Front Cover
 Title Page
 Table of Contents
 Materials and methods
 Results and discussion
 Literature cited
 Back Cover

Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 830
Title: Forage production and utilization from a south Florida multicropping system
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00027618/00001
 Material Information
Title: Forage production and utilization from a south Florida multicropping system
Series Title: Bulletin - University of Florida Agricultural Experiment Station ; 830
Physical Description: Book
Language: English
Creator: Mislevy, P.
Dantzman, C. L.
Prevatt, J. W.
Overman, Allen J.
Horton, G. M. J.
Johnson, F. A.
Publisher: Florida Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida,
Publication Date: 1982
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Bibliographic ID: UF00027618
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

Table of Contents
    Front Cover
        Front Cover
    Title Page
        Title Page
    Table of Contents
        Table of Contents
        Page 1
    Materials and methods
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
    Results and discussion
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
    Literature cited
        Page 36
        Page 37
    Back Cover
        Back Cover
Full Text

August 1982

Florida Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
F. A. Wood, Dean for Research

Forage Pro auction and U ilization
from a South FIorida
Multicropping System

P. Mislevy, C.L. Dantzman, J.W. Prevatt, A.J. Overman,
G.M.J. Horton, and F.A. Johnson

Bulletin 830

* J V'' .- I:

Forage Production and Utilization from a
South Florida Multicropping System

P. Mislevy,

C. L. Dantzman, J. W. Prevatt, A. J. Overman,
G. M. J. Horton, and F. A. Johnson

P Mislevy is Professor of Agronomy and C. L. Dantzman is Associate
Professor of Soil Chemistry at the ARC. Ona: J. W Prevatt is Assistant Pro-
fessor of Food and Resource Economics. Gainesville: A. J. Overman is Pro-
fessor of Nematology. AREC, Bradenton: G. M. J. Horton is Associate Professor
of Animal Nutrition. ARC. Ona: and E A. Johnson is Associate Professor of
Entomology. Gainesville.

Introduction .. .................... .
M materials and M ethods ............................................... 2
Plant studies ................................................... 2
Seed bed preparation ............................................ 2
C dropping sequence .............................................. 2
Water control ................................................. 2
Lime and fertilizer practices ...................................... 4
Harvesting and ensiling practices ................................... 5
Weed and insect control .... ... .................. ... ....... 5
Nematode monitoring ............... ...................... .. 8
Animal utilization studies .. .. .. ................... .. ............ 8
Silage levels for growing steers .................................... 8
Protein sources for growing steers fed silage ........................... 9
Lasalocid and monensin in a high-silage diet ......................... 10
R results and D discussion ............................................. I 1
Plant studies ..................................................... 11
Corn production ...................... ......... ....... 11
Problem s .......................................... ........ 14
Corn quality ......................... ............ .. ......... 14
Aeschynom ene yield and quality ................................... 15
Oats yield and quality .......... .... .............. ............ 16
Forage sorghum yield and quality ................................. 16
Soil organic matter and nutrient status .............................. 17
Nem atode populations ......................................... 20
Production costs ................................................ 24
A nim al utilization studies ........................................... 29
Silage levels for growing steers .................................... 29
Corn silage ....................................... .......... 29
Sorghum silage ............................................... 29
Sorghum vs. corn silage ........................................ 29
Feed costs per pound of gain .................................... 30
Response to zeranol im plants .................................... 31
Protein sources for growing steers fed silage ....................... 31
Response to zeranol implants and protein sources ............... 32
Lasalocid and monensin in a high-silage diet ...................... 32
Sum m ary .......................................... ........ 33
Literature cited ................... ............. .............. 36
Acknowledgm ents ....................................... ........... 37

Trade names, where used in this publication, are for the purpose of providing specific
information. Use of brand names does not imply endorsement of products by IFAS. nor
does it imply disapproval of products not named.

Florida has moderate temperatures, adequate moisture, and high solar ra-
diation conducive to year-round plant growth. The "Sunshine State" contains
approximately 34 million acres (13.8 million ha) of land with about 12 million
acres (4.9 million ha) in some form of native or improved pasture. This pasture
land provides feed for about 2.8 million livestock for an average of 4.3 acres
(1.7 ha) per animal unit.
Improved perennial forage grasses generally provide abundant feed from
June to September, but from October to May forage production is quite low.
Thus the unsupplemented carrying capacity is limited to the cool season pro-
duction capability of the pasture.
Several hundred thousand weaned beef calves averaging 350 to 450 lbs (160
to 204 kg) are shipped out of the state annually to winter pastures and feed
lots. Florida cattlemen could earn an extra $100 million by fattening these
cattle within the state. Unfortunately, they do not have an adequate supply of
economical feed.
Calves weaned in south Florida are generally lightweight and are ideally
suited for backgrounding (preparation of cattle from weaning until placement
on finishing rations). Diets for backgrounding cattle consist of high quality
roughages such as silage plus supplementary protein and minerals. While corn
(Zea mars L.) and sorghum (Sorghnu bicolor Moench) silages can be grown
in south Florida, most of the supplementary protein in animal feeds is pro-
duced out-of-state and is the most expensive macroingredient in the ration.
Consequently, use of cheaper sources of crude protein can reduce the costs of
backgrounding diets considerably. Daily gains can be increased by hormone-
like implants, and improvements in both daily gain and feed efficiency due to
some feed additives may be greater on high roughage rations than with high
energy, grain-based feeds.
The viability of an intensive beef cattle industry in south Florida is contin-
gent on the ability to produce and utilize locally grown high-energy feeds such
as grain and high quality silages.
Dairy cattle require a continuous supply of high energy feedstuff to sustain
milk production, and perennial grasses do not provide these nutrients through-
out the year. Consequently, Florida dairy producers must purchase shelled
corn, citrus pulp. and other high energy feeds in addition to protein, vitamins,
and minerals.
The purpose of this multicropping system study was to explore the physical
and economic feasibility of producing 2 or 3 crops in succession per annum
on the same land under water control. In addition, the cumulative effect of
long-term continuous cropping on nematodes, insects, soil nutrients, and soil
organic matter (OM) was investigated. Forages produced by these multicrop-
ping systems were used in cattle feeding studies to evaluate the utilization of
corn and forage sorghum silages by Brahman crossbred cattle in south Florida.


The study was conducted in a 30-acre (12 ha) field composed of the follow-
ing soil types: Ona (sandy, siliceous, hyperthermic, typic, haplaquod), Po-
mona (sandy, siliceous, hyperthermic, ultic haplaquod) and Placid fine sand
(sandy, siliceous, hyperthermic, typic, humaquepts) located at the Agricultural
Research Center (ARC) Ona, Florida. Prior to 1976, the flatwoods site sup-
ported pine trees (Pinus palustris mill.) and saw palmettos [Serenoa repens
(Bartr.) Small] with approximately 4 acres (1.6 ha) of sand ponds. This report
contains the results from 5 years of continuous cropping, utilizing annual
Seed Bed Preparation
The field was tilled once annually (late January) with a mold board plow to
a depth of 8 to 9 inches (20-23 cm) and disked once. All other crops during
the year were no-till seeded into the residue of the previous crop.
Cropping Sequence
The annual crop rotation for the first 3 years of this study was corn, aes-
chynomene (Aeschynomene americana L) and oats (Avena sativa L) (Table 1).
However, in 1978 (the third cropping year) 10 of 30 acres (4 of 12 ha) of
aeschynomene were substituted with forage sorghum and were seeded in June
followed by a ratoon crop (sorghum regrowth following harvest) grown in the
fall. During 1979 and 1980 the crop rotation sequence was corn and forage
sorghum, followed by a fall ratoon crop of sorghum. The third crop of the
initial cropping year was Florida 501 oats harvested in January of 1977. In
1978 and 1979 when Florida 501 and Florida 70 Q were 18 in (46 cm) and
26 in (66 cm) high, respectively, they were harvested for haylage. The ratoon
crop of sorghum was ensiled in early January of 1979, 1980, and 1981 when
they averaged 48 (1.2), 12 (0.3) and 12 in (0.3 m) high, respectively. The
grain was at the dough stage in 1979 and plants were in vegetative stage of
maturity in 1980 and 81.
Water Control
Irrigation was provided when needed throughout the year (usually from late
March through May) from a 6-in diameter (15 cm), 300 ft (91 m) deep well
powered by a 15-hp motor driving a turbine pump. The well supplied about
170 gpm (643 1pm) which terminated at 6 risers. A traveling water gun con-
nected to one of the 6-inch (15 cm) risers distributed water over a 250-ft
(76 m) diameter circle.
A rim-ditch 7 ft (2.1 m) deep and 16 ft (4.9 m) wide was constructed
around the entire 30-acre (12 ha) site, thus using an additional 4 acres (1.6
ha) of land beyond the 12-ha area. Two small drainage ditches were con-
structed leading from two sand pond areas to the rim-ditch allowing drainage
of pond areas. The rim-ditch was sloped so that all surface water entering

after heavy rainfall accumulated in one area. An automatic low lift [8-in di-
ameter (20 cm) 450 angle axial flow propeller pump. 1500 gpm (5677 Ipm) at
7 ft (2.1 m) tdr.. 12-ft (3.7 m) discharge pipe and a 5-hp motor] pump was
installed in that area to remove water.
Water was applied mainly to the corn at 1.0 in (2.5 cm) per application as
needed. The average seasonal irrigation applied on corn was 7.5 (19). 9.4
(24). 5.4 (14). 4.6 (12). and 3.0 in (7.5 cm) in 1976. 1977. 1978. 1979. and
1980. respectively. Total water received from rainfall and irrigation by the corn

Table I. The cropping sequence followed in the multicropping study from 1976 to
(Seeding Rate lb/A)
Seeding Row Spacing or
Crop and Year Date Brand Variety inches Plant Population
1976 28 Feb DeKalb XL 395 36 18.000-
1977 16 Feb DeKalb XL 80 30 22.000
16 Feb Asgrow RX 114 30 22.000
16 Feb DeKalb XL 395 30 22.000
1978 10 Feb Asgrow RX 114 30 22.600
10 Feb DeKalb XL 80 30 22.600
10 Feb Funks G 4810 30 22.600
10 Feb Funks G 5945 30 22.600
10 Feb DeKalb XL 395 A 30 22.600
1979 and 1980 9 Feb Funks G 4507 30 25.000
9 Feb Asgrow RX 114 30 25.000
9 Feb McCurdy 75-200 30 25.000
9 Feb DeKalb XL 395 A 30 25.000
1976 Late June Grain drill 7 (12)
1977 Early July Grain drill 7 (6)
1978 Early July Grain drill 7 (6)
Forage sorghum
1978 29 June DeKalb FS 25A 30 (10)
1979 29 June Pioneer 923 30 (6)
29 June McCurdy F 75 30 (6)
29 June DeKalb FS 25A 30 (6)
1980 2 July Pioneer 923 30 (16)
2 July DeKalb FS 25 A 30 (16)
1976 Mid Nov Florida 501 Grain drill 7 (96)
1977 Early Nov Florida 501 Grain drill 7 (96)
Early Nov Florida 70 Q Grain drill 7 (80)
1978 Late Oct Florida 501 Grain drill 7 (96)
Late Oct Florida 70 Q Grain drill 7 (80)
tInches x 2.54 cm tPlants/A x 2.47 = plants per ha
Pounds/A x 1.12 = kg/ha
'Following the initial harvest in early October. a ratoon crop developed.

for both 1976 and 1977 was 15.0 in (38 cm) each year. 22.5 in (57 cm) in
1978. 15.8 in (40 cm) in 1979. and 23.1 (59 cm) in 1980 (Fig. I). No irri-
gation was applied to the aeschynomene or forage sorghum. However, the oats
received 1.1 in (2.8 cm) to initiate germination in 1978.

Lime and Fertilizer Practices
Lime (CaCo,) was applied prior to seeding corn in 1976 and again during
the summer of 1977. Both lime and fertilizer practices for the corn. aeschy-
nomene. oats, and sorghum for 1976 through 1980 are presented in Table 2.
Before and after each crop. 24 sites were randomly selected for monitoring

Table 2. Lime and fertilizer practices applied on the multicropping study from 1976 to
Crop N PO, K,O FTE 503"
-- b/A
1976 250 100 200 30
1977 250 100 200 10
1978 250 100 200
1979 250 100 200 30
1980 250 100 300
1976 0 30# 60#
1977 0 30 60
1978 0 30 60
1976 50 50 100
1977 75 50 100 10
1978 75 50 100
Sorghum (June)
1978 90 80 160 -
1979 90 80 160
1980 120 80 160 -
Sorghum (ratoon)
1978 100
1979 75
1980 80
t In addition to the tabulated nutrients below, dolomite (Ca MgCO,) was applied at
3 T/A (6.7 metric tons/ha) in 1976, prior to seeding corn and CaCO, at 2 T/A
(4.5 metric tons/ha) in 1977. In addition 10 lb/A (11 kg/ha) of CuO and ZnO were
each applied to the aeschynomene crop in 1976.
Contain the following elemental content: iron. 18.0%; zinc. 7.0%c: manganese. 7.5%;
copper, 3.0%; boron. 3.0%. molybdenum. 0.2%.
Pounds/A x 1.12 = kg/ha.
Nitrogen was applied as follows: 50 lb/A (56 kg/ha) seeding. 100 lb/A (112 kg/ha)
corn 8 inches (20 cm) and 100 lb/A (112 kg/ha) corn 24 inches (60 cm) tall. Nitro-
gen applied on other crops generally in a split application.
# Fertilizer applied when plants were 4 to 6 inches (10 to 15 cm) tall.

the soil fertility status. Twelve soil sample cores 1 inch (2.5 cm) in diameter
were taken to a depth of 6 in (15 cm) from each sample site after each crop
was harvested. The soil samples were double acid extracted and analyzed for
CaO. MgO. K,O. and P,O, as described by Blue (1979). Soil pH was measured
by means of a dipping electrode. Organic matter was measured using the
Walkley-Black procedure as modified by Walkley (1947).

Harvesting and Ensiling Practices
The entire corn plant was direct cut (harvested and ensiled immediately, not
allowing plants to lose moisture in the field) when the ear was at the dent stage
of maturity and plants contained approximately 28. 35. 32. 48. and 45% dry
matter in 1976. 1977. 1978. 1979. and 1980. respectively. The entire corn
plant was cut to a 4 to 5 in (10 to 13 cm) stubble by a two-row forage harvester
and chopped into Vs to 1/ in (3 to 6 mm) sections and preserved in sealed upright
silos as silage.
Aeschynomene was cut in 1976 to a 3 in (7.5 cm) stubble between the full
bloom and seed stage. However. in 1977 and 1978 the plants were harvested
at the early bloom stage. Harvested plants were allowed to dry in windows
until moisture dropped from 72 and 75% in 1976 and 1977. respectively, to
approximately 50%c. In 1978. all aeschynomene was preserved as hay.
Oats were harvested in a similar manner to aeschynomene [plants averaging
12% dry matter (DM)I. They were allowed to dry in the window until mois
ture dropped to 48% and then ensiled.
The sorghum crop in 1978. 1979. and 1980 was direct cut similar to corn
either when the grain was at the hard dough stage or after a severe frost. No
preservatives were added to the corn, aeschynomene, sorghum, or oats forage
during the ensiling process.
Corn. aeschynomene. oats, and sorghum were sampled and dried at 60 C
for percentage DM. yield. in vitro organic matter digestion (IVOMD) (Moore
et al., 1972). and crude protein (CP) (Moore and Kelly. 1970) for the 1976
through 1979 crops. With few exceptions, each wagon load of harvested corn,
aeschynomene, sorghum, and oats forage was weighed when it entered the
silo area to obtain total forage yield. Samples from every 10th load of corn
forage and every 5th load of aeschynomene, sorghum, and oats forages were
analyzed for IVOMD and CP during 1976 to 1979 and in 1976 for acid deter-
gent fiber, neutral detergent fiber, and acid detergent lignin (Van Soest and
Wine, 1967). Corn grain yields for 1976 to 1980. in addition to forage yield
of oats for 1976. were obtained by randomly sampling the 30-acre (12 ha)
area. All other yields were determined by weighing the harvested forage as it
entered the silo area.

Weed and Insect Control
The insecticide-nematicide carbofuran. 2.3-Dihydro-2. 2-dimethyl-7-ben-
zofuranyl methylcarbamate (Furadan)' 10 G was applied in the furrow di-
rectly over the seed when the corn was seeded in 1976. 1977. and 1979.




1979 -


Figure 1. Rainfall and irrigation received on the multicropping study from 1976 to 1980.
Data are recorded on 15-day intervals for each month per year.

respectively (Table 3). In 1978 and 1980 the insecticide-nematicide fensul-
fothion, 0,0-Diethyl 0-[4-(methylsulfinyl)phenyl]phosphorothioate (Dasanit)
15 G was applied in a similar manner. Both products were used to provide
insect control (lesser corn stalk borer, armyworm, wireworm, etc.) until plants
attained a height of about 12 in (30 cm). The pesticide methiocarb, 3,5-Di-
methyl-4-(methlythio phenol methylcarbamate (Mesurol) 50% Hopper Box
Treater was used from 1977 to 1980 at a rate I Ib (454 gms) formulation per
100 lb (45.4 kg) corn seed as a bird repellant.
The herbicides used from 1976 to 1980 on the corn crops were either atra-
zine plus alachlor or atrazine plus metolachlor, formulated as Bicep. [Atra-
zine, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine, is available as
AAatrex. Alachlor, 2-chloro-2'-6'-diethly-N-(methoxymethyl)-acetanilide, is
available as Lasso. Bicep is composed of atrazine, 2.0 lb (0.91 kg), +
metolachlor: 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-methyl-
ethyl) acetamide (Dual), 2.5 lb (1.1 kg) active per gal (3.8 L).] Herbicides
were applied pre-emergence over the entire study.
No herbicides or insecticides were used on the aeschynomene or oats crops.
Following the corn crop in June and the initial harvest of sorghum in October,
the stubble was sprayed immediately with Paraquat CLI 1.1'-Dimethyl-4,4'-
bipyridinium ion: as dichloride salt to desiccate all annual and perennial weeds
(Table 3). Care must be exercised when Paraquat CL is applied to sorghum
stubble, because this must be done within 3 days after harvesting the sorghum
crop to prevent killing of new developing sorghum tillers.
Nematode Monitoring
Sixteen stations in the dry area and 6 stations in the wet area of the field
were randomly chosen for monitoring nematode populations. Soil samples
were collected at each station at a depth of 0 to 6 inches (0 to 15 cm) in the
area of the root-zone of plant stubble remaining after each crop harvest. Ne-
matode population estimates were made by identifying and counting individ-
uals recovered from 150 mL of soil using the modified Baermann technique
(Christie and Perry 1951).
Four dietary levels of corn and sorghum silages for growing steers were
compared in one trial. Protein supplements for newly weaned steers fed a
high-silage diet were compared in another study. The efficacy of two feed
additives were also evaluated in a third investigation.
Silage Levels for Growing Steers
One-hundred and twenty Brahman crossbred steers with an average weight
of 375 lbs (170 kg) were studied. The steers were randomly allotted to 12
pens of 10 animals and fed one of eight treatment rations for 168 days. There
were two replicates (pens) of animals for each of the 4 levels of sorghum
silage, and one pen of the steers for each of the 4 levels of corn silage.
The digestibilities of the two silages were measured using 4 steers per sil-
age. Steers were fed 1 lb (0.45 kg) soybean meal plus 85% of the ad libitum

Table 3. Weed and insect control measures practiced in the multicropping study from
1976 to 1980.
Rate Rate
Crop Insecticide (active) Herbicide (active)
lb/AT lb/At
1976 Furadan 10 G 1.6 Aatrex" 4L- 2.0
Lasso" 4EC 2.0
1977 Furadan 10 G 2.0 Aatrex" 4L 2.0
Lasso" 4EC 2.0
Bicep" 4.5
1978 Dasanit 15 G" 2.0 Aatrex 4L 2.0
Lasso" 4EC 2.0
Bicep 4.5
1979 Furadan 10 G 2.0 Aatrex" 4L 2.0
Lasso" 4EC 2.0
Bicep" 4.5
1980 Dasanit 15 G 2.0 Aatrex' 4L 2.0
Lasso" 4EC 2.0
Aeschynomene None None
Oats None None -
Forage sorghum
1978 Dasanit 15 G" 2.0 Paraquat CL" 0.5
1979 Dasanit 15 G" 2.0 Paraquat CL" 0.5
1980 Dasanit 15 G' 2.0 Paraquat CL" 0.5
SPounds/A x 1.12 kg/ha
f In 1977. 1978. and 1979 about V" of the field containing corn was sprayed with Aatrex
and Lasso and A was sprayed with Bicep.
Paraquat was applied on the corn stubble (June), prior to seeding the forage sorghum
and on the sorghum stubble (October) prior to development of the ratoon crop.

silage intake. Total fecal collections were made after an adaption period of
14 days.
Corn and forage sorghum silages were both fed at four levels 25,45.60,
and 75% of the diet on a DM basis. The composition of the supplements fed
with the silage is shown in Table 4. Five of the 10 steers in each pen were
implanted with zeranol (Ralgro)' at the start of the trial and again 84 days
later. The steers were weighed after a 16-hr shrink on day 1 and following the
168-day trial. Unshrunk weights were obtained every 28 days during the in-
terim period. Feed refusals were collected weekly
Protein Sources for Growing Steers Fed Silage
Ninety-six steers with an average weight of 400 lbs (182 kg) were randomly
allotted to 16 pens of 6 animals. Four replicates (pens) were fed one of the
four protein sources for 140 days (Table 5). The steers were weighed after a
16-hr shrink on day 1 and again after 140 days. Unfasted weights were re-
corded every 28 days in the intervening period. Feed refusals were collected
' Product of International Mineral Corporation. Terre Haute. IN.

The four protein sources were: unsupplemented control; urea; soybean
[Glycine max (L) Merr.] meal; and dehydrated alfalfa Medicago sativa L pel-
lets plus urea. The crude protein content in the control ration was about 9%.
The other three rations were formulated to contain approximately 13.5% CP.
The diet consisted of 75% corn silage and 25% of a corn-based supplement
on a DM basis. Three of the 6 steers in each pen were implanted with zeranol
on day I and again on day 84.
Lasalocid and Monensin in a High-Silage Diet
One hundred and twenty-eight Brahman x Charolais steers with an average
weight of 650 lbs (296 kg) were allotted by weight into 16 groups. Four rep-
licates (pens) of 8 cattle were fed one of the four treatment rations for
112 days.
The steers were fed a diet containing 72.8% corn silage and 27.2% of a
corn and soybean meal-based supplement on a DM basis (Table 6). Additives
were included in the supplement and were fed continuously from day I of the

Table 4. Composition of supplements fed with corn and sorghum silage.

Ingredient. Percent Silage in the Ration
C Dry Matter 25 45 60 75
Corn, whole 90.3 85.7 80.8 68.8
Soybean meal 7.3 11.5 15.7 26.2
Mineral mix 1.4 1.8 2.5 4.0
Molasses 1.0 1.0 1.0 1.0

Table 5. Composition of supplements containing different protein sources for steers fed
a high-silage ration.
Unsupple- Alfalfa
mented and
Ingredient, % DM Control Urea Soybean Urea
Corn. whole 95 91 61.7 42.5
Soybean meal 33.3
Alfalfa pellets 50.0
Urea 281 4.0 -2.5
Molasses I 1 I 1
Biophos 2 2 2
Mineral mix 2 2 2

Table 6. Composition of basal ration fed to steers (dry matter basis).
Ingredient Percentage
Corn silage 72.8
Corn 17.6
Soybean meal 8.2
Urea 281 .4
Mineral mix 1.0

experiment until termination on day 112. The four treatments were: non-med-
icated control: 33 mg monensin (Rumensin)y-/kg feed: 33 mg lasalocid (Bov-
atec), /kg feed: and 49.5 mg lasalocid/kg feed.
The steers were weighed after a 16-hr shrink on day 1 and following the
112-day trial. Unfasted weights were recorded on days 28. 56. and 84. Final
weights at the end of the trial were adjusted to 61% dressing percentage based
on warm carcass weights. Average daily gains were calculated with initial
shrunk weights and final adjusted weights. Carcass data were collected from
chilled carcasses approximately 72 hrs after slaughter. Rectal fecal samples
were collected from all steers for the measurement of oocysts and nematode
eggs on day 1 prior to feeding the medicated supplements and again on
day 111.

Corn Production
Yield and chemical composition of corn. aeschynomene. oats, and sorghum
for 1976 through 1980 are presented in Table 7: however, no IVOMD and CP
are presented for 1980. The 'Dekalb XL 395' corn, harvested in mid-June
1976 at 28.4% DM, produced 5.6 T/A (12.5 metric tons/ha) DM or 19.3 T/
A (43.2 metric tons/ha) of green forage (as harvested). As fertility and cultural
practices improved, average corn DM yields improved for 1977. 1978, and
1979 to 6.7 (15), 6.9 (15.5), and 7.3 T/A (16.5 metric tons/ha), respectively.
The yields increased about 1.7 T/A (3.8 metric tons/ha) from 1976. However,
5 years after initiation of the study, DM yields decreased to 6.3 T/A (14 metric
tons/ha). These lower yields may have been due to a later planting in 1980
(March 6) because of a freeze (March 3) which destroyed the initial crop.
Green forage yields for the first two years (1976 and 1977) were quite similar,
averaging 19.2 T/A (43 metric ton/ha) each year. However, in 1978 yields
increased to 20.1 T/A (45 metric tons/ha), followed by a sharp decrease in
1979 and 1980 because forage was drier at harvest. The DM at harvest in
1976 was low (28.4%); however, by using early maturing varieties, increasing
plant population, and seeding corn at an earlier date, DM increased to 35.4,
32, 48, and 45% in 1977, 78, 79, and 80, respectively. Corn grain production
from the multicropping system also increased yearly until 1979 (Tables 7 and
8), then decreased 16% in 1980. Dry matter yields of 5.6 T/A (12.5 metric
tons/ha) are considered to be quite low. A yield range between 6.5 to 7.3 T/A
(14.6 to 16.0 metric tons/ha) forage production is considered to be average to
good. When all production variables such as fertility, water control, plant pop-
ulation, proper variety, weed control, and insect control are in correct pro-
portions and no problem areas (poor drainage, nematodes, etc.) occur in field,
corn DM yields should range between 8 (18) and 9 T/A (20 metric tons/ha)
in 120 days or less (Mislevy et al. 1980).
Product of Eli-Lilly. Indianapolis. IN.
Product of Hoffmann-La Roche. Nutlev. NJ.

Table 7. Forage indices of corn. aeschynomene. sorghum. and oats grown from 1976 to 1980 in a multicropping system at ARC. Ona.



Dry Matter Grain to Forage
Harvest Stalk Dry
Time Harvest Ensiling Ratio Green Matter Graint IVOMD-.
-- ------ ---T/A- -- bu/A %


3 Corn:


19 3 5.6

October 27.5 48.7



Protein- NDF ADF ADLs
% - - -

9.0 55.0 26.2 3.0

8.7 70.0 55.3 11.9

25.0 37.4 20.8 1.5

35.4 40:60 19.1 6.7


October 25.8 50.7





11.0 54.2

7.4 1.9

9.0 1.0

32 49:51 20.1 6.9

24 85#3

24 24
32 32

45.1 9.3

77.0 13.4

66.5 7.0

12.0 2.9
5.0 1.6

10.5 50 6.9 0.74

Forage January

70.2 15.1

Table 7. Continued.

Dry Matter

Harvest Ensiling
---- -- ---

Grain to

F orange
Green Matter Grain-; IVOMD:I: Protein:i: NDF ADF ADL

---- T/A -
1979 -

51:49 15.3 7.3

9:91 9.6 3.3





2.4 0.75



50:50 14.2 6.3

16:84 14.8 4.6

0.8 0.4

Corn grain yields were determined at the time corn was being harvested as forage Gram yields based on 15.5' moisture.
:: Values were determined by averaging the analysis of several selected subsamples, as loiage entered the silo.
NDF = Neutral detergent fiber: ADF = acid detergent fiber and ADL = acid detergent lignn.
1[ Grain to stalk ratios were determined from subsamples hand harvested in the field (percent on a dir basis).
# Initial harvest of torage sorghum seeded in June following a spring corn crop.
it Second harvest or first ratoon crop of sorghum.
:I: Harvested for hay.
T/A x 2.24 metric tons/ha: bu/A x 1.15 = 0.1 m' (hectoliter)/ha: lb/A x 1.12 = kg/ha




October 31.6
October 52.8

Janua ry

Problems: The low soil pH (4.3) resulted in some initial 1976 corn pro-
duction problems. Dolomite was applied only 2 weeks prior to corn seeding,
and time was inadequate for the lime to go into solution, react with soil par-
ticles. and raise the pH. Perhaps aluminum (Al) and manganese (Mn) toxicity
could have been responsible for various nutritional deficiency symptoms. Be-
cause the soil pH averaged only 5.0 in 1977, the corn crop still showed a few
deficiency symptoms.
In 1978, 4.0 in (10 cm) of rain were received (after corn was seeded and
before emergence) on soil already containing adequate moisture. This may
have created a serious oxygen (0,) shortage in the soil, especially in soil hav-
ing an organic pan located at or near the soil surface. This lack of O0 may
have promoted phosphorus (P) deficiency in corn seedlings. As moisture de-
creased in the upper 2 to 3 in (5 to 7.5 cm) of soil. 0, returned. With the
application of 100 lb/A (112 kg/ha) N (ammonium nitrate form) the purple
colored leaves on the corn seedlings died and new developing leaves were a
normal dark green color. Forage production was slightly reduced in these low
lying moisture laden (0, stress) areas.
In 1979, for the first time in 4 cropping years, insect damage was evident
on the root system of corn in a small restricted area. Examination indicated
the problem was caused by wireworms (unknown species) and lesser cornstalk
borers (Elasmopla lls lignosellis Zeller). Although the insecticide-nematicide
Furadan 10 G` was used at corn seeding and provided some insect control
[lesser corn stalk borer, armyworm (Spodoptera fri-giperda Smith), wire-
worm, etc.], plants appeared stunted and observations indicated that plants
had damaged root systems (possibly consumed by insects). Preliminary inves-
tigations indicated that parathion. 0,0-diethyl O-P-nitrophenyl phosphoro-
thioate granules applied preplant to corn would curtail this problem. Additional
studies indicated that the problem was not completely solved and other soil-
borne pests still existed. These studies are presently being continued to deter-
mine the soil-borne problems responsible for reduced root systems.
Sandblasting occurred in I out of 5 years, completely destroying the leaves
of corn when it was approximately 6 in (15 cm) and sorghum approximately
4 in (10 cm) tall. Within 7 to 14 days after the sandblasting, corn showed
signs of recovery: however, the sorghum died. Once the leaf was lost due to
some outside physical factor. DM yields appear to be reduced.

Corn Quality
Corn is a moderate to highly digestible crop as indicated by the 73.0,
69.0, 66.5, and 64c IVOMD for 1976, 1977, 1978, and 1979, respectively
(Table 7).
These corn crops produced digestible organic matter or estimated TDN
yields ranging from 7,829 to 9,246 lb/A (8.768 to 10,356 kg/ha). The CP
content of corn averaged 9.0, 8.1, 7.0, and 7.0% with an average of 1,008
(1,130), 1,085 (1,215), 966 (1,082), and 1,022 Ib/A (1,145 kg/ha) CP pro-
duced in 1976, 1977, 1978, and 1979, respectively

Grain to stalk ratios (on a DM weight basis) were determined from the corn
hybrids grown from 1977 through 1980 (Tables 7 and 8) and averaged 50:50
over the 4-year period. The grain to stalk ratio is an important factor to con-
sider when selecting corn hybrids for silage since the energy content of silage
is related to the proportion of grain. This is the amount of grain intake by the
animal while consuming corn forage or silage. Producing a corn crop with a
high forage DM yield and low grain yield results in a low grain-stalk ratio
(30:70) (Mislevy et al. 1980). Corn hybrids that produced a high grain yield
and low forage DM yield may result in a 60:40 ratio. Good commercial hy-
brids should produce high forage and grain yields with approximately a 50:50
ratio or higher. Various factors such as corn hybrid, plant population, mois-
ture, and fertility affect the grain-stalk ratio. The high grain-stalk ratio ob-
tained in this study may be partly due to the excellent grain yields obtained.

Aeschynomene Yield and Quality
Dry matter yield of mature aeschynomene averaged 2.6 T/A (5.8 metric
tons/ha) in 1976 with IVOMD averaging a low 41.7c% (Table 7). Dry matter
yields for 1977 [1.9 (4.3)] and 1978 [1.5 T/A (3.4 metric tons/A)] were low.

Table 8. Grain to stalk ratios and grain yields of corn and sorghum varieties grown
from 1978 to 1980 in a multicropping system at ARC. Ona.

Crop Grain to Stalk Ratio Grain Yield

Corn, Brand Variety -1978- bu/A
DeKalb XL 80 48:52
Asgrow RX 114 41:59
DeKalb XL 395 32:68
DeKalb XL 80 44:56
Asgrow RX 114 52:48
Funks G 4810 50:
Funks G 5945 50:50
DeKalb XL 395 A 48:52
Funks G 4507 57:43 157
Asgrow RX 114 47:53 148
McCurdy 75-200 52:48 154
DeKalb XL 395 A 47:53 171
Sorghum, Brand Variety
Pioneer 923 18:82 30
DeKalb FS 25 A 4:96 12
McCurdy F 72 8:92 15

t Grain to stalk ratios were determined from subsamples hand harvested in the field
(percent on a dry basis).
SGrain yields were determined at time corn and sorghum was being harvested as
forage. Corn grain yields are based on 15.5c moisture and sorghum grain yields on
oven dry matter. Bu/A x 1.15 hectoliter/ha.

with slightly higher digestibility because of early harvesting (flower stage).
Other studies conducted by Mislevy et al. (1981) revealed aeschynomene
clipped at a pre-flower stage [12 to 20 in (30 to 51 cm) tall] averaged 58%
IVOMD and 16 to 18% CP However, DM yields at this short vegetative stage
were quite low. Therefore aeschynomene was not a desirable forage species to
be grown under an intensified harvest management system.

Oats Yield and Quality
There was a serious stand loss of oats in 1976 when birds consumed both
seed and germinating seedlings. Cooler than normal temperatures for 60 days
following the seeding of oats resulted in reduced plant growth. During the
week of January 17, 1977, temperatures fell to lows of 190 to 240 F (- 7 to
-4' C) and by late January the oats had attained a height of only 12 in
(30cm). Plants were then grazed for several days and plowed under because
of the limited time remaining before corn seeding. Forage at this stage of
maturity contained 15.7% DM and yielded only 0.8 T/A (1.8 metric tons/ha).
Forage quality of the 1976 oats crop was exceedingly high in digestibility and
CP which averaged 85.7 and 25.0%, respectively (Table 7). Even though oats
DM yields were only one-third that of aeschynomene in 1976, yield of diges-
tible organic matter and CP was 1,160 (1,300) and 334 lb/A (375 kg/ha),
respectively These respective values were 56 and 74% of that produced by
aeschynomene. Seeding oats about 10 days earlier in the fall of 1977 and
1978, along with more favorable weather conditions, resulted in vegetative
growth of 18 to 26 in (45 to 65 cm) by late January. Allowing oats plants to
become taller and more mature in January 1978 and 1979, resulted in lower
percentage IVOMD and CP (Table 7).
Since the oats crop must be removed by mid to late January so the land can
be prepared for the following corn crop, oats generally do not have adequate
time to complete their life cycle and produce high yields. Consequently, oats,
like aeschynomene, was not a desirable crop to be grown in an intensified
multicropping system.

Forage Sorghum Yield and Quality
Forage sorghum harvested in mid-October yielded 2.9 (6.5), 3.3 (7.4), and
4.6 T/A (10.3 metric tons/ha) DM in 1978, 1979, and 1980, respectively
(Table 7). The IVOMD and CP of forage sorghum grown during the summer
averaged 56.6 and 5.2% in 1978 and 35 and 3.3 % in 1979, respectively
Forage quality was low in 1979 because plants were at the seed shattering
stage when ensiled. In addition, soil conditions were wet in August of 1979,
which also resulted in less grain and lower quality forage.
When sorghum is seeded in June following a spring corn crop, it is of
utmost importance to seed sorghum at least 10 days before the end of June so
that the sorghum plants have time to attain a height of 6 to 10 in (15 to 25
cm) before the rainy season commences. This practice will increase sorghum
yield, reduce the weed population, and allow better utilization of fertilizer.

Growing two to three crops per year on the same land area increased
crabgrass (Digitaria sanguinalis L.) and common bermudagrass (Cynodon
dactnlon Pers.) problems, especially in the second and third crops. These weed
problems can be partially overcome by applying Paraquat CL at 0.5 lb AI/A
(0.56 kg/ha) to the corn stubble in June, just prior to seeding the next crop.
Following the early October forage sorghum harvest, Paraquat CL at 0.5
lb AI/A (0.56 kg/ha) was immediately sprayed on sorghum stubble to reduce
annual and perennial weeds. The ratoon crop in 1978 then developed and
yielded 1.6 T/A (3.6 metric tons/ha) DM by early January averaging 53%
IVOMD and 8.8% CP Delaying the removal of the summer sorghum crop
from early October to late October resulted in a sorghum yield reduction in
January because of shorter days and the commencement of cooler tempera-
tures. In 1980. DM yields of the third crop (sorghum ratoon crop) produced
from October to January were further reduced from 1979. due to high popu-
lations of nematodes.

Soil Organic Matter and Nutrient Status
Most organic matter in the soil accumulates as the result of plants that die
and decompose. Cattle manure, insects, and small animals also contribute to
the OM. The amount of OM is influenced by climate, soil texture, and the
nature of vegetation, as well as topography and drainage. Over a long period
of time OM in a soil reaches equilibrium with its environment. Soil OM is
lowered when a field is brought under cultivation, thus leading to accelerated
breakdown and release of plant nutrients. When a new crop is established, the
soil OM adjusts to a level which may be higher or lower than the original
condition. Organic matter improves soil productivity in several ways. It in-
creases moisture holding capacity, which is needed in the sandy soils of central
Florida and it causes a decreased rate of seepage, allowing more water to be
available for plant use. It also helps bind soil particles into clusters. Organic
matter prevents excessive aeration in sandy soils thus helping to reduce its
decomposition rate. The leaching of fertilizer elements is reduced by OM and
it allows for slower changes in pH. It acts as a storehouse of organic and
inorganic plant nutrients. It allows P and sulfur to be more available and other
elements to be more soluble. It increases growth of microorganisms which
help recycle plant nutrients. One percent OM in the top 6 in (15 cm) of soil
amounts to 10.0 tons/A (22.4 metric tons/ha) which contain from 300 to 1.000
lbs (136 to 454 kg) of N.
The OM of the field in its native condition (before the multiple cropping
system began in 1976) was 3.7% (Fig. 2). Following soil preparation and the
growth of the first two crops (corn and aeschynomene) the soil OM measured
2.7%, a loss of 1 percentage unit. Much of the plant nutrients released by
decomposition of the OM were probably available to the first two crops. After
the first oats crop and the second year rotation in 1977 (corn, aeschynomene,
and oats), the OM measured over 4%. During the following rotations from
1978 to 1981. the OM ranged from 3 to 5%, with a final value being 4.1%.


F J 0 F J 0 F J 0 F J 0 F J 0 F
1976 1977 1978 1979 1980 1981


F J 0 F J 0 F J 0 F J 0 F J 0 F
1976 1977 1978 1979 1980 1981


600 -

oo 2 2 0
400 0 0 1,*- 2 2-
0 Cl C) U \ ( z 0 z

9 9
0 0
SU)3 U CO W u C 0

0 T

F J 0 F J 0 F J 0 F J O F J 0 F
1976 1977 1978 1979 1980 1981


4 100





<- 100

e" 60



1980 1981

F J 0 F J 0 F J 0 F J 0 F J 0 F
1976 1977 1978 1979 1980 1981

F = Feb./J= June/O= Oct.

Figure 2. Effect of 60 months of multicropping on the level of soil OM. CaO. MgO.
K.O. and PO-.


z 0
2 U < 0
>- I
I I ,, II
z z c z z u0 0 z 0 0-
O i < 0 / O O, 00 0 0 0
u o 0
o 0
w jU)q

1976 1977 1978 1979

This OM percentage was influenced to some extent by the plants grown, the
accumulated residues, and the fertility practice used.
The soil in its native condition was very acid (pH 4.3) and low in fertility.
Before land preparation, the CaO level was 512 lb/A (570 kg/ha) (Fig. 2) and
the MgO was 166 lb/A (186 kg/ha) (Fig. 2) as estimated by the double acid
extraction techniques. These values were below the minimum levels recom-
mended for crops used in this rotation. After liming with 3 T/A (6.7 metric
tons/ha) of dolomite and following the first year's growth of corn and aeschy-
nomene, the CaO content increased to 1022 lb/A (1145 kg/ha) and MgO to
528 lb/A (590 kg/ha). The need for additional Ca was evident by mid-1977 at
which time 2 T/A (4.5 metric tons/ha) of high calcic lime (CaCO,) were ap-
plied. The calcic lime application was followed by a considerable increase in
CaO level. Between 1977 and 1981 CaO decreased to approximately 2,000
lb/A. (2240 kg/ha) and MgO gradually decreased to approximately 230
lb/A (258 kg/ha).
Soil KO and P,O, levels at the initial (native) condition were 31 (35) and
14 lb/A (16 kg/ha), respectively, (Fig. 2). Following soil preparation and the
first year's crops these elements increased to 79 lb/A (88 kg/ha) K,O and
42 lb/A (47 kg/ha) P,O,. Following recommended fertilizer practices the soil
elemental content measured about 140 Ib/A (157 kg/ha) for both K,O and
PO, after the January 1981 harvest, 5 years after initiation of the study.

Nematode Populations
Multicropping systems in sandy soils may be conducive to the development
of economically damaging populations of nematodes. Population levels and
dominance of specific genera depend on crop sequence. This is the result not
only of crop suitability as a host for nematodes, but also of competition among
species for feeding sites on plant roots and the vigor of the plant fed upon by
each nematode species. Monitoring nematode populations after each crop in
the drier portion of the field showed that three of the six genera found in the
experimental area increased dramatically during the third year of cropping.
Except for Hoplolaimus, the lance nematode. populations of all genera were
sharply reduced during the last six months of the fourth year, but recovered
the following year (Fig. 3). During the first three years, Paratrichodorus
christiei, the stubby-root nematode, gradually increased regardless of the crop
planted (Fig. 3). Stubby-root nematode populations "exploded" in the corn
crop grown in the spring of 1978. However, in 1979, there was a gradual
decline in the stubby-root nematode until corn was planted again in the spring
of 1980. There was a slight population response to the sorghum and oats in
the fall of 1978, but the decline was general throughout 1979. Unlike the drier
areas of the field, the pond areas did not support high numbers of this parasite
on corn (Fig. 3). Paratrichodorus favored oats in the wetter area of the field.
The spiral nematode, Helicotvlenchus was slow to become established, but
developed heavy infestations in the second oats crop (Fig. 3). In the corn crop,
there was a sharp population reduction in 1978 in both the drier and wetter

portions of the field. The spiral nematode then reached a 4-year population
peak on the corn in June 1979. After this peak. the pest then steadily declined
through January 1980. to be followed by a peak in the spring corn corp. Peak
density in the low sand pond portion of the field occurred during the second
oats crop: but after May 1978 the population subsequently declined to merely
detectable levels in the pond areas.
The lance nematode. Hoplolainmus, was detectable in the drier section of
the field in the first aeschynomene crop and increased on the second oats crop
(Fig. 3). During the summer of 1978. populations subsided, but in the 10
acres (4 ha) planted to sorghum in 1978. populations again increased. The
4-year peak density of the lance nematode occurred in June 1979 following
corn. However. October 1979 counts in sorghum were low, and not signifi-
cantly different from October counts in the previous year. In 1980. as in the
previous year. the lance nematode increased on the corn. The lance and root
lesion (Pratvlenchus) nematodes have not been detected in the low sand-pond
areas (Fig. 3). The lesion nematode was detectable in the first aeschynomene
crop grown on the drier areas. This nematode attained a mean peak of 57
individuals/150 mL soil following the corn crop in the drier area during 1978.
then gradually all disappeared by January 1980. By the end of 1980. however,
the lesion nematode had peaked in the ratoon sorghum at approximately the
same level as it did in 1978.
The stunt nematode. Tvlenchorhvnchus clayltoi was not responsive to the
crop during the first two years. but steadily increased during the third year on
all crops grown in the drier soil (Fig. 3). During the fourth year, the stunt
nematode decreased substantially. but increased again in the 1980 sorghum
Concentrations of nematode infestations in a newvx cleared flatwoods soil
are usually related to the initial plant species and distribution in the native
cover. Pine trees. palmettos. and grasses growing singularly or in clumps as
native cover on Ona fine sand support specific nematode communities which
use the plant root systems as a food source. During land preparation these
concentrations of nematodes are diluted and somewhat redistributed by the
machinery used to manipulate the soil. However, during the first few crop
seasons, nematode densities were still "spotty" in the described field. Culti
vation. water flow, and root exploration of host plants eventually can be ex-
pected to spread the communities of nematodes farther from the point of
origin. The no-till management of the 30-acre (12 ha) block involved in this
multicropping evaluation probably delayed the equalization process which has
been observed in other cultures.
This concept has been supported by the variation in nematode counts which
was obtained during the 5-year study among the stations sampled in the field.
Stubby root nematodes occurred with greatest frequency in the soil samples
collected for assay. The nematode was found in 100%/ of the replicates col-
lected at all stations on all sampling dates in 1980. in 93% in 1979. and in








0 F J 0 F J 0 F J 0 F J 0 F
1976 1977 1978 1979 1980 1981
= 2
400 |
z 0
LJ rC Co,
300 -

50 0
Z_ D :D D



1976 1977 1978 1979 1980 1981

F= Feb./J = June/O = Oct.

2 /

w o \
z z II
C zI I z
I I z r :>
CO Z 6 COn Z Z /K > Z .9 Z, (9 (9
o u < ?' C ) u 0 u ( QML
Ci I
I '
I I I/ l \ /

n, I,

i A\^



400- : 2
w I I
z CO o.
w 0- I
300 o o
50 Z
o oD o)
z X r
O Z C / Z Z Z z
200, I NH
00 w 0 0 R 0 0T 0 0 J 0 T
0 C9 7 0 17 197 1/ 9 80) 19, 81

100 w4


0 F J 0 F J 0 F J 0 F J 0 F
1976 1977 1978 1979 1980 1981






100 ,- V

0 F J 0 F J 0 F J 0 F J 0 F
1976 1977 1978 1979 1980 1981
Figure 3. Effect of 60 months of multicropping on the spiral (Helicotylenchus). stunt
(Tylenchorhynchus). lesion (Pratylenchus), stubby root (Paratrichodorus). lance
(Hoplolaimus) and ring (Criconemoides) nematode populations found in the
dry and low sand pond areas of the field.

80% of the replicates sampled in previous years. In contrast, the lance nema-
tode was detected in 72% of all 1980 samples, in 50% of all 1979 samples,
and in only 23% of previous samples. Localized variation measured within
single sampling dates emphasizes the difficulty encountered in determining
population dynamics of any natural biological system. Numbers of the spiral
nematode for example, ranged from 0 to 1620 per 150 mL soil among repli-
cates collected in January 1978 following the second crop of oats. In fact, this
species was not detected in certain blocks of the field until October 1977.
However, on only two sampling dates in the last 3.5 years of the study did the
mean population of the spiral species fall below 200 individuals per 150 mL
In the third year, populations of the ring nematode Criconemoides reached
detectable levels in soil extracts derived by the modified Baermann technique
(Fig. 3). This is not the technique of choice for recovery of ring nematodes:
therefore, random checks using the sugar-flotation technique were made
throughout the experiment to confirm the progress of the population. Popu-
lations in the sandy soil remained very low throughout the 3rd, 4th, and 5th
year. No ring nematodes were recovered from the low pond areas.
No apparent plant or soil relationship was associated with the level of ne-
matode population found at the various stations. Although nematode popula-
tions, in general, increased with time in the 12-ha block, this study was not
designed to collect data on economic damage caused by feeding of the para-
sites on the crop roots. However, the genera under observation are considered
obligate plant parasites which must feed on living plant roots in order to re-
produce and may prove to play an important role in crop production.
Production Costs
In agriculture, production practices are subject to change due to an infinite
variety of physical and environmental conditions. These conditions dictate the
level of inputs necessary to produce a useable crop. Production costs there-
fore, also vary with the quantities of inputs and their demand (Osburn and
Schneeberger 1978).
Calculating production costs is a prerequisite for determining the economic
feasibility of the multicropping forage program. Understanding the importance
and use of the production costs is a valuable asset in managing any operation.
The estimation of production costs allows the producer to develop enterprise
budgets that provide a means to thoroughly evaluate the costs and returns of
that enterprise.
Production costs are generally differentiated as being either fixed costs
(ownership costs) or variable costs (operating costs) (Hopkin et al. 1973).
Fixed costs are those that the producer has already committed himself to. such
as depreciation and interest. Variable costs are those that the producer has yet
to make a decision on. such as seed and fertilizer.
In this study returns over variable costs were recorded for each enterprise.
However, fixed costs were not included in this study because these costs vary

greatly among producers depending on their machinery complement set and
other fixed factors of production.
The enterprise budgets for corn forage. forage sorghum, and forage sorghum
ratoon indicate the variable costs incurred per acre during 1980. as shown in
Tables 9, 10. and I The variable costs in each budget describe the cultural
practices (plowing, fertilizing, planting. spraying. etc.). quantities of inputs
utilized (fertilizer, seed, herbicide. etc.). prices of the inputs, and value per
Summarizing the results of the multicropping enterprises between 1976 and

Table 9. Estimated variable costs per acre for growing and harvesting corn forage in
a multicropping system. Ona. 1980.+


FTE 503 "
Custom applied
Parathion 10G
Plant corn
Dasanit 15G
Mesurol "
Corn seed
AAtrex "

Ammonium nitrate
Custom applied
Ammonium nitrate
Custom applied
Harvest, haul, and pack.
Interest #


Unit Quantity Price Value/A
ton 1.00 24.60 24.60
acre 1.00 5.03 5.03

February acre
February acre
February acre





145 50
2 50

1.00 2.92
0.50 12.04
0.50 18.50



March ton 0.15 155.00 23.25
March acre 1.00 2.50 2.50
April ton 0.15 155.00 23.25
April acre 1.00 2.50 2.50
February-May acre-inch 3.00 7.89 23.67
June acre 1.00 32.84 32.84
January-June dollar 291.78 0.07 20.42

+ Average dry matter yield during five production seasons (1976-1980) was 6.5 tons/
acre on Pomona fine sand and Ona fine sand soils. Value/A x 2.471 Value/ha.
t Lime was applied at the rate of 3 tons every three years.
A killing freeze occurred during one of the five years of production which resulted
in additional corn planting expenses.
Irrigation requirements will vary from year to year with respect to rainfall.
# Interest was calculated using 14C/ annual for six months.

Table 10. Estimated variable costs per acre for growing and harvesting forage sorghum
in a multicropping system, Ona. 1980.t


Unit Quantity Price Value/A

Sticker X-77 "'
Paraquat "
Plant sorghum
Sorghum seed
Mesurol '
Dasanit 15G
Custom applied
Harvest. haul.
and pack.







1.00 2.9
0.13 12.3
0.25 41.3
1.00 2.9
16.00 O.C
0.20 14.7
13.33 1.2

'2 2.92
i8 1.61
.0 10.33
11 2.91
50 9.60
'5 2.95
20 16.00

0.40 163.50 65.40
1.00 2.50 2.50

1.00 24.92 24.92

dollar 139.17 0.058

%147 21

tAverage dry matter yield during three production seasons (1978-1980) was 3.6 tons/
acre on Pomona fine sand and Ona fine sand soils. Value/A x 2.471 value/ha.
Interest was calculated using 14% annual rate for five months.

Table II. Estimated variable costs per acre for growing and harvesting a forage
sorghum ratoon crop in a multicropping system. Ona 1980.-

Sticker X-771

Month Unit
October acre

Fertilizer November
Ammonium nitrate
custom applied
Harvest. haul, and pack January
Interest* October-


Quantity Price Value/A

1.00 2.92
0.25 41.30
0.13 12.38




2 1.11


t Average dry matter yield during three production seasons (1978-80) was 0.9 tons;
acre on Pomona fine sand and Ona fine sand soils. Value /A x 2.471 Value/ha.
1 Interest was calculated using 14% annual rate for four months.

Table 12. Summary of yields and variable costs.


Crop value above-:
Variable costs

Corn forage
Corn forage
Corn forage
S Oats
Sorghum ratoon
Corn forage
Sorghum ratoon
Corn forage
Sorghum ratoon

$277.69 5.6
80.44 2 6
52.51 0.8
277.69 6.7
80.44 1.9
103.84 I 0
277.69 6 9
80.44 1.5
121.83 2.9
103.84 0.7
73.88 1.6
299.46 7.3
148.31 3.3
52.22 0.7
312.210 6.3
147.21 4.6
61.38 0.4

Note: Variable costs include those costs incurred to grow a crop, such as seed. fertilizer, and chemicals. The fixed costs of the land, machinery.
and irrigation system are not considered in this analysis, since they vary widely among producers.
' Crop value is assumed to have the same value as a leedsluff that is similar in iutritionual composition. These values are ulili/eid solel\ lir the
purposes of comparison and should not be interpreted as their market price.
4 Crop value above variable costs is the assumed c rop \alue ninus variable costs. S A \ 2 47 = $/ha.
Parentheses indicate loss.






$/T I)M
74 60(

$/T DM
I 10
I ())



171 .100
232.00 (

443. 80(
( 13,38)

1980 reveals the yields, variable costs, crop value, and crop value above var-
iable costs (Table 12). These factors constitute an overview of the five years
of production and reflect the production potential and profitability of each
Corn forage during the 5-year period produced an average yield of 6.5 tons
of DM per acre (14.6 metric tons/ha) with an average crop value above vari-
able costs of $372.25/A or $920/ha. The low yields associated with acschy-
nomene. oats, and forage sorghum ratoon crops resulted in less than desirable
returns. The forage sorghum during 1978 to 1980 produced an average yield
of 3.6 tons of DM per acre (8.1 metric tons/ha) with an average crop value
above variable costs of $254.38/A ($570/ha). Summarizing the information in
Table 12 reveals that yield, production costs, and crop value are the major
factors affecting crop value above variable costs.
Total variable costs of corn and sorghum silages produced during the 1980
production year and led to Brahman cross-bred steers are reported in Table
13. The cost of silage per ton includes the cost of producing, harvesting.
hauling, packing, storing, storage losses, and feeding corn and sorghum sil-
ages. The 1980 corn and sorghum silages produced in this study resulted in
total variable costs of $35.99 and $28.38, respectively, per ton of silage. Pro-
ducers should be aware, however, that the total costs of silage per ton is very
sensitive to changes in yield and storage loss. These costs are the basis for
determining the feed cost per 100 pounds of milk production or feed cost per
pound of gain.
The budgets presented in this report were derived from production practices
and input costs used in this multicropping study. Individual producers may

Table 13. Estimated cost to produce, harvest, haul, pack, store, and feed corn and
forage sorghum silages from a multicropping system, southwest Florida,
Ona. 1980.-1
Item Corn Silage Forage Sorghum Silage
Cost/Ton to produce, harvest, haul & $26.19 $19.57
Cost to store/ton 1.93 1.93
Sub-total $28.12 $21.50
Storage loss (15% ) 4.22 3.23
Cost to feed/ton# 3.65 3.65
Total cost of silage/ton $35.99 $28.38
A Average dry matter production observed was 6.5 and 3.6 tons per acre (14.07 and
10.40 tons per acre on a wet basis), respectively
t Costs to produce, harvest, haul and pack corn and forage sorghum silages are from
Tables 9 and 10 respectively. Costs and yield will vary considerably depending on
what inputs were used during the production process.
Storage cost was estimated for a 10' x 45' x 185' bunker silo
Storage loss was estimated at 15C(.
# Cost to feed was estimated using a front end loader and side delivery feed wagon.

follow different production practices. use other equipment. and;or obtain in-
puts at different prices. These factors ma\ result in differing N iclds. production
costs, and crop values from those reported in this study.


Silage Levels for Growing Steers
Corn silage: The dry matter digestibility of the silage was 66.1 which is
within the normal range for corn silage (Ensminger and Olentine. 1978). Av-
erage daily gains of steers decreased by 9% from 2.36 to 2.16 lb ( 1.07 to 0.98
kg) as the proportion of corn silage in the ration increased from 25 to 75%
(Table 14). Feed consumption increased slightly from 14.4 to 15.3 lb day
(6.45 to 6.95 kg/day ). and the feed conversion ratio increased from 6. 10 to
7.00 lb (kg) feed/lb (kg) body weight gain. The data show that satisfactory
gains in excess of 2 lbdav (0.9 kg day) by growing steers were possible with
diets containing up to 75% corn silage. without any large difference in effi-
ciency of feed utilization. These results are consistent with data reported by
Keith et al. (1981).
Sorghum silage: The digestibility of DM in the sorghum silage was 52.2%:
while typical of sorghum silage (Ensminger and Olentine. 1978) it was 27%
lower than that of corn silage. Daily gains decreased by 36%. from 2.44 to
1.55 lb (1.11 to 0.70 kg). when the proportion of sorghum silage in the ration
increased from 26 to 75% (Table 15). The lower gains at the high sorghum
silage level were associated with a 21 /I decrease in feed consumption (14.2
vs 17.6 lb/day) (6.45 vs 7.99 kg day) and a 29% increase in the amount of
feed required per unit of gain (9.20 rs 7.13 lb feed/lb gain). Gains of 2 lb/day
(0.9 kg/day) were not obtained on the 75% sorghum silage diet.
Sorghum silage vs corn silage: Gains by steers fed the two low levels of
corn silage and forage sorghum silage (25 and 45% of the ration) were similar
(2.31 v's 2.38 Ib/day) (1.05 s: 1.08 kg/day). However. steers fed sorghum
silage consumed 23C/ more feed than those fed corn silage, and required 19%
more feed per pound of gain. Increasing the proportion of silage in the ration

Table 14. Performance of steers ted different proportions of corn silage during the
growing period.
Percent Corn Silage in Ration
Item 25 48 62 75
Starting wt. Ib 383 362 371 378
Finishing wt, lbt 779 742 739 740
Total gain. lbt 396 380 368 363
Daily gain. lbt 2.36 2.26 2.19 2.16
Daily intake, lbt 14.4 14.7 15.3 15.0
Feed/gain 6.10 6.49 7.00 6.96
t k = x x 0.454

reduced total feed consumption with sorghum silage but did not alter the intake
of corn silage ration. Average daily gain and feed efficiency decreased more
with sorghum silage than with corn silage. The responses were probably re-
lated to differences in the available energy content of the diets as reflected by
digestibility, and perhaps also the palatability of the two silages. The sorghum
silage was very palatable and yet less digestible than the corn silage. The
amount of supplement was regulated by the amount of silage consumed. And
at the low silage levels, steers consumed more high-energy supplement with
sorghum silage than with corn silage. The higher intakes of the highly diges-
tible supplement more than compensated for the lower digestibility of the small
amount of sorghum silage on the low silage diet, with the possible result that
total energy intakes were similar with both corn and sorghum silages. With
higher levels of silage in the diet, however, the lower digestibility of sorghum
silage was associated with low total DM intakes, reduced energy consumption,
and lower daily gains compared to corn silage diets.
Feed cost per pound of gain: Feed costs per pound of gain were calculated
using the diets previously described in Table 4. The feed costs per pound of
gain, as reported in Table 16, ranged from $.37 to $.42 and $.49 to $.50 for
corn forage and forage sorghum silages, respectively The four corn forage
silage rations revealed a decreasing cost per pound of gain as the percentage
of corn silage was increased in the ration. Feed costs for the forage sorghum
silage diets, however, were constant except for the lowest ration level (26%

Table 15. Performance of steers fed different proportions of sorghum silage during
the growing period.
Percent Sorghum Silage in Ration
Item 26 45 61 75
Starting wt, lb 381 385 370 367
Finishing wt. Ibt 791 777 702 627
Total gain. Ib- 410 389 332 260
Daily gain. lbh 2.44 2.32 1.98 1.55
Daily intake. lbi 17.6 18.2 16.9 14.2
Feed/gain 7.13 7.85 8.52 9.20
Skg x x 0.454

Table 16. Estimated feed costs for corn and sorghum silages, multicropping study. Ona.
Corn silage Sorghum silage
Percent in Cost per Percent in Cost per
ration (DM basis) pound of gain ration (DM basis) pound of gain
25% $.42 26% S.49
48% $.41 45% S.50
62% $.40 61% $.50
75% $.37 75% $.50

silage) which showed a variation of S.01 per pound of gain. These costs per
pound of gain are currently cost competitive with other complete mix rations.
Response to zeranol implants: Zeranol implants at the start of the trial
and again 84 days later improved average daily gains by 131 (Table 17).
Implanted steers averaged 45 lb (20 kg) heavier than non-implanted steers
after the 168-day trial.

Protein Sources For Growing Steers Fed Silage
The CP content in the unsupplemented control diet (9 %) was less than in
the other three protein-supplemented diets (13.5%). and below the recom-
mended level of about 13% for 400 lb (182 kg) steers gaining 2 lb (0.91 kg)
per day (NRC. 1976). This was reflected by substantially lower gains on the
control diet than on the other three diets (Table 18). Gains on the diet in which
all the supplemental N was in the form of urea (1.94 lb/day) (0.88 kg/day)
were more than double those on the protein-deficient control ration (0.95
lb/day) (0.43 kg/day). Highest gains, however, were observed with steers fed
soybean meal, and these were 9% higher than with alfalfa urea (2.16 i.s
1.99 lb/day) (0.98 vs 0.90 kg/day). Lower gains with urea than with soybean

Table 17. Effect of zeranol implants on the performance of steers fed different propor-
tions of silage.
Item Non-implanted Zeranol
Starting wt. Ibt 378.4 372.6
Finishing wt. lbt 712.4 751.3
Total gain. lbt 334.0 378.7
Avg. daily gain, lbt 1.99 2 25
Improvements, Ibt 45
c( 13
Skg = x 0.454

Table 18. The effect of protein source on the performance of grow ing ,teers fed a high
silage ration.
Item Control Urea Alfalfa-urea Soybean
Starting wt. lbt 413 412 416 414
Finishing wt, Ibt 546 683 694 717
Total gain. lbt 133 271 278 303
Daily gain. lbt 0.95 1.94 1.99 2.16
Daily intake. lbt 11.34 13.56 14.37 14.13
Feed/gain 11.94 6.99 7.22 6.54
Gain. lbt 138 145 170
/ 104 109 128
Intake. Ib 2.22 3.03 2.79
Feed/gain. Ibt 4.95 4.72 5.40
%C 71 65 83
t kg = x 0.454

meal were also reported by Young et al. (1973). Feed efficiency ranged from
6.54 to 11.94 lb (kg) feed/lb (kg) gain for soybean meal and unsupplemented
control rations, respectively.
These findings illustrate the requirement of lightweight calves for high-qual-
ity, natural protein such as soybean meal for optimal gains. However, the data
also show that satisfactory gains by growing or backgrounding calves fed a
high corn silage diet are possible with urea providing the only source of sup-
plementary N other than that derived from the silage and corn grain.
Response to zeranol implants and protein sources: There was evidence
of a zeranol x protein interaction. Zeranol implants had no effect on the
performance of steers fed the unsupplemented control ration (Table 19). How-
ever. when either urea, alfalfa pellets, or soybean meal were included in the
ration, implanted steers gained 20, 57. and 57 lb (9, 26, and 26 kg) more
weight than their non-implanted pen mates during the 112-day trial. These
differences represented an 8. 22, and 22% advantage due to the two zeranol
implants on day I and 84 for urea, alfalfa pellets and soybean meal, respec-
tively Zeranol is a protein-anabolic agent and has been shown to increase body
protein deposition. These data demonstrate that adequate natural protein is
required for the hormone-like implant to manifest this effect in growing steers.
Non-protein N in the form of urea was not as effective as plant protein for the
expression of the zeranol response with light-weight backgrounding steers un-
der the conditions of this investigation.

Table 19. Effect of protein source on gain response to zeranol implants.
Protein source: Control Urea Urea + Alfalfa Soybean
Implant: None Zeranol None Zeranol None Zeranol None Zeranol
Starting wt. Ibt 428 399 405 419 434 387 403 427
Finishing wt, lbt 566 526 666 700 689 699 669 750
Total gain. lbi- 138 127 261 281 255 312 266 323
Avg. daily gain. .99 .91 1.86 2.01 1.82 2.23 1.90 2.31
Improvement. lb-; -11 20 57 57
S-8 8 22 21
- kg = x 0.454

Lasalocid and Monensin in a High-Silage Diet
While there are several reports in the literature of lower feed intakes with
lasalocid and monensin (Berger and Ricke. 1980) there were no treatment
effects on voluntary feed consumption in the present investigation (Table 20).
Similar intakes across treatments were probably due to the ingredient com-
position of the ration, with high grain rations in the earlier work contrasting
with the high silage ration in the present study.
Monensin increased gains by 8% and feed efficiency by 8%/. Lasalocid, fed at
33 mg/kg feed, increased average daily gain by 18C/% and feed-to-gain ratio by

15% in accord with Brethour (1979). Smaller improvements in gain (3 ) and
feed efficiency (4%9) were observed w ith the higher level of lasalocid. These re-
sults indicated that under the conditions of this experiment. 33 mg lasalocid kg
of feed was more effective than 49.5 mg lasalocid kg or 33 mg monensin kg of

Tahle 20. The effect of monensin and lasalocid on teedlot perlorlmance of steers.
Lasalacid. nme kg diet
Item Control Mlonensn 33 49.
Initial wt. lbK 644 655 651 664
Final wt. Ib- 845 872 888 871
Total gain. lb; 201 217 237 207
Daily gain. Ib-; 1.79 1.94 2.12 I.5
Daily intake. lb-' 18.7 I8.6 18.8 18.6
Feed/gain 10.47 9.66 8.94 10.08
Gain. lb- 16 36 6
c7 S IS 3
Feed/-ain. 1 8 15 4
kg \ 0.454

Fecal examination revealed that approximately 43( of the steers had coccidial
infections at the start of the trial. Over 450 nmm of rain fell during the experi
mental period (February to June 1980). This is higher than normal for that time
of the year. and was associated with a high ooc\st discharge at the end of the
experimental period in control steers. The very wet conditions in the dirt pens
were conducive to the proliferation of coccidia. The absence of coccidia in
treated steers at the end of the trial indicates that both lasalocid and monensin
at 33 mg/kg of diet were effective therapeutic agents against naturally occurring
coccidiosis in cattle.
Fecal nematode eggs were detected in about 29C/ of the steers at the start
of the trial and in about one-third of the animals after 111 days. Fecal egg
counts were not affected by the treatments and averaged 68 and 21 eggs per
gram feces on days 1 and 111, respectively. These data suggest that the steers
had developed some immunity to the gastrointestinal parasites with time and
that none of the treatments reduced the incidence of these infections.


A successful multicropping system requires, timeliness of crop seeding, proper
fertility, water management, proper variety. adequate plant population. weed
control, insect control, and nematode control.
In a year-round highly intensified forage program, corn can be grown from
February to June averaging 6.5 T/A (14.5 metric tons/ha) DM. followed by for-
age sorghum from June to January averaging 4.5 TA ( 10.8 metric tons ha) DM.

This combination will provide approximately 11 T/A (24.5 metric tons/ha)
DM of a high energy forage. Oats and aeschynomene can produce high quality
forage (harvested early), but yields of these crops are too low to be incorpo-
rated into a highly intensified multicropping system.
Initially the native soil condition was very low in pH (4.3) and low in ele-
mental content: CaO, 512 lb/A (573 kg/ha); MgO, 166 lb/A(185 kg/ha); KO,
31 lb/A (35 kg/ha); and PO,, 14 lb/A (16 kg/ha) and the OM was 3.7%.
After rototilling 3 T/A (6.7 metric tons/ha) of dolomitic limestone into the
seedbed in early 1976 and applying 2 T/A (4.5 metric tons/ha) of calcic lime-
stone (CaCO3) in early 1977, the soil averaged 2120 lb/A (2370 kg/ha) CaO
235, lb/A (263 kg/ha)MgO, and a pH of 5.6 after 5 years of cropping. The
application of recommended fertilizer rates to each crop resulted in a buildup
of soil fertility to the following levels after 5 years of multicropping KO0, 137
lb/A(153 kg/ha); PZOs, 141 lb/A (158 kg/ha). The OM content was 4.1%.
Of the six nematode genera found in the 30 acres (12 ha), spiral, lance, and
stubby-root have attained the greatest number during the 5-year test period. The
spiral and lance nematodes peaked in the corn and oats. Sorghum also supported
lance nematodes, although not as abundantly as corn. The stubby-root nema-
todes were most numerous in the third and fifth years, increasing on corn in both
Stunt and stubby-root nematodes parasitized corn. Stunt reduced root and top
growth. Stubby-root interfered with root elongation. Krusberg (1959) found that
the stunt nematode, T. clavtoni, parasitized not only corn, but also sorghum and
Since there was no opportunity to evaluate crop production in this field in the
absence of nematodes, no conclusions can be drawn concerning the economic
damage resulting from the populations which did develop on the corn, sorghum.
aeschynomene. and oats.
The costs and returns analysis indicated that the production of corn forage
was very profitable over the 5-year period. Growing aeschynomene, oats, and
sorghum ratoon crops in an intensified multicropping system was not always
profitable. The crop value per acre above variable costs from producing corn
forage, ranged from $170.31 in 1976 to $476.54 in 1979. In addition, the
production of the initial forage sorghum crop in the multicropping system was
profitable during the 3 years of production. The total cost of corn and sorghum
forage per ton was $35.99 and $28.38, respectively
Rations containing 25 and 45% sorghum or corn silage supported gains in
excess of 2.25 lb (1.0 kg)/day when fed to 375 lb (170 kg) steers. At the 75%
level of silage, gains decreased by 9 and 36% for corn and sorghum silage,
respectively. Feed costs per pound of gain for corn and forage sorghum silage
ranged from $0.37 to $0.42, and $0.49 to $0.50, respectively Corn silage was
utilized more efficiently than sorghum silage at all ration levels. Zeranol im-
plants increased gains by 13%.
Protein supplements for 400 lb (182 kg) steers fed a 75% corn silage grow-

ing ration were compared. Protein levels in unsupplemented control and pro-
tein supplemented rations were 9 and 13.5%. respectively. Urea alone doubled
daily gains (0.95 vs 1.94 Ib: 0.43 vs 0.88 kg/day) for control and urea rations.
respectively. Respective daily gains with alfalfa pellets and soybean meal were
1.99 and 2.16 lbs (0.90 and 0.98 kg). Zeranol implants did not affect the
performance of steers fed the unsupplemented control ration, but increased
gains by steers fed urea. alfalfa. and soybean meal by 8. 22. and 22%. re-
Two feed additives. lasalocid and monensin. were compared with 650 lb
(296 kg) steers fed a 75% corn silage ration. Lasalocid fed at 33 mg kg of
feed increased feed efficiency and average daily gain by 15 and 18%. respec-
tively. Monensin fed at 33 mg/kg of feed increased feed-to-gain ratio and gains
by 8%.
The implication of this research with respect to the production of feedstutls
is of particular importance to Florida's beef and dairy industries.
The results from this interdisciplinary study reveal that corn forage and
forage sorghum silages can be successfully produced in an intensified multi-
cropping system and fed to livestock at competitive feed cost levels. The pro-
duction of a competitively priced high quality feedstuff is an opportunity that
livestock producers with an intensified feeding operation cannot afford to oer-


Berger. L. L., and S. C. Ricke. 1980. Comparison of lasalocid and monensim or
teedlot cattle. J. Anim. Sci. 51 (Suppl. 1):345.
Blue. W G. 1979. Forage production and N contents and soil changes during 25 years
of continuous white clover-Pensacola bahiagrass growth on a Florida spodosol.
Agron. J. 71 (5):795-798.
Brethour. J. R. 1979. Lasalocid for finishing steers. J. Anim. Sci. 49 (Suppl. 1):357.
Christie, J. R.. and V G. Perry. 1951. Removing nematodes from soil. Proc. Helm.
Soc. Wash. 18:106-108.
Ensminger. M. E., and C. G. Olentine. Jr. 1978. Feeds and Nutrition. The Ensminger
Publishing Company. Clovis. California.
Graham. T. W 1951. Nematode root rot of tobacco and other plants. S. C. Agr. Exp.
Sta. Bull. 390, 25 pp.
Hopkin. John A., Peter J. Barry, and C. B. Baker. 1973. Financial management in
agriculture, Interstate Printers and publishers. Inc. Dansville. IL.
Keith. E. A., V F. Colenbrander, T. W Perry, and L. Bauman. 1981. Performance
of teedlot cattle fed brown midrib-three on normal corn silage with various levels of
additional corn grain. J. Anim. Sci. 52:8-13.
Krusherg. L. R. 1959. Investigations on the life cycle, reproduction. feeding habits and
host range of Tvlienclhorhinchuis clayloni Steiner. Nematologica 4:187-197.
Mislevy. P. R. S. Kalmbacher, P H. Everett and E. S. Horner. 1980. Commercial corn
variety testing results from south-central Florida. 1980. Agricultural Research Cen-
ter. Ona. Research Report RC-1980-10.
Mislevy, P. R. S. Kalmbacher. and E G. Martin. 1981. Cutting management of the
tropical legume american jointvetch. Agron. J. 73(5):771-775.
Moore. H. P and R. E. Kelly 1970. Total nitrogen in fertilizer and feed by means of
the auto analyzer with continuous digestion. Advances in automated analyses. Vol.
II. Technicon. 1970. p. 47-51.
Moore. J. E., G. O. Mott. D. G. Dunham and R. W. Omer. 1972. Large capacity in
vitro organic matter digestion procedure. J. An. Sci. 35(1):232 abstr. No. 261.
NRC. 1976. Nutrient Requirements of Domestic Animals. No. 4. Nutrient Require-
ments of Beef Cattle. National Academy of Sciences National Research Council.
Washington. D.C.
Osburn. Donald D. and Kenneth C. Schneeberger. 1978. Modern Agricultural man
agement. Reston Publishing Company. Inc. Reston. Virginia.
Rohde. R. A. and W R. Jenkins. 1957. Host range of a species of Trichodori and its
host parasite relationships on tomato. Phytopathology 47:295-298.
Van Soest. P. J.. and R. H. Wine. 1967. Use of detergents in the analysis of fibrous
feeds. IV Methods for determination of plant cell walls. J. Ass. Offic. Anal. Chem.
Walkley. A. 1947. A critical examination of rapid method for determining organic
carbon in soils. Soil Sci. 63:251-264.
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This research project has been supported by a number of commercial organizations.
Grateful appreciation is expressed to the companies and indi iduals listed below \\ho
have contributed gifts. grants or assistance over the 5-year experimental period.
Asgrow Florida. Plant Citv. Florida
Ronald Barnett. AREC. Quincy
Henry Boyd. Lakeland. Florida
Hollis Brannen. Dundee. Florida
Chain O' Lakes Groves. Inc.. Winter Haxen. Florida
Chemagro Agr. Div.. Mobay Chemical Corp.. Kansas Cit\. Missouri
Chevron Chemical Co.. San Francisco. California
Tom Christian. Bradenton. Florida
Ciba-Geigy Corporation. Greensboro. North Carolina
Cloverdale Dairy Farm. Mvakka City. Florida
DeKalb Seed Company. DeKalb. Illinois
Dixie Lime and Stone. Ocala. Florida
E. I. Dupont de Nemours Company. Inc.. Wilmington. Delaware
Eli Lilly & Company. Greenfield. Indiana
Harold Fauver. Sanford. Florida
F.M.C. Corporation. Tampa. Florida
Funks Seeds International. Bloomington. Illinois
Florida Irrigation Service. Alturas. Florida
Harry Gause. Limestone. Florida
Gehl Company. West Bend. Wisconsin
Hardee County Agriculture Soil Conservation Ser ice
Hoffman La Roche. Nutley. Nex, Jersey
International Minerals and Chemical Corporation. Libertyville. III.
J & J Hauling, Nocatee. Florida
Lykes Brothers. Inc.. Brooksville. Florida
Monsanto Company. St. Louis, Missouri
W O. McCurdy and Sons. Fremont. lowva
C. M. Payne and Sons, Inc. Sebring. Florida
Pioneer Hi-bred Int.. Tipton. Indiana
Shepard Spreader Service. Plant City. Florida
Smitty Groundhog. Inc.. Sanford. Florida

All programs and related activities sponsored or assisted by the Florida Agricultural
Experiment Stations are open to all persons regardless of race, color, national origin,
age, sex, or handicap.

This publication was promulgated at a cost of $3432.55 or 85.8 cents per
copy to present research on production and utilization of forage crops under
a multicropping system.

ISSN 0096-607X


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