• TABLE OF CONTENTS
HIDE
 Front Cover
 Credits
 Table of Contents
 Introduction
 Drying equipment
 Field operations and Method of...
 Results
 Summary
 Conclusions and Acknowledments
 Historic note






Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; 507
Title: Mechanical drying and harvesting of peanuts
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027736/00001
 Material Information
Title: Mechanical drying and harvesting of peanuts
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 14 p. : ill. ; 23 cm.
Language: English
Creator: Myers, J. Mostella ( Julian Mostella ), 1921-
Rogers, Frazier
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1952
 Subjects
Subject: Peanuts -- Harvesting -- Florida   ( lcsh )
Peanuts -- Drying -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: J. Mostella Myers and Frazier Rogers.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00027736
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000925792
oclc - 18267397
notis - AEN6448

Table of Contents
    Front Cover
        Page 1
    Credits
        Page 2
        Page 3
    Table of Contents
        Page 4
    Introduction
        Page 5
    Drying equipment
        Page 6
    Field operations and Method of procedure
        Page 7
    Results
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Summary
        Page 13
    Conclusions and Acknowledments
        Page 14
    Historic note
        Page 15
Full Text



Bulletin 507


November 1952


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA








Mechanical Drying and

Harvesting of Peanuts

J. MOSTELLA MYERS and FRAZIER ROGERS


JEC i -


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BOARD OF CONTROL

Frank M. Harris, Chairman, St. Petersburg
Hollis Rinehart, Miami
Eli H. Fink, Jacksonville
George J. White, Sr., Mount Dora
Mrs. Alfred I. duPont, Jacksonville
George W. English, Jr., Ft. Lauderdale
W. Glenn Miller, Monticello
W. F. Powers, Secretary, Tallahassee

EXECUTIVE STAFF
J. Hillis Miller, Ph.D., Presidents
S. Wayne Reitz, Ph.D.. Provost for Agr.3
Willard M. Fifield, M.S., Director
J. R. Beckenbach, Ph.D., Asso. Director
L. O. Gratz, Ph.D., Assistant Director
Rogers L. Bartley, B.S., Admin. Mgr.S
Geo. R. Freeman, B.S., Farm Superintendent

MAIN STATION, GAINESVILLE

AGRICULTURAL ECONOMICS
H. G. Hamilton, Ph.D., Agr. Economist's
R. E. L. Greene, Ph.D., Agr. Economist 3
M. A. Brooker, Ph.D., Agr. Economist 3
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Associate
D. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate4
M. R. Godwin, Ph.D., Associate
H. W. Little, M.S., Assistant 4
W. K. McPherson, M.S., Economist
Eric Thor, M.S., Asso. Agr. Economist
J. L. Tennant, Ph.D., Agr. Economist
Cecil N. Smith, M.A., Asso. Agr. Economist
Levi A. Powell, Sr., M.S.A., Assistant

Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agri. Economist
J. C. Townsend, Jr., B.S.A., Agricultural
Statistician 2
J. B. Owens, B.S.A., Agr. Statistician 2
J. K. Lankford, B.S., Agr. Statistician

AGRICULTURAL ENGINEERING
Frazier Rogers, M.S.A., Agr. Engineer'1
J. M. Johnson, B.S.A.E., Agr. Eng."
J. M. Myers, B.S., Asso. Agr. Engineer
J. S. Norton, M.S., Asst. Agr. Eng.

AGRONOMY
Fred H. Hull, Ph.D., Agronomist 2
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
R. W. Bledsoe, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Darrel D. Morey, Ph.D., Associate 2
Fred A. Clark, M.S., Assistant2
Myron C. Grennell, B.S.A.E., Assistant'
E. S. Homer, Ph.D., Assistant
A. T. Wallace, Ph.D., Assistant 3
D. E. McCloud, Ph.D., Assistant3
E. C. Nutter, Ph.D., Asst. Agronomist
ANIMAL HUSBANDRY AND NUTRITION
T. J. Cunha, Ph.D., An. Husb.1 a
G. K. Davis, Ph.D., Animal Nutritionist
S. John Folks, Jr., M.S.A., Asst. An. Husb.
Katherine Boney, B.S., Asst. Chem.
A. M. Pearson, Ph.D., Asso. An. Husb.3
John P. Feaster, Ph.D., Asst. An. Nutri.
I. D. Wallace, Ph.D., Asst. An. Hush. a
M. Koger, Ph.D., An. Husbandman 3
E. F. Johnston, M.S., Asst. An. Husbandman
J. F. Hentges, Jr., Ph.D., Asst. An. Husb.

DAIRY SCIENCE
E. L. Fouts, Ph.D., Dairy Tech.' 3
R. B. Becker, Ph.D., Dairy Husb.3
S. P. Marshall, Ph.D., Asso. Dairy Husb.'
W. A. Krienke, M.S., Asso. Dairy Tech.3
P. T. Dix Arnold, M.S.A., Asst. Dairy Hush.2
Leon Mull, Ph.D., Asso. Dairy Tech.
H. H. Wilkowske, Ph.D., Asst. Dairy Tech.
James M. Wing, M.S., Asst. Dairy Husb.


EDITORIAL
J. Francis Cooper, M.S.A., Editors
Clyde Beale, A.B.J., Associate Editor
L. Odell Griffith, B.A.J., Asst. Editor
J. N. Joiner, B.S.A., Assistant Editor 3
William G. Mitchell, A.B., Assistant Editor

ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist
L. C. Kuitert, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
F. A. Robinson, M.S., Asst. Apiculturist
R. E. Waites, Ph.D., Asst. Entomologist

HOME ECONOMICS
Ouida D. Abbott, Ph.D., Home Econ.'
R. B. French, Ph.D., Biochemist

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist
F. S. Jamison, Ph.D., Horticulturist 3
Albert P. Lorz, Ph.D., Horticulturist
R. K. Showalter, M.S., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. H. Sharpe, M.S., Asso. Horticulturist
V. F. Nettles, Ph.D., Asso. Horticulturist
F. S. Lagasse, Ph.D., Asso. Hort.2
R. D. Dickey, M.S.A., Asso. Hort.
L. H. Halsey, M.S.A., Asst. Hort.
C. B. Hall, Ph.D., Asst. Horticulturist
Austin Griffiths, Jr., B.S., Asst. Hort.
S. E. McFadden, Jr., Ph.D., Asst. Hort.
C. H. VanMiddelem, Ph.D., Asst. Biochemist
Buford Thompson, M.S.A., Asst. Hort.
James Montelaro, Ph.D.. Asst. Horticulturist

LIBRARY
Ida Keeling Cresap, Librarian

PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist s
Phares Decker, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist and Botanist
Robert W. Earhart, Ph.D., Plant Path.2
Howard N. Miller, Ph.D., Asso. Plant Path.
Lillian E. Arnold, M.S., Asst. Botanist
C. W. Anderson, Ph.D., Asst. Plant Path.

POULTRY HUSBANDRY
N. R. Mehrhof, M.Agr., Poultry Husb.13
J. C. Driggers, Ph.D., Asso. Poultry Husb.

SOILS
F. B. Smith, Ph.D., Microbiologist'
Gaylord M. Volk, Ph.D., Soils Chemist
J. B. Neller, Ph.D., Soils Chemist
SNathan Gammon, Jr., Ph.D., Soils Chemist
Ralph G. Leighty, B.S., Asst. Soil Surveyor3
G. D. Thornton, Ph.D., Asso. Microbiologist
Charles F. Eno, Ph.D., Asst. Soils Micro-
biologist 4
H. W. Winsor, B.S.A., Assistant Chemist
R. E. Caldwell, M.S.A., Asst. Chemist'
V. W. Carlisle, B.S., Asst. Soil Surveyor
J. H. Walker, M.S.A., Asst. Soil Surveyor
S. N. Edson, M. S., Asst. Soil Surveyor3
William K. Robertson, Ph.D., Asst. Chemist
0. E. Cruz, B.S.A., Asst. Soil Surveyor
W. G. Blue, Ph.D., Asst. Biochemist
J. G. A. Fiskel, Ph.D., Asst. Biochemist
H. F. Ross, B.S., Soils Microbiologist
L. C. Hammond, Ph.D., Asst. Soil Physicist
H. L. Breland, Ph.D., Asst. Soils Chem.

VETERINARY SCIENCE
D. A. Sanders, D.V.M., Veterinarian'
M. W. Emmel, D.V.M., Veterinarian 3
C. F. Simpson, D.V.M., Asso. Veterinarian
L. E. Swanson, D.V.M., Parasitologist
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
W. R. Dennis, D.V.M.. Asst. Parasitologist
E. W. Swarthout, D.V.M., Poultry
Pathologist









BRANCH STATIONS

NORTH FLORIDA STATION, QUINCY

W. C. Rhoades, Jr., M.S., Entomologist in
Charge
R. R. Kincaid, Ph.D., Plant Pathologist
L. G. Thompson, Jr., Ph.D., Soils Chemist
W. H. Chapman, M.S., Asso. Agronomist
Frank S. Baker, Jr., B.S., Asst. An. Hush.
T. E. Webb, B.S.A., Asst. Agronomist
Frank E. Guthrie, Ph.D., Asst. Entomologist
Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist
Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Pensacola
R. L. Smith, M.S., Associate Agronomist
Mobile Unit, Chipley
J. B. White, B.S.A., Associate Agronomist

CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, Ph.D., Asso. Plant Path.
C. R. Stearns, Jr., B.S.A., Asso. Chemist
J. W. Sites, Ph.D., Horticulturist
H. O. Sterling, B.S., Asst. Horticulturist
H. J. Reitz, Ph.D., Horticulturist
Francine Fisher, M.S., Asst. Plant Path.
I. W. Wander, Ph.D., Soils Chemist
J. W. Kesterson, M.S., Asso. Chemist
R. Hendrickson, B.S., Asst. Chemist
Ivan Stewart, Ph.D., Asst. Biochemist
D. S. Prosser, Jr., B.S., Asst. Horticulturist
R. W. Olsen, B.S., Biochemist
F. W. Wenzel, Jr., Ph.D., Chemist
Alvin H. Rouse, M.S., Asso. Chemist
H. W. Ford, Ph.D., Asst. Horticulturist
L. C. Knorr, Ph.D., Asso. Histologist4
R. M. Pratt, Ph.D., Asso. Ent.-Pathologist
J. W. Davis, B.S.A., Asst. in Ent.-Path.
W. A. Simanton, Ph.D., Entomologist
E. J. Deszyck, Ph.D., Asso. Horticulturist
C. D. Leonard, Ph.D., Asso. Horticulturist
W. T. Long, M.S., Asst. Horticulturist
M. H. Muma, Ph.D., Asso. Entomologist
F. J. Reynolds, Ph.D., Asso. Hort.
W. F. Spencer, Ph.D., Asst. Chem.
I. H Holtsberg, B.S.A., Asst. Ento.-Path.
K. G. Townsend, B.S.A., Asst. Ento.-Path.
J. B. Weeks, B.S., Asst. Entomologist
R. B. Johnson, M.S., Asst. Entomologist
W. F. Newhall, Ph.D., Asst. Biochem.
W. F. Grierson-Jackson, Ph.D., Asst. Chem.
Roger Patrick, Ph.D., Bacteriologist
Marion F. Oberbachebar, Ph.D., Asst. Plant
Physiologist
Evert J. Elvin, B.S., Asst. Horticulturist

EVERGLADES STATION, BELLE GLADE
W. T. Forsee, Jr,., Ph.D., Chemist Acting in
Charge
R. V. Allison, Ph.D., Fiber Technologist
Thomas Bregger, Ph.D., Physiologist
J. W. Randolph, M.S., Agricultural Engr.
R. W. Kidder, M.S., Asso. Animal Husb.
C. C. Seale, Associate Agronomist
N. C. Hayslip, B.S.A., Asso. Entomologist
E. A. Wolf, M.S., Asst. Horticulturist
W. H. Thames, M.S., Asst. Entomologist
W. N. Stoner, Ph.D., Asst. Plant Path.
W. G. Genung, B.S.A., Asst. Entomologist
Frank V. Stevenson, M.S., Asso. Plant Path.
Robert J. Allen, Ph.D., Asst. Agronomist
V. E. Green, Ph.D., Asst. Agronomist
J. F. Darby, Ph.D., Asst. Plant Path.
H. L. Chapman, Jr., M.S.A., Asst. An. Hush.
Thos. G. Bowery, Ph.D., Asst. Entomologist
V. L. Guzman, Ph.D., Asst. Hort.
M. R. Bedsole, M.S.A.. Asst. Chem.
J. C. Stephens, B.S., Drainage Engineer 2
A. E. Kretschmer, Jr., Ph.D., Asst. Soils
Chem.


SUB-TROPICAL STATION, HOMESTEAD
Gee. D. Ruehle, Ph.D., Vice-Dir. in Charge
D. O. Wolfenbarger, Ph.D., Entomologist
Francis B. Lincoln, Ph.D., Horticulturist
Robert A. Conover, Ph.D., Plant Path.
John L. Malcolm, Ph.D., Asso. Soils Chemist
R. W. Harkness, Ph.D., Asst. Chemist
R. Bruce Ledin, Ph.D., Asst. Hort.
J. C. Noonan, M.S., Asst. Hort.
M. H. Gallatin, B.S., Soil Conservationist

WEST CENTRAL FLORIDA STATION,
BROOKSVILLE
William Jackson, B.S.A., Animal Husband-
man in Charge

RANGE CATTLE STATION, ONA
W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Agronomist
D. W. Jones, M.S., Asst. Soil Technologist

CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Vice-Dir. in Charge
J. W. Wilson, Sc.D., Entomologist
P. J. Westgate, Ph.D., Asso. Hort.
Ben. F. Whitner, Jr., B.S.A., Asst. Hort.
Geo. Swank, Jr., Ph.D., Asst. Plant Path.

WEST FLORIDA STATION, JAY
C. E. Hutton, Ph.D., Vice-Director in Charge
H. W. Lundy, B.S.A., Associate Agronomist
W. R. Langford, Ph.D., Asst. Agronomist

SUWANNEE VALLEY STATION,
LIVE OAK
G. E. Ritchey, M.S., Agronomist in Charge

GULF COAST STATION, BRADENTON
E. L. Spencer, Ph.D., Soils Chemist in Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. A. Kelbert, Asso. Horticulturist
Robert 0. Magie, Ph.D., Plant Pathologist
J. M. Walter, Ph.D., Plant Pathologist
Donald S. Burgis, M.S.A., Asst. Hort.
C. M. Geraldson, Ph.D., Asst. Horticulturist
Amegda Jack, M.S., Asst. Soils Chemist


FIELD LABORATORIES

Watermelon, Grape, Pasture-Leesburg
C. C. Helms, Jr., B.S., Asst. Agronomist
L. H. Stover, Assistant in Horticulture

Strawberry-Plant City
A. N. Brooks, Ph.D., Plant Pathologist

Vegetables-Hastings
A. H. Eddins, Ph.D., Plant Path. in Charge
E. N. McCubbin, Ph.D., Horticulturist
T. M. Dobrovsky, Ph.D., Asst. Entomologist

Pecans-Monticello
A. M. Phillips, B.S., Asso. Entomologist
John R. Large, M.S., Asso. Plant Path.

Frost Forecasting-Lakeland
Warren O. Johnson, B.S., Meteorologist2

1 Head of Department
2 In cooperation with U. S.
3Cooperative, other divisions, U. of F.
On leave
























CONTENTS


PAGE

IN TRODUCTION ................... ................ ..................... .... ...... .......... 5


DRYING EQUIPMENT .................. -- ................................................ 6


FIELD OPERATIONS ...........................------......-- --....... ......... ............... 7


M ETHOD OF PROCEDURE ....................................... ........................ .. ........... 7


R ESU LTS .................. ........................... .............. .................. ............ 8


SUMMARY --...................... .................... .............. ........................ 13


CON CLUSION S ............ ................... ......................... ................................. 14


ACKNOWLEDGMENTS ......................... ........----------------........... ....-... ....... 14










Mechanical Drying and Harvesting of
Peanuts
J. MOSTELLA MYERS and FRAZIER ROGERS

INTRODUCTION

Interest in peanut drying in Florida has been brought about
mainly by the increased mechanization of peanut production.
The high labor cost of stacking peanuts and hauling them to
a stationary thresher or picker is making it necessary for pea-
nut farmers to turn to the peanut combine to reduce harvesting
cost. Man's inherent desire to improve his methods is also a
factor that affects the trend toward increased mechanization.
The mechanization of peanut harvesting, of which drying is an
integral part, aids in reducing damage to the kernels due to
unfavorable weather during the harvesting season.
Several manufacturers have developed, and are selling, peanut
combines. These do a satisfactory job of removing the peanuts
from the green or partially dried vines. Much improvement
should be made in these combines in the next few years.
The amount of moisture that must be removed from peanuts
by mechanical drying before they can be marketed or placed
in storage varies widely. This moisture content depends on the
length of the field-drying period, stage of maturity of the pea-
nuts, and weather conditions.

Fig. 1.-Threshing peanuts from the stack with a stationary thresher is
a costly process that is giving way to combine harvesting.







Florida Agricultural Experiment Stations


Before peanuts can be sold on the market, the moisture must
be reduced to approximately 7 percent. Even with a long period
of field or stack drying, many peanuts are still above 7 percent
moisture when threshed or picked.
Those interested in peanut production agree that developments
in harvesting are correlated very closely with developments in
drying peanuts. Mechanical equipment for harvesting, al-
though not readily available, is becoming more popular every
year. For this reason, the Agricultural Engineering Depart-
ment of the University of Florida Agricultural Experiment Sta-
tion has carried on studies to determine an economical and
satisfactory method of artificially drying peanuts.


Fig. 2.-One


of the new combines used in harvesting peanuts.

DRYING EQUIPMENT


For farm-size operations it appears that a batch type drier,
as described in Agricultural Experiment Station Bulletin 477,
is well adapted to peanut drying. Since drying equipment is
generally used to dry many crops other than peanuts, it is not







Mechanical Drying and Harvesting of, Peanuts


deemed necessary to modify the design of the crop drier de-
scribed in this publication. It is of utmost importance that the
design features described in Bulletin 477 be followed. If the
crop drier fails to furnish sufficient air and heat, or the ducts
are improperly designed, it is very unlikely that a successful
drying operation can be obtained.
Caution should be taken to practice safety from a fire hazard
standpoint around a crop drying installation. Keep combustible
material away from the close vicinity of the crop drier, especially
the fan intake. To make the operation of a fuel-oil-fired drier
safer, the following safety and operating controls should be
installed: (1) a manually reset high limit switch near the heater
to turn off the fuel if the fan should stop, (2) a protector-relay
or stack switch to cut off the fuel should the burner stop firing,
(3) a high limit switch in the main duct to cut off the fuel should
the air temperature become too high, and (4) a thermostat to
select the desired temperature.

FIELD OPERATIONS
An efficient digging and shaking operation can be accom-
plished by using a tractor equipped with a two-row plow and
a chain type shaker and windrower. The peanuts and vines
should be permitted to dry in the field until the peanuts can be
picked from the vines economically with a peanut combine. This
usually requires 11/2 to 2 days when weather conditions are good
for field drying. Heat from the sun may damage the shelling
qualities of peanuts if they are exposed directly for more than
two days. The damage observed was excess slippage of the
skin and parting of the cotyledons when these peanuts were
mechanically shelled.

METHOD OF PROCEDURE
To establish a drying procedure that would minimize damage
to quality and germination of peanuts, a number of tests were
conducted on laboratory and standard mechanical driers. The
laboratory driers were designed so that the air temperature and
rate of air could be regulated very accurately. In the laboratory
drier, peanuts were dried in depths up to four feet and in quan-
tities up to 400 pounds. The standard mechanical drier used
in conducting these tests had 600 square feet of floor space and
a maximum capacity of approximately 25 tons of peanuts per
loading.







Florida Agricultural Experiment Stations


The peanuts used for these experiments were of the Runner
variety. A two-row tractor-powered digger-shaker-windrower
and a Lilliston peanut combine were used to harvest the pea-
nuts. The peanuts were permitted to dry in the window from
one to five days before combining. In all cases, the peanuts
were placed on the drier the same day they were combined.
Fifteen loadings of peanuts were dried on the laboratory
driers. Various air temperatures were used, with each loading
being subjected to a constant air temperature during the entire
drying period. The air temperatures used were 950 F., 1000 F.,
1050 F., 1100 F., 115 F., 1200 F., 125 F., 1300 F., 1350 F., and
140 F. Tests conducted at air temperatures between 1050 F.
and 1250 F. were duplicated. The amount of air forced through
the peanuts was not varied, it being 40 cfm 1 per square foot of
drying area for all tests. Samples of peanuts were taken from
each test lot at varied intervals during the drying period. This
was done to determine what effect the final moisture content
(wet basis) and the length of drying period had on the
mechanically dried peanuts.
A control sample (check), as well as the samples taken from
the drier that had a moisture content of more than 9 percent,
were spread thinly on a concrete floor under an open shelter to
complete drying. The samples were then placed in storage for
three months before they were tested for taste, discoloration,
skin slippage and germination.
The standard mechanical drier was loaded six times with
bags of peanuts in order that the experimental results obtained
from the laboratory driers could be tested on a farm-size drier.
The depth of loadings varied from one foot to three feet and
the drying air was heated approximately 30 F. above the
ambient air temperature, except on hot days when a limit con-
trol was used to keep the temperature from rising above 1150 F.
Air was forced through these peanuts at rates of from 30 to
84 cfm per square foot of floor area.

RESULTS
Peanuts can be dried from a partially cured state (40 percent
moisture on a wet basis or under) by mechanical means on a

Scfm = cubic feet per minute.
2 Wet basis may be defined as the weight of water removed divided by
the weight of the "green" peanuts. All moisture contents referred to in
this bulletin are calculated on a wet basis.








Mechanical Drying and Harvesting of Peanuts


batch-type crop drier with no apparent injury to the peanuts.
Air temperatures in excess of 1150 F. appear to injure peanuts
by increasing skin slippage. Air temperature up to 140' F. did
not appear to reduce the germination of peanuts, provided the
splits were screened out. Table 1 shows that the mechanically
dried peanuts showed a slightly higher percentage of germina-
tion than the naturally dried checks, irrespective of the tem-
perature treatments. There is no satisfactory explanation for
this occurrence unless it was due to length of drying period.
The mechanically dried peanuts were dried in from one to two
days while the naturally dried checks required approximately
two weeks for drying.

TABLE 1.-PERCENT GERMINATION AND DAMAGE IN THE FORM OF SKIN
SLIPPAGE OF MECHANICALLY DRIED PEANUTS AS AFFECTED BY VARIOUS
DRYING AI TEMPERATURES.
Percent
No. Tempera- Percent Damage in
Treatment Samples ture of Germina- the Form of
No. Averaged Drying Air tion Skin
Slippage

1 2 95" F. 90.00 2.00
check 1 94.00 2.00
2 3 100 F. -81.67 0.00
check 1 80.00 0.00
3 8 105* F. 89.87 1.00
check 2 -, 85.13 1.50
4 3 110 F. 93.33 2.00
check 1 82.00 0.00
5 11 115* F. 90.18 4.60
check 3 88.55 5.45
6 5 120* F. 90.20 4.72
check 2 81.20 0.00
7 7 125* F. 91.71 5.71
check 2 85.86 1.71
8 3 1300 F. 96.67 9.20
check 1 82.00 0.00
9 1 135* F. 94.00 20.00
check 1 91.00 12.00
10 1 140 F. 89.00 18.00
check 1 80.00 2.00

Difference required for significance be-
tween treatments for percent 5% 4.48
germination 1% 11.95

Difference required for significance be-
tween treatments for percent damage 5% 1.32
in the form of skin slippage 1% 1.58

Table 1 also shows that there is very little difference in per-
cent damage in the form of skin slippage between naturally







Florida Agricultural Experiment Stations


dried and mechanically dried peanuts when drying air tempera-
tures between 950 F. and 115 F. were used. However, for*air
temperatures between 1200 F. and 1400 F., there was as much
as 16 percent more damage in the mechanically dried peanuts
than in the naturally dried peanuts.
Some moisture levels to which peanuts are dried appear
definitely to affect the quality of mechanically cured peanuts.
Table 2 shows that peanuts dried to less than 7 percent mois-
ture content had more damage in the form of skin slippage than
peanuts that were not dried this low. Peanuts dried to a mois-
ture content in the range of 3 to 5 percent had more than
13 percent damage in the form of skin slippage.

TABLE 2.-PERCENT GERMINATION AND DAMAGE IN TIE FORM OF SKIN
SLIPPAGE OF MECHANICALLY DRIED PEANUTS AS AFFECTED BY VARIATIONS
IN MOISTURE PERCENTAGE OF THE PEANUTS AT TIME OF REMOVAL FROM
THE DRIER.
Percent
No. Percent Percent Damage in
Treatment Samples Moisture Germina- the Form of
No. Averaged After tion Skin
SDrying _I Slippage
1 3 3-5 89.33 13.33
check 2 7-9 82.00 0.00
2 12 5-7 90.58 7.33
check 5 7-9 87.33 4.50
3 9 7-9 92.66 4.00
check 4 7-9 85.44 3.11
4 13 9-11 90.00 4.92
check 4 7-9 85.38 2.15
5 7 11-15 88.57 3.33
check 3 7-9 84.00 1.14

Difference required for significance be-
tween treatments for percent 5% 4.48
germination 1% 11.95

Difference required for significance be-
tween treatments for percent damage 5% 1.32
in the form of skin slippage 1% 1.58

The moisture content to which the peanuts were dried did not
seem to affect materially the germination; however, the highest
percent germination was obtained when peanuts were reduced
in moisture content to the range of 7 to 9 percent. It was ob-
served that the moisture content of peanuts dropped 1 to 2
percent during the period they were being cooled, unloaded
from the drier, and moved into storage. This period was usually
about 12 hours.







Mechanical Drying and Harvesting of Peanuts


The moisture content of peanuts at the time they are placed
on the drier does not appear to affect, to any great extent, the
germination or damage in the form of skin slippage, provided
peanuts are not over-dried or the temperature of the drying
air is not excessive. Table 3 shows that the percentage of
damage in the form of skin slippage increases as the initial
moisture content increases, but the amount of damage does not
appear to be serious for moisture contents up to approximately
40 percent.

TABLE 3.-PERCENT GERMINATION AND DAMAGE IN THE FORM OF SKIN
SLIPPAGE OF MECHANICALLY DRIED PEANUTS AS AFFECTED BY MOISTURE
CONTENT OF THE PEANUTS BEFORE DRYING.*
S : [ Average
No. Average Average Average I Percent
Treat- Sam- Moisture Moisture I Lngth of Average Damage
ment ples Content Content I Drying Percent ] in the
No. Aver- I Before After Period Germina- Form of
aged Drying Drying I in Hours tion Skin
I I _____ Slippage

1 4 12.00 8.14 14.75 92.50 2.00
check 1 12.00 91.00 4.00
2 3 25.00 8.07 24.27 84.00 2.67
check 1 25.00 80.00 0.00
3 4 38.62 8.70 29.00 87.75 5.00
check 1 38.62 82.00 0.00

Difference required for significance
between treatments for percent 5% 4.48
germination 1% 11.95

-Difference required for significance
Between treatments for percent
damage in the form of skin 5% 1.32
slippage 1% 1.58
All samples were mechanically dried with air temperatures between 1000 F. and
1200 F. Checks were dried by spreading on concrete floor under shelter. Drying time was
from 1 to 2 weeks, and the average moisture content after drying was between 7 and 9
percent.

Results of the test conducted on the standard crop drier
(Table 4) indicate that peanuts can be dried economically with
the type drying equipment described in Experiment Station
Bulletin 477. The time required to dry peanuts varied from
24 to 36 hours when the recommended drying procedure was
followed.
Since peanuts are a fairly large seed, they offer little resist-
ance to the flow of air. Four feet of loose peanuts with air
moving through them at a rate of 40 cfm per square foot of
floor area offer a resistance of approximately 0.25 inch of water







Florida Agricultural Experiment Stations


static pressure. Most crop drying fans or blowers have the
ability to deliver air economically against a static pressure of
1.00 inch or more of water.

TABLE 4.-RESULTS OF TESTS CONDUCTED ON STANDARD CROP DRIER.
Moisture Cost of
Pounds Content Rate of Depth Fuel and
Test of of Seed Air in Drying of Seed Power
No. Seed Before Cfm/Sq. Time in on per Ton
Dried Drying in Foot Hours Drier of Dried
Percent in Feet Peanuts*

1 11,960 27.40 42 33.0 1.33 $2.32
2 2,380 21.32 84 23.0 1.00 4.27
3 9,595 30.80 42 29.5 2.00 2.77
4 10,735 39.20 30 54.0** 2.00 3.11
5 2,730 30.40 84 25.5 1.00 4.85
6 8,690 31.45 42 26.0 3.00 2.65

Based on a cost of 12 cents per gallon for No. 2 fuel oil and 3 cents per kwh for
electricity.
** Irier operated 30 hours with heated air and 24 hours with unheated air.

It is obvious, then, that the capability of the fan or blower
is not the limiting factor as to the depth at which peanuts can
be properly dried. See Figures 3 and 4 for the resistance
offered by peanuts for other loading depths and rates of air.
There is a limiting factor, however, in the depth at which pea-


Fig. 3.-Resistance of bagged peanuts, bin walls and floor (1a" mesh hard-
ware cloth) to air flow. (From Bulletin 477.)







Mechanical Drying and Harvesting of Peanuts


AIR PRESSURE (INCHES WATER)
Fig. 4.-Resistance of loose peanuts, bin walls and floor (%1" mesh hard-
ware cloth) to air flow. (From Bulletin 477.)

nuts should be dried; this is the variation in moisture content
from top to bottom of the layer after drying is completed.
The variation in moisture content from top to bottom of a
layer of dried peanuts is approximately 0.5 percent per foot
of depth when an air rate of 40 cfm per square foot of drying
area and an air temperature of 1150 F. is used. Thus, for a four
foot loading depth, the peanuts on the bottom will be approxi-
mately 2 percent lower in moisture content than those on top.
No off-taste or discoloration inside the kernels was detected in
any of the treatments used in this experiment. A rate of air
of approximately 40 cfm per square foot of drying area proved
adequate for loading depths up to four feet.

SUMMARY
High labor costs and damage to peanuts caused by, adverse
weather conditions are forcing peanut producing farmers to
turn to mechanization in an effort to increase profits. The
mechanical drying of peanuts is an integral part of this program.
Peanuts can be dried economically on a batch-type crop drier.
The two most important practices that affect the quality of
mechanically dried peanuts are (1) the final moisture content
of the peanuts and (2) the temperature of the drying air. Best







Florida Agricultural Experiment Stations


results were obtained when peanuts were dried to a moisture
content range of from 7 to 9 percent and when the drying air
temperature was 115' F. or less.

CONCLUSIONS
1. Peanuts can be dried from a partially cured state (40
percent moisture content on a wet basis, or under) by mechani-
cal means with no serious injury to the peanuts.
2. The drying air temperature should be no higher than
115 F.
3. A rate of air of 40 cfm per square foot of drying floor area
is adequate.
4. The moisture content should be reduced to at least 9
percent (wet basis) but not lower than 7 percent (wet basis).
5. A reliable moisture tester should be used in determining
moisture contents.
6. Peanuts should be dried in depths not over four feet.
7. Peanuts can be dried in burlap bags provided layers of
bags are crisscross and the bags are about 75 percent filled.
They may be dried loose in bins provided it is economical to
keep the lots separated and unloading is mechanized.

ACKNOWLEDGMENTS
The authors express their appreciation to Mr. June Sims, student, of
Marianna, Florida, for his assistance in conducting the drying tests, and to
Mr. Ernest Haufler, farmer, of Gainesville, Florida, for furnishing the
peanuts for the experiments.









HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






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