Growing cassava in Flordia -- its...

Title: Florida quarterly bulletin of the Agricultural Department
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00077083/00083
 Material Information
Title: Florida quarterly bulletin of the Agricultural Department
Uniform Title: Avocado and mango propagation and culture
Tomato growing in Florida
Dasheen its uses and culture
Report of the Chemical Division
Alternate Title: Florida quarterly bulletin, Department of Agriculture
Florida quarterly bulletin of the Department of Agriculture
Physical Description: v. : ill. (some fold) ; 23 cm.
Language: English
Creator: Florida -- Dept. of Agriculture
Publisher: s.n.
Place of Publication: Tallahassee Fla
Publication Date: -1921
Frequency: quarterly
monthly[ former 1901- sept. 1905]
Subject: Agriculture -- Periodicals -- Florida   ( lcsh )
Agricultural industries -- Statistics -- Periodicals -- Florida   ( lcsh )
Genre: periodical   ( marcgt )
Dates or Sequential Designation: -v. 31, no. 3 (July 1, 1921).
General Note: Description based on: Vol. 19, no. 2 (Apr. 1, 1909); title from cover.
General Note: Many issue number 1's are the Report of the Chemical Division.
General Note: Vol. 31, no. 3 has supplements with distinctive titles : Avocado and mango propagation and culture, Tomato growing in Florida, and: The Dasheen; its uses and culture.
 Record Information
Bibliographic ID: UF00077083
Volume ID: VID00083
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 28473206
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    Growing cassava in Flordia -- its uses
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Full Text

Vol. 28 Number 4 c 4P'




OCTOBER 1, 1918



Entered January 81, 1908, at TallahaMee, Florida, as eeond-clam
matter under Act of Cengrea of June, 1900.
"Acceptance for mailing at special rate of postage provided for
in Section 1103, Act of October 3, 1917, authorized Sept. 11, 1918."


.r~ A/^' .'*


(From Bulletin No. 58, U. S. Dept. of Agrl.)
In Bulletin No. 44 of the~Division of Chemistry is found
a description of the sweet cassava, with remarks on-its
culture, properties, and uses. This bulletin is out of
print, and it is therefore advisable, in treating of the sub-
ject of the growing and manufacture of starch from cas-
sava, to show the nature of its contents. Cassava grows
in this country in the southern peninsula of Florida, and
well up into the frost belt, and is also found in other ex-
treme portions of the United States. From a careful
study of the climatic conditions under which the plant
flourishes, it is safe to assume that it may also be grown
with success in southern Alabama, Mississippi, Louisiana,
Texas, Arizona and southern California.
The name "cassava" should properly apply only to the
purified starch derived from the roots of the plant, but it
has passed into general use to designate the plant itself.
According to the Division. of Botany, the plant is known
by various names, as, for instance, Janiyha manihot, Man-
ihot utilissima, Jatropha Manihot, Manihot aipi, Manihot
loeflingii, and Manihot palmata. One of its common
names is manioc plant. The fleshy root of this plant
yields the greatest portion of the daily food of the na-
tives of many portions of tropical America, and one of
its forms of starch is imported largely into this coun-
try as tapioca. It is a woody or shrubby plant, growing
from fleshy, tuberous roots, the stems being smooth, with
nodules where the leaves grow.
There is properly only one variety of the plant growing
in Florida, while that variety which grows in the Tropics
contains so much hydrocyanic acid as to render it poison-
ous. The variety grown in the subtropical region of Flor-
ida, however, contains only a small quantity of hydro-
cyanic acid, and is therefore commonly known as sweet
cassava. Some of the growers of the plant in Florida
claim that two varieties grow in the State, one of which
is poisonous on account of the large amount of hydro-

cyanic acid which it contains, and the other nonpoisonous,
as it contains only a little hydrocyanic acid. It is quite
probable, however, that after the poisonous variety has
grown for a long while in a subtropical climate it would
lose largely its poisonous properties. The leaves of the
poisonous variety in the Tropics usually have seven
branches, palmately divided. The leaves of the sweet
variety are usually only five-parted. The botanists clearly
recognize two distinct varieties. For instance, in the
Treasury of Botany (p. 718) the following remarks are
It is quite clear that while the root of one is bitter and
a virulent poison, that of the other is sweet and whole-
some, and is commonly eaten cooked as a vegetable. Both
of them, especially the bitter, are most extensively culti-
vated over the greater part of tropical America and yield
an abundance of wholesome'and nutritious food, the
poison of the bitter kind being got rid of during the
process of preparation it undergoes. The poisonous ex-
pressed juice, if allowed to settle, deposits a large quan-
tity of 'starch known as Brazilian arrowoot or tapioca
meal, from which the tapioca of the shops is prepared by
simply torefying the moist starch upon hot plates, the
heating causing the starch grains to swell and burst and
become agglutinated together. A sauce called cassareep,
used for flavoring soups and other dishes, particularly the
West Indian dish known as pepper pot, is also prepared
from this juice by concentrating and rendering it harm-
less by boiling. Another of the products of cassava is an
intoxicating beverage called piwarrie, but the manner of
preparing it is not calculated to render it tempting to
Europeans. It is made by the women, who chew cassava
cakes and throw the masticated materials into a wooden
bowl, where it is allowed to ferment for some days and
then boiled.. It is said to have an agreeable taste.


The sweet cassava as grown in Florida is a common
article of diet, as well as the source of the domestic
starch used over large portions of the peninsula. The
roots of the cassava are grated and used directly as hu-
man food, and they are also fed to cattle, pigs, mules and


horses, with very happy effects, being a food which is
greatly relished. Cassava flour is prepared as a domestic
product in many parts of Florida and other localities
where the cassava is grown. In the preparation of cassava
flour the root is peeled, chopped into thin slices or grated,
spread in the sun for two or three days until sufficiently
dry, and then ground into a fine powder. In this state
it is used for making a kind of bread for puddings and
for other culinary purposes. In the making of puddings
the addition of milk, eggs, sugar, etc., to suit the taste is
recommended. As a substitute for wheat flour in making
bread, the cassava flour is of course inferior in general
nutritive and culinary properties. It ocntains an ex-
cessive amount of carbohydrates, and is therefore not as
well balanced a ration as bread which is made from wheat.
For instance, in ordinary wheat flour the nitrogenous
bodies vary from 8 to 14 per cent, while in cassava flour
they rarely reach as much as 2 per cent. The chemical
composition of the cassava roots and of the cassava flour,
as determined in this laboratory, is shown in the follow-
ing tables:


Serial number ............................... 5547
Per cent.
Ash .......................................... 1.95
Petroleum ether extract (fat) .................. 1.27
Ether extract (resins, organic acids, etc.) ...... .74
Alcohol extract (amids, sugars, glucosids, etc.).. 17.43
Crude fiber ................................... 4.03
Starch .......................... .... ......... .. 71.85
Protein (nitrogen X 6.25) .................. .... 3.47


Serial numbers ..................... 5922 5923
Per cent. Per cent.
Moisture ......................... 10.56 11.86
Ash ............................... 1.86 1.13
Petroleum ether extract (fat) ........ 1.50 .86
Ether extract (resins and organic
acids) .................... ....... 64 .43

Alcohol extract (amids, sugars, gluco-
sids) ............................ 13.69 4.50
Dextrin, gum, etc., by difference..... 2.85 5.63
Crude fiber ....................... 2.96 4.15
Protein (nitrogenX6.25) ........... 1.31 1.31
Starch ........................... 64.63 70.13
Most extraordinary statements have been made in re-
gard to the yield of cassava per acre. Careful measure-
ments, however, show that the magnitude of the crop is
usually very much les than is stated in the reports which
have been made. An average crop, under favorable con-
ditions, may be placed at 5 tons of roots per acre. In
many cases, however, the yield, where no fertilization is
practiced and where the roots are grown upon sandy soil,
is much less than this. In the statement above, showing
the composition of the root, the analysis of a single sam-
ple of roots is given. In order to determine the composi-
tion of a more general sample, large quantities of roots
were obtained from Florida and subjected to analysis,
and the means obtained follow. In this case the roots
were peeled in order to determine the composition of the
material as it would be prepared for human food. In
addition to the analysis of. the peeled roots, the fiber
remaining after the removal of the starch was also sub-
jected to analysis, and likewise the bark which was re-
moved from the root. In the case of the bark, however,
the starch was not determined separately, but is included
in the undermined portion, forming, of course, a consid-
erable portion thereof.


Bark of Root w Peeled Root
Fresh Dry E S Fresh Dry

SPer Per Per IPer Per
Cent. Cent. I Cent. I Cent. Ient.
Moisture ....................... 61..80 ...... .. . 61.30 .....
Fat (ether extract) ............ .17 0.44 0.301 .;6 1.70
Protein (nitrogen X 6.25) ....... .64 1.661 1.021 2.209 5 91
Starch diastase Ex. inserted with I
HC1) ...................... 1 30.98 80.061 64.641 ...... ......
Fiber .......................... .88 2.26 10.68 3.83 9.89
Ash ............................ .51 1.31 1.42 2.02 5.23
Undetermined .................. 5.52 14.27 21.94 29.901 77.27
Total ...................... 100.001100.00 100.001100.001100.00

With the starch, in the analysis given above, is reckoned
also the soluble carbohydrates, consisting almost exclu-
sively of caie sugar, and of which, in an analysis of
another portion of the dry substance, as high as 17 per
cent was found. In the laboratory it is not difficult to
prepare crystallized cane sugar from the aqueous extract
of the fresh pulp. I have made such a preparation. The
percentage of sugar in the plant, however, is too low to
excite any -reasonable hope of the preparation of this
article on a commercial scale. The most promising way
to save it is by conversion into glucose, as indicated in
another place. The undetermined portion consists of the
digestible fiber and carbohydrates of the pentose series.
The pentosans in the fiber were determined by the furol
process, as modified by Krug, and the amount in the air-
dried material was found to be 3.92 per cent, and in the
material after the removal of the starch 5.33 per cent.
The fresh root was found to contain 38.7 per cent of
dry matter, being considerably more than was found in
the fresh sample of the previous analysis. Of this 38.7
per cent, 30.98 consisted of starch and soluble carbohy-
Experiments were made to determine the yield of air-
dry starch which could be obtained from the roots by lab-
oratory work. Two sets of experiments were made. In

the first set the roots were pulped on a Pellet rasp, used
for preparing beet pulp for instaneous diffusion. Twelve
kilos of the unpeeled root were rasped in this way and the
starch separated by washing through a sieve of bolting
cloth. The washings and settling werq collected and
dried in the ordinary method of starch manufacture. The
yield of pure starch was 3,105 grams, equivalent to 25.9
per cent of the total weight of the root. The starch was
almost absolutely pure, containing only a trace of nitro-
genpus matter. In the second experiment 10 kilos of the
root were ground in a pulping machine, used for pre-
paring green fodder for analysis. The pulp was much
coarser than that produced by the Pellet rasp. Treated
in the same way, the yield of air-dry starch was 2.360
grams, or 23.6 per cent. One of the striking points in
connection with the work is that the residue after extrac-
tion of the starch, consisting largely of fiber, contained
still a larger percentage of starch, showing that the
process employed did not secure the whole of the starch
from the pulp. The diameter of the starch granules is a
little over 0.01 mm., being much smaller than the aver-
age of potato starch. *
The relations of the mineral components of the cassava
plant to the plant food in the soil, with the exception of
nitrogen, are best studied from the ash. A large quan-
tity of ash, therefore, was prepared from the peeled root
and from the bark, and analysis of these samples were
obtained. The data are given in the following table:



Peeled Root Bark of Root

A. B. Mean A. B. Mean

Per Per Per
Cent. Cent. Cent.
Carbon ....... 0.30 0.31 0.31
Silica (soluble in solution
of NaCO,) ........... .97 91 .94
Silica (insoluble in solution
Sof NoCOi) ............ 7.15, 7..15 7.15
Ferric oxid (Fe2O,) .......I *66 .66 .66
Calcium oxid (CaO) ...... 10.63 10.64 10.64
Magnesium oxid (MgO) .. 7.36 7.35 7.35
Sodium oxid (NaO) ..... 1.12 1.28 1.20
Potassium oxid (K20) .... 41.72 41.54 41.63
Phosphoric acid (PO,).... 15.58 15.59 15..58
Sulphuric acid (SO.) .... 3.67 3.80 3.73
Carbonic acid (CO) ...... 9.15 9.12 9.14
Chlorin (Cl) ............. 2.761 2.75 2.75

Total ................. 1101.07 101.10 101.08
Oxygen equivalent to chlorin .62 .62 .62

Difference ............ 100.45 100.48 100.46


Per Per Per
Cent. Cent. Cent.
0.791 0,77 0.78

10.531 11.361 10.94

52.99 52.161 52.58
2.46 2.441 2.45
6.58 6.65 6.62
3.31 3.33 3..32
.84 1.051 .95
14.73 14.681 14.70
2.44 2.461 2.45
1.71 1.711 1.71
2.53 2.501 2.51
1.41 1..421 1.41

100.32 100.531100.42
.31 .311 ..31

From the above numbers it is seen that the ash of the
peeled root is especially rich in potash, almost one-half
of the total weight being composed of this substance. The
potash is combined chiefly with carbonic and phosphoric
acids. In the ash of the bark, as might be expected, silica
is the predominant element, comprising more than half
the total weight.
Assuming a yield of 5 tons of root per acre, the weights
of the important fertilizing materials removed by such a
crop can be readily calculated from the data given.
Since the bark form approximately 2.2 per cent of
the entire root, the total crop would be made up of the
following amounts of bark and peeled root which would
contain the amounts of mineral matter given below:


! .



SUBSTANCE Pounds Pounds
of Ash

Peeled root ................................ 9,780 49.88
Bark of root ................................ 220 4.44

Total ................................... 10,000 54.32

The most important mineral matters contained therein
are shown in the following table:


Ash from Ash from Total Ash
MATERIAL Peeled Root Bark from 5 tons
(49.88 (4.44 (54.32
pounds) pounds) pounds)

Lime (CaO) ..................
Magnesia (MgO) ..............
Potash (K,0) ................
Phosphoric acid (P0,) ........

Residue ..................







The less valuable mineral plant foods-that is, those
that are of so little note as to require no conservation
or addition-ramount to 15.60 pounds per acre, and the
more valuable to 32.72 pounds per acre.


Cassava was grown for one year at the Department
experiment station at Runnymede (post office, Narcoos-
see), Osceola county, Fla. The crop was grown as food
for stock. The field in which the crop was grown is high-
pine sand, with almost no other ingredient. The soil on
which it was grown was apparently pure sand.


Attempts were also made to grow the cassava in a piece
of very wet muck land at the station in which sugar cane
would not grow to any advantage. An immense develop-
ment of tops was secured, some of the plants reaching a
height of 10 feet and resembling young trees. The root
development was fair, but not commensurately increased
with the top growth. Some of the stems were easily 2
inches in diameter. On well-drained muck land I think
the crop would be large and profitable.
In sand land the planting should be preceded by the
removal of stumps, sprouts, etc., and the soil given a thor-
ough plowing. It is advisable to spread about 300 pounds
of fine raw Florida phosphate floats or about 150 pounds
of superphosphate containing 12 per cent. available acid
to the acre. This may be applied as to top-dressing and
thoroughly worked into the soil by a deep running culti-
vator. The rows should be marked out in furrows 3 to 4
inches deep and from 31/ to 44 feet apart. To get a good
stand about double the number of cuttings required to
produce 2,500 hills per acre should be planted. The excess
of plants can be removed with a hoe as soon as vigorous
growth is assured, leaving one hill every 3 or 4 feet.
About 150 pounds of kainit per acre should be dropped in
the hills before planting, together with an equal amount
of cotton seed meal, or half that amount of Chile salt-
peter (nitrate of soda).
The cultivation should be such as to keep the field free
of all weeds and the surface of the soil well stirred. While
the plants are young, deep cultivation is not objection-
able, but as soon as the root system begins to develop,
superficial culture must be practiced not to exceed 2
inches in depth. Some cultivators draw the soil to the
plant during cultivation, so as to form a ridge at the time
of laying by. Where nitrate of soda has been used an ad-
ditional 50 or 75 pounds per acre should be sown broad-
cast jusf before the final cultivation. The above method
is the one which should be followed for the poorest kind
of sand soils, where a maximum crop is desired. For
muck soils, the cotton seed meal and nitrate of soda
should be omitted and about 500 pounds of Florida phos-
phate floats used per acre. If sand soils are covered with
a good layer of muck before the plowing the nitrogenous
fertilizers may also be omitted or reduced in quantity.



In ordinary seasons with the treatment outlined above,
a crop of from 4 to 7 tons per acre will be secured. On
sand soils containing a little organic matter approaching
the hammock variety, a fair yield of from 2 to 4 tons per
acre will be secured by good cultivation without fertil-
For seed, the stems of the unfrosted plants are cut into
pieces about 6 inches in length, care being taken that each
piece has two or more eyes. In planting, these pieces
may be laid directly down in the furrows and covered,
but the general practice is to place them obliquely in the
furrows so that one end may not be covered. In case of a
threatening frost before a field is ready for planting, the
unfrosted tops may be cut, thrown into heaps, and pro-
tected with leaves or trash from the action of the frost.
They should, however, be embedded, in moderately moist
earth if they are to be kept for any length of time before
planting. In case of frost before the seed is saved, the
stumps, i, e., the pointsiof union of the top with the root,
will usually be found uninjured, and these may be cut
away and planted instead of the cuttings just described.
The larger parts of the stems immediately above the
ground make the best seed.
The roots should be left in the ground'until they are
needed for use, whether for food, for starch, or for glu-
cose. The crop can be harvested at any time during the
year, but the best season is from October to May. The
roots should not be allowed to grow more than two sea-
sons, and for most purposes it is believed that an annual
harvest will prove the more profitable.
As is the case with all new and promising plants, the
most extravagant statements have been made in regard
to the amount of cassava which can be produced per acre.
In many of the returns received from our correspondents
in Florida statements were 'made in regard to the yield
which were entirely beyond the bounds of reason. These
extravagant statements, of course, did not proceed from
any desire on the part of the correspondents to misstate
the facts, but on account of their misapprehension of
them. Statements of yield are made, as a rule, not upon
accurately measured and weighed products,but upon a
glance over a field or the taking of a few hills. It is easy,
therefore, for the most honest and upright correspondent

to fall into gross error in regard to the amount which
will be furnished by an acre. In my own observation of
small areas, anid from the accredited statements of those
S authorities which seem to merit the highest consideration,
I am convinced that on the ordinary pine land of Florida,
with proper preparation and cultivation and appropriate
fertilization, a yield of from 4 to 7 or perhaps 8 tons per
acre may be reasonably expected. It is difficult to see,
however, how it is possible for such yields as have been
reported-viz., 40, 50, and even 60 tons per acre-to be
gathered. In. exceptional conditions, as is the case with
all crops, exceptional yields may be obtained, but these
must not be considered in the practical study of the prob-
lem of profitable production.
The profit which the farmer may make from growing
this crop and the manufacturer from using it should, in
my opinion, be based upon a yield of 4 or 5 tons per acre.
If it be desired to make starch from the plant, we may
suppose a minimum rate of yield that 20 per cent. of
the weight of the fresh root may be obtained as mer-
chantable starch of a high grade On a yield of 4 tons per
acre this would amount to eight-tenths of a ton, or 1,600
pounds. Compare this with the weight of starch obtained
from Indian corn producing 40 bushels per acre. The
yield of merchantable starch of a high grade may be
placed at 35 pounds per bushel, which for 40 bushels
would amount to 1,400 pounds. It is thus seen that the
rate of yield per acre in the matter of starch from cassava
would be fully equal if not superior to that from Indian
If the matter of the manufacture of glucose be consid-
ered, the estimate is even more favorable. Our experi-
ments have shown that after the removal, of the bark the
whole root may be rasped and. treated directly for the
manufacture of glucose, either by inversion with diasttse
or by treating with dilute sulphurip acid. In the latter
case'not only were the starch and sugar present in the
root obtained as glucose, but also a considerable quantity
of the digestible fiber. It is not an extravagant state-
ment, therefore, to suppose that fully 30 per cent. of the
weight of the fresh root could be obtained\as commercial
glucose. This would give a yield per acre bf 1.2 tons, or
2,400 pounds. These statements .are made, of course, sub-

ject to the practical determination of the manufacturer
of glucose and starch from this plant. Attempts have al-
ready, been made in the manufacture of starch, but of
course the full development of this industry must await
the investment of capital and the necessary adjustment
of new machinery to new processes.
According to the best information, the general course
of procedure in the manufacture of starch from cassava
is the same as with potatoes. All the machinery used in
the potato-starch factories can be employed just as well
in the cassava factories, but the character of the rasps
and bolting cloths must be adapted to the changed condi-
tions due to the difference in the raw materials em-
ployed. There are many makers of potato-starch appar-
atus in the United States, and some manufacturers prefer
one form of apparatus and some another. The same is
true ine regard to the working process; one person pre-
fers the tabling of the starch directly from the grater
after sifting, while aiiother prefers the -settling tanks,
and still others a combination of both.
It is evident that the methods of work must be adapted
to the conditions which obtain and the character of the
materials to be employed. In some seasons both the cas-
sava and potatoes yield better results than in others, and
only large experience can determine in the multitude
of details the best method to be pursued.
During the season of 1898-99 a yield of 20 per cent. of
commercial starch on the weight of cassava root em-
ployed was obtained, and therefore with improved ma-
chinery and improved cultivation it will not be dif-
ficult to bring this yield up to 25 per cent.
It is evident from a careful study of the problem in
so far as it has been worked out in practical experi-
ence, and theoretically considered, tha very little
change in machinery and methods will be found peces-
sary in adapting a starch factory to the preparation of
starch from cassava. Since cassava will yield nearly
double the percentage of starch obtained from an equal
weight of potatoes, it is evident that in this plant the
practical man will find a promising source of profit in
those sections of our country where the soil and cli-
mate are situated to the growth of cassava.


Large areas in Florida are well situated to cassava
growing which so far have not been found profitable for
other agricultural purposes.

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