samples D and E, grown on the old land in
the very dry season, while not differing much in their general
weight-proportion to the dried plants, show more lime and
less alkalies than that of the hemp grown on the richer land.
For some reason not immediately apparent, perhaps because
of a previous buckwheat crop, they gave rather more than the
average quantity of earthy phosphates.

In the usual mode of management of the hemp crop the
leaves mostly fall on the ground on which it is grown. A
large proportion of them drop before the hemp is cut, more
fall when it is spread on the ground to dry after cutting, and
when it is taken up to be stacked. It would be well, doubt-
less, to beat off, in this process, all the leaves that can thus
be separated, so that they may be more regularly distributed
over the soil than if thrashed off when stacking it. It is also
the general practice now to cut the hemp as nearly as possible
to the surface of the ground, and leave the roots, with a few
inches of the stem attached, to rot in the soil.

In order to ascertain the relative fertilizing influence of the
leaves and roots, three hemp plants were collected, July 25th,
1864, in the dry season, from the rich field above described.
These, one male and two female plants, were about six to

449



12



CHEMICAL EXAMINATION OF THE ASHES OF



seven feet high. The leaves, stems, and roots, carefully sep-
arated and thoroughly air-dried, weighed as follows :

The leaves weighed 23.916 grammes, equal to about 30. per cent, of the whole plant.

The roots " 7.433 ' " 9.3

The stems ' ' 48 . 430 ' ' ' ' 60 . 7 ' ' ' '

These were separately incinerated and their ashes analyzed,
with the following results :

TABLE II. OF THE RELATIVE ASH INGREDIENTS OF THE LEAVES, ROOTS,
AND STEMS OF THE HEMP, CARBONIC ACID EXCLUDED.





THE LEAVES.


THE STEMS.


THE ROOTS.


In 100 p'ts
of ash.


In 100 p'ts
of dried
leaves .


In loop'ts
of ash.


In 100 p'ts
of dried
stems.


In loo p'ts

of ash.


In 100 p'ts
of dried
roots.


I ime . .


48.819

5.726

27-955
.236
9.264

2.209

.171

5.620


4.992

.585
2.858)
.024 /

947
.226
.017

575


23-371
5-803

49-599

13-374

1 .215

.576

1 .062


0.949
.194

1.659

447
.040
.019
-035


20.368
8.297

5 2 - 2 33
I5-I64

J-344
.405
2.189


0-7'3
.291

1.829

531

.047
.014
077


Magnesia . .


J'otash


Soda ....


Phosphoric acid


Sulphuric acid


Chlorine


Silica




Per cent, of phosphates


19. 1 60


1-959


28.158


0.942


26.885


0.949




Per cent, of ash




10.225




3-346




3.502







By examination of the above table it is to be seen, that the
leaves of the flowering hemp contain more of the essential
mineral ingredients of the soil than all the other parts of
the plant ; constituting, as they do, about 30 per cent, of the
whole plant in the air-dried state, and yielding 10.225 per cent,
of their weight of ash, the carbonic acid being excluded ; while
the stems and roots, which together form the remaining 70 per
cent, of the weight of the plant, give an average of less than
3.5 per cent, of ash.

Nor is this great excess of the ash proportion in the leaves
due entirely to the influence of the greater evaporation which
takes place on their surfaces, causing a deposit or incrustation
of lime and magnesia salts and silica of the nature of stalag-
mites ; for we see that whilst the amount of silica in the leaves
is nearly fourteen times greater than that in the stems, and

45



THE HEMP AND BUCKWHEAT PLANTS, &C. 13

more than seven times greater than in the roots ; the lime
more than five times as great as that in the stems, and seven
times more than in the roots ; the magnesia three times more
than that in the stems, and twice as much as that in the roots;
ti\z. phosphoric acid 'and phosphates and the alkalies are in nearly
double proportion in the leaves also, and the sulphuric acid
five times greater in them than in the stems, and about four
times greater than in the roots. So that whilst the leaves,
when in their fully matured state or when they naturally fall,
may possibly contain scarcely any but the less soluble salts
which may be left in their tissues on the evaporation of the
carbonated water which held them in solution in the sap, they
contain, when in the growing, active condition, like all other
green herbage, a very large proportion of salts of potash,
and of all the mineral elements of plant nourishment, and
hence may greatly enrich the soil on which they decay. It is
obviously to the interest of the hemp farmer, therefore, so to
manage as to spread them as regularly as possible over his
hemp ground.

The dried hemp plants are allowed to remain in the stack
until the cool season of early winter, when they are generally
spread out evenly upon the same ground on which they had
been grown, to undergo the process of dew-rotting. The
hemp is permitted to remain on the ground until, by the action
of the atmospheric waters and other agencies, it has become
so far decomposed that all its soluble parts and soft tissues
are removed and washed into the soil beneath or dissipated in
the air, and the tough hemp fibre can be easily separated from
the more woody portion of the stems. It is then taken up,
"braked" out, and the clean merchantable hemp fibre sep-
arated from the "hemp-herds," or "hemp s/iives"-the. broken
fragments of the woody parts of the stems which are usually
burnt up by the hemp-brakers on the spots where they fall
near their hemp-brakes.

In order to study the changes which occur in the mineral
constituents of the hemp during this process of dew-rotting,
samples of dew-rotted hemp plants, ready for the brake, were

45'



CHEMICAL EXAMINATION OF THE ASHES OF



gathered, in December, from the two lots of the experimental
field above mentioned, of the crop of the dry season of 1874.
These were thoroughly air-dried, incinerated, and their ash
submitted to analysis, with the following results:

TABLE III. OF THE ASH ANALYSES OF DEW-ROTTED HEMP PLANTS,
CARBONIC ACID, &c., EXCLUDED. '





(D) SAMPLE FROM LOT 3.
PLASTERED. (SEE D.)


(E) SAMPLE FROM LOT 4.
NOT PLASTERED. ' V SEB B. )


In 100 parts of
ash.


In 100 parts of
dried hemp
plants.


In 100 parts of
ash.


In 100 parts of
dried hemp
plants.


Lime .


68.846

8-335
5-7i6
.429
13-979
965
.050
i. 680


1-235
.149
.102
.008

.251
.017
.001

.030


63-651

8-343
5-682
.760
I5-7I3
I-55 2
.042

4-257


0.942
.124
.084
.OI2

233
.023
.OOI
.063


Magnesia . . ... . . . .


Potash


Soda


Phosphoric acid .


Sulphuric acid . .




Silica . .




Per centage of earthy phosphates


27.144


.487


29.920


443


Per cent, of ash to the dried rotted hemp .




'793




1.480









On comparing these results with those given in tables I. A.
and I. B., in the columns D and E, where the results of the
analyses of the ashes of this same growth of hemp are given
in the imrotted state, it will be seen that a great diminution
has taken place in the amount and proportions of the ash and
its several ingredients.

To exhibit this diminution of the ash ingredients, which
takes place in the ordinary process of dew-rotting, we place
the averages from table I. B. and the above table side by side
in
452



THE HEMP AND BUCKWHEAT PLANTS, &C.



TABLE IV. COMPARATIVE VIEW OF THE ASH OF THE UNROTTED AND
THE DEW-ROTTED HEMP PLANTS, CARBONIC ACID BEING EXCLUDED.





Average of D
and E. Un-
rotted hemp
plants.


Average of D
and E. Dew-
rotted hemp
plants.


Proportions removed by dew-
rotting.




2.036


I .089




Magnesia


.4.1 H


1-6




Potash .


.one


CO?




Soda . . .... . .


OIQ


Ol O




Phosphoric ;ici<l .


Z2A


2A '




Sulphuric acid . ....


06 1






Chlorine


,OI I


.OOI




Silica. .


.n8


CM. 7












Per cent, of earthy phosphates


1.166


.46;


More than one half.










Per cent, of ash to the dried plants . . .


4.165


1.636


More than one half.



When we also take into consideration the fact that the dried
hemp plants lose at least one third of their weight in the dew-
rotting, we can judge how large a proportion of the essential
mineral ingredients are restored to the soil in this process.

The above table also shows us that the more soluble ingre-
dients, such as the alkalies, &c., are removed from the plants
in the larger proportions.

These analyses and comparisons enable us clearly to un-
derstand why the culture of hemp, when judiciously managed,
especially when it is spread out and dew-rotted on the same
surface on which it was grown, is so little exhausting to the
soil, as compared with the method in which the water-rotting
process is used.

In order to ascertain how much of the essential elements of
the soil are carried off in the merchantable product the hemp
fibre as ordinarily sold analyses were made of some of this,
both in the usual condition as it is to be found in our hemp
factories, and after it had been well washed with water to
remove from it as much of its adhering dirt and soluble matter
as possible.

Two samples of the "hemp-herds," or refuse woody por-
tions of the stems, separated in the operation of braking,
were also incinerated, in the air-dried state, and the ashes

453



i6



CHEMICAL EXAMINATION OF THE ASHES OF



submitted to chemical analysis. The results are given in the
following table :

TABLE V. COMPARISON OF THE ASH INGREDIENTS OF DEW-ROTTED
HEMP FIBRE AND HEMP HERDS, CARBONIC ACID EXCLUDED.





HEMP FI'riRE, UN-
WASHED.


HEMP FIBRE,
WASHED.


HEMP-HERDS, 1873.
MOIST SEASON.


HEMP HERDS, 1874.
DRY SEASON.


In loopt's
of ash.


In loop'ts
of dried
hemp.


In zoop'ts
of ash.


In loop'ts
of hemp.


In loop'ts
of ash.


In loop'ts
of dried
herds.


In 100 p'tS
of ash.


In loop'ts
of dried
herds.


Lime


59.960

8.<>I2

7-35'
.712
15.852
1.710
. 092
5.621


0.984
'4'

. 121
.OI2
.260
.029
.OO2
.092


68.694

6.222
3-789
.801
15-335
.487
.048

4 02 4


o. 722

.040
.008
.161
.005

. OOI

.049


51-998
8.426
19.615

-9 J 5
14.401
2.016


0.446
.072
.168
.008
.124
.017


62.992

8.066
8.670

754
12.215
2.138


0.676
.097

093
.008
131
.023


Magnesia
Potash . ...


Soda


Phosphoric acid


Sulphuric acid ....


Silica


2 629


.022


4.465


.048




Per cent, of earthy phos-
phates . .


S'-SS?


.518


29.486


.310


29 275


.251


24.807


.267




Percent, of ash to the air-
dried material. ....












.859




1.076



















The hemp fibre, which was analyzed in the ordinary un-
washed condition, was obtained from a factory in Lexington.
It was of the crop of 1874, dark colored, and containing, per-
haps, more than the average quantity of dirt or fine soil adher-
ing to it. Washing with cold water removed some but not
all of this adhering dirt, as well as much of the soluble matters
contained in it, reducing the per centage of the ashy residue
more than one third. Had it been thoroughly cleaned and
bleached the ash per centage would have been still more con-
siderably reduced. All the nitrogenous matters, holding phos-
phates in a comparatively soluble condition, all the alkaline
salts, would thus be dissolved out, and very little else than
silica, with a small proportion of the earthy carbonates, would
be left in the clean hemp fibre ; so that exhaustion of the soil
from its production would be quite insignificant.

Calculating on the data of the above tables, we find that
an average crop of hemp of 800 pounds to the acre removes
from the soil only a little more than thirteen pounds of ash
ingredients, or, when in the washed condition, less than eight
pounds and a half, while it is well known that a crop of wheat
of twenty bushels takes nearly twenty pounds in the grain

454



THE HEMP AND BUCKWHEAT PLANTS, &C.



alone ; a crop of fifty bushels of corn removes more than thirty
pounds in the grain alone, and a crop of tobacco of one thou-
sand pounds, more than one hundred and seventy-six pounds.
When we compare the relative proportions of the ingre-
dients of these several ashes, the result is still more to the
advantage of the hemp crop, as is to be seen in the following
table :

TABLE VI. OF THE PROPORTIONS OF MINERAL INGREDIENTS REMOVED
FROM THE SOIL IN CERTAIN AVERAGE CROPS.





In 800 Ibs
unwashed
hemp.


In 800 Ibs
of washed
hemp.


In 20 bus'ls
of wheat.*


In 50 bus'ls
of corn.*


In 1,000 Ibs
tobacco, in-
cluding the
stalks.*


In 2, 400 Ibs
of ordinary
hemp-h'ds.


Lime, in pounds


7.872
I.I28
.968
.096
2.080
232
.Ol6
.736


5-776
.520
.320
.064
1.288
.040
.008
392


1.63
2-43

5-45
13
9.12
.08

35
.41


O.22
3 .6l
8.06
6.22
11.85

not est.
not est.
7i


68.00

8.67

69-73
6.80
8.13
8.40
i .06
5-86


i o . 704

1.728
4.032
.192
2.976
.408
a trace.
.528




Potash,


Soda,
Phosphoric acid, . .


Sulphuric acid, . .


Chlorine, . .


Silica,


13.128


8.408


19.60


30.67


176.65


20.568




Total earthy phosphates


4.144


2.480








6.024









*From volume IV, Reports of Kentucky Geological Survey (old series), page 321.

We see that while an average crop of hemp takes only an
amount of potash from the acre varying from less than one
pound to less than one third of a pound, the wheat crop takes
nearly five and a half pounds, the corn crop more than eight,
in the grain alone, and the tobacco crop nearly seventy pounds ;
and while the hemp crop carries off only from one and a quar-
ter to two pounds of phosphoric acid, the wheat will take more
than nine, the corn more than eleven, in the grain alone, and
the tobacco more than eight pounds. We notice also that the
removal of the hemp-herds (which are believed by some of
our practical farmers to bear a proportion in weight to the
hemp fibre of three to one) will take from the land greatly
more of its essential ingredients than the hemp fibre itself;
for while the merchantable hemp holds less than a pound of
potash and two pounds of phosphoric acid in its composition,

455



iS CHEMICAL EXAMINATION OF THE ASH-ES OF

the equivalent quantity of hemp-herds holds more than four
pounds of potash and nearly three pounds of phosphoric acid.

As we have stated, it is the common practice of our farmers
to permit the hemp-herds to be burned up in the heaps where
they fall near the hemp-brakes. Some erroneously believe,
indeed, that they would exert an injurious or poisonous influ-
ence on the land if spread over it; but it is evident that this
practice tends more rapidly to reduce the fertility of the hemp
field than the sale of the hemp fibre ; and that it would be
beneficial to adopt some plan of reducing the hemp-herds to
the condition of vegetable mould, and to spread it over the
surface, where it would not only tend to keep up the propor-
tion of humus, but would re-supply much of the essential min-
eral elements in a soluble or available form. If it is found
that the recently scattered hemp-herds seriously interfere
with the cultivation or growth of the next succeeding hemp
crop, it would doubtless pay to haul them into heaps to rot, or
to spread them over some other field, which might be in prep-
aration for hemp in a system of rotation adapted to this cul-
ture.

The common practice in our region has been to cultivate
the rich new land in hemp continuously until it no longer
yields a profitable product, and then to resort to other newly-
cleared woodland pasture, or open blue grass fields, to renew
the process. Sometimes land comparatively old in cultiva-
tion has been used for hemp, after it has been rested and
has increased its humus during two or three years in clover,
or for a longer time in open blue grass pasture ; but as yet
no regular system has been adopted by which the abundant
humus and ready supply of soluble mineral ingredients of the
soil, necessary to this luxuriant vegetation, can be secured or
maintained. As the hemp product carries but little of these
away from the land, leaving most of them behind, after a tem-
porary use of them during its season of growth, the mainte-
nance of the productiveness of the hemp soil seems an easy
problem to solve, where the land is well drained and naturally
of a suitable composition and consistence, as is our blue grass
456



THE HEMP AND BUCKWHEAT PLANTS, &C. 1 9

land. But the capability of the production of hemp, even in
this fertile soil, appears to be limited, and its humus and other
soluble essential ingredients, on the abundance of which this
crop is so greatly dependent, seem gradually to undergo dimi-
nution in the ordinary system of culture.

That this gradual deterioration is not due wholly to the
removal of the crop is evident from the foregoing facts and
considerations. But it appears that the humus and its soluble
and available constituents are decomposed and removed, under
the influence of the atmospheric agencies, faster than they are
renewed by the decay of the leaves and other decomposable
parts of the hemp plant. The small proportions of these car-
ried off in the merchantable hemp need, indeed, scarcely be
taken into consideration in this connection.

The humus is a very decomposable and oxidable substance ;
the atmospheric oxygen combines continuously with its carbon
and hydrogen to produce carbonic acid and water, so neces-
sary as plant food, while the essential mineral elements of the
mould thus set free, being in a soluble condition, are subject
to the washing agency of water, which may diffuse them more
or less through the neighboring fields, or gradually carry some
of them off in the drainage. This action would be the greatest
when the ground is no longer covered with a growing vegeta-
tion, which would absorb the rich soil solution and bring its
valuable fixed ingredients to the surface, but is doubtless con-
stant whenever water in sufficient quantity falls to saturate the
soil or to pass through it. For although many experimenters
have established the fact that the soil has a power of absorp-
tion sufficient not only to enable it to withdraw and hold cer-
tain substances dissolved in the water which passes through
it, and even to decompose some chemical compounds, and to
separate and hold some of the elements and replace them
by others less essential, yet it is equally well established by
numerous experiments that pure water, such as rain water,
which passes through a fertile soil, carries off from it, in solu-
tion, a notable quantity of its essential elements, which, as
already intimated, may either be lost to the locality by the

VOL. I.-CHEM. 30. 457



2O CHEMICAL EXAMINATION OF THE ASHES OF

drainage or diffused through the adjoining grounds, according
to the well-known laws of osmose.

To maintain the high degree of active fertility necessary to
successful hemp culture, even in our rich blue grass lands,
seems, therefore, to require something more than the most
judicious management of that crop itself; for we find that,
although the removal of the hemp causes a scarcely sensible
diminution of the mineral elements of the soil, the field on
which it is continuously produced for a series of years becomes
at length unproductive of this crop, because, doubtless, of a
gradual decrease of its proportions of humus and of those
soluble salts which are required by the hemp plant in such a
large and ready supply as is necessary to its rank and rapid
development, during its short season of growth.

As the prevalent mode of culture, if carried on indefinitely,
would inevitably reduce all our hemp lands below the level of
profitable production, the adoption of a new system, which
would promise greater durability to hemp culture, is greatly
desirable.

According to the prevalent system, the hemp ground is ex-
posed, more or less, to the decomposing and leaching influence
of the atmospheric agencies for more than six months in the
year, with scarcely any growing plant upon its surface to
absorb and retain the dissolved fertilizing materials or the
nutritive gases which are produced in it by decomposition.
These, therefore, may pass off in the drainage or become lost
to the field by the continuous process of diffusion.

The growth of the hemp begins early in May; it is ended,
by the cutting of the crop, late in August. During these four
months it is probable the active vegetation absorbs and retains
the dissolved essential elements of the soil, so that waste of
them by oxidation, diffusion, or drainage, is little or nothing.
The drying of the cut hemp spread on the ground is a short
process, and the subsequent influence of the roots of the
hemp left in the ground is merely mechanical, and does not
prevent oxidation of the humus or the leaching out or diffu-
sion of its soluble materials; neither does the hemp, when
458



THE HEMP AND BUCKWHEAT PLANTS, AC. 2\

spread out to dew-rot, prevent this action of the atmosphere
or the water, although it may give much soluble fertilizing
matters to the soil ; and very few weeds of any kind spring up
in the hemp field to take up and retain for future use these
valuable gaseous and soluble substances which pervade the
soil, and are escaping, mostly in solution, in all the water
which passes through it.

The obvious remedy for this loss is to keep the surface of
the ground, as much as possible, covered with an active vege-
tation which would absorb and retain upon the surface these
fleeting elements of fertility, and keep up, in its subsequent
decay, the large proportion of humus which is necessary to a
heavy hemp production.

Some of our farmers, for this purpose, have very judiciously
resorted to the sowing of rye after the cutting of the hemp,
to be plowed in, the following spring, as early as may be neces-
sary to kill it and allow it to rot. The rye grows with great



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