• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Table of Contents
 Introduction
 Review of literature
 Experiments during 1955-1960
 Experiments during 1960-1963
 General discussion
 Summary and conclusions
 Sample calculations; analysis of...
 Literature cited; acknowledgem...






Group Title: Technical bulletin - Agricultural Experiment Stations, University of Florida - 694
Title: Mechanical dewatering of forage crops
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027539/00001
 Material Information
Title: Mechanical dewatering of forage crops
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 39, 1 p. : ill., chart ; 23 cm.
Language: English
Creator: Casselman, T. W
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1965
 Subjects
Subject: Forage plants -- Drying -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 40.
Statement of Responsibility: T.W. Casselman ... et al..
General Note: Cover title.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00027539
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000929280
oclc - 18361369
notis - AEP0057

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Review of literature
        Page 3
        Page 4
    Experiments during 1955-1960
        Page 5
        Experimental dewatering equipment
            Page 5
        Experimental procedure
            Page 5
            Page 6
            Page 7
            Page 8
        Results and discussion
            Page 9
            Moisture reduction in fresh forage
                Page 9
                Page 10
            Effect of dewatering on nutrient content
                Page 11
                Page 12
                Page 13
                Page 14
            Ensilability of dewatered forage in glass jars
                Page 15
    Experiments during 1960-1963
        Page 15
        Page 16
        Experimental dewatering and ensiling equipment
            Page 15
            Comparison of dewatering, wilting, chopping and flail-cutting upon ensilability of paragrass
                Page 15
            Effect of two dewatering pressures on chemical composition of small grain forage at different stages of maturity
                Page 17
                Page 18
                Page 19
        Experimental procedure
            Page 20
            Experiment I
                Page 20
            Experiment II
                Page 20
        Results and discussion
            Page 21
            Experiment I
                Page 21
                Page 22
            Experiment II
                Page 23
                Page 24
                Page 25
                Page 26
                Page 27
                Page 28
                Page 29
    General discussion
        Page 30
    Summary and conclusions
        Page 31
        Page 32
    Sample calculations; analysis of variance table
        Page 33
        Sample calculations
            Page 33
        Analysis of variance tables
            Page 33
            Page 34
            Page 35
            Page 36
            Page 37
            Page 38
            Page 39
    Literature cited; acknowledgements
        Page 40
Full Text





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.






Copyright 2005, Board of Trustees, University
of Florida










TECHNICAL BULLETIN 694
AUGUST 1965

AGRICULTURAL EXPERIMENT STATIONS
UNIVERSITY OF FLORIDA, GAINESVILLE
J. R. BECKENBACH, DIRECTOR







T. W. CASSELMAN, V. E. GREEN, JR.
R. J. ALLEN, JR., F. H. THOMAS


MECHANICAL DEWATERING
OF FORAGE CROPS


A


Ro


c.rf Al ir ~ ..
*I'V
-r -11


~Fj~F.'








CONTENTS


Page
Introduction 3

Review of Literature ..... 3

Part I. Experiments during 1955-1960. --------------- -- 5
Experimental Dewatering Equipment.. -------- 5
Experimental Procedure ...---------------------- 5
Results and Discussion.... ---------------------- 9
Moisture Reduction in Fresh Forage .. ---------------. 9
Effect of Dewatering on Nutrient Content ------ 11
Ensilability of Dewatered Forage in Glass Jars---- 15

Part II. Experiments during 1960-1963 .....---------- 15
Experimental Dewatering and Ensiling Equipment.---- 15
Experiment I. Comparison of dewatering, wilting, chopping,
and flail-cutting upon ensilability of paragrass 15
Experiment II. Effect of two dewatering pressures on chemi-
cal composition of small grain forage at
different stages of maturity ---- 17

Experimental Procedure --------------- -- 20
Experiment I ..---------------- 20
Experiment II ------------------------ 20

Results and Discussion .--------------------- 21
Experiment I ------------ 21
Experiment II -------------------- 23

General Discussion -----.------------- 30

Summary and Conclusions ..... ...----------------------- 31

Appendix ---------------------- 33
Sample Calculations --.---------------------- 33
Analysis of Variance Tables ......-------- ..- .-- 33

Literature Cited -----.------- ---...-.. -------- 40

Acknowledgements --.--- ---- -------------- 40


A contribution from the Everglades Experiment Station.







MECHANICAL DEWATERING OF
FORAGE CROPS
T. W. Casselman, V. E. Green, Jr., R. J. Allen, Jr.,
and F. H. Thomas

INTRODUCTION

Mechanical dewatering, as used in this bulletin, will indicate a
process in which some of the moisture in forage materials is re-
moved mechanically as a first step in the processing of a livestock
feed. The objective of mechanical dewatering of forage crops is to
reduce the moisture content, without excessive loss of nutrients,
to a level that will allow economic thermal dehydration.
All forages when converted into dry feeds with acceptable
storage characteristics must have excess water removed, preferably
without appreciable loss of the desirable nutrients found in the
original crop. The time-honored method of field curing hay,
utilizing the sun's energy to remove excess moisture, appears on
the surface to be an economical system. Unfortunately, this
system has certain inherent disadvantages, i.e., leaching and
shattering losses due to exposure to the weather and mechanical
handling. In some areas such as south Florida, this system is
impractical due to high humidity, high soil moisture, and frequent
rain showers. Under these climatic conditions vegetative growth
is rapid and lush, and green weight yields are high. These same
climatic conditions, however, are responsible for the problems
encountered in processing high moisture forage. Large quantities
of water must be removed from the plant, and the commonly used
methods are not adequate. Mechanical dewatering was studied
as a means of removing some of the initial moisture in a forage
prior to further processing, and the results of these studies are
reported herein.

REVIEW OF LITERATURE
Since 1942, British researchers have studied the principles of
mechanical dewatering to extract protein from plant materials for
human consumption. Pilot plant production of plant protein for

SAssistant Agricultural Engineer, Associate Agronomist, Assistant
Agronomist and Assistant Chemist, respectively, Everglades Experiment
Station, Belle Glade, Florida.







MECHANICAL DEWATERING OF
FORAGE CROPS
T. W. Casselman, V. E. Green, Jr., R. J. Allen, Jr.,
and F. H. Thomas

INTRODUCTION

Mechanical dewatering, as used in this bulletin, will indicate a
process in which some of the moisture in forage materials is re-
moved mechanically as a first step in the processing of a livestock
feed. The objective of mechanical dewatering of forage crops is to
reduce the moisture content, without excessive loss of nutrients,
to a level that will allow economic thermal dehydration.
All forages when converted into dry feeds with acceptable
storage characteristics must have excess water removed, preferably
without appreciable loss of the desirable nutrients found in the
original crop. The time-honored method of field curing hay,
utilizing the sun's energy to remove excess moisture, appears on
the surface to be an economical system. Unfortunately, this
system has certain inherent disadvantages, i.e., leaching and
shattering losses due to exposure to the weather and mechanical
handling. In some areas such as south Florida, this system is
impractical due to high humidity, high soil moisture, and frequent
rain showers. Under these climatic conditions vegetative growth
is rapid and lush, and green weight yields are high. These same
climatic conditions, however, are responsible for the problems
encountered in processing high moisture forage. Large quantities
of water must be removed from the plant, and the commonly used
methods are not adequate. Mechanical dewatering was studied
as a means of removing some of the initial moisture in a forage
prior to further processing, and the results of these studies are
reported herein.

REVIEW OF LITERATURE
Since 1942, British researchers have studied the principles of
mechanical dewatering to extract protein from plant materials for
human consumption. Pilot plant production of plant protein for

SAssistant Agricultural Engineer, Associate Agronomist, Assistant
Agronomist and Assistant Chemist, respectively, Everglades Experiment
Station, Belle Glade, Florida.







Florida Agricultural Experiment Stations


human consumption has been studied since 1948 (7) 2. In 1963
installation of a bulk protein extraction unit at Kingston, Jamaica,
was completed, indicating that mechanical removal of juice and
nutrients is feasible.3
The general procedure has been to pulp the fresh leaves or
plants into a semi-liquid, fibrous mass, before removing the juice in
a mechanical press. Pirie (5) described several types of mechanical
presses which can remove 50 to 90 percent of the fluid from a pulp
initially containing 80 to 90 percent water. He also reported that
50 to 60 percent of the protein in the initial crop can be collected
in the expressed juice by this method (6). The protein-containing
solids can be separated from the juice by heat coagulation or acid
precipitation. The remaining fibrous materials from which much of
the nutrients and moisture have been removed is generally dis-
carded, but could be used as roughage for ruminants.
To remove the greatest amount of the protein in the juice,
Pirie (5) recommended that the layer of material after pressing
should not exceed 1 inch in thickness. As the compressed mat
increased in thickness, more of the protein in the solid mass of
forage was retained by the filtering action of the compressed
fibers. The expressed juice emerging thus contained less nutrients.
Protein retention in the fibrous portion of the plant should be the
goal in adapting these principles to the mechanical dewatering of
forage crops.
Italian researchers (12) utilized these principles in the PAST
(Prodotti Alimentari Sistema Tallarico) system to obtain up to
one-third more hay as compared with normal hay-making pro-
cedures by avoiding leaf shattering and leaching losses associated
with normal hay making. They reported hay thus made to be
higher in nutritive value than sun-cured hay.
Experimental mechanical dewatering of forage crops and
potential forage crops grown in the Florida Everglades was begun
in 1955 at the Everglades Experiment Station. The major ob-
jectives of these studies were to determine: 1) the feasibility of
dewatering local forage crops using available equipment, 2) the
amount of water which can be removed from crops by mechanical
dewatering over a range of initial moisture contents, 3) the effect
of pressing on the nutritive content of various crops, and 4) ways
to utilize the pressed forage effectively.

2 Numbers in parentheses refer to Literature Cited.
SPersonal communication from N. W. Pirie to V. E. Green, Jr., dated
February 27, 1963.







Mechanical Dewatering of Forage Crops


Much of the early work has been published (8, 9, 10, 11). This
bulletin is a compilation of all mechanical dewatering studies per-
formed at the Everglades Experiment Station. The results are
presented in two parts: Part I covers the period 1955 to 1960
and Part II covers the period 1960 to 1963.

PART I. EXPERIMENTS DURING 1955-1960
Experimental Dewatering Equipment

Dewatering was accomplished with several screw-type presses
of different sizes.4 These presses are commercially available and
are currently employed in many industrial operations. They con-
sist of broken flight augers. Each auger section has a pitch less
than the preceding section, turning at a low speed within a cylin-
drical screen (Figure 1).
In theory the press operates as follows. As the forage moves
through the press by auger sections of progressively decreasing
pitch, the volume moved per revolution of the screw decreases.
Compaction results to generate the pressures necessary to expel
the juice. To aid in keeping the cylinder full and the pressure
constant, an air controlled choke cone at the outlet of the press is
forced against the outcoming forage by an adjustable pressure air
cylinder. Stop bars attached to the frame of the press and
extending into the screw between the flight sections prevent the
forage from rotating with the screw, thus causing it to move
parallel with the axis of the screw shaft.
The four press sizes used in these early studies were 4, 10, 12,
and 16 inches in diameter. The 4 and 10-inch sizes (Figure 2)
were laboratory models and loaned by the manufacturer to the
Everglades Experiment Station. The 16-inch unit was installed
and operated at a commercial forage processing plant. The 12-
inch press, belonging to the Everglades Experiment Station, was
trailer mounted for field operations (Figure 3).

Experimental Procedure

Representative samples of fresh forage, pressed forage, and
expressed juices were obtained from a number of laboratory and
field experiments and from a commercial operation for a wide

Presses used in these studies were manufactured by Dan B. Vincent,
Inc., Tampa, Florida.







Mechanical Dewatering of Forage Crops


Much of the early work has been published (8, 9, 10, 11). This
bulletin is a compilation of all mechanical dewatering studies per-
formed at the Everglades Experiment Station. The results are
presented in two parts: Part I covers the period 1955 to 1960
and Part II covers the period 1960 to 1963.

PART I. EXPERIMENTS DURING 1955-1960
Experimental Dewatering Equipment

Dewatering was accomplished with several screw-type presses
of different sizes.4 These presses are commercially available and
are currently employed in many industrial operations. They con-
sist of broken flight augers. Each auger section has a pitch less
than the preceding section, turning at a low speed within a cylin-
drical screen (Figure 1).
In theory the press operates as follows. As the forage moves
through the press by auger sections of progressively decreasing
pitch, the volume moved per revolution of the screw decreases.
Compaction results to generate the pressures necessary to expel
the juice. To aid in keeping the cylinder full and the pressure
constant, an air controlled choke cone at the outlet of the press is
forced against the outcoming forage by an adjustable pressure air
cylinder. Stop bars attached to the frame of the press and
extending into the screw between the flight sections prevent the
forage from rotating with the screw, thus causing it to move
parallel with the axis of the screw shaft.
The four press sizes used in these early studies were 4, 10, 12,
and 16 inches in diameter. The 4 and 10-inch sizes (Figure 2)
were laboratory models and loaned by the manufacturer to the
Everglades Experiment Station. The 16-inch unit was installed
and operated at a commercial forage processing plant. The 12-
inch press, belonging to the Everglades Experiment Station, was
trailer mounted for field operations (Figure 3).

Experimental Procedure

Representative samples of fresh forage, pressed forage, and
expressed juices were obtained from a number of laboratory and
field experiments and from a commercial operation for a wide

Presses used in these studies were manufactured by Dan B. Vincent,
Inc., Tampa, Florida.







Mechanical Dewatering of Forage Crops


Much of the early work has been published (8, 9, 10, 11). This
bulletin is a compilation of all mechanical dewatering studies per-
formed at the Everglades Experiment Station. The results are
presented in two parts: Part I covers the period 1955 to 1960
and Part II covers the period 1960 to 1963.

PART I. EXPERIMENTS DURING 1955-1960
Experimental Dewatering Equipment

Dewatering was accomplished with several screw-type presses
of different sizes.4 These presses are commercially available and
are currently employed in many industrial operations. They con-
sist of broken flight augers. Each auger section has a pitch less
than the preceding section, turning at a low speed within a cylin-
drical screen (Figure 1).
In theory the press operates as follows. As the forage moves
through the press by auger sections of progressively decreasing
pitch, the volume moved per revolution of the screw decreases.
Compaction results to generate the pressures necessary to expel
the juice. To aid in keeping the cylinder full and the pressure
constant, an air controlled choke cone at the outlet of the press is
forced against the outcoming forage by an adjustable pressure air
cylinder. Stop bars attached to the frame of the press and
extending into the screw between the flight sections prevent the
forage from rotating with the screw, thus causing it to move
parallel with the axis of the screw shaft.
The four press sizes used in these early studies were 4, 10, 12,
and 16 inches in diameter. The 4 and 10-inch sizes (Figure 2)
were laboratory models and loaned by the manufacturer to the
Everglades Experiment Station. The 16-inch unit was installed
and operated at a commercial forage processing plant. The 12-
inch press, belonging to the Everglades Experiment Station, was
trailer mounted for field operations (Figure 3).

Experimental Procedure

Representative samples of fresh forage, pressed forage, and
expressed juices were obtained from a number of laboratory and
field experiments and from a commercial operation for a wide

Presses used in these studies were manufactured by Dan B. Vincent,
Inc., Tampa, Florida.

















HEAVY RING YOKES


A SUPPORT BARS


DRAINAGE SCREEN .FO. SEEN PRESURE RIEULATOR
UNDER INLET HOPPER
S HOPPER SPECIAL TYPE PRESS SCREW
FOR TURNING THE MATERIAL

STOP BARS LARGE PRESSURE CYLINDER




PNEUMATIC
CUSHION



SI ,- I2 WAY VALVE .


PRESS LIQUOR DRAIN POSITIVE FORWARD
POSITIVE FORWARD
SPLIT SCREEN HOUSING STAINLESS STEEL DRAIN SCREEN IN CONE & REVERSE ACTION
FOR EASY ACCESS & CLEANING PERFORATED SCREEN
0

Figure 1.- Cutaway drawing showing essential construction features of the mechanical dewatering press used in the Everglades
Station studies. (Illustration courtesy of Dan B. Vincent, Inc.)






Mechanical Dewatering of Forage Crops


variety of crops. However, certain common conditions were met
whenever samples were taken: 1) fresh forage samples were all
harvested and chopped by standard forage crop harvesters before
being pressed; 2) in the case of manually harvested crops and
vegetable wastes in particular, efforts were made to simulate the
action of the chopping effect of a harvester as closely as possible;
and 3) on all presses the air pressure on the choke cone was


wSF2S--^
A MI'.JI^^f WR JL


Figure 2.- Four-inch portable press (above) in operation pressing grass.
Expressed juice is collected in glass jar and pressed grass in tub. Ten-inch
press (below) showing choke cone and controlling air cylinder on output end.


'~=c~Ck

~1~" ~'"








Florida Agricultural Experiment Stations


- 4.6.P$f -.--%IS~ '* ;~;
* ~~I ~~ "? i


Figure 3.-Trailer mounted 12-inch press (foreground) was used in the
Everglades Station field studies. The shredder, mounted on the front part of
the trailer, macerates the fresh forage prior to pressing. The flail type harvester
(background) was used to cut the forage.

maintained at 40 to 50 pounds per square inch (psi).
For convenience, forage crops and potential forage crops were
divided into four arbitrary classes: pasture grasses, including
paragrass, pangolagrass, caribgrass, bermudagrass, St. Augustine-
grass, and other pasture type grasses normally grown in this area;
other grasses, including oats, sorghum, sweet corn stover, and
sugarcane tops and leaves; legumes, including white clover and
alfalfa; and vegetables and vegetable wastes such as celery stalks
and tops, turnip tops, endive, and beet tops.
Samples were prepared and chemical analyses performed.
Crude protein, fat, fiber, nitrogen-free extract, and ash determina-
tions were those outlined by the A.O.A.C. (1). For more accurate
estimation of "true" protein, alcohol-insoluble N was determined
by employing the A.O.A.C. macro-Kjeldahl crude protein method
on subsamples that were extracted in a Soxhlet for 24 hours with








Mechanical Dewatering of Forage Crops


refluxing 70 percent ethyl alcohol. Calcium, magnesium, potas-
sium, and sodium contents were determined employing chloride
standards for Mg, K, and Na and an acetate standard for Ca by
the flame photometer method using a model D. U. Beckman
spectrophotometer with a flame (hydrogen-oxygen) attachment.
Samples of expressed juices were prepared for analysis by heating
and adding concentrated hydrochloric acid and centrifuging at
about 1000 times gravity. Acidifying the juice samples to a re-
action of pH 4, either with acid or on standing, presented the
coagulum, which was readily precipitated. Heating accelerated the
flocculation.
Silages were prepared and tested by the following procedure:
plant materials, fresh forage or pressed forage, were packed as
tightly as possible with a wooden hammer handle into quart glass
jars. Densities of packing were determined by weighing the full
jars, finding the moisture contents of the plant materials used,
and calculating dry weight per unit volume directly. After sealing,
the glass jar "silos" were allowed to incubate in semi-darkness at
room temperature. Determinations of pH were made according
to the hotwater extraction method employing a glass electrode
described by Barnett (2). Moisture contents (or dry matter
contents) of forages were determined by drying the samples in
forced draft ovens at about 90 C.


Results and Discussion

Moisture Reduction in Fresh Forage
The average effect of mechanical dewatering on moisture re-
moval in terms of the ratio of units of moisture to units of dry
matter (M/DM) over a wide range of moisture conditions for
numerous crops is shown in Figure 4. The M/DM ratio is numer-
ically equivalent to the moisture content expressed on a dry weight
basis divided by 100. The dry weight basis of moisture content
expression is frequently used in drying studies because the mois-
ture lost is easily obtained by subtraction. For example, if a fresh
sample enters the press at 85 percent moisture (wet basis) it
contains 5.67 units of moisture per each unit of dry matter
(M/DM = 5.67); after leaving the press, M/DM = 2.33 (refer
to Figure 4 and the dashed lines). Therefore, under these con-
ditions, after treatment by the press, the forage has lost 3.34 units
of moisture or over half the original amount of water. An M/DM








Mechanical Dewatering of Forage Crops


refluxing 70 percent ethyl alcohol. Calcium, magnesium, potas-
sium, and sodium contents were determined employing chloride
standards for Mg, K, and Na and an acetate standard for Ca by
the flame photometer method using a model D. U. Beckman
spectrophotometer with a flame (hydrogen-oxygen) attachment.
Samples of expressed juices were prepared for analysis by heating
and adding concentrated hydrochloric acid and centrifuging at
about 1000 times gravity. Acidifying the juice samples to a re-
action of pH 4, either with acid or on standing, presented the
coagulum, which was readily precipitated. Heating accelerated the
flocculation.
Silages were prepared and tested by the following procedure:
plant materials, fresh forage or pressed forage, were packed as
tightly as possible with a wooden hammer handle into quart glass
jars. Densities of packing were determined by weighing the full
jars, finding the moisture contents of the plant materials used,
and calculating dry weight per unit volume directly. After sealing,
the glass jar "silos" were allowed to incubate in semi-darkness at
room temperature. Determinations of pH were made according
to the hotwater extraction method employing a glass electrode
described by Barnett (2). Moisture contents (or dry matter
contents) of forages were determined by drying the samples in
forced draft ovens at about 90 C.


Results and Discussion

Moisture Reduction in Fresh Forage
The average effect of mechanical dewatering on moisture re-
moval in terms of the ratio of units of moisture to units of dry
matter (M/DM) over a wide range of moisture conditions for
numerous crops is shown in Figure 4. The M/DM ratio is numer-
ically equivalent to the moisture content expressed on a dry weight
basis divided by 100. The dry weight basis of moisture content
expression is frequently used in drying studies because the mois-
ture lost is easily obtained by subtraction. For example, if a fresh
sample enters the press at 85 percent moisture (wet basis) it
contains 5.67 units of moisture per each unit of dry matter
(M/DM = 5.67); after leaving the press, M/DM = 2.33 (refer
to Figure 4 and the dashed lines). Therefore, under these con-
ditions, after treatment by the press, the forage has lost 3.34 units
of moisture or over half the original amount of water. An M/DM




















LEGEND
* Pasture Grasses
o Other Grasses
o Legumes
A Veg. B Veg. Wastes


Fresh


I
I


SPressed Forage
S -Pressed Forage


60 65


70 75 80 85
PERCENT MOISTURE,WET BASIS


90 95


i.
18

I

.-1
14
0
o
12 m
C

10 m
m
8
z

6

a
4

-4
-I
2


10
00


- I I I I


I.... I .


I







Mechanical Dewatering of Forage Crops


ratio of 2.33 is equivalent to 70 percent moisture on the wet
basis. Any M/DM figure can be converted to moisture content
(wet basis) using the following expression:
M/DM
% moisture wet basis = X 100
M/DM + 1
Thus in the above example when M/DM = 2.33,
% moisture = [(2.33)/(2.33 + 1)] X 100 = 70.
The amount of moisture removed by the mechanical dewatering
press depends upon several interrelated factors which include
initial moisture content, age of crop, type of crop, preparation of
material before pressing, and others. It is evident from the scatter
in the data that, even within the same class, the freehand curve
for pressed forage is an average of what occurred when these
materials were pressed under the conditions described. However,
the curves do indicate that the pressing operation became signifi-
cantly more important as the moisture content increased.
The upward trend of the curve in the high moisture region
prompted the trial of additional mechanical and chemical treat-
ment of crops prior to pressing. A shredder, similar to a hammer
mill but with swinging blades and without a screen, was used to
shred and macerate material before pressing. In some cases 11/4
percent hydrated lime by weight was added to the shredded
materials.
Table 1 shows the effects of mechanical and chemical treat-
ments on the reduction of the M/DM ratio for the crops treated.
Shredding significantly reduced the M/DM ratio in the higher
moisture crops. The effect on grasses was not so pronounced,
though it did help in some cases. Addition of lime further aided in
the removal of water.

Effect of Dewatering on Nutrient Content
Representative fresh forage and pressed forage samples were
analyzed for crude protein, fat, fiber, ash, and nitrogen-free-extract
(NFE). Contents of crude protein and ash were generally lower,
and contents of fiber were slightly higher in pressed forage than
in fresh forage. In certain cases percent NFE was increased by
pressing. In the permanent pasture grasses and white clover, the
percentage of fat increased on pressing; in celery strippings and
oats it decreased (Table 2).








Florida Agricultural Experiment Stations


Table 1.- Units moisture per unit of dry matter (M/DM) for a represent-
ative selection of plant materials that were subjected to several different treat-
ments prior to pressing.
Pressed Forage
Plant Material Shredded
& Original plus 11/4%
Moisture Content, Fresh Not Hydrated
% Wet Basis Forage Shredded Shredded Lime
Veg. & veg. wastes
Celery stalks (95.3) 20.3 8.2 5.0 3.2
Endive (94.8) 18.2 5.8 4.1 2.4
Turnip tops (93.9) 15.4 2.8 -
Sugar beet tops (93.6) 14.6 6.6 3.6 2.0
Mangel (Wurzel) tops (92.9) 13.1 3.6 3.5 2.7
Collards (91.5) 10.8 2.6 -
Stock beet tops (90.8) 9.9 4.8 3.0 2.7
Celery leaves (90.6) 9.6 3.2 2.9 1.5
Pasture grasses
Paragrass (87.4) 6.9 2.3 1.8 -
Alexandergrass (87.0) 6.7 1.9 2.0 -
Napiergrass (85.2) 5.8 2.3 2.0 -
Pangolagrass (82.6) 4.8 1.8 -
Caribgrass (82.2) 4.6 2.2 -
St. Augustinegrass (80.5) 4.1 2.8 2.2 -
Bermudagrass (77.0) 3.3 1.8 1.8 -
Other grasses
Oats (88.5) 7.7 2.3 -
Sorghum (82.0) 4.5 1.7 -
Sweet corn stover (77.9) 3.5 2.4 2.5 -
Legumes
White clover (88.0) 7.3 1.6 -
Alfalfa (82.6) 4.6 2.1 -

Vitamin A equivalent and crude protein contents of sorghum
were reduced to some extent by pressing (Table 3). Some of the
vitamin A equivalent, like crude protein, was found to be recover-
able in the coagulum. Such separation of protein and vitamin A
equivalent from the pressed material and their recovery in coagula
were explored further with other crop materials. The dried coag-
ulum from oats contained about 35 percent crude protein and
over 450,000 U.S.P. units of vitamin A equivalent per pound; that
from celery tops contained over 40 percent crude protein and more
than 400,000 units of vitamin A equivalent (Table 4). Celery
stalks or petioles alone (no leaves), however, yielded a coagulum
containing 17 percent crude protein and about 30,000 units of
vitamin A equivalent. Such values will vary depending on many
factors and should be considered only as approximations. Coagula
from cabbage, escarole, white turnips, and carrots, while rich in
crude protein, contained much less vitamin A equivalent than did








Table 2.- Dry matter, crude protein, fat, fiber, ash, and nitrogen-free-extract in fresh forage and pressed forage of several
Everglades-grown crops.a

Plant Dry Matter Crude
Plant Treatment Dr Mater Proteinb Fatb Fiberb Ashb NFE
Material Percent (N 6.25)


Celery tops
(leaves and
petioles)

Celery leaves


St. Augustinegrass


Paragrass


Napiergrass


Caribgrass


Oats


White clover


Fresh
Pressed
Pressed twice

Fresh
Pressed

Fresh
Pressed

Fresh
Pressed

Fresh
Pressed

Fresh
Pressed

Fresh
Pressed

Fresh
Pressed


a The chemical analyses, courtesy of A. Duda and Sons, Oviedo, Florida, were performed by Thornton Laboratories, Inc., Tampa, Florida.
b Percent of oven dried weight.








Florida Agricultural Experiment Stations


Table 3.- Dry matter, crude protein, and vitamin A equivalent contained
in fresh and pressed sorghum.a

Fresh Pressed

Dry matter percent 11.0 31.4
Crude protein percent (N X 6.25) 11.6 9.2
Vitamin A equivalent, U.S.P. units/lb. 65,800 45,400

a Seeded 1:1 mixture Tracy sorgo and Early Hegari, harvested at "soft dough" and
"hard dough" stage, respectively.
b Percent of dry weight.

Table 4.- Crude protein and vitamin A equivalent contained in coagula
from the expressed juices of several crops.

Vitamin A
Plant Matel Crude Equivalent
Plant Material Protein (U.S.P.
(N X 6.25) %a units/lb.)

Oats (January) 37.5 517,500
Oats (March) 34.0 450,000
Celery tops 41.0 427,000
Celery tops (Coagulum washed with water) 40.0 216,000
Celery stalks 17.0 31,500
Carrot tops 36.0 54,500
Escarole 26.5 49,000
Cabbage 30.0 108,000
White turnips 38.5 144,500

a Percent of dry weight.

Table 5.- K, No, Ca, and Mg contained in the supernatants of expressed
juices from several Everglades-grown plant materials.

Plant Material K Na Ca Mg
(Parts per million)

Vegetables & veg. wastes
Turnip tops 4000 320 1450 550
Snap bean tops 2000 50 750 300
Celery, packinghouse strippings:
First pressing 3900 1250 2500 800
Second pressing 2000 600 650 250
Celery, entire tops 2300 800 1450 1110
Pasture grasses
Caribgrass 1350 1050 25 540
Pangolagrass 1650 1200 20 540
Paragrass 2600 1750 40 610
St. Augustinegrass 2050 2050 40 910
Other grasses
Sugarcane leaves, young 3400 50 1000 1000
Sweet corn stover 1500 50 200 300
Sorghum tops, "dough" stage 2500 60 250 800







Mechanical Dewatering of Forage Crops


those from oats and celery tops. Some minerals contained in the
supernatant liquids after the coagulum had been removed for
several plant materials are given in Table 5.

Ensilability of Dewatered Forage in Glass Jars
Pressed forage provided notably higher dry matter densities
when ensiled. In many cases it ensiled more rapidly than parent
fresh forage, and produced what was judged better quality silage.
The data from several laboratory studies of packing densities and
acidities attained with fresh and pressed silages of a variety of
pasture, field, and truck crops are shown in Table 6.
Dewatered pasture grasses ensiled satisfactorily without addi-
tional preservatives. It is a practice in the commercial production
of silage to add additional carbohydrates or microbe inhibitors to
make satisfactory silage of the common and most abundant
summer growing pasture grasses of the Everglades, i.e. St. Augus-
tine, pangola, carib, and para (3). Effects due to these additions
to fresh and pressed grasses at the time of packing in the labora-
tory may be seen in Table 7. The molasses consistently improved
the fresh forage silage as indicated by the lower pH values
attained. The sodium metabisulfite reduced acid formation both
in fresh and in pressed forage silage of all four grasses but exerted
a more decided influence upon fresh than upon pressed grass
silage. In virtually all cases, satisfactory silage resulted from the
pressed grass even when no preservative was added.

PART II. EXPERIMENTS DURING 1960-1963

Experimental Dewatering and Ensiling Equipment

Experiment I
Field silos were erected in November 1960, and filled with
dewatered, wilted, chopped, and flail-cut paragrass, all without
additives, to compare the effect of these methods of grass treat-
ment on silage quality.
Two wire-supported vinyl plastic sleeve silos were used. One
was circular, being 14 feet in diameter and 41/ feet high, and the
other was rectangular, being 8 feet wide, 13 feet long, and 4/2 feet
high. Each silo was partitioned into four equal parts to separate
the four different grass treatments. The different shapes of the
two silos were incidental, and no comparison of silos was made.







Mechanical Dewatering of Forage Crops


those from oats and celery tops. Some minerals contained in the
supernatant liquids after the coagulum had been removed for
several plant materials are given in Table 5.

Ensilability of Dewatered Forage in Glass Jars
Pressed forage provided notably higher dry matter densities
when ensiled. In many cases it ensiled more rapidly than parent
fresh forage, and produced what was judged better quality silage.
The data from several laboratory studies of packing densities and
acidities attained with fresh and pressed silages of a variety of
pasture, field, and truck crops are shown in Table 6.
Dewatered pasture grasses ensiled satisfactorily without addi-
tional preservatives. It is a practice in the commercial production
of silage to add additional carbohydrates or microbe inhibitors to
make satisfactory silage of the common and most abundant
summer growing pasture grasses of the Everglades, i.e. St. Augus-
tine, pangola, carib, and para (3). Effects due to these additions
to fresh and pressed grasses at the time of packing in the labora-
tory may be seen in Table 7. The molasses consistently improved
the fresh forage silage as indicated by the lower pH values
attained. The sodium metabisulfite reduced acid formation both
in fresh and in pressed forage silage of all four grasses but exerted
a more decided influence upon fresh than upon pressed grass
silage. In virtually all cases, satisfactory silage resulted from the
pressed grass even when no preservative was added.

PART II. EXPERIMENTS DURING 1960-1963

Experimental Dewatering and Ensiling Equipment

Experiment I
Field silos were erected in November 1960, and filled with
dewatered, wilted, chopped, and flail-cut paragrass, all without
additives, to compare the effect of these methods of grass treat-
ment on silage quality.
Two wire-supported vinyl plastic sleeve silos were used. One
was circular, being 14 feet in diameter and 41/ feet high, and the
other was rectangular, being 8 feet wide, 13 feet long, and 4/2 feet
high. Each silo was partitioned into four equal parts to separate
the four different grass treatments. The different shapes of the
two silos were incidental, and no comparison of silos was made.














Table 6.- Moisture contents, packing densities, and degree of acidity obtained
Everglades-grown crops in glass jars.


upon ensiling fresh and pressed forages of


Silage from Fresh Forage Silage from Pressed Forage

Moisture Moisture
Plant Material (Percent Dry Matter (Percent Dry Matter
wet basis) (Lbs./cu. ft.) pHa wet basis) (Lbs./cu. ft). pHa


Vegetables and veg. wastes
Chinese cabbage 96.1 2.3 (Spoiled) 77.3 12.9 3.9
Turnip tops 93.9 3.6 4.4 74.0 18.1 4.1
Celery tops 89.2 5.8 4.3 73.9 16.6 4.2
Celery leaves 92.2 3.6 4.6 82.7 13.8 4.5

Pasture grasses
Pangolagrass 82.1 8.1 4.3 72.6 15.4 3.9
Paragrass 81.2 5.8 4.8 75.9 9.9 4.2
Caribgrass 80.6 7.0 4.8 73.3 13.6 4.0
St. Augustinegrass 78.1 8.4 5.0 74.6 11.9 4.3
Napiergrass 87.0 5.9 4.9 59.8 21.8 3.9

Other grasses
Green oats 85.7 6.3 3.9 67.7 16.3 3.9
Sorghum 82.3 7.6 3.8 68.6 14.3 3.8
Sweet corn stover 80.6 8.9 3.8 73.8 15.5 3.8

a After two weeks or more.







Mechanical Dewatering of Forage Crops


those from oats and celery tops. Some minerals contained in the
supernatant liquids after the coagulum had been removed for
several plant materials are given in Table 5.

Ensilability of Dewatered Forage in Glass Jars
Pressed forage provided notably higher dry matter densities
when ensiled. In many cases it ensiled more rapidly than parent
fresh forage, and produced what was judged better quality silage.
The data from several laboratory studies of packing densities and
acidities attained with fresh and pressed silages of a variety of
pasture, field, and truck crops are shown in Table 6.
Dewatered pasture grasses ensiled satisfactorily without addi-
tional preservatives. It is a practice in the commercial production
of silage to add additional carbohydrates or microbe inhibitors to
make satisfactory silage of the common and most abundant
summer growing pasture grasses of the Everglades, i.e. St. Augus-
tine, pangola, carib, and para (3). Effects due to these additions
to fresh and pressed grasses at the time of packing in the labora-
tory may be seen in Table 7. The molasses consistently improved
the fresh forage silage as indicated by the lower pH values
attained. The sodium metabisulfite reduced acid formation both
in fresh and in pressed forage silage of all four grasses but exerted
a more decided influence upon fresh than upon pressed grass
silage. In virtually all cases, satisfactory silage resulted from the
pressed grass even when no preservative was added.

PART II. EXPERIMENTS DURING 1960-1963

Experimental Dewatering and Ensiling Equipment

Experiment I
Field silos were erected in November 1960, and filled with
dewatered, wilted, chopped, and flail-cut paragrass, all without
additives, to compare the effect of these methods of grass treat-
ment on silage quality.
Two wire-supported vinyl plastic sleeve silos were used. One
was circular, being 14 feet in diameter and 41/ feet high, and the
other was rectangular, being 8 feet wide, 13 feet long, and 4/2 feet
high. Each silo was partitioned into four equal parts to separate
the four different grass treatments. The different shapes of the
two silos were incidental, and no comparison of silos was made.







Mechanical Dewatering of Forage Crops


those from oats and celery tops. Some minerals contained in the
supernatant liquids after the coagulum had been removed for
several plant materials are given in Table 5.

Ensilability of Dewatered Forage in Glass Jars
Pressed forage provided notably higher dry matter densities
when ensiled. In many cases it ensiled more rapidly than parent
fresh forage, and produced what was judged better quality silage.
The data from several laboratory studies of packing densities and
acidities attained with fresh and pressed silages of a variety of
pasture, field, and truck crops are shown in Table 6.
Dewatered pasture grasses ensiled satisfactorily without addi-
tional preservatives. It is a practice in the commercial production
of silage to add additional carbohydrates or microbe inhibitors to
make satisfactory silage of the common and most abundant
summer growing pasture grasses of the Everglades, i.e. St. Augus-
tine, pangola, carib, and para (3). Effects due to these additions
to fresh and pressed grasses at the time of packing in the labora-
tory may be seen in Table 7. The molasses consistently improved
the fresh forage silage as indicated by the lower pH values
attained. The sodium metabisulfite reduced acid formation both
in fresh and in pressed forage silage of all four grasses but exerted
a more decided influence upon fresh than upon pressed grass
silage. In virtually all cases, satisfactory silage resulted from the
pressed grass even when no preservative was added.

PART II. EXPERIMENTS DURING 1960-1963

Experimental Dewatering and Ensiling Equipment

Experiment I
Field silos were erected in November 1960, and filled with
dewatered, wilted, chopped, and flail-cut paragrass, all without
additives, to compare the effect of these methods of grass treat-
ment on silage quality.
Two wire-supported vinyl plastic sleeve silos were used. One
was circular, being 14 feet in diameter and 41/ feet high, and the
other was rectangular, being 8 feet wide, 13 feet long, and 4/2 feet
high. Each silo was partitioned into four equal parts to separate
the four different grass treatments. The different shapes of the
two silos were incidental, and no comparison of silos was made.








Mechanical Dewatering of Forage Crops


Treatments were randomly placed in each silo.
A flail-type forage harvester was used to harvest all treatments.
The press has been described and is shown in Figure 3.

Experiment II
The effect of two dewatering pressures on chemical compo-
sition at different stages of maturity of oats, ryegrass, and field
corn was determined.
The press used previously was modified by removing the
shredder, conveyer, and front axle. The press was towed behind
a forage harvester which discharged directly into the press hopper.
This combination resulted in a machine unit capable of harvesting,
conveying, and pressing the forage in a continuous operation.

Figure 5.- Flail type chopper and forage press in operation. Standing crop
is cut and shredded by harvester (1), delivered (2) to input hopper (3) of press.
Some juice (4) is removed in the press proper and some (5) by the choke cone.
Pressed material falls into screw conveyor (6), is conveyed to blower (7) powered
by two cylinder air cooled engine (8), and blown to rear (9). A 20-HP air-
cooled engine (10) powers the press. A sampling platform (11) is removable and
can be replaced with a towed wagon to catch the pressed forage. Fresh forage
samples were taken at (2), pressed forage at (9), and juice at (4) and (5).
Engines (8) and (10) have since been replaced with a 45 HP diesel engine
(donated by Massey-Ferguson, Inc., Detroit, Michigan) which provides ample
power to run the press and all its accessories.


KI '
-~ ~ ~ ~ ; e 5n~w---









Table 7.-Dry matter and density at time of ensiling, and acidity attained at four subsequent intervals for silages made from
pressed and unpressed pasture grasses and treated with different preservatives.


pHa
Grass and Dry Matter Dry Matter p
Mechanical Percent Density 2 5 16 52
Treatment Preservative (Wet basis) (Lbs./cu. ft.) Weeks Weeks Weeks Weeks


Carib
Fresh



Pressed



Para
Fresh



Pressed




Pangola
Fresh



Pressed


None
Molassesb
Na2S205,

None
Molasses
Na2,SO



None
Molasses
Na2S2O,

None
Molasses
Na2S2O,



None
Molasses
Na2S2O,

None
Molasses


4.55
3.90
5.45

4.00
3.80
5.00



4.30
4.00
5.40

3.90
3.90


4.60
4.00
Spoiled

4.20
3.90
4.50


4.35
3.90
4.90

3.80
3.85




Fresh


Pressed


None
Molasses
Na2S2O5

None
Molasses
Na2S20,


Mean Values
Fresh None 19.5 7.5 4.60 4.60 4.60 4.50
Molasses 22.9 10.3 3.95 3.90 4.00 3.90
Na2S2,O 19.5 8.6 5.20 5.10 5.00 4.60
Mean 20.6 8.8

Pressed None 25.9 13.0 4.05 4.00 4.10 4.05
Molasses 28.5 14.6 3.90 3.85 3.90 3.80
Na2SO, 25.9 13.6 4.70 4.60 4.40 4.20
Mean 26.8 13.7

a Each value represents the mean pH of duplicate glass jar silage preparation.
b Sugarcane molasses added at 5 percent of fresh weight and containing 80 percent dry matter.
c Sodium metabisulfite added at 0.5 percent of fresh weight.







Florida Agricultural Experiment Stations


Other detachable components were added to facilitate sampling of
fresh and pressed forage and expressed juice during operation
(Figure 5).


Experimental Procedure

Experiment I
Forage for the flail-cut grass treatment was blown into self-
unloading wagons by the forage chopper and deposited in the
appropriate compartment of each silo. Forage for the chopped
grass treatment was harvested and handled in the same manner.
It was chopped before being blown into the appropriate compart-
ment of each silo. Forage for the wilted grass treatment was cut
and allowed to fall to the ground. When the desired moisture
level of about 75 percent was reached, the grass was picked up
with a recut type flail harvester, and deposited in the silo. The
grass for dewatering was shredded, dewatered (Figure 3), and
placed in the silo.
Fiberglass bags containing 1,000 gram samples from each
treatment were buried as the silos were filled. In each compart-
ment of each silo 12 samples were buried-four about 18 inches
from the bottom, four approximately halfway up, and four about
12 inches from the top. The silos were tightly packed by having
men continuously walk on the forage during filling. When the silos
were filled, they were covered and sealed with vinyl sheeting.
The samples were ensiled for three months and analyzed by pro-
cedures already described.

Experiment II
In early 1962, oats, ryegrass, and solid planted field corn
were pressed under different conditions of crop maturity 5 using
two pressures. Samples of fresh and pressed forage and of ex-
pressed juice were analyzed. Dry matter, primary elements
(protein, phosphorus, potassium), secondary elements (calcium,
magnesium), micro-nutrients (manganese, copper, iron), ash, ether
extract, and crude fiber were determined.

6 Fourteen weeks and 16 weeks refer to the "age" of oats and ryegrass
measured from date of planting. However, 9 weeks after planting both
crops were clipped and the clippings removed because of a heavy weed
infestation. The resulting regrowth, free of weeds, was harvested and pressed
5 and 7 weeks later. The solid planted field corn was harvested 8 weeks
after planting.







Florida Agricultural Experiment Stations


Other detachable components were added to facilitate sampling of
fresh and pressed forage and expressed juice during operation
(Figure 5).


Experimental Procedure

Experiment I
Forage for the flail-cut grass treatment was blown into self-
unloading wagons by the forage chopper and deposited in the
appropriate compartment of each silo. Forage for the chopped
grass treatment was harvested and handled in the same manner.
It was chopped before being blown into the appropriate compart-
ment of each silo. Forage for the wilted grass treatment was cut
and allowed to fall to the ground. When the desired moisture
level of about 75 percent was reached, the grass was picked up
with a recut type flail harvester, and deposited in the silo. The
grass for dewatering was shredded, dewatered (Figure 3), and
placed in the silo.
Fiberglass bags containing 1,000 gram samples from each
treatment were buried as the silos were filled. In each compart-
ment of each silo 12 samples were buried-four about 18 inches
from the bottom, four approximately halfway up, and four about
12 inches from the top. The silos were tightly packed by having
men continuously walk on the forage during filling. When the silos
were filled, they were covered and sealed with vinyl sheeting.
The samples were ensiled for three months and analyzed by pro-
cedures already described.

Experiment II
In early 1962, oats, ryegrass, and solid planted field corn
were pressed under different conditions of crop maturity 5 using
two pressures. Samples of fresh and pressed forage and of ex-
pressed juice were analyzed. Dry matter, primary elements
(protein, phosphorus, potassium), secondary elements (calcium,
magnesium), micro-nutrients (manganese, copper, iron), ash, ether
extract, and crude fiber were determined.

6 Fourteen weeks and 16 weeks refer to the "age" of oats and ryegrass
measured from date of planting. However, 9 weeks after planting both
crops were clipped and the clippings removed because of a heavy weed
infestation. The resulting regrowth, free of weeds, was harvested and pressed
5 and 7 weeks later. The solid planted field corn was harvested 8 weeks
after planting.







Florida Agricultural Experiment Stations


Other detachable components were added to facilitate sampling of
fresh and pressed forage and expressed juice during operation
(Figure 5).


Experimental Procedure

Experiment I
Forage for the flail-cut grass treatment was blown into self-
unloading wagons by the forage chopper and deposited in the
appropriate compartment of each silo. Forage for the chopped
grass treatment was harvested and handled in the same manner.
It was chopped before being blown into the appropriate compart-
ment of each silo. Forage for the wilted grass treatment was cut
and allowed to fall to the ground. When the desired moisture
level of about 75 percent was reached, the grass was picked up
with a recut type flail harvester, and deposited in the silo. The
grass for dewatering was shredded, dewatered (Figure 3), and
placed in the silo.
Fiberglass bags containing 1,000 gram samples from each
treatment were buried as the silos were filled. In each compart-
ment of each silo 12 samples were buried-four about 18 inches
from the bottom, four approximately halfway up, and four about
12 inches from the top. The silos were tightly packed by having
men continuously walk on the forage during filling. When the silos
were filled, they were covered and sealed with vinyl sheeting.
The samples were ensiled for three months and analyzed by pro-
cedures already described.

Experiment II
In early 1962, oats, ryegrass, and solid planted field corn
were pressed under different conditions of crop maturity 5 using
two pressures. Samples of fresh and pressed forage and of ex-
pressed juice were analyzed. Dry matter, primary elements
(protein, phosphorus, potassium), secondary elements (calcium,
magnesium), micro-nutrients (manganese, copper, iron), ash, ether
extract, and crude fiber were determined.

6 Fourteen weeks and 16 weeks refer to the "age" of oats and ryegrass
measured from date of planting. However, 9 weeks after planting both
crops were clipped and the clippings removed because of a heavy weed
infestation. The resulting regrowth, free of weeds, was harvested and pressed
5 and 7 weeks later. The solid planted field corn was harvested 8 weeks
after planting.







Mechanical Dewatering of Forage Crops


Four samples each of fresh chopped forage, pressed forage, and
expressed juice were taken for each crop at each of the two
cuttings. All samples were taken after the press had filled and
the unit was operating smoothly. Sample sizes were 500 grams
each for the fresh chopped and pressed forage treatment and 1
pint for the expressed juices.
The bags of forage samples were oven dried immediately to
determine dry matter content. The juice samples were frozen
and kept for laboratory analyses.
Plant samples were oven dried at 750 + 20 C, and dry weights
were recorded. They were ground in a stainless steel chambered
Wiley Mill and subsampled for chemical analyses. Crude fat,
crude fiber, ash, N, P, K, Cu, Fe, Mn, Ca, and Mg were determined
according to published procedures (1, 4).
The juice samples were thawed. One hundred ml were pipetted
into beakers, evaporated to near dryness on a hotplate, and placed
in a 750 C oven for 24 hours. The residue was analyzed for P, K,
Cu, Fe, Mn, Ca, and Mg. The samples had begun to ferment
before an acceptable technique was found for nitrogen analysis.
The data were analyzed by the method of orthogonal com-
parisons to evaluate the influence of pressures, type of crop, and
age of crop upon the dewatering characteristics of the press and
upon the nutrient contents of each component. Analysis of
variance tables for each constituent are in the Appendix (Tables
A-E).

Results and Discussion

Experiment I
Moisture content of the paragrass prior to dewatering varied
from 80 to 85 percent, and after dewatering, 72 to 75 percent.
In general, the mechanically dewatered paragrass yielded the
best grade of silage as judged by dry matter losses, pH values, and
its general appearance and odor (Table 8). The higher dry
matter losses and pH values generally occurred in the samples
buried near the top of the silo. This probably was a result of
insufficient packing in this region and lack of air exclusion. The
remaining samples showed low dry matter losses and low values
for pH. The low dry matter losses can be explained by the re-
duction of cell respiration due to destruction of some of the cells
during the dewatering process. The excellent packing characteris-
tics and lower moisture content of pressed paragrass are important







Mechanical Dewatering of Forage Crops


Four samples each of fresh chopped forage, pressed forage, and
expressed juice were taken for each crop at each of the two
cuttings. All samples were taken after the press had filled and
the unit was operating smoothly. Sample sizes were 500 grams
each for the fresh chopped and pressed forage treatment and 1
pint for the expressed juices.
The bags of forage samples were oven dried immediately to
determine dry matter content. The juice samples were frozen
and kept for laboratory analyses.
Plant samples were oven dried at 750 + 20 C, and dry weights
were recorded. They were ground in a stainless steel chambered
Wiley Mill and subsampled for chemical analyses. Crude fat,
crude fiber, ash, N, P, K, Cu, Fe, Mn, Ca, and Mg were determined
according to published procedures (1, 4).
The juice samples were thawed. One hundred ml were pipetted
into beakers, evaporated to near dryness on a hotplate, and placed
in a 750 C oven for 24 hours. The residue was analyzed for P, K,
Cu, Fe, Mn, Ca, and Mg. The samples had begun to ferment
before an acceptable technique was found for nitrogen analysis.
The data were analyzed by the method of orthogonal com-
parisons to evaluate the influence of pressures, type of crop, and
age of crop upon the dewatering characteristics of the press and
upon the nutrient contents of each component. Analysis of
variance tables for each constituent are in the Appendix (Tables
A-E).

Results and Discussion

Experiment I
Moisture content of the paragrass prior to dewatering varied
from 80 to 85 percent, and after dewatering, 72 to 75 percent.
In general, the mechanically dewatered paragrass yielded the
best grade of silage as judged by dry matter losses, pH values, and
its general appearance and odor (Table 8). The higher dry
matter losses and pH values generally occurred in the samples
buried near the top of the silo. This probably was a result of
insufficient packing in this region and lack of air exclusion. The
remaining samples showed low dry matter losses and low values
for pH. The low dry matter losses can be explained by the re-
duction of cell respiration due to destruction of some of the cells
during the dewatering process. The excellent packing characteris-
tics and lower moisture content of pressed paragrass are important








Table 8.- Effect of treatment prior to ensiling on quality of paragrass silage.


D.M. Silage Samplese D.M. Lost Crude Protein (%)e
Position in 1000 gm During pH
of Bag Bagged Sam- Wet Dry D.M. Ensiling Near Before
Treatment in Siloa pie (gms)b (gms) (gns) (%)d (%) Bag Ensiling Silage


B 253 1022 238 23.3 5.9 5.1 12.4 10.1
Dewatered C 260 995 260 26.4 0.0 4.5 13.7 12.5
T 268 957 236 24.6 12.0 5.8 12.4 12.2
Mean 260 991 246 24.8 6.0 5.1 12.8 11.6

B 240 865 209 24.2 12.9 8.1f 12.4 10.6
Wilted C 242 788 210 26.6 13.2 8.5f 13.2 10.8
T 277 1014 269 26.5 2.9 4.6 12.7 11.2
Mean 253 889 229 25.8 9.7 7.1 12.8 10.9

B 188 894 155 17.4 16.6 5.7 14.2 11.4
Chopped C 183 895 156 17.4 14.7 5.3 11.0 12.0
T 219 870 165 19.0 24.6 7.0f 13.4 10.9
Mean 190 886 159 17.9 18.6 6.0 12.9 11.4

B 158 789 131 16.6 17.1 5.5 16.4 13.9
Flail-cut C 218 955 190 19.9 12.8 6.4 13.2 10.1

Mean 188 872 161 18.3 14.9 5.9 14.8 12.0

aB = Bottom, C = Center, and T = Top. Each figure is an average of 8 samples.
b These samples taken at time of ensiling.
c These samples taken when silos were opened 3 months after ensiling.
d Wet basis.
e Percent of dry weight.
f These samples obviously spoiled and had a very strong ammonia odor.







Mechanical Dewatering of Forage Crops


contributing factors for the formation of good quality silage
obtained with this treatment.
The chopped and flail-cut grass silage experienced dry matter
losses above 13 percent, and pH values were above 5.5. All of the
chopped silage samples buried near the top in the circular silo
were spoiled. The silage resulting from these two treatments
was judged not to be as good quality as that made from the
pressed material.
The wilted paragrass made silage intermediate in quality be-
tween the pressed and other two treatments, but it spoiled rapidly
upon being opened. The wilted grass was very spongy and did not
pack well.


Experiment II
The results of these determinations are given in Tables 9
through 13.
Moisture extraction: Sixty psi pressure extracted significantly
more juice from all crops tested than 40 psi pressure (Table 9).
The percent dry matter in the juice remained almost constant,
indicating that dry matter and moisture expressed are propor-
tional. Consequently, an increase in pressure increased moisture
expressed but also increased the dry matter expressed with the
juice.
Corn contained more moisture than either oats or ryegrass,
both before and after pressing. Ryegrass contained more moisture
than oats before and after pressing; however, oats lost more mois-
ture than did ryegrass when pressed.
The effect of cutting date was more pronounced with oats than
with ryegrass. Approximately the same percentage of moisture
was expressed from ryegrass on each harvest date; the percentage
of moisture expressed from oats was much less on the second date.
This was probably due to differences in the maturity of the two
crops at the second cutting; oats were in the boot stage and rye-
grass had not started to head.
Crude protein: Oats and ryegrass contained significantly more
protein than corn (Table 10). Ryegrass contained significantly
more crude protein than oats before and after pressing. Oats lost
more protein during pressing than did ryegrass. This may be a
function of moisture expressed, since oats did lose significantly
more moisture upon pressing. Maturity did not significantly
influence protein content in these tests.








Table 9.- Average moisture and dry matter contents of fresh and pressed forage and expressed juice for three crops, two growth
ages, and two pressures.a b


Pressed Juice
Fresh 40 psi 60 psi 40 psi 60 psi

AT'P 14 Wkrs nf AgPe


Moisture, %c (M/DM)
Total, lbs.
Moisture, Ibs.
Dry Matter, lbs.

Moisture, % (M/DM)
Total, lbs.
Moisture, lbs.
Dry matter, Ibs.

Moisture, % (M/DM)
Total, lbs.
Moisture, lbs.
Dry matter, lbs.

Moisture, % (M/DM)
Total, lbs.
Moisture, lbs
Dry matter, lbs.

Moisture, % (M/DM)
Total, lbs.
Moisture, lbs.
Dry matter, Ibs.


85.1 (5.71) 71.7 (2.53)
2000 608
1702 436
298 172
OATS 16 Wks. of Age


85.0 (5.67)
2000
1700
300
RYEGRASS
86.8 (6.58)
2000
1736
264
RYEGRASS
84.2 (5.33)
2000
1684
316


76.2 (3.20)
968
738
230
- 14 Wks. of Age
80.3 (4.08)
931
748
183
- 16 Wks. of Age
75.9 (3.15)
955
725
230


CORN 8 Wks. of Age
89.7 (8.71) 79.0 (3.76)
2000 707
1794 559
206 148


71.7 (2.53)
623
447
176

71.6 (2.52)
761
545
216

77.8 (3.50)
694
540
154

75.6 (3.10)
949
717
232

77.2 (3.38)
651
503
148


90.95 (10.04)
1392
1266
126

93.26 (13.84)
1032
962
70

92.46 (12.25)
1069
988
81

91.78 (11.16)
1045
959
86

95.55 (21.45)
1293
1235
58


91.16 (10.31)
1377
1255
122

93.23 (13.77)
1239
1155
84

91.58 (10.87)
1306
1196
110

91.96 (11.43)
1051
966
85

95.73 (22.40)
1349
1291
58


a The pressures, 40 psi and 60 psi, were taken on the pneumatic cylinder controlling the choke cone at the output of the press and are not
necessarily the pressures to which the forage is subjected within the press.
b Calculations of weights are based on laboratory determinations and assume 1 ton of fresh material entering press.
c Wet basis.







Mechanical Dewatering of Forage Crops


Phosphorus: Significantly more P was found in the juice
expressed at 60 psi than at 40 psi (Table 10). Pressures did not
significantly affect the percent P in the pressed material.
Corn contained significantly less P than did oats and ryegrass
before and after pressing. The corn juice did not differ signifi-
cantly in P content from the oats and ryegrass juice.
Oats contained significantly more P in the fresh material than
ryegrass, but after pressing there was no significant difference in
the P content of the two crops. However, the oats juice contained
significantly more P than did ryegrass juice.
Maturity of oats and ryegrass significantly increased the P
content in the fresh, pressed, and juice components. Pressed oat
forage contained significantly less P at the first cutting than did
ryegrass, but the reverse was true at the second cutting. However,
the oats juice contained significantly more P at the second cutting
than at the first, while the P in the ryegrass juice remained
nearly constant. This was probably related to the difference in
maturity of the two crops.

Potassium: The effect of pressures on K content was not
significant considering the three crops together (Table 10). How-
ever, corn was lower in K content than oats and ryegrass in both
fresh and pressed material, but corn juice was higher in K content
than oats and ryegrass juice. Oats lost a significantly larger
portion of the K content in the juice than did ryegrass. Also the
second cutting contained significantly more K in both fresh and
pressed material than the first. Juice K content was essentially
the same for both cuttings.

Calcium and magnesium: The three crops varied significantly
in the contents of both Ca and Mg (Table 11). Pressures had no
significant effect on the distribution of Ca and Mg in the pressed
material and juice.
The fresh material at the first cutting had significantly lower
Ca and Mg content than that at the second cutting. This was also
true for Ca and Mg in the pressed material and for Mg in the
juice.

Copper, manganese, and iron: Maturity had a significant
effect on Cu, Mn, and Fe contents of crops (Table 12). Cu and
Fe decreased with age of crop, while Mn increased. Pressures had
no significant effect on the relative distribution of the elements
between the juice and pressed materials.

















Table 10.-Primary elements in fresh and pressed forage and the expressed juice for three crops, two growth ages, and two
pressures.a


Crop Protein (%) b Phosphorus (%) b Potassium (%) b
Fresh Pressed Juicec Fresh Pressed Juice Fresh Pressed Juice
40 60 40 60 40 60 40 60 40 60 40 60


Oats 14 wks. 23.6 19.5 18.9 29.2 30.3 .425 .278 .272 .529 .578 3.82 2.29 2.30 2.59 2.47
Oats 16 wks. 23.5 20.4 18.7 33.7 35.8 .445 .348 .370 .670 .807 5.19 2.86 3.08 3.00 3.16
Ryegrass 14 wks. 25.6 23.2 24.1 31.1 27.7 .347 .322 .291 .463 .419 3.50 2.72 2.51 2.64 1.65
Ryegrass 16 wks. 25.2 24.4 23.7 27.3 28.9 .364 .348 .309 .487 .426 5.68 3.58 3.26 2.20 2.41
Corn 8 wks. 18.2 15.9 14.4 24.1 27.9 .319 .223 .225 .511 .525 3.92 2.38 2.03 2.94 4.65


a The pressures, 40 psi and 60 psi, were taken on the pneumatic cylinder controlling the choke cone at the output of the press and are
not necessarily the pressures to which the forage is subjected within the press.
b Percent of dry weight.
c Protein values in the juice were calculated using protein determinations for fresh and pressed samples (see calculations in Appendix).















Toble 11.- Secondary elements in fresh and pressed forage and the expressed juice for three crops, two crop ages, and two
pressures.a


Calcium (%) b Magnesium (%) b
Crop Fresh Pressed Juice Fresh Pressed Juice
40 60 40 60 40 60 40 60


Oats 14 wks. 0.898 0.724 0.634 0.438 0.789 .256 .190 .164 .554 .480
Oats 16 wks. 0.920 0.665 0.754 0.955 1.158 .300 .226 .205 .546 .590
Ryegrass 14 wks. 1.038 0.917 0.887 1.024 0.733 .298 .178 .253 .554 .675
Ryegrass 16 wks. 1.351 1.026 1.026 0.944 1.013 .422 .306 .297 .744 .630
Corn 8 wks. 0.653 0.488 0.481 1.147 1.272 .397 .235 .193 .861 .850


a The pressures, 40 psi and 60 psi, were taken on the pneumatic cylinder controlling the choke cone at the output of the press and are
not necessarily the pressures to which the forage is subjected within the press.
b Percent of dry weight.
















Table 12.- Micro-nutrients in fresh and pressed forage and the expressed juice for three crops, two crop ages, and two pressures.a


Manganese (ppm) b Copper (ppm) b Iron (ppm) b
Crop Fresh Pressed Juice Fresh Pressed Juice Fresh Pressed Juice
40 60 40 60 40 60 40 60 40 60 40 60


Oats 14 wks. 63 41 58 65 71 13.0 18.7 13.6 14.4 13.8 397 752 442 528 505
Oats 16 wks. 94 68 84 90 142 11.2 10.3 10.2 12.2 13.7 172 215 145 402 266
Ryegrass 14 wks. 64 64 52 72 75 15.9 17.8 22.6 15.4 17.0 251 302 561 349 678
Ryegrass 16 wks. 92 82 80 80 80 14.8 13.4 14.8 14.0 13.3 186 166 201 279 188
Corn 8 wks. 54 37 35 97 110 8.7 9.6 7.8 7.2 6.3 171 186 210 285 230

a The pressures, 40 psi and 60 psi, were taken on the pneumatic cylinder controlling the choke cone at the output of the press and are
not necessarily the pressures to which the forage is subjected within the press.
b Parts per million of dry weight for fresh and pressed material and ppm of non-volatile (105C) residue for juice.
















Table 13.- Crude fiber, ash, and ether extract in fresh and pressed forage for two pressures.a


Crude Fiber (%) b Ash (%) b Ether Extract (%) b
Crop Fresh Pressed Fresh Pressed Fresh Pressed
40 60 40 60 40 60


Oats 14 wks. 28.8 33.1 35.0 14.9 8.2 9.6 3.3 3.7 2.2
Ryegrass 14 wks. 24.2 29.0 29.8 15.0 10.6 9.5 3.7 3.3 3.9
Corn 8 wks. 29.3 31.3 37.4 10.4 6.6 5.4 3.0 2.8 2.7

a The pressures, 40 psi and 60 psi, were taken on the pneumatic cylinder controlling the choke cone at the output of the press and are not
necessarily the pressures to which the forage is subjected within the press.
b Percent of dry weight.








Florida Agricultural Experiment Stations


Crude fiber, ash, and ether extract: Contents of these con-
stituents in fresh and pressed forage for two pressures are given
in Table 13.
With all crops, pressures did not significantly influence the
amount of these constituents in the pressed forage, but there was
a tendency for a higher crude fiber content at 60 psi pressed forage,
especially in the oats and corn. This is probably related to the
higher initial moisture content of corn and the "ease" of de-
watering of oats as compared to ryegrass. The important thing is
that as water was removed, the fiber content of the forage in-
creased upon pressing. Ash content (mostly minerals described
earlier) decreased in the press cake and increased in the juice.
There was very little difference in the ether extract (fat) contents
before and after pressing, indicating that little fat was lost in the
juice.


GENERAL DISCUSSION

Mechanical dewatering of crops to be used for feed may have
merit, particularly if the initial moisture content is above 80
percent. The economics of such a step would depend on several
factors: 1) value of the processed feed; 2) cost of equipment;
3) initial moisture content; 4) nutrient losses during the pressing
operation; 5) ease of removing water from the crop and its effect
on the expense of the process; 6) speed of moisture removal; and
7) cost of other methods of moisture removal.
Figure 4 shows that if a forage enters a dehydration process
at 85 percent moisture and comes out at 70 percent moisture
without loss of dry matter, the total weight of the material has
been cut in half, and over half of the water content has been
removed. Table 9 (M/DM) shows the effectiveness of the me-
chanical press in removing moisture from various crops. A direct
subtraction is valid with M/DM ratios and gives the units of
water removed by pressing per unit of dry matter.
Table 1 lists a number of crops which have been subjected to
pressing and the effect on moisture by pressing. This table also
shows that plant species differ considerably in their release of
moisture by mechanical means. Furthermore, the treatment before
entering the press affects the moisture removed. The nutrient loss
in the expressed juice appears to be a function of moisture re-
moved. Therefore, unless the expressed juice is processed to








Mechanical Dewatering of Forage Crops


recover these nutrients, the objective should be to bring the
moisture down to a level where other dehydration methods could
be economically used. This area needs more investigation to de-
termine where mechanical dewatering should stop and other
methods of dehydration or processing should begin.
The solid materials in the juice are high in vitamin A equiva-
lent and crude protein (Table 4). There are possibilities of
recovery of these solids and their use as an ingredient in a
concentrate. However, this juice also contains appreciable quanti-
ties of fertilizer elements (Table 5) and should be considered in
figuring profits from solids recovered. For example, assuming two
5-tons-per-acre cuttings of 16-week-old oats pressed at 40 psi, the
fertilizer elements in pounds returned to the field on a per-acre
basis with the juice are: N-37.8, P-5.6, K-20.7, Ca-6.6,
Mg-3.8, Mn-0.06, Cu-0.008, and Fe-0.28. Since the organic
soils in the Everglades are deficient in all of these elements except
N and since the majority of these elements do not add substan-
tially to the feeding value of cattle feed, their return to the soil
merits consideration.
Pressed forage is readily usable in several different ways. It
ensiled well without additives, due in part to its excellent packing
characteristics and lower moisture content. In general, untreated
pasture grasses in the Everglades area do not ensile satisfactorily
(3). It can be fed green in feed bunks. The few feeding observa-
tions indicated that cattle often prefer it to fresh chopped forage.
Italian researchers have reported similar results (12).
Mechanical dewatering will probably have the greatest impact
in dried feed processing, if successful. Regardless of the end
product, whether in bulk, pelleted, or wafered form, thermal
dehydration is usually the means employed for drying the forage
to the desired moisture level for further processing or storage.
Removal of part of the water in a forage crop by mechanical
means can have an appreciable effect upon the performance and
cost of operation of a thermal dehydrator.

SUMMARY AND CONCLUSIONS
Dehydrating forage crops mechanically was initiated at the
Everglades Experiment Station in 1955.
Screen enclosed auger-type presses of various sizes were used.
Numerous forage crops and potential forage crops were mechani-
cally dewatered. The initial moisture and moisture after pressing








Florida Agricultural Experiment Stations


were the primary means of evaluation. However, changes in
nutrient components due to pressing were also studied.
The data obtained in these studies showed that the higher
the initial moisture content of a crop, the greater the amount of
water removed by mechanical pressing. An increase in pressure
from 40 to 60 psi increased the amount of moisture extracted.
However, the increased pressure also increased the dry matter
expressed with the juice. The small increase in moisture extracted
at the higher pressure plus the undesirable increased loss of dry
matter probably would prohibit economical use of the higher
pressure.
Different plant species reacted differently to pressing. Like-
wise, the same plant reacted differently at different stages of
maturity. Moisture and nutrient changes associated with ma-
turity in the fresh forage were reflected in the pressed forage and
expressed juices. Maturity did not appreciably alter the distribu-
tion of mineral elements resulting from pressing.
Mechanical dewatering was beneficial in the production of
grass silage and proved that good grass silage can be made, with-
out additives, from forages grown in the Everglades.







Mechanical Dewatering of Forage Crops


APPENDIX

Sample Calculations
Total weight of pressed forage and expressed juice emerging
from the press and the water (M) and dry matter (DM) con-
tained in each.


From Table 9, oats 16 weeks
analyzed as follows:


Fresh:



Pressed:


Expressed Juice:


M =
DM =
M/DM =
M =
DM =
M/DM =
M =
DM =
M/DM =


old pressed at 40 psi pressure

85.0%
15.0%
5.67
76.2%
23.8%
3.20


93.26%
6.74%
13.84


Assuming 2000 pounds fresh material entering press, then:
M entering = 2000 X .85 = 1700 pounds, and
DM entering = 2000 X .15 = 300 pounds

If: X = total weight of pressed material emerging, and
Y = total weight of expressed juice emerging,

Then:
X + Y = 2000
.2380X + .0674Y = 300.

Solving simultaneously:
X = 968 pounds pressed forage emerging


containing:




containing:
.0674 X
.9326 X


.238 X 968 = 230 pounds DM and
.762 X 968 = 738 pounds M.
Y = 1032 pounds expressed juice emerging


1032 = 70 pounds DM and
1032 = 962 pounds M.







Mechanical Dewatering of Forage Crops


APPENDIX

Sample Calculations
Total weight of pressed forage and expressed juice emerging
from the press and the water (M) and dry matter (DM) con-
tained in each.


From Table 9, oats 16 weeks
analyzed as follows:


Fresh:



Pressed:


Expressed Juice:


M =
DM =
M/DM =
M =
DM =
M/DM =
M =
DM =
M/DM =


old pressed at 40 psi pressure

85.0%
15.0%
5.67
76.2%
23.8%
3.20


93.26%
6.74%
13.84


Assuming 2000 pounds fresh material entering press, then:
M entering = 2000 X .85 = 1700 pounds, and
DM entering = 2000 X .15 = 300 pounds

If: X = total weight of pressed material emerging, and
Y = total weight of expressed juice emerging,

Then:
X + Y = 2000
.2380X + .0674Y = 300.

Solving simultaneously:
X = 968 pounds pressed forage emerging


containing:




containing:
.0674 X
.9326 X


.238 X 968 = 230 pounds DM and
.762 X 968 = 738 pounds M.
Y = 1032 pounds expressed juice emerging


1032 = 70 pounds DM and
1032 = 962 pounds M.







Mechanical Dewatering of Forage Crops


APPENDIX

Sample Calculations
Total weight of pressed forage and expressed juice emerging
from the press and the water (M) and dry matter (DM) con-
tained in each.


From Table 9, oats 16 weeks
analyzed as follows:


Fresh:



Pressed:


Expressed Juice:


M =
DM =
M/DM =
M =
DM =
M/DM =
M =
DM =
M/DM =


old pressed at 40 psi pressure

85.0%
15.0%
5.67
76.2%
23.8%
3.20


93.26%
6.74%
13.84


Assuming 2000 pounds fresh material entering press, then:
M entering = 2000 X .85 = 1700 pounds, and
DM entering = 2000 X .15 = 300 pounds

If: X = total weight of pressed material emerging, and
Y = total weight of expressed juice emerging,

Then:
X + Y = 2000
.2380X + .0674Y = 300.

Solving simultaneously:
X = 968 pounds pressed forage emerging


containing:




containing:
.0674 X
.9326 X


.238 X 968 = 230 pounds DM and
.762 X 968 = 738 pounds M.
Y = 1032 pounds expressed juice emerging


1032 = 70 pounds DM and
1032 = 962 pounds M.








Florida Agricultural Experiment Stations


To determine pounds of elements in fresh and pressed forage
and juice. Table 10 shows the following analysis for oats 16 weeks
old pressed at 40 psi.


Protein (%)
Pr.
20.4


Juice


Phosphorus
Fr. Pr.
0.445 0.348


(%)
Juice
0.807


Pounds protein per ton of fresh inbound material:
In fresh: .235 X 300 = 70.5 pounds


In pressed: .204 X 230
In juice:


46.9 pounds
23.6 pounds (by subtraction)


It was necessary to obtain protein in juice by subtraction be-
cause it was difficult to obtain in the laboratory and the samples
had begun to spoil before a suitable method was found.


% protein in juice then =


23.6
- X 100 = 33.7%
70


Pounds phosphorus per ton of fresh inbound material:
In fresh .00445 X 300 = 1.335 pounds
In pressed .00348 X 230 = 0.800 pounds
In juice: .00807 X 70 = 0.565 pounds
The other constituents are obtained similarly and all are
tabulated below:


Element


Fresh


Pressed


Juice Total (Pr. & Juice)


Protein 70.5 46.9 23.6 70.5
Phosphorus 1.335 0.800 0.565 1.365
Potassium 15.57 6.61 2.07 8.68
Calcium 2.760 1.536 0.659 2.195
Magnesium 0.900 0.522 0.377 0.899
Manganese 0.0282 0.0157 0.0062 0.0219
Copper 0.0034 0.0024 0.0008 0.0032
Iron 0.0516 0.0496 0.0277 0.0773


Except for K and Fe, the sum of the elements found in the
pressed forage and juice was nearly equal to that found in the
fresh forage. The discrepancy for K can possibly be attributed to
the method of determination. Potassium was determined on a


Fr.
23.5









Mechanical Dewatering of Forage Crops


Beckman DU with flame attachment, and it is an established fact
that some anions interfere with K determined by this method.
No corrections were made.
The sum of the Fe components was greater than that found
in the fresh material. Since the forage was processed with iron
machinery, it is quite probable that the pressed forage and juice
picked up additional iron due to the corrosive nature of the juice.


Analysis of Variance Tables

Table A.- Analysis of variance table: Moisture contents of fresh and
pressed forage and expressed juice for three crops, two growth ages, and two
pressures.


Mean Squares
Source d.f.
Fresh Pressed Juice


Subplots 39
Whole plots 9 20.54 36.91 11.55
a t 1 2.35* 28.05** 0.04
Cuttings & crops 4 43.68 69.44 25.55
b t 1 114.94** 53.48** 82.53**
c t 1 7.32** 158.86** 0.33
d t 1 14.98** 1.85 8.21**
c X d 1 10.47** 63.56** 11.03**
Pressure X cuttings
+ crops 4 1.94 6.60 1.70
a X b 1 0.01 0.08 0.15
a X c 1 4.57** 0.53 0.38
a X d 1 0.94 2.48 0.33
a X c x d 1 2.25* 23.29** 0.84
Error 30 0.38 1.75 0.30

t Key to comparison symbols:
a = pressures, 40 psi. vs. 60 psi
b = oats + ryegrass vs. corn
c = oats vs. ryegrass
d = 14 wks. cutting vs. 16 wks. cutting, oats and ryegrass only.
c X d, a X b, etc. = various interactions
= significant at 5% probability level
** = significant at 1% probability level










Table B.- Analysis of variance table: Primary elements in fresh and pressed forage and the expressed juice for three craps,
two crop ages, and two pressures.


Protein Phosphorus Potassium
Source d.f. Mean Squares Mean Squares Mean Squares
Fresh Pressed Fresh Pressed Juice Fresh Pressed Juice


Subplots 39
Whole plots 9 30.90 49.12 0.011 0.010 0.056 3.45 0.96 2.50
a t 1 0.13 5.47 0.003 0.001 0.003 0.00 0.17 0.39
Cuttings + crops 4 68.64 107.01 0.023 0.021 0.114 7.34 2.01 3.64
b t 1 246.26** 267.26** 0.038** 0.055** 0.005 2.56** 2.45** 10.52**
c t 1 27.57** 159.31** 0.051** 0.000 0.311** 0.06 1.20** 2.71*
d t 1 0.53 0.91 0.003* 0.022** 0.080** 25.38** 4.35** 1.00
c X d 1 0.19 0.01 0.000 0.008** 0.057** 1.36 0.03 0.31
Pressures X
Cuttings + crops 4 0.85 2.14 0.001 0.001 0.013 0.43 0.11 1.90
a X b 1 0.33 1.44 0.000 0.000 0.000 1.08 0.12 5.74**
a X c 1 0.48 3.64 0.001 0.004* 0.042** 0.00 0.28* 0.33
a X d 1 1.76 3.38 0.002* 0.000 0.003 0.55 0.01 1.10
a X c X d 1 0.81 0.08 0.001 0.001 0.005 0.07 0.04 0.41
Error 30 2.27 2.30 0.0004 0.0006 0.002 0.33 0.06 0.56


t Key to comparison symbols:
a = pressures, 40 psi vs. 60 psi
b = oats + ryegrass vs. corn
c = oats vs. ryegrass
d = 14 wks. cutting vs. 16 wks cutting, oats and ryegrass only.
c X d, a X b, etc. = various interactions
= significant at 5% probability level
** = significant at 1% probability level








Table C.- Analysis of variance table: Secondary elements in fresh
two crop ages, and two pressures.


Calcium
Mean Squares
Pressed


and pressed forage and the expressed juice for three crops,



Magnesium
Mean Squares
Juice Fresh Pressed Juice


Subplots 39
Whole plots 9 0.238 0.160 0.236 0.020 0.009 0.069 "
a t 1 0.021 0.000 0.084 0.008 0.000 0.000 P
Cuttings + crops 4 0.517 0.352 0.396 0.041 0.017 0.138"*
b t 1 1.015** 0.759** 0.688** 0.039** 0.001 0.428**
c t 1 0.655** 0.582** 0.069 0.054** 0.031** 0.094**
d t 1 0.224** 0.047* 0.589** 0.057** 0.031** 0.030
c X d 1 0.168** 0.018 0.236** 0.012* 0.005* 0.001 M
Pressures X
Cuttings + crops 4 0.013 0.009 0.114 0.003 0.004 0.018
a X b 1 0.008** 0.000 0.003 0.008 0.003 0.000
a X c 1 0.002 0.000 0.300** 0.000 0.006* 0.001 -
a X d 1 0.001 0.027 0.023 0.000 0.003 0.007
a x c x d 1 0.046** 0.010 0.128* 0.001 0.004 0.062** o
Error 30 0.001 0.010 0.024 0.002 0.001 0.008


t Key to comparison symbols:
a = pressures, 40 psi vs. 60 psi
b = oats + ryegrass vs. corn
c = oats vs. ryegrass
d = 14 wks. cutting vs. 16 wks cutting, oats and ryegrass only.
c X d, a X b, etc. = various interactions
= significant at 5% probability level
** significant at 1% probability level
= significant at 1% probability level I.


Source


Fresh


~









Table D.--Analysis of variance table: Micro-nutrients in fresh and pressed forage and the expressed juice for three crops, two
growth ages, and two pressures.


Manganese
d.f. Mean Squares
Fresh Pressed Juice


Copper
Mean Squares
Fresh Pressed Juice


Iron
Mean Squares
Fresh Pressed Juice


Subplots
Whole plots
at
Cuttings + crops
bt
ct
d t
c x d
Press. X cuttings
+ crops
a X b
a~b
ax c
ax d
ax cX d
Error


9 1321.80
1 207.02
4 2690.97
1 3812.26**
1 2.53
1 6932.53**
1 16.53
4 231.34

1 684.75*
1 236.53
1 1.53
1 2.53
30 137.26


t Key to comparison symbols:
a = pressures, 40 psi vs. 60 psi
b = oats + ryegrass vs. corn
c = oats vs. ryegrass
d = 14 wks. cutting vs. 16 wks cutting, oats and ryegrass only.
c X d, a X b, etc. = various interactions
= significant at 5% probability level
** = significant at 1% probability level


Source


1392.39
115.60
2791.57
5760.00**
378.13
5000.00**
28.13
312.41

72.90
1081.12*
40.50
55.12
158.47


2159.89
2160.90**
3384.88
2363.91**
1755.28**
5913.28**
3507.03**
934.65

5.25
1582.03**
913.78**
1237.53**
116.88


31.25
1.68
65.22
160.20**
84.83**
16.10**
0.75
4.67

3.69*
0.17
0.16
13.65**
0.62


88.29
0.19
171.04
269.10**
125.22**
289.80**
0.05
27.56

7.10
66.99**
1.09
35.07**
2.44


46.34
0.31
101.07
356.41**
15.96**
28.13**
3.78
3.11

2.75
0.00
0.00
9.68*
1.69


35586
3168
74170
41731**
34584**
168200**
52164**
5106

9060
13
840
10512
4285


154073
490
269610
138062**
44104*
847602**
48672*
76931

2325
209628**
66
95703**
9333


97109
255
149067
128879**
21476
426657**
19257
69364

9015
79102*
142444**
46894
11626








Table E.- Analysis of variance table: Crude fiber, ash, and
at 14 weeks and corn at 8 weeks.


ether extract in fresh and pressed forage. Oats and ryegrass cut


Crude Fiber Ash Ether Extract
Source d.f. Mean Squares Mean Squares Mean Squares
Fresh Pressed Fresh Pressed Fresh Pressed


Subplots 23
Whole plots 5 19.70 65.28 23.74 16.08 1.38 1.73
a t 1 17.14* 19.69 0.73 0.60 2.30* 0.93
Crops 2 36.36 115.07 55.07 35.32 0.85 1.80
b t 1 25.67** 66.04* 111.05** 65.22** 1.18 1.37
c t 1 47.06** 164.10** 0.07 5.42* 0.50 1.68
Press. X crops 2 8.62 76.59 3.44 9.16 1.45 2.33
a X b 1 6.84 55.43* 5.71 2.70 0.00 0.17
a X c 1 1.78 21.16 1.16 6.46* 2.89* 4.48*
Error 18 2.70 9.82 1.32 1.18 0.38 0.66

t Key to comparison symbols:
a = pressures, 40 psi vs. 60 psi
b = oats + ryegrass vs. corn
C = oats vs. ryegrass
a X b, a X c = interactions
= significant at 5% probability level
** = significant at 1% probability level








LITERATURE CITED

1. Association of Official Agricultural Chemists. Official Methods of
Analyses. Washington, D. C. Ninth edition. 1960.
2. Barnett, A. J. G. Silage Fermentation. Academic Press, New York.
1954.
3. Harrison, D. S. and R. J. Allen, Jr. Harvesting Grass Silage in the
Everglades. Soil and Crop Sci. Soc. Fla. Proc. 16:314-320. 1956.
4. Jackson, M. L. Soil Chemical Analysis. Prentice-Hall Company, New
York. Page 289. 1958.
5. Pirie, N. W. The large-scale separation of fluids from fibrous pulps.
J. Biochem. and Microbiol. Technol. and Eng. 1(1):13-25. 1959.
6. Pirie, N. W. Leaf proteins. Annual review of Plant Physiology 10:33-52.
1959.
7. Pirie, N. W. Some suggestions on the initiation of work on the use of
leaf protein as a human food. Mimeo. Rothamsted Exp. Sta.,
Harpenden, Herts., Britain.
8. Randolph, J. W., D. B. Vincent and R. V. Allison. Preliminary studies
of mechanical dewatering as an aid to dehydration of Florida forages.
Soil and Crop Sci. Soc. Fla. Proc. 16:321-333. 1956.
9. Randolph, J. W., J. P. Winfree, and V. E. Green, Jr. Mechanical
dewatering of forage crops. Everglades Exp. Sta. Mimeo Report 58-14,
April 25, 1958, Belle Glade, Florida.
10. Randolph, J. W., L. Rivera-Brenes, J. P. Winfree, and V. E. Green, Jr.
Mechanical dewatering as a potential means for improving the supply of
quality animal feeds in the tropics and sub-tropics. Soil and Crop Sci.
Soc. Fla. Proc. 18:97-105. 1958.
11. Randolph, J. W., J. P. Winfree, V. E. Green, Jr., and R. J. Allen, Jr.
Mechanical moisture reduction in forage. Assn. So. Agr. Workers Proc.
55th Ann. Cony. Page 56. 1958.
12. Tallarico, G. and B. Fagotti. La conservazione dei foraggi freschi.
Litostampa. Via Brescia 19, 1957, Rome, Italy.













ACKNOWLEDGMENTS

The authors acknowledge the contributions of J. W. Randolph
(deceased), former Agricultural Engineer, Everglades Experiment
Station, and J. P. Winfree, former Assistant Soils Chemist, Ever-
glades Experiment Station, who collected the data and made
chemical analyses in the "Part I" section of this bulletin.




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