Title Page
 Table of Contents
 Canal point variety update...
 Influence of cultivar selection...
 Sugarcane leaf N status and rust...
 A two-year evaluation of flood-tolerance...
 Phosphorus concentrations in drainage...
 Report on the 20th congress of...
 Calcium silicate slag effects on...
 A comparison of soil insect pests...
 Post-freeze deterioration of sugarcane...
 Effects of the December 1989 freeze...


Sugarcane growers seminar
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00054444/00002
 Material Information
Title: Sugarcane growers seminar
Series Title: Belle Glade EREC research report
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Belle Glade EREC (Fla.)
Everglades Research and Education Center
Florida Cooperative Extension Service
Publisher: Everglades Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Cooperative Extension Service.
Place of Publication: Belle Glade Fla
Creation Date: 1990
Frequency: annual
Subjects / Keywords: Sugarcane -- Periodicals   ( lcsh )
Sugarcane -- Congresses -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
conference publication   ( marcgt )
serial   ( sobekcm )
Bibliography: Includes bibliographical references.
Dates or Sequential Designation: Annual
General Note: Description based on: 1989; title from cover.
General Note: Last issue consulted: 1993.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
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 - 001831947
oclc - 40943253
notis - AJQ6045
lccn - 2003229204
System ID: UF00054444:00002

Table of Contents
    Title Page
        Page i
    Table of Contents
        Page ii
    Canal point variety update (1990)
        Page 1
        Page 2
    Influence of cultivar selection on the epidemiology of sugarcane rust
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
    Sugarcane leaf N status and rust severity
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
    A two-year evaluation of flood-tolerance in canal point clones
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    Phosphorus concentrations in drainage water from fields in the EAA and potential BMPs
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
    Report on the 20th congress of the international society of sugar cane technologist, Sao Paulo, Brazil
        Page 53
        Page 54
    Calcium silicate slag effects on sugarcane ratoon crops
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
    A comparison of soil insect pests of Florida sugarcane versus Australia sugarcane
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
    Post-freeze deterioration of sugarcane varieties in Florida
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
    Effects of the December 1989 freeze on juice quality at 3 locations
        Page 90
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
        Page 97
        Page 98
Full Text


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

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

EV- 1990-3.-----_-
Central Science
JUL 1990
niv rsty of Florida




MAY 17, 1990



MAY 17, 1990

Frank J. Coale, Presiding & Editor
Extension Agronomist


Canal Point Variety Update (1990) 1
B. Glaz

Influence of Cultivar Selection on the Epidemiology 3
of Sugarcane Rust
R.N. Raid and J.C. Comstock

Sugarcane Leaf N Status and Rust Severity 14
D.L. Anderson, L.J. Henderson, R.N. Raid, and M. Irey

A Two-Year Evaluation of Flood-Tolerance in 26
Canal Point Clones
C.W. Deren, G.H. Snyder, and J.D. Miller

Phosphorus Concentrations in Drainage Water From 31
Fields in the EAA and Potential BMPs
F.T. Izuno, C.A. Sanchez, F.J. Coale, D.B. Jones, and
A.B. Bottcher

Report on the 20th Congress of the International Society 53
of Sugar Cane Technologists, Sao Paulo, Brazil
P.Y.P Tai and 0. Sosa, Jr.

Calcium Silicate Slag Effects on Sugarcane Ratoon crops 55
D.L. Anderson and G.H. Snyder

A Comparison of Soil Insect Pests of Florida Sugarcane 73
Versus Australia Sugarcane
R.H. Cherry

Post-Freeze Deterioration of Sugarcane Varieties 80
in Florida
F.J. Coale and M.F. Ulloa

Effects of the December 1989 Freeze on Juice Quality 90
at 3 Locations
J.D. Miller, P.Y.P. Tai, and M.F. Ulloa

The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employr authored to provide research, educational
Information and other services only to Individual and Intitutlon, that function without regard to race, color se, age, handicap or national origin.

Canal Point Variety Update (1990)

Barry Glaz, Agronomist

Each year at Canal Point, many crosses are made among a

diverse group of sugarcane varieties. About 100,000 true seeds

(each seed is a unique variety) from these crosses are planted in

the seedling stage of our variety selection program. The

commercial release of a Canal Point sugarcane variety will not

occur until at least 8 to 10 years after the variety is initially

planted in this seedling stage. On the average, 1 or 2 of the

original 100,000 new varieties will become commercial varieties.

To remain in the program, each of the 100,000 seedlings must

successfully pass two years of visual inspection. About 10,000

varieties that pass the first year of visual inspection are

planted in Stage I at Canal Point. About 10% of the Stage I

varieties pass the visual selection criteria of Stage I. These

1000 varieties are planted in Stage II at Canal Point. Yields

are estimated in Stage II to determine the 131 varieties that are

planted in Stage III. There are Stage III experiments with 131

new varieties planted at 4 locations each year. Each of these

experiments has 2 replications. In Stage III, yields of all

varieties are estimated in plant cane and first ratoon. This is

the first stage in which varieties are evaluated as ratoon cane.

The 8-10 most promising Stage III varieties advance to Stage IV.

There are Stage IV experiments at 9 locations. We harvest Stage

IV experiments from plant cane through second ratoon. After a

variety completes Stage IV successfully, 1 or 2 additional years

are often necessary to accumulate enough seed cane for commercial

release. The Florida Sugarcane Variety Committee approves all

variety advances after Stage II. The committee advances

varieties that yield at least as well as the commercial check (CP

70-1133), unless they have a major negative characteristic. High

fiber content or disease susceptibility are two reasons for not

advancing high-yielding varieties. Also, the committee may

advance varieties that are not high yielding but that have other

favorable characteristics. High sugar content early in the

harvesting season or suitability to mechanical harvesting are two

such characteristics. This presentation will summarize the

production of the following Stage IV varieties: CP 84-1062, CP

84-1198, CP 84-1322, CP 84-1591, CP 84-1714, CP 85-1207, CP 85-

1308, CP 85-1382, CP 85-1432, CP 85-1491, and CP 85-1498.



Richard N. Raid, Plant Pathologist

Jack C. Comstock, Plant Pathologist


Sugarcane rust, caused by the fungus Puccinia melanocephala

H. & P. Syd, is undoubtedly the most recognizable sugarcane disease

in Florida. Present in Florida since 1979, it is characterized by

small yellow to reddish-brown foliar lesions which frequently form

spore-producing pustules. Soon after its introduction into the

state, large variations in cultivar susceptibility were noted.

Screening for rust resistance has since become an important part

of the sugarcane breeding programs of the USDA Field Station at

Canal Point and the U.S. Sugar Corporation. Presently, host plant

resistance is the sole economically feasible form of rust control.

Average yield losses of up to 40% have been estimated for extremely

susceptible cultivars. However, very little information is

available on the overall impact of rust on the sugarcane industry.

The success of the breeding programs in developing cultivars

that are resistant to rust has been variable. Although the rust

resistance of some cultivars has appeared to remain durable, for

example CP 70-1133, other cultivars once reported as resistant are

now considered susceptible. The objective of this experiment was

to investigate the influence of cultivar selection on spatial and

temporal spread of sugarcane rust from a point source of inoculum.


Four cultivar strip-plots were planted during December, 1989

at the Everglades Research and Education Center (EREC), Belle

Glade. Plot dimensions were approximately 1250 X 150 ft and

consisted of the cultivars CP 74-2005, CP 78-1247, CP 72-2086, and

CL 73-239. Cultivars were separated from each other by 10-ft

alleyways. Five blocks (150 ft X 150 ft) were created in each of

the cultivar strips, with a minimum of 60 ft of continuous

sugarcane between blocks within the strips. To investigate the

influence of soil amendments on sugarcane rust, three blocks were

amended with phosphate fertilizer (400 lbs/acre 0-39-0 broadcast),

calcium silicate slag (4 tons/acre broadcast), and sulfur (700

lb/acre banded), respectively, prior to planting. Amendments were

in addition to fertilizer applied according to EREC Soil Testing

Laboratory recommendations.

On February 12, 1990, a single potted-plant of the cultivar

H49-5, which had been previously inoculated with P. melanocephala

and now exhibited sporulating pustules, was transplanted to the

center of each block to serve as a point source (focus) of inoculum

for future spread of the disease. These plants had been grown in

the greenhouse and were inoculated with rust spores at Canal Point.

Source plants were selected for uniformity with respect to both

size and rust severity. Plants were covered during transport to

the EREC and into the experimental blocks to minimize inadvertent

spread of rust spores.

Rust severity was visually assessed at approximately weekly

intervals beginning on March 3. Four top visible dewlap leaves

were examined on plants located at distances 0, 5, 10, 20, 40, and

75 feet from the established point sources in each of the four

cardinal directions, north, south, east, and west.


Since the investigation being reported is still in progress,

the following results and discussion are strictly preliminary.

Examination of the initial stages of rust development suggest no

significant influence on rust epidemics by selected soil

amendments. Therefore, results and discussion in this report will

be limited to cultivar influence. Spread of sugarcane rust from

established point sources was significantly influenced by cultivar

selection. Figures 1 3 graphically depict the spread of rust

from a point source over time in three of the four cultivars

investigated, CP 78-1247, CP 74-2005, and CL 73-239. Cultivar CP

72-2086 has remained free of detectable rust levels throughout the

early stages of the study and is not represented. Disease

gradients, represented by decreasing rust severity levels with

increasing distance from inoculum point sources, were easily

detectable during March and April in all three susceptible

cultivars (Figures 1-3). By the first week of May, these gradients

were no longer evident, being obliterated by large quantities of

inoculum throughout the experimental area. The influence of the

prevailing wind direction (easterly winds) on rust spread is

evident in the higher rust levels at distances west of the point

source than east of the point source (negative distance values in

Fig. 1-3). This influence is not surprising, since wind is the

primary means of dissemination for rust diseases. The relatively

strong westerly spread, particularly during the early epidemic

stages, suggests that there was very little fluctuation in wind

direction during this period.

Mean rust severities (averaged across all distances) in the

three susceptible cultivars during the early stages of the epidemic

are displayed in Figure 4. Cultivar CL 73-239 was the cultivar

most conducive to early rust spread, followed by CP 74-2005 and CP

78-1247, respectively. However, as the rust season has progressed,

there has been a reduction in the relative differences in rust

severities on the various cultivars (Figure 5). Without additional

studies, explanations concerning these results remain as points for

conjecture. However, several possible hypotheses involve canopy

architecture, existence of rust variants (races), or variations in

host resistance relative to physiological age.

Observations on sugarcane rust over the past several years

have demonstrated wide variations in the severity of rust on the

cultivar CP 78-1247. Based solely upon observations of sugarcane

rust during 1988, one would have predicted that CP 78-1247 would

be the cultivar exhibiting the most severe rust epidemic in the

present study. That year, CP 78-1247 was among the most severely

rusted cultivars at every multiple-cultivar field test in which it

was present. During 1989, however, CP 78-1247 rust severities

appeared to be highly location dependent. This location

dependency, along with early observations concerning rust spread

in this experiment, lends support to a hypothesis concerning

sugarcane rust variants.


We are grateful to the Sugarcane Grower Cooperative and the

New Hope Sugar Cooperative for their assistance on certain aspects

of this research.

Figure 1. Sugarcane rust severity on cultivar CP 78-1247 at the

point source (0 distance) and various distances downwind (positive

distances), and upwind from the point source of rust inoculum.

Progression of the epidemic over time is express in days following

initiation of the point source.

Figure 2. Sugarcane rust severity on cultivar CP 74-2005 at the

point source (0 distance) and various distances downwind (positive

distances), and upwind from the point source of rust inoculum.

Progression of the epidemic over time is express in days following

initiation of the point source.

Figure 3. Sugarcane rust severity on cultivar CL 73-239 at the

point source (0 distance) and various distances downwind (positive

distances), and upwind from the point source of rust inoculum.

Progression of the epidemic over time is express in days following

initiation of the point source.

Figure 4. Mean rust severities (averaged across all distances) for

CP 78-1247, CP 74-2005, and CL 73-239 at various times following

initiation of a point source of inoculum.

Figure 5. Mean rust severities (averaged across all distances) for

CP 78-1247, CP 74-2005, and CL 73-239 on April 30, 1990 or 77 days

following initiation of a point source of inoculum.

CP 78-1247

Rust Severity (%)

20 __
1 0 -.. ....... ...


-75 -40 -20 -10 -5 0 5 10 20 40 75
Distance (ft)

After Inoculation
- Day 39 Day 46 [ Day 53 I Day 63 1 Day 68

CP 74-2005

Rust Severity (%)

-75 -40 -20 -10 -5 0 5 10 20 40 75
Distance (ft)

After Inoculation
SDay 39 Day 46 i Day 53 Day 63 Day 68


CL 73-239

Rust Severity (%)

-75 -40 -20 -10 -5 0 5 10 20 40 75
Distance (ft)

After Inoculation
1 Day 39 Day 46 l Day 53 M Day 63 Mi Day 68



1990 Sugarcane Rust Epidemics
by Cultivar

% Rust Severity


5 _.- .-- ._--_ __ __ // ~7 ^ ----

Days After Inoculation

1990 Sugarcane Rust Epidemics
by Cultivar

% Rust Severity








CP 74-2005 CL 73-239 CP 78-1247


Mean severity on April 30, 1990

Sugarcane Leaf N Status and Rust Severity

D.L. Anderson, L.J. Henderson, R.N. Raid, and M. Irey


Sugarcane rust is a leaf fungus (Puccinia melanocephala) that
has affected sugarcane production in Florida since 1979 (Purdy et
al., 1983). From year-to-year, the intensity of rust epidemics has
varied. Predictability of rust epidemics has been difficult,
primarily because the number of factors influencing sugarcane rust
is great. Factors influencing the intensity of rust epidemics
appear to be temperature (Hsieh et al., 1977; Irey, 1987),
moisture, dew periods, and humidity (Purdy, 1985), growth stage
(Purdy, 1985), light (Burgess, 1979; Purdy, 1985; Sandoval et al.,
1983), varietal resistance (Tai et al., 1981), races (Comstock,
1986; Liu, 1980; Raid, 1989), wind direction (Bernard, 1980),
inoculum source (Purdy, 1985), soil (Anderson et al., 1990), and
plant nutrition (Anderson and Dean, 1986).

Selective breeding for host resistance to rust has been the
primary means limiting the extent and severity of epidemics.
Influential factors such as temperature, moisture, dew period,
humidity, light, races, and wind are not controllable. Removal of
susceptible cultivars is a method of reducing inoculum
availability. To some extent, knowledge of soil factors enhancing
rust severity could also assist growers in minimizing the effects
of rust in what are considered "rust-prone" regions. Although
associations of plant nutrition and rust are difficult to describe
in terms of cause-and-effect, cultivar variability in nutrient

uptake and efficiency may partially explain rust resistance.

During 1988, severe rust epidemics were observed in Florida.
Greater rust epidemic severity was observed in certain geographical
areas of the sugarcane industry located in south Florida. High
variability in rust severity was also observed among cultivars and
within individual fields. Anderson et al. (1990) showed that soil
variability was highly correlated with variability in rust severity
observed during the 1988 epidemic. The objective of these studies
was to quantify the influence of leaf nutrient content on rust
severity as it relates to the variability in rust severity within
and across each site and soil.


Five sites located on mineral and organic soils showed high
variability in rust severity within and between sites (Table 1).
These sites were selected for disease assessment and nutrient
analysis of respectively assessed leaf tissues. Rust severity
ratings and sampling were made during the month of May 1988 at
growth stage 4 (Chiarappa, 1971) on sugarcane plants spatially
located on sample grids at specific x and y coordinates within each
field (Anderson et al., 1990).

Ratings were made on a percentage basis using a pictorial
scale after Purdy and Dean (1981), indicating the extent of leaf
area visibly affected by rust. Twenty top-visible dewlap (TVD)
leaf blades were used for establishing a mean rust severity rating
at each field grid coordinate. Five 2.5-cm soil cores were
collectively sampled to a 15-cm depth around each rated plant and

were bulked. Soils were sieved to pass through a 60-mesh screen
and air-dried at 30 C for 3 days prior to soil analyses. Soils
were analyzed for soil Ph, water-extractable P (P,), acetic acid-
extractable P (Pa), K, Ca, and Mg (Anderson et al., 1990; Thomas,

The twenty TVD leaf blades previously assessed for rust
severity were collected for nutrient analysis. Leaves were rinsed
with distilled water and dried at 700 C. The dry leaf tissue was
ground to pass a 20-mesh screen in a stainless steel Wiley mill.
Tissues were analyzed for P, K, Ca, Mg, Cu, Fe, Mn, and Zn
concentrations in the TVD leaf blades was determined by the nitric-
perchloric acid digestion (Anderson and Henderson, 1987). Total N
was determined by micro-Kjeldahl.

Relationships between rust ratings, soil, and leaf nutrient
concentration were analyzed using simple and multiple regression
procedures (SAS, 1985).


The sites used were the same as reported by Anderson et al.
(1990) and represent a wide cross-section of soils cultivated by
the Florida sugarcane industry (Table 1). Anderson et al. (1990)
reported that low soil pH was significantly correlated (P<0.10)
with high rust severity ratings across and within each site. Of
all the plant nutrients listed in Table 2, leaf Mn content was most
significantly correlated (P < 0.01) to soil pH across all sites (r
= -0.81), as well as at each site. Across all sites, leaf Mn
content is greatly reduced in concentration as the soil pH

approaches 8.2 (Figure 1), which is in agreement with Anderson and
Ulloa (1989). This relationship is also highly site dependent
(Figure 2).

One might conclude from Figure 2 that high leaf Mn contents
are undesirable in terms of its association to rust. However,
since both rust and Mn are significantly (P < 0.01) correlated to
soil pH, this conclusion can not be made. The only assumption that
should be made is that soil pH has more than one influence on the
sugarcane plant, one nutritional and another pathological.

The relationship of other plant nutrients to rust is
inconclusive at best (Table 2). Not evident from simple
correlation statistics is the overall effect of plant nutrition
over a broad range. Over a wide range of nutritional conditions,
Anderson and Dean (1986) demonstrated that there are plant
nutritional conditions where rust intensity may increase, decline,
or not change at all. Defining these relationships may require the
use of several regression equations. Extremes in plant response
occur across several environments (sites), and the relationship
between any two parameters is frequently better within environments
than when compared across all environments (Table 2). Interpreting
environment or location effects is a major undertaking for
statisticians and scientists working in the natural environment.
Common regression statistic techniques for interpreting data across
environments are commonly inappropriate.

Of the eight leaf nutrients determined, only a relationship
between rust severity and leaf N could be discerned across all
sites (Figure 3). From Figure 3 several conclusions can be made:

1. Rust appears to be more severe in a range of leaf N
contents. As N leaf content increases to 15 g kg"', rust
severity increases, but decreases as the N leaf content
increases beyond that threshold.
2. Analysis of variance and regression techniques used to
determine relationships across many environments or sites
may be inappropriate.
Although the association between leaf N and sugarcane rust has
not yet been reported, there have been numerous reports of a
relationship of N with rust pathogens (Puccinia recondita,
Pennisetum typhoides, Puccinia coronata, Puccinia hordei, and H.
vastatrix) on other crops such as wheat, pearl millet, ryegrass,
barley, and coffee, respectively. It has been long recognized that
disease expression can be altered by nutrient deficiencies,
excesses, or imbalances of major or minor elements (Nelson and
MacKenzie, 1977). Anderson and Dean (1986) reported that a number
of nutrient imbalances were related to rust. The contradiction is
that it appears that there are no general rules applying to any
given nutrient and its effect on rust. The relationship of
Puccinia melanocephala with leaf N on sugarcane is similar to that
found with other crops. For disease control purposes, a greater
understanding of the relationship between nitrogen fertilization,
mineralization, soil type and rust disease expression is needed.

The authors would like to express their appreciation to Mr. H.

J. Andreis, Vice President, Research Department, U.S. Sugar Corp.,

Clewiston, FL for his encouragement and support of these studies.

Anderson, D. L., and J. L. Dean. 1986. Relationship of rust

severity and plant nutrients in sugarcane. Phytopath. 76:581-


Anderson, D.L. and L.J. Henderson. 1988. Comparing sealed

chamber digestion with other digestion methods used for

plant tissue analysis. Agron. J. 80:549-552.

Anderson, D. L., R. N. Raid, M. S. Irey, and L. J. Henderson.\

Association of sugarcane rust severity with soil factors in

Florida. Plant Disease 74:000-000 (in press).
Anderson, D. L., and M. F. Ulloa. 1989. Sugarcane responses to

Mn sources and S application on two Florida Histosols. J. Am.

Soc. Sugar Cane Technol. 9:44-51.

Bernard, F. A. 1980. Considerations of appearance of sugarcane
rust disease in the Dominican Republic. Proc. Int. Soc. Sugar
Cane Technol. 17:1382-1386.

Burgess, R. A. 1979. An outbreak of sugarcane rust in Jamaica.

Sugarcane Pathol. Newsl. 22:4-5.

Chiarappa, L., ed. 1971. Crop loss assessment methods. Page
4.4.6/1 in: FAO Manual on the Evaluation and Prevention of

Losses by Pests, Diseases, and Weeds. Comm. Agr. Bur.,

Farmham, England. Supplement 1.
Comstock, J. C. 1986. Rust races. Page 31 in: Hawaiian Sugar

Planter's Assoc. Annu. Report, 1986.

Hsieh, W., C. Lee, and S. Chan. 1977. Rust disease of sugarcane

in Taiwan: The causal organism Puccinia melanocephala Sydow.
Taiwan Sugar 24:416-419.
Irey, M. S. 1987. Effect of the environment on sugarcane rust

epidemics in Florida. Am. Soc. Sugar Cane Technol. 7:30-35.
Lui, L. J. 1980. Observations and considerations on sugarcane
rust Puccinia melanocephala incidence, varietal reaction, and
possible occurrence of physiologic races in the Dominican
Republic, Puerto Rico, Jamaica, and Venezuela. Sugarcane
Pathol. Newsl. 25:5-10. Nov.
Nelson, R. R., and D. R. MacKenzie. 1977. The detection and

stability of disease resistance. Chapter 3 in: Breeding
plants for disease resistance: Concepts and applications.
R.R. Nelson, ed. Pennsylvania State University Press,
University Park, PA.
Purdy, L. H. 1985. Sugarcane rust. Chapter in: The Cereal

Rusts. Academic Press, Inc., N.Y. p. 237-256.
Purdy, L. H., Lii-Jang Liu, and J. L. Dean. 1983. Sugarcane

Rust, a newly important disease. Plant Disease 67:1292-1296.
Raid, R. N. 1989. Physiological specialization in sugarcane

rust (Puccinia melanocephala) in Florida. Plant Disease
Sandoval, I, V. Picornell, R. Chaves, and N. Ramos. 1983.
Puccinia melanocephala H. & P. Syd.: Biological and ecological
aspects. Sugar Cane 2:15-18.
Tai, P. Y. P., J. D. Miller, and J. L. Dean. 1981. Inheritance

of resistance to rust Puccinia melanocephala in sugarcane.
Field Crops Res. Amsterdam, Elsevier Scientific 4:261-268.

Table 1. Sites and soils used in these studies (Anderson et al.

Site Soil Name Taxonomic Class
1 Pahokee muck Euic, hyperthermic Lithic Medisaprist
2 Okeelanta muck Sandy, siliceous, euic, hyperthermic
Terric Medisaprist
3 Pahokee muck Euic, hyperthermic Lithic Medisaprist
5 Pahokee muck Euic, hyperthermic Lithic Medisaprist
6 Immokalee sand Sandy, siliceous hyperthermic Arenic

Table 2. Mean rust severity, leaf tissue nutrient concentration data, and
correlations (r) from five sugarcane field sites (Anderson et al, 1990).

No. Rust
Site Obs. Cultivar Severity N P K Ca Mg Fe Mn Zn

% ------------ g kg-1 ---------- ---- mg kg -1------

1 80 CP78-1247 28.9 15.5 1.55 19.4 4.24 2.03 75.0 17.6 19.3
-0.14 0.63 0.01 0.07 0.27 0.04 0.59 -0.10
ns ** ns ns ns ** ns

2 49 CP78-1247 29.9 16.3 1.81 22.8 5.07 1.46 71.6 30.1 14.1
-0.83 0.26 0.48 -0.18 0.82 0.21 0.85 -0.40
** + ** ns ** ns ** **

3 16 CP78-1247 16.9 16.1 1.64 26.3 3.83 1.59 86.4 14.2 15.7
-0.77 -0.02 0.73 -0.48 0.72 0.42 0.82 -0.52
** ns ** + ** ns ** +

5 20 CP72-1210 4.7 12.1 1.85 19.6 3.35 1.40 40.6 33.7 6.85
0.73 0.69 0.68 -0.13 0.62 -0.04 -0.63 0.74
** ** ** ns ** ns ** **

6 49 CP72-1210 5.2 12.9 1.80 8.97 3.23 1.10 58.9 81.4 15.4
0.31 0.44 -0.38 -0.11 -0.31 0.08 0.06 -0.03
** ** ns ns ns ns

All 214

a Simple correlation statisti

0.18 0.13 0.24 0.24 0.45 0.27 0.14 0.11 V

c (r) between rust severity and indicated tissue concentration.

b **, *, and + indicate significant at P<0.01, PO0.05, and P<0.10,
respectively, ns, nonsignificant.

Figure 1. Relationship between the top-visible dewlap (TVD) leaf Mn
content and soil pH across five sites (n=214).




5 I II 1I I I I I I
5 6 7

Soil pH

SITE + + 1

* 2 o 3 o005 6

I I a I II1 I I I . 11

1 1 I 1 1 1 I I 1 4 1


Figure 2. Relationship between percent (%) rust severity and the
top-visible dewlap (TVD) leaf Mn content across five
sites (n=214).

* *+

++ -+

20 40 60 80 100 120 140 160

TVD Leaf Mn (mykg)


++ 1 ***2 oan3 ooo05


* 0 6

Figure 3.

Relationship between percent (%) rust severity and the
top-visible dewlap (TVD) leaf N content across five sites
(n=214) .



- 20

8 9 10 11 12 13 14 15 16 17 18 19 20

TVD Leaf N (gkg)

+.t I

* 2 n rir,3 (o o5 0 6


A Two-Year Evaluation of Flood-Tolerance

in Canal Point Clones.

C. W. Deren, Plant Breeder

G. H. Snyder, Soil Chemist

J. D. Miller, Plant Breeder


Water seems to be a perennial problem in the EAA. There is

either too little or too much. And currently, water quality is

becoming a concern in addition to water quality.

Flood-tolerant sugarcane may be of value in addressing both

water quantity and quality concerns in the EAA. For areas which

drain poorly, either due to very shallow muck or other soil

properties, flood-tolerant cane may reduce the necessity of

immediately pumping off excess water, thereby saving energy and

labor costs. Some insects and perhaps rodents can be controlled by

flooding. And if plans for flow-ways or other management practices

which use vegetation to remove excess nutrients are implemented, a

flood-tolerant cane may have more economic value than other

alternative plants.

This experiment screened a representative sample of the Canal

Point sugarcane breeding population for flood-tolerance under

extended flood. It was also designed to estimate heritability of



Clones evaluated in this study were chosen based upon their

pedigrees and historical information relating to flooding in

Florida sugarcane experimental plots. Six parent clones from the

Canal Point breeding population were selected for their expected

level of flood-tolerance. Each parent clone had 30-40 half or

full-sib progeny randomly chosen to be tested, which came to a

total of 160 clones evaluated.

The plant cane crop was planted in late January, 1988 in two

treatment areas, flood and control. The flood treatment was

planted in old rice fields where irrigation facilities were in

place; the control was planted in the sugarcane experiment area.

Each treatment area was divided into three equal-sized blocks. All

160 test clones were planted randomly into each block in single-row

plots 2.1m (7 ft.) long. Plots were fertilized according to soil

test recommendations.

A flooding of approximately 15 -25 cm ( 6-10 in.) was

initiated on July 1, 1988 after plants were well established and

continued until December 16, 1988. In the ratoon crop, flooding

commenced July 1, 1989 and was maintained until November 17, 1989.

Plots were harvested approximately two weeks after draining. Whole

plots were cut by hand and weighed. Plots were not burned. A

five-stalk sample was taken from each plot for milling. Data taken

or calculated were: number of primary shoots, number of stalks at

harvest, mill sample weight, average stalk weight, brix, percent

sucrose, Mg sugar per ha, and Mg cane per ha. Plot yields were

calculated on a 3.5 m (12 ft.) basis to account for alley effects.


Results discussed are based upon preliminary analysis of data.

As would be expected, yields of cane (Mg/ha'1) and sugar (Mg/ha'1)

were significantly (P< .01) reduced in the flooded treatment for

both years. The decreased sugar yields were due to reduced cane

yield, since Brix and Mg sugar per Mg cane had no treatment effect

(P= 0.20 for Brix and P= 0.83 for sugar).

Clones had a wide range of yield of cane and sugar in the

flood treatment (Table 1). Entry POJ 2725, which was expected to

perform poorly under flood, had a yield in flood of approximately

27% of the control yield for Mg/ha "1 of cane. Flood treatment

yields for CO 281, however, had 76% of the control yield. Most CP

commercial clones had flood treatment yields that were 50-60% of

the control yield.

Due to the small plots, ample light, and trash included in

plot weights, these yield estimates are probably overestimated.

However, these estimates serve well as a means of comparison

between clones. It should also be noted that flooding was

accomplished by pumping and surface irrigation. The performance of

these clones may be different under stagnant, highly anaerobic


The Canal Point sugarcane breeding population appears to have

genetic potential for selection of flood-tolerant clones. Many

clones tested withstood almost eleven months of flooding over two

crop years. Ratooning was very vigorous in many clones and ratoon

yields of several clones that survived the first crop year were

high. Further testing of selected clones in larger plots and with

more replications is necessary to verify these preliminary results.

Table 1. Two-year mean yield of cane for selected parent clones
and checks grown in flood.


CP 70-1133

CP 72-2086

CP 72-1210

CP 70-1527

CP 77-1776

CP 63-306









Flood yield as
% of crntrno vliri








CP 57-526

CO 281

POJ 2725

& nf nnnt-rnl viola


Forrest T. Izuno, Agricultural Engineer
Charles A. Sanchez, Vegetable Nutritionist
Frank J. Coale, Extension Agronomist
David B. Jones, Rice Agronomist
A. B. Bottcher, Agricultural Engineer


The nutrient enrichment of drainage water leaving the EAA

has been focused on heavily by water managers, growers, and

environmentalists. Phosphorus (P), in particular, has been

determined to be the limiting nutrient in Lake Okeechobee.

Hence, the additional P inputs to the Lake during agricultural

drainage pumping are being touted as a contributor to its

increased eutrophication. Phosphorus entering the WCAs has also

been alleged to be causing a transition from native plant species

to cattails. Consequently, concerned groups have challenged

water managers and growers in the EAA to reduce P concentrations

in drainage water leaving the area. One proposed method of

reducing P loads and concentrations leaving the EAA requires the

development and implementation of agricultural "best management

practices" (BMPs).

Although there has been an ample amount of P concentration

data collected in the Lake Okeechobee-EAA-WCA-ENP system, little

of it has been connected with any scientific study.

Additionally, the data focus on the Lake, WCAs, ENP, and pump

stations bordering the EAA. Very little monitoring has been done

within the EAA. However, the EAA growers, through BMPs, are

being asked to reduce P loads and concentrations at farm level

discharge points. In order to develop and implement effective

BMPs, some idea of drainage water total-P (TP) concentrations

occurring under present management conditions is necessary.

Ideally, those baseline levels should be determined at sites that

have also been prepared for screening potential BMPs.

Although the South Florida Water Management District (SFWMD)

has a water quality monitoring program for the EAA, it primarily

centers on the discharge points from the entire area. Limited

monitoring of farm and field level water quality has been done by


In 1976, the engineering consulting firm CH2M-Hill was

contracted by the Florida Sugar Cane League (FSCL), in

cooperation with the SFWMD, to determine P balances from typical

sugarcane, pasture, and vegetable farms in the EAA (CH2M-Hill,

1978). The project included the intensive monitoring of a 1,500

ha sugarcane plantation, a 630 ha vegetable farm, and a 4,000 ha

cattle ranch. Monitoring exercises were conducted between May

1976 and September 1977. In addition to these sites, five other

sites were selected for occasional monitoring.

Mean TP concentrations in drainage water from sugarcane,

vegetable, and cattle sites were 0.126 mg/l, 0.340 mg/l, and

0.120 mg/1, respectively. The vegetable farm average

concentration was significantly higher than the sugarcane and

cattle sites. The higher concentrations were attributed to the

higher fertilization rates and the longer period of time that the

land had been intensively farmed.

Terry et al. (1980) conducted a lysimeter study to determine

the effects of water table levels on ortho-P (PO3"). Ortho-P

concentrations reported averaged 0.11, 0.43, and 1.39 mg/l for

sugarcane grown with 90, 60, and 30 cm water tables,


The SFWMD has been monitoring TP concentrations in Lake

Okeechobee for years. They report mean TP annual concentrations

in the Lake as ranging from 0.049 to 0.099 mg/l between 1973 and

1985 (SFWMD, 1986). Flow-weighted TP concentrations entering the

southern rim of the Lake from the EAA ranged from 0.095 to 0.314

mg/l between 1973 and 1979. During 1983 through 1985, mean

annual TP concentrations at the same stations ranged from 0.188

to 0.573 mg/l.

Waller and Earle (1975) reported that TP concentrations in

bulk precipitation during rainfall events averaged 0.142 mg/l at

a SFWMD pump station between 1972 and 1974. At another SFWMD

pump station, the average bulk precipitation TP concentration was

0.085 mg/l between April 1976 and March 1977 (CH2M-Hil1, 1978).

The study sites used by CH2M-Hill (1978) yielded bulk

precipitation TP concentrations ranging from 0.050 to 0.110 mg/l.

With the above in mind, the primary objective of this study

was to establish the current TP concentrations in drainage water

from sugarcane, vegetable, rice, and fallow fields in the EAA.

At the same time, preliminary BMP screening was to begin. To

accomplish the above, experimental sites had to be designed and

installed such that the effects of changing agricultural

practices on TP concentrations could be determined over time at

the same sites. Secondary objectives were to measure bulk

precipitation TP concentrations at test sites within the EAA and

at the main farm pump station or in the immediate area receiving



Since it was desirable to be able to look at agricultural

BMP effects on TP at the same sites as the background work was

being done, four experimental plot sites (Figure 1) were

installed in 8 to 12 ha blocks. Each site had four 0.7 ha plots

for each of the two or three different growing conditions. Plot

areas encompassed half the land area on both sides of the plot

ditches. The first site was split between sugarcane grown under

standard grower practices and fallow drained fields. The second

site was planted to sugarcane, with half the sites growing under

restricted drainage conditions. The third site was planted to

radishes in the winter and rice in the summer. During the

summer, half the plots were left fallow flooded. The final site

was planted to cabbage. Two different fertilizer application

methods and rates were used. The two treatments were: 1)

broadcast fertilizer at soil test recommendation levels, and 2)

banded fertilizer at about 50% of the recommended rate. The

additional four plots at the 12-plot site received no phosphorus


Each of the experimental sites had a bulk precipitation

collector installed nearby. Automatic water samplers were also

installed at each of the main pump stations serving the entire

farm area where the experimental plots were located.

The above sites allowed for the obtaining of TP

concentrations during rainfall/drainage events for the following:

1) sugarcane fields with a restricted and unrestricted drainage

rates; 2) radish fields; 3) rice fields; 4) cabbage fields with

traditional, banded, and control fertilizer application methods

and amounts; 5) fallow drained fields; 6) fallow flooded fields;

7) main farm canals serving the areas; and 8) rainfall.

At the head of each plot, an automatic water sampler was

installed. These water samplers were manually turned on when

drainage events occurred. They were set to collect 500 ml

samples on 1, 2, 4, or 8 hour intervals, depending on the

anticipated drainage event duration. Because of the different

crop drainage requirements and the spatial variability in

rainfall in the EAA, anywhere from 6 to 40 treatment block events

were monitored for each condition. Each treatment block average

TP concentration consisted of the time averaged concentrations

from the 4 randomly located plots within each block. The

monitoring period began in July 1988 and ended in December 1989,

encompassing complete rainy and dry seasons.

When possible, the autosampler bases which contained 24

sample bottles each, were filled with ice at the time the

samplers were turned on. All samples were retrieved from the

field within 48 hours of the collection of the first sample in

the set. Aliquots of each sample were digested using the

Persulfate Digestion Method (American Public Health Association,

1985) for TP analysis. The TP analyses were conducted using a

TRAACS 800 autoanalyzer and the Automated Ascorbic Acid Reduction

Method (Technicon, 1986; American Public Health Association,



Field TP Concentrations

The number of block events and summary statistics for all

cropping conditions are presented in Table 1. Total-P

concentrations for the 30 sugarcane block events averaged 0.28

mg/l. The 30 block events were derived from 2 sites, having a

combined total of 12 plots, separated by about 15 km. Organic

soil depths in 4 of the plots averaged about 60 cm, while the

remaining 8 plots had an average depth of about 1.5 m. The 4-

plot group received 5.4 kg elemental P per ha. The 8-plot group

received no P fertilizer. The 0.28 mg/l average TP concentration

measured was higher than the 0.126 mg/1 TP concentration reported

by CH2M-Hill (1978). However, the data reported here were skewed

upwards by high TP concentrations (up to 1.50 mg/1) that occurred

throughout the EAA during a 10 to 18 cm rainfall that occurred in

September 1989 following a prolonged dry period.

Total-P concentrations from the 8 radish block events

averaged 0.25 mg/l. The 8 block events were derived from 2 sets

of 4 plots at a single location. Comparing this average with the

0.340 mg/l TP concentration for the generic vegetable farm

reported by CH2M-Hill (1978) shows that the radish plots were

0.09 mg/l lower. This should be expected since radishes are one

of the vegetable crops that receives less P fertilizer than many

of the other vegetables grown in the EAA.

The rice experimental block (4 plots), planted on half the

plots that had been in radishes, yielded an average TP

concentration of 0.69 mg/1. The average includes the initial

flood and drain-down period prior to establishment of the

permanent flood, and the final field drain-down prior to harvest.

By breaking the extended event periods down into the data

collection periods (there were essentially 3 separate sampling

periods within each of the two events that were monitored), 6

block events were recorded. Although the final drain-down period

after an extensive period of inundation (about 80 days) resulted

in higher TP concentrations (up to 2 mg/1) than did the initial 5

day flood-drain cycle (up to 1 mg/1), the two events were

combined for the purposes herein.

The experimental site planted to cabbage had 12 plots (3

blocks). The 12 randomly located plots were broken into 3 blocks

of 4 plots each of broadcast P fertilizer at full soil test

recommendation, banded P fertilizer at 50% of recommendation, and

no P fertilizer applied. A total of 35 block events were

recorded. The ranges of amounts of P fertilizer applied, and

methods of application, encompassed the entire spectrum of

potential P fertilization practices except for liquid

applications. The monitoring period for the site extended beyond

the harvest of the cabbage crop, up to planting of the second

crop, since the effects of applied fertilizer could not be

expected to stop upon harvest. The average TP concentration for

the blocks and treatments was 0.45 mg/l TP. This average

concentration was higher than the generic vegetable average TP

concentration (0.340 mg/1) reported by CH2M-Hill (1978). It is

suspected that the higher levels of TP were due to the major

rainfall that occurred in September 1989 after a prolonged dry

period. During this rainfall event, TP concentrations increased

at all experimental sites in the study.

The four fallow plots were randomly located in the same

experimental site as 4 of the sugarcane plots. Fallow plots were

included in the baseline study since a substantial amount of land

in the EAA is fallow during a year. Water tables in the fallow

plots were managed identically to those in the cropped plots.

Total-P concentrations for the 16 block events averaged 0.43


During planting of rice at the site previously planted to

radishes, four plots were left fallow. These plots were flooded

and drained at the same time as the rice crop. Since fallow

flooding is a typical practice used in the EAA to control pests,

weeds, and organic soil subsidence, the treatment was included in

the baseline data requirements. Fallow flooded plot sampling was

handled the same as the rice plots. Total-P concentrations

averaged 0.99 mg/l, subject to the same qualifications as the

rice plots.

Main Receiving Canals and Bulk Precipitation TP Concentrations

Water samples were also taken from the main canals serving

the experimental site. Samples were collected during drainage

events when plot drainage was occurring. A total of 40 sampling

events yielded an average TP concentration of 0.20 mg/l. The

average concentration was not broken down by crop since the main

canals served areas with mixtures of all the cropping conditions

included in this baseline study.

Bulk precipitation collected during a total of 16 rainfall

events at the four experimental sites ranged from 0.03 to 0.23

mg/l TP. The overall average TP concentration for the four sites

was 0.07 mg/l. Site averages ranged from 0.05 to 0.09 mg/1 TP.

These TP concentrations fall within the ranges reported by Waller

and Earle (1975) and CH2M-Hill (1978).

Total-P Differences Between Field Conditions

Table 2 shows which cropping practices resulted in

statistically different TP concentrations at the 95% confidence

level (t-test, Statistical Graphics Corporation, 1986). Also

indicated, are the relationships between the TP concentrations

for paired conditions. As can be seen, the cabbage

concentrations were not significantly different from the

sugarcane, fallow drained, rice, and radish concentrations.

Similarly, no statistical differences were seen between the

fallow drained TP concentrations and those for sugarcane, rice,

and radish crops. Sugarcane TP concentrations were not

significantly different from radish block and canal

concentrations. Finally, there were no differences in TP

concentrations between fallow flooded and radish fields and

radish blocks and main canals.

Statistical differences in TP concentrations at the 95%

confidence level were shown between rice and radishes, sugarcane,

and canal water samples, with rice TP concentrations being

higher. Flooded fallow plot TP concentrations were significantly

greater than fallow drained, sugarcane, radish, cabbage, and

canal samples. Finally, average drainage TP concentrations in

the cabbage and fallow drained plots were significantly higher

than those in the main canals.

Potential BMPs

From the preliminary data described above, and by examining

the differences between BMP treatments for each crop, it is

possible to identify agricultural practices which have potential

for alleviating the P concentration problems facing the EAA. It

should, however, be understood that the following discussion is

preliminary, based on only 1 year of data.

There are two fundamental concepts which must be applied to

the clean-up of drainage water leaving the EAA. First, the

basin-wide P mass balance must be altered such that the net

import of P into the area is greatly reduced. In other words, P

in the system must be used as efficiently as possible. This

cannot help but alter the amount of P leaving the area according

to mass conservation principles. The second fundamental activity

that must occur is that the potential slug discharges of water

high in P are managed such that they do not occur at the present


Towards the above ends, BMPs can be developed in 3

categories: 1) improved water management; 2) improved fertility

management; and 3) alternative crops. In the water management

area, pumping off farms can be reduced by 20%. This will lead to

an almost direct 20% reduction in P leaving farms. Excessive

land drainage can also be reduced by using better management

techniques and reducing drainage response times. In fact,

preliminary data are showing that faster draining of fields

results in lower P concentrations (Figure 2).

In the fertilizer management arena, there are several

practices that should prove to be viable. The data appear to

show a relationship between fertilizer inputs and P in drainage

water. Hence, applying the minimum amount of fertilizer, while

not sacrificing yields, should be a viable BMP. This requires a

scientifically calibrated soil test recommendation procedure.

Figure 3 shows preliminary differences between TP concentrations

in water leaving broadcast and banded cabbage fields. Both

banded (at 50% of soil test recommendations) and broadcast (at

100% of soil test recommendations) result in TP concentrations

higher than the plots with no P fertilizer applied. The

broadcast plots have higher TP concentrations than the banded.

After the cultivation of vegetables, rather than merely fallow

flooding, an aquatic crop such as rice could be grown. Figure 4

shows that the rice crop reduces the amount of TP in drainage

waters. The still high P concentration water could then be

recycled as fertigation water for vegetable, sugarcane, or sod


As an aside, data are showing that there are no differences

in TP concentrations leaving fallow drained fields and sugarcane

fields. In Figure 5, TP concentrations for the two treatments

appear to be nearly identical except early in the period of

record. The apparent inconsistency is due to the anomalous June

28 and 29, 1988 data. At that time all plots were fallow and the

effects of ditch excavation are seen. If these data were

disregarded, and the period of record began on July 20, 1988, one

can see that sugarcane and fallow fields would have virtually

identical concentrations.

It must be stressed that the trends discussed above are

preliminary. The data were collected during an extremely dry

period. Additionally, the authors feel strongly that, while

trends are apparent, there are insufficient data to draw

scientifically significant conclusions. Recommendations are that

a minimum of 3 years' of data will be required.


Baseline TP concentrations for various crops and field

conditions in the EAA were determined using experimental sites

designed for evaluating the effects of agricultural BMPs on

drainage water quality. The database used in developing the

average TP concentrations was derived from 6 to 40 block events

for each treatment category. Average TP concentrations ranged

from 0.20 mg/l for main canals during rainfall-drainage events to

0.99 mg/l TP during the drain-down of fallow flooded plots.

Rainfall averaged 0.07 mg/1 during the same period.

The data show that some cropping practices and field

conditions in the EAA result in significantly increased TP

concentrations. Most significantly, flooding practices for

either rice cultivation or pest, weed, and subsidence control

result in elevated TP levels in drainage water at drain-down. In

the cases of the cultivation of drained crops such as cabbage,

radishes, and sugarcane, there appears to be a relationship

between the amount of P fertilizer applied and drainage water TP

concentrations. However, further data are needed prior to

establishing the relationship.

Total-P concentrations leaving fallow plots in drainage

water during the study period appear to be higher than

concentrations for sugarcane and radishes, two of the crops

receiving lesser amounts of P fertilizer. These data indicate

that at low P fertilization rates, the mineralization of P that

occurs as the organic soils oxidize overshadows the effects of

fertilizer amendments.

The alternative management practices discussed appear to

have potential for reducing TP concentrations leaving farms in

drainage water. The extent of the effectiveness of the BMPs will

depend greatly on the interactions of all BMPs implemented as a

package. There remains a great amount of research that must be

done prior to implementation of BMPs.

A significant finding of this study was that there is a

tremendous amount of variability in TP concentrations for all

sampling conditions. This indicates the necessity of collecting

a tremendous amount of data to achieve statistically significant

results. The variability can be attributed to both temporal and

spatial influences. The data generated in this study serve as

baseline TP concentrations against which the effects of future

agricultural BMP effects can be compared. Further discussions

regarding differences in TP concentrations between treatments

within crops, such as the effects of reducing fertilizer usage

through banded applications as compared to traditional

broadcasting, will be forthcoming as the database is enlarged.


American Public Health Association. 1985. Phosphorus. In
Standard Methods for the Examination of Water and Wastewater.
Part 424, American Public Health Association, Washington, D.C.
pp 437-453.

CH2M-Hill. 1978. Water quality studies in the Everglades
Agricultural Area of Florida: Phase II. Project Report
submitted to the Florida Sugar Cane League, Clewiston,
Florida. July.

South Florida Water Management District. 1986. Lake Okeechobee
water quality monitoring annual report: October 1984 -
September 1985. South Florida Water Management District, West
Palm Beach, Florida.

Statistical Graphics Corporation. 1987. Statgraphics. STSC,
Incorporated, Rockville, Maryland.

Technicon Instruments Corporation. 1986. Industrial methods
manual number 812-86T. Tarrytown, New York.

Terry, R. E., Gascho, G. J., and S. F. Shih. 1980. Effect of
depth to water table on quality of water in the EAA.
Proceedings of the 6th International Peat Congress,
International Peat Society, Duluth, Minnesota.

Waller, B. G. and J. E. Earle. 1975. Chemical and biological
quality of water in part of the Everglades, southeastern
Florida. WRI 56-76. U. S. Geological Survey, Tallahassee,

Wiggins, T. S. 1987. Phosphorus in drainage waters of the
Everglades Agricultural Area and the development of a
procedure to determine its distribution in a farm conveyance
system for locating an optimum sampling point. Thesis
presented to the University of Florida in partial fulfillment
of the requirements for the M. S. Engineering degree.

Table 1: Total-P concentration summary statistics for baseline
conditions in the EAA.

Condition Sample* Average Variance Minimum Maximum
Size TP Cone. TP Conc. TP Cone.
mg/l mg/1 mg/1

Sugarcane 30 0.28 0.10 0.08 1.50
Radishes 8 0.25 0.05 0.06 0.62
Cabbage 35 0.45 0.26 0.12 2.39
Rice 6 0.69 0.14 0.25 1.27
Fallow Drained 16 0.43 0.19 0.10 1.65
Fallow Flooded 6 0.99 0.62 0.50 2.58
Canal 40 0.20 0.02 0.06 0.64
Precipitation 16 0.07 0.002 0.03 0.23

* Sample size is the number of sets of 4-plot averages
or treatment blocks used.

Table 2: Significant differences in means of TP concentrations
for baseline conditions in the EAA, indicating the
relationship between paired conditions.

Significant Difference*

No Significant Difference

Cabbage > Canal Cabbage > Fallow Drained
Fallow Drained > Canal Cabbage > Sugarcane
Fallow Flood > Radishes Cabbage > Radishes
Fallow Flood > Cabbage Sugarcane > Canal
Fallow Flood > Sugarcane Sugarcane > Radishes
Fallow Flood > Canal Fallow Drained > Radishes
Fallow Flood > Fallow Drained Fallow Drained > Sugarcane
Rice > Canal Fallow Flooded > Rice
Rice > Radishes Radishes > Canal
Rice > Sugarcane Rice > Cabbage
Rice > Fallow Drained

*95% confidence level t-test (Statistical Graphics, Inc., 1987)

- !V

r-------------------- ---*>
/ I
/ \
/ \

2 /4
% /
\ /

, 2 4
%. /
Y ,p

*1l 5_

-I /
% - //





FIGURE 1: Typical BMP experimental site layout


w I n
*1 6

- ------------ _- --

/ -I

I----- ---- --j -------------/





0.00 i I I I I I I I I I
11/25/88 01/21/89 01/24/89 03/09/89 08/23189 08/25/89 09/17/89 09/20/89 09/25/89 09/27/89



FIGURE 2 Total P concentrations for fast and slow drainage rates on sugarcane fields












2.20 -

0 2.00 -
2f 1.80-

< 1.60-

CIo 1.40-

O 1.20 -

1.00 -


0.60 -



01/21/89 03/03/89 03/08/89 04/16/89 04/22/89 08/09/89 08/14/89 09/25/89 09/27/89 11/30/89 12/21/89 12/28/89

FIGURE 3: Total P concentrations for cabbage fertizer practices




2.20 -


=- 1.00-

o .oo I --------------------- I
0.80 -

0.60 -

0.20 -

01/21/89 03/03/89 04/22/89 06/19/89 06/20/89 06/22/89 09/05/89 09/08/89 09/12/89 11/30/89

FIGURE 4: Total P concentrations for rice and falow flooded fields


3.00 -




2.20 -

S 2.00-


< 1.60

Fe- 1.00




0.20 -

06/28/88 08/29/88 07/20/88 07/22/88 08/16/88 11/25/88 01/21/89 03/08/89 04/22/89 08/03/89 08/13/89 08/16/89 09/25/89 09/27/89

FIGURE 5: Total P concentrations for sugarcane and falow fields

Report on the 20th Congress of the International
Society of Sugar Cane Technologist, Sao Paulo, Brazil

P.Y.P. Tai and Omelio Sosa, Jr.

U.S.D.A., ARS Sugarcane Field Station
Canal Point, Florida


Approximately 900 delegates from 60 countries, of which 39

were from the United States, attended the 20th Congress of the

International Society of Sugar Cane Technologist (ISSCT) in Sao

Paulo, Brazil. The Congress activities included field trips

(agriculture and manufacturing), plenary sessions, poster

sessions, symposia and others. The Brazilian sugar industry gave

the delegation two demonstrations of agricultural field

operations from field preparation, planting, harvesting, cane

loading to disposal of by-products (vinasse and filter cake mud

with emphasis on efficiency, effectiveness, environmental

protection and safety. The visit to the Copersucar Technology

Center gave the delegates an opportunity to see the state-of-the-

art laboratory equipment and facilities for performing sugar and

sugarcane research (a total budget of $24 million in 1988/89).

The use of technologies made available by the center was

estimated to provide an extra net income of US $114 million for

the Brazilian sugar industry in 1987/88 (US $24 million from

improved sugarcane varieties, US $20 million from improved

sugarcane milling, US $45 million from improved fermentation

processes in alcohol production, US $20 million from improved

distillation techniques and US $5 million from the use of liquid

fertilizers). Brazil has made a strong commitment to its sugar

industry. Brazil's sugar production of 8,500 million MT raw

value is only second in the world to India's production of 10,300

million MT. The prominence of the Brazilian sugar industry could

be attributed to several factors, one of which undoubtedly has

been its large investment in research. The plenary and poster

sessions of the 20th ISSCT Congress included Agronomy,

Agricultural Engineering, Plant Physiology, Sugar Processing,

Factory Engineering, Entomology, Plant Pathology, Plant Breeding,

By-products and Energy. The technical papers gave most recent

information about sugarcane and sugar research achievements

around the world. Sic symposia were held to cover the subjects

on energy, harvesting, sugar technology, sugar trade, and

biotechnology. The program of the 20th ISSCT Congress was very


Calcium Silicate Slag Effects on Sugarcane Ratoon Crops'I

D.L. Anderson and G.H. Snyder2/

It is well documented that sugarcane (Saccharum spp.) and

rice (Oryza sativa L.) respond positively to applications of

calcium silicate slag in certain low-Si mineral soils (Anderson

et al., 1987; Elawad and Green, 1979; Fox et al., 1967b). It has

been reported that Si increases the efficiency of utilization and

root adsorption of P within the plant, decreases Mn toxicity,

increases the oxidation power of rice roots, increases water-use

efficiency, improves insect and disease resistance, strengthens

tissues, and that in sugarcane, enzyme-Si complexes act as

protectors or regulators of photosynthesis and enzyme activity

(Silva, 1973). Calcium silicate slag applications to certain

mineral soils also are thought to make soil P more soluble,

decrease P fixation, correct Ca and Mg deficiencies, increase

soil Ph, and increase Si plant uptake (Fox et al., 1967a).

Bair (1966) observed that leaf Si of sugarcane grown on some

organic soils in the Everglades was below that limiting sugarcane

production in Hawaii. Gascho and Andries (1974) demonstrated

that both sugarcane and sugar yields increased when several

organic soils in the Everglades were amended with calcium

1/ 1990 Sugarcane Growers Seminar, May 17, Everglades Research and
Education Center, University of Florida, Belle Glade, FL.

2/ Associate professor and professor, respectively, Everglades Res.
Ed. Ctr., P.O. Box 8003, Belle Glade, FL 33430

silicate slag. Gascho (1977) suggested that a large portion of

muck-grown sugarcane in Florida would benefit from application of

calcium silicate slag because of the low-Si status of organic

soils in the region. Snyder et al. (1986) observed substantial

yield increases of rice grown on Histosols in response to calcium

silicate slag. Rice is commonly grown in rotation with sugarcane

in the Everglades. Anderson et al. (1987) showed that sugarcane

production following rice benefitted from slag applied to rice,

and Alvarez et al. (1988) determined that slag application for

production of a single sugarcane crop was economically justified

only in a rice-sugarcane rotation because the increased income

generated from the sugarcane crop alone did not offset the cost

of using slag. Since the cost associated with purchase,

transport, and application of slag is appreciable, it is

important to know the degree to which slag benefits ratoon

sugarcane crops. In a Hawaii mineral soil, Khalid et al. (1978a)

showed that appreciable quantities of Si from calcium silicate

slag remained in the upper soil profile over a 5-year period, and

that a portion of this Si was found to be bioavailable (Khalid

and Silva, 1978). The mechanisms (unspecified) of Si retention

in the Oxisol used in Hawaiian studies might not be operative in

the low-ash organic soils of the Everglades. Therefore, a study

was conducted to determine the residual effects of calcium

silicate slag on sugarcane production on Everglades Histosols.


Two sites were selected at locations approximately 5 km

apart in the eastern Everglades Agricultural Area (EAA). The

soil at both sites was a Terra Ceia muck (Euic, hyperthermic

Typic Medisaprist). Additional site and soil description have

been reported elsewhere (Anderson et al., 1987).

Calcium silicate slag of the composition: 200.6, 5.2, 4.2,

2.0 20.6, 9.9, 51.8, 3.7, and 1.5 g of Si, P, K, Mg, Ca, Fe, Al,

S, and Na kg"1 slag, respectively, was broadcast before previous

rice production (BR) at rates of 0, 2.5, 5, 10, and 20 Mg ha'1 on

plots 6.1 by 10 m using a randomized complete block design with

four replications. After rice production and before the

planting of sugarcane (BC), slag was also broadcast at the same

rates on plots previously left without applied slag.

Sugarcane Culture

Sugarcane response to calcium silicate slag application was

measured for the first-year "plant" crop, first-ratoon, and

second-ratoon crops (CROP 1, 2, and 3, respectively) at both

sites. Cultural practices for planting, fertilizing, harvesting

and measuring cane and sugar yields of sugarcane has been

described previously (Anderson et al., 1987).

During each year of ratoon regrowth at both locations, 20 kg

P ha'" from triple superphosphate and 100 kg K ha'1 from KC1 were

broadcast in March of each year. Fifteen 2.5 cm soil cores were

collectively sampled to a 15-cm depth within each plot before

each year of crop growth. Soils were sieved to pass through a

60-mesh screen and air-dried at 30 C for 3 days prior to soil

analyses. Soils were analyzed for Ph, water-extractable P, K,

Ca, and Mg (Anderson, 1983; Anderson and Beverly, 1985). During

each year of crop growth, the top-visible dewlap (TVD) leaf

blades with midribs were collected for tissue Si analyses at

stage five of growth (Chiarappa, 1971) which occurs during June

and July in Florida. The plant tissue was dried at 70 C and

ground in a stainless steel Wiley mill to pass a 60-mesh sieve.

Total Si in TVD leaf tissue was determined (Elliot et al., 1988).

Accumulation of Si by Rice After Sugarcane Production

Soil samples 15-cm deep were collected from each replication

of each 1984-applied slag rate of the BR timing on 30 Mar 1987 at

Sites 1 and 2. Soils were sieved to pass through a 60-mesh

screen and placed into 20-cm deep in pots having a surface area

of 0.01 m2, using 1 pot per original field replication, for a

total of 4 pots per treatment. Ten g of slag (10 Mg ha"') was

mixed with soil in an additional set of pots containing soil that

had received slag at 0 and 20 Mg ha1" in 1984 (BC). Pots

containing soil from the Site 2 were seeded (10 seeds pot") with

'Lebonnet' rice on 7 April 1987, and thinned to 3 plants on 17

April, at which time the pots were flooded. Nitrogen and K were
applied at the rate of 100 and 50 kg ha"', respectively, on 26

May. The seeding, thinning, flooding, and fertilization dates

for the pots containing soil from Site 1 were 21 May, 1 June, 1

June, and 23 June 1987, respectively. The plants were cut at the

soil surface on 20 July and 9 Sept for Sites 2 and 1,

respectively, dried, ground, and analyzed for Si as previously


The analyses of variance (ANOVA) and standard error of

regression were used to evaluate main effects. Simple and

multiple regression procedures were used to evaluate the effects

of CROP, application, Rate, and soil and plant tissue variable

components on cane and sugar yields (SAS, 1985). Auto-correlated

parameters were eliminated from regression equations. Only

statistically significant (P_0.1) linear, quadratic, or simple

1:1 interaction term regressions and variables were included in

final regression equations describing yield as a function of main

effect and independent variable parameters.

Soil analysis of check plots before the plant crop and

Julian dates (day-year) of soil, tissue, and harvest data

collection at each site and for each CROP are given in Table 1.

At both sites, cane and sugar yields (Mg ha'") were significantly

(P<0.01) affected by the CROP (plant, first-ratoon, or second-

ratoon), RATE of calcium silicate slag application, and the

TIMING (BR or BC) of slag application (Table 2). Main effect

interactions were nonsignificant (P>0.10). Since there was no

significant (P : 0.10) RATE x TIMING of application interaction,

overall comparison of yield responses to the rate of slag

application at each site and for each CROP can be assessed

(Figure 1). Although site 1 had significantly (P < 0.01) higher

yields than Site 2, at both sites, cane and sugar yields did not

appreciably drop until the third year of production. On

sugarcane not receiving slag application, cane yields declined

24% and 44.8% and sugar yields declined 21.6% and 49.6% between

CROP 1 and CROP 3 at sites 1 and 2, respectively. However, on

sugarcane receiving 20 Mg slag ha'1, cane and sugar production in

CROP 3 declined in the range of 0.3% to 29.2% from that of plant

crop yields (Table 3).

In the Everglades, sugarcane yields decrease with each

successive CROP (Crane et al., 1982). Neverless, for each year

the yield of cane that received slag was greater than that of the

cane not receiving slag. Despite the yield declines observed

after each CROP and at each location, calcium silicate slag

application increased cane and sugar yields from 11.8 to 50.0%

above sugarcane not receiving slag application (Table 4). During

the first two years of production at both sites, application of 5

Mg slag ha"' or greater maintained or increased yields above

yields of the plant crop receiving no slag (Figure 1, Table 5).

The TIMING of slag application is also important. Greater

cane and sugar yields were generally achieved from slag

application immediately before sugarcane planting than before the

previous cropping of rice (Table 4). Yield gains up to 10% were

realized as a result of application TIMING. At site 2, yield

differences due to the TIMING of application were greater than at

site 1. Alvarez et al. (1988) indicated that on a one-year

rotation basis, application of slag to cane may not be economical

if benefit to the preceding rotation crop (rice) is not

considered. Therefore, observed agronomic advantages due to

application TIMING (BR or BC) may not necessarily equate to an

economic advantage.

Sugarcane is replanted after several years of ratoon growth

due to successive decline in production below an economic

threshold. This economic yield threshold is below the average

industry production, but varies with each grower and
circumstance. Average production in the Florida industry during

the 1989-90 season was 72.8 Mg cane ha'" and 7.59 Mg sugar ha'l

(FSCL, 1990). The economic threshold for replanting is

determined by the grower based on objective and subjective

knowledge of the crop. Factors determining stubble replacement

include the time of harvest, cultivar, expected cane and sugar

yield, price of sugar, cost of slag including application when

slag is applied, rotation system, planting costs and predicted

losses in net yield if not replanted (Alvarez et al, 1988; Crane
et al., 1982). Yield declines after three years would probably

not warrant replanting at either site (Figure 1). However,

appreciable yield declines at site 2 could indicate poorer yield

expectations beyond three years, which may force the grower to
consider replanting this site. A clear agronomic advantage of

calcium silicate slag application is that observed yield

increases could extend production and thus reduce the crop system

costs associated with replanting.

The simplest and most significant (P<0.01) regression
equations that described cane and sugar yield data from all crops

and locations as a function of the main effects and pre-crop soil

extraction data (PROC STEPWISE, p. 269-336, SAS, 1987) were:

Cane (Mg ha"') = 45.2 + 32.12*CROP 11.76*(CROP)2 + 0.12*RATE

+ 0.069*(Soil Mg) R2=0.85,


Sugar (Mg ha'') = -2.2 1.44*CROP + 0.11*RATE + 0.05*(Soil Mg)

0.000035 (Soil Mg)2 R2=0.82.

These equations indicate that three parameters are needed to

describe sugarcane response to calcium silicate slag: CROP age

(1st, 2nd, or 3rd), RATE of slag application, and Mg soil test


Kidder and Gascho (1977) noted that Mg deficiencies could be

provoked from application of calcium silicate slag on low Mg

content soils (< 88 mg L"1 soil), although it was not stated

whether this would result in a subsequent yield decline. The

above equations show that for each 100 mg L"1 soil drop in soil

extractable Mg, there are 6.9 and 4.65 Mg ha'" of respective

losses in cane and sugar yields. Yield declines associated with

extractable soil Mg have not been recorded for Florida

conditions. However, Kidder and Gascho (1977) noted that

fertilization with 40 kg Mg ha'" could be required at planting.

Soil test levels of Mg generally declined with each CROP year.

Therefore, Mg fertilization to maintain pre-plant soil test

levels (Table 1) may be advisable for each CROP of sugarcane.

Application of slag in 1984 resulted in increased

accumulation of Si by rice grown in 1987 in soil from both sites

(Table 1). At Site 1 a substantial increase in tissue Si was

observed for the 1984 BR slag application rate of 10 Mn ha',

whereas at Site 2 the increase in Si was only minor for the 1984

BR slag application rates below 20 mg ha'". Post-sugarcane slag

application in 1987 significantly increased tissue Si in rice

plants grown at both sites. There was a significant interaction

between the 1984 and 1987 applications to soil only from Site 2

(Table 2). Clearly, the 1987 planting of rice was able to

accumulate Si from the 1984 BR slag application, but even greater

accumulation was observed for the 1987 application.

Long-term benefits to the application of calcium silicate
slag were seen after 3 years of crops. In Florida, sugarcane is

ratooned for 2 to 3 years after the plant crop before replanting

in continuous sugarcane or other crop rotation. In this system,

single application of silicate slag before planting the rotation

crop or before sugarcane is effective in significantly increasing

yields. Yield decline is associated with each successive ratoon
cropping of sugarcane (Crane et al., 1982). On the average,

sugarcane that had not received slag application declined 34.8%

and 35.4% respectively in cane and sugar yields between the first

and third year of crop production (Figure 1). However, sugarcane
receiving an application of 20 Mg slag ha"1 declined only 19.2%

and 14.9%, respectively in cane and sugar yields (Table 3). With

a single application of calcium silicate slag before production

it may be capable of extending sugarcane production additional

years before replanting. Benefits from this single application

are also evident by rice grown after sugarcane production, thus

achieving greater economic and agronomic benefits from the

application of slag.


The authors appreciate the assistance of Seminole Sugar

Corporation (currently New Hope Sugar Corp.), for their supply of

labor and permission for use of the sites in these studies.

Partial support of these studies was also provided by the Western

Ag-Minerals Company, Houston, TX, and the Potash and Phosphate

Institute, Atlanta, GA. Appreciation is also extended to Dr.

Frank G. Martin, Statistics Department, University of Florida,

Gainesville, for his manuscript suggestions.


Alvarez, J., G. H. Snyder, D. L. Anderson, and D. B. Jones.

1988. Economics of calcium silicate slag application in a

rice-sugarcane rotation in the Everglades. Agric. Systems


Anderson, D. L. 1983. Soil testing and analysis. AREC Research

Report EV-1983-5, Everglades Res. Educ. Center, Univ. of

Florida, Belle Glade.

Anderson, D. L., and R. B. Beverly. 1985. The effects of drying

upon extractable phosphorus, potassium and bulk density of

organic and mineral soils of the Everglades. Soil Sci. Soc.

Am. J. 49:362-366.

Anderson, D. L., D. B. Jones, and G. H. Snyder. 1987. Response

of a rice-sugarcane rotation to calcium silicate slag on

Everglades Histosols. Agron. J. 79:531-536.

Bair, R. A. 1966. Leaf silicon in sugarcane, field corn, and St.

Augustinegrass grown on some Florida soils. Soil Crop Sci.

Soc. Fla. Proc. 26:64-70.

Chiarappa, L. 1971. Crop loss assessment methods. Page 4.4.6/1

in: FAO Manual on the Evaluation and Prevention of Losses by

Pests, Diseases, and Weeds. Comm. Agr. Cur., Farmham,

England. Supplement 1.

Crane, D. R., T. H. Spreen, J. Alvarez, and G. Kidder. 1982.

An analysis of the stubble replacement decision for Florida

sugarcane growers. Bull. 822. Inst. Food and Agr. Sci.,

University of Florida. Gainesville. 74 pp.

Elliot, C. L., G. H. Snyder, and D. B. Jones. 1988. Rapid

gravimetric determination of Si in rice straw. Commun. in

Soil Sci. Plant Anal. 19(13):1543-1550.

Elawad, S. H., and V. E. Green, Jr. 1979. Silicon and the rice

plant environment: a review of recent research. II. Riso


Fox, R. L., J. A. Siliva, D. Y. Teranishi, M. H. Matsuda, and

P. C. Ching. 1967a. Silicon in soils, irrigation water,

and sugarcane in Hawaii. Hawaii Farm Sci. 16(4):1-4.

Fox, R. L., J. A. Siliva, O. R. Younge, D. L. Plucknett, and

G. D. Sherman. 1967b. Soil and plant silicon and silicate

response by sugarcane. Soil Sci. Soc. Amer. Proc. 31:775-


Gascho, G. J. 1977. Silicon status of Florida sugarcane. Soil

and Crop Sci. Soc. Fla. Proc. 36:188-191.

Gascho, G. J., and H. J. Andreis. 1974. Sugarcane response to

calcium silicate slag applied to organic and sand soils.

Int. Soc. Sugar Cane Technol. Proc. 15:543-551.

Khalid, R. A., J. A. Silva, and R. L. Fox. 1978. Residual

effect of calcium silicate in tropical soils: I. Fate of

applied silicon during five years cropping. Soil Sci. Soc.

Amer. J. 42:89-94.

Khalid, R. A., and J. A. Silva. 1978. Residual effects of

calcium silicate in tropical soils: II. Biological

extraction of residual soil silicon. Soil Sci. Soc. Amer.

J. 42:94-97.

Kidder, G., and G. J. Gascho. 1977. Silicate slag recommended

for specified conditions in Florida. Agronomy Facts. No.

65. Fla. Coop. Ext. Ser., University of Florida. 2 pp.

FSCL. 1990. News Release. Florida Sugar Growers Fare Well

Despite Freeze. Florida Sugar Cane League, Clewiston, FL

33440. 20 March.

SAS. 1985. SAS/STAT Guide for Personal Computers. Ver. 6 ed.

SAS Institute Inc., Cary, NC.

SAS. 1987. SAS/GRAPH Guide for Personal Computers. Ver. 6 ed.

SAS Institute Inc., Cary, NC.

Silva, J. A. 1973. Plant, mineral nutrition of, McGraw-Hill

Yearbook of Science and Technology. McGraw-Hill Book Co.,


Snyder, G. H., D. B. Jones, and G. J. Gascho. 1986. Silicon

fertilization of rice on Everglades Histosols. Soil Sci.

Soc. Amer. J. 50:1259-1263.

Table 1. Mean pre-growth soil analyses from 0 Mg slag ha"' plots and Julian
dates (day-year) of planting, soil and tissue sampling, and harvesting.

Site Planting

Mean Pre-growth Soil Analysis
pH Pw Pa K Ca Mg


Tissue Harvest

Julian Date ---- mg L1 soil ----- ----- Julian Dates ------

1 352-1984 6.1 6 22 72 3026 680 66-1985 171-1985 48-1986
6.0 24 42 221 3536 729 93-1986 178-1986 33-1987
6.4 6 27 57 2958 539 83-1987 176-1987 17-1988

2 354-1984 5.8 4 15 61 2412 519 62-1985 164-1985 31-1986
6.4 21 33 109 2712 465 93-1986 182-1985 16-1987
6.2 6 19 70 2160 341 21-1987 175-1987 352-1987

Table 2.

Analyses of variance (ANOVA) of sugarcane yields
significantly affected by the application of calcium
silicate slag at each site (n=215).

Site Variable


F P> F R2

1 Mg Cane ha"'

2 Mg Cane ha'1

1 Mg Sugar ha''

2 Mg Cane ha'1

Timing x Rate
Crop x Rate
Crop x Timing
Crop x Rate x Timing

Timing x Rate
Crop x Rate
Crop x Timing
Crop x Rate x Timing

Timing x Rate
Crop x Rate
Crop x Timing
Crop x Rate x Timing

Timing x Rate
Crop x Rate
Crop x Timing
Crop x Rate x Timing









** and ns represents statistical significance at P < 0.01 and
P > 0.10, respectively.
+ Timing refers to the timing of calcium silicate slag
application either before rice or before sugarcane.


Table 3. Percent yield increases and declines comparing yields
sugarcane receiving 20 Mg slag ha"1 to yields of the
plant-crop receiving no slag application.

------- Cane-----
Site Crop Yield & BR BC

------- ugar -------
Yield a BR BC /

Mg ha" ---- % ---- Mg ha' -- % ----

1 1 110.1 11.8 17.2 13.4 10.0 17.5
2 109.6 -0.4 15.0 12.9 8.8 8.4
3 83.1 -10.1 -8.6 10.6 -0.6 -0.3

2 1 94.6 25.6 30.0 11.6 29.9 32.2
2 89.0 16.0 25.3 10.5 11.8 24.5
3 51.9 -28.3 -23.9 5.8 -29.2 -24.1

w Yield from plots receiving no slag application.
k/ BR and BC represent calcium silicate slag application before
the rice crop that preceded sugarcane and immediately before
sugarcane, respectively.

Table 4. Percent yield increases comparing yields of sugarcane
receiving 20 Mg slag ha'I relative to the respective crop
yields of sugarcane receiving no slag application.

------- Cane-----
Site Crop Yield & BR BC

------ Sugar -------
Yield / BR BC /

Mg ha'' ---- % ---- Mg ha ---- % ---

1 1 110.1 11.4 17.2 13.4 10.0 17.5
2 109.6 14.8 15.5 12.9 13.2 13.0
3 83.1 19.9 21.0 10.6 26.4 26.7

2 1 94.6 25.6 30.0 11.6 29.9 32.2
2 89.0 23.3 33.2 10.5 23.0 37.0
3 51.9 30.8 38.8 5.8 40.0 50.0

A Yield from plots receiving no slag application.
BR and BC represent calcium silicate slag application before
the rice crop that preceded sugarcane and immediately before
sugarcane, respectively.

Table 5. Significant (P S 0.01) regression equations predicting
the response of yield to the RATE of application of
calcium silicate slag (X).

Site Crop

Cane (Mg ha'") = bo + blX b2X2

- 0.0858

- 0.0977

- 0.0387

(rate)2 30.08
(rate)2 17.92
(rate)2 31.10

Site Crop

Sugar (Mg ha'1) = b, + bIX b2X2

- 0.0145

- 0.0052

(rate)2 21.14
(rate)2 42.52


+ 0.76
+ 2.52
+ 0.75
+ 3.04
+ 1.10
+ 1.66








Table 6. Post-sugarcane Si accumulation in rice (1987) in response
to BR calcium silicate slag applied in 1984 at two sites.

Rice Straw Si
1984 Slag Site 1 Site 2

Mg ha'1 g kg"1

0 13.9 8.1
2.5 15.2 10.0
5.0 15.0 10.5
10.0 27.2 10.7
20.0 23.1 28.5

LSD,, ,,, 6.7 6.7

Table 7.

Effect of calcium silicate slag application in 1984 (BR)
and 1987 on accumulation of Si by rice in 1987.

Slag Rice Straw Si
1984 1987 Site 1 Site 2

Mg ha'" ---- g kg"' ------

0 0 13.9 8.1
0 10 38.2 37.8
20 0 23.1 28.5
20 10 47.2 37.0

Slag 1984 ** **
Slag 1987 ** **
Slag 1984 x Slag 1987 ns **

** and ns indicate P < 0.01 and P > 0.10,

Figure 1. Cane and sugar yield (Mg ha'") response to application
of calcium silicate slag (Mg ha').


, 120-

8 80,

C 60-





0 5 10 15 20
Slag Applied (Mg ha-1)

Crop 1 -
Crop 2 ........
Site 1 Crop 3 --

0 5 10 15 20
Slag Applied (Mg ha-1)




0 5 10 15 20
Slag Applied (Mg hal1)



- 10



0 5 10 15 20
Slag Applied (Mg ha1)

*******- -

-^ "'*'" """

Crop 1 -
Crop 2 ****....
Site 1 Crop 3 --


Ronald H. Cherry, Sugarcane Entomologist


Sugarcane is Florida's most valuable field crop and is primarily grown in

the Everglades of southern Florida. Since 1971, several species of sugarcane

grubs have been noted causing significant damage to Florida sugarcane. Of these

pests, the white grub Ligyrus subtropicus is the species of primary economic

importance. This grub has been shown to reduce tons of sugar per hectare in

Florida by 39% in areas of high infestation. Sugarcane is also a major field

crop in Australia with almost all of the crop being grown in Queensland. During

1986, the total area harvested in Queensland was 728,758 acres. Sugarcane grubs

are the most important insect pests of Australian sugarcane. During 1986, an

estimated 145,000 tons of sugarcane were lost to these pests in Queensland. The

objective of this presentation is to compare the soil insect pests of Florida

sugarcane versus Australia sugarcane.


Ron Cherry has worked at the Everglades Research and Education Center at

Belle Glade, Florida since 1981 as the sugarcane entomologist. Much of his work

has focused on the ecology and control of sugarcane grubs. From July, 1989 to

February, 1990, Ron Cherry was on sabbatical leave in Australia working on

sugarcane grubs. He worked with the Bureau of Sugar Experiment Stations (BSES)

which is the principal research and extension organization serving the

Queensland sugar industry. BSES cooperates in its research with numerous

agencies such as CSIRO, USDA, universities, etc. at both the national and

international level. Ron was stationed at the Bundaberg experiment station,

Queensland, working with Dr. Peter Allsopp on sugarcane grubs. Information

presented in this paper is based on his experience in Florida sugarcane versus

Australia sugarcane.


A comparison of physical features and major soil insect pests of Florida

sugarcane versus Australia sugarcane is shown in Table 1. The geographic range

of Florida sugarcane is compact being grown primarily in southern Florida around

the southern end of Lake Okeechobee. In contrast, Australia sugarcane has a

broad geographic range of more than 1,000 miles along the Queensland coast.

Florida sugarcane is mostly grown on muck soils and less so on sandy muck and

sandy soils. Australia sugarcane is grown on many more diverse soil types such

as volcanic soils, sandy soils, loams, highly organic soils, etc. The

topography of Florida sugarcane isvery flat. In contrast, Australia sugarcane

may be grown on flat land, gently rolling topography, or even in mountainous


There are differences in the types of soil insect pests attacking Florida

versus Australia sugarcane. Ground pearls (Family Margarodidae: Order

Homoptera) are not pests in Florida sugarcane, but are significant pests in

Australian sugarcane. Grubs (Family Scarabaeidae: Order Coleoptera) are pests

in both Florida and Australia sugarcane. Soldier flies (Family Stratiomyidae:

Order Diptera) are not pests in Florida sugarcane, but are significant pests in

Australia sugarcane. Wireworms (Family Elateridae: Order Coleoptera) are pests

in both Florida and Australian sugarcane.

A comparison of sugarcane grubs in Florida versus Australia is shown in

Table 2. Without doubt, the single most important grub species in Flroida

sugarcane is Ligyrus subtropicus. In contrast, several grub species are

important in Australia sugarcane depending on soil type and geographic range.

Ligyrus subtropicus has a one year life cycle in Florida while important species

of grubs in Australia sugarcane may have a one or two year life cycle. The

bacterial milky disease (Bacillus popilliae), fungal Metarhizium disease

(Metarhizium anisopliae), and entomogenous nematodes are found naturally

occurring in sugarcane grubs in both Florida and Australia.

Several different control methods are used for grub control in Florida

versus Australia. In Florida, discing ratoon fields out of production kills

large numbers of grubs. In Australia, the effect of discing ratoon fields out

of production for grub control is unknown. In Florida, flooding standing cane

is used for grub control. Field flooding for grub control is not commonly used,

if at all, in Australia. Reduced ratooning in Florida will help reduce grub

infestations in sugarcane. The effect of reduced ratooning on grub populations

in Australian sugarcane is unknown. In Florida, no insecticides are available

for grub control. In contrast, soil insecticides are used in Australia for grub

control both at planting and during the ratoon crops.


Florida and Queensland are both "Sunshine States" and the major sugarcane

producers for the United States and Australia, respectively. Overall, the soil

insect pest problem is more diverse and complex in Australia than Florida. The

greater complexity of the soil insect pest problem in Australia is largely

explained by the large number of soil types and large geographic range of

Australian sugarcane which has permitted numerous species to become sugarcane


Table 1. A comparison of physical features and major soil insect pests of

Florida sugarcane versus Australia sugarcane.

Florida Australia

Physical Features

Geographic Range Compact Broad

Soil Types Few Many

Topography Flat Variable

Soil Insect Pests

Ground Pearls Not Pest Pest

Grubs Pest Pest

Soldier Flies Not Pest Pest

Wireworms Pest Pest

Table 2. A comparison of sugarcane grubs in Florida versus Australia.



Pest Species

Life Cycle

Milky Disease

Metarhizium Disease

Entomogenous Nematodes

Effective Control



Reduced Ratoon

Soil Insecticide


One year










One or Two years







Recent Publications Since 1987

Allsopp, P., and R. Bull. 1989. Spatial patterns and sequential sampling plans

for melolonthine larvae (Coleoptera: Scarabaeidae) in southern Queensland

sugarcane. Bull. Ent. Res. 79:251-258.

Allsopp, P., and B. Hitchcock. 1987. Soil insect pests in Australia: Control

alternatives to persistent organochlorine insecticides. Standing Comm.

Agric. Tech. Rep. Series No. 21.

Cherry, R. 1988. Correlation of crop age with populations of soil insect

pests in Florida sugarcane. Journal of Agricultural Entomology. 5:241-245.

Cherry, R., and D. Boucias. 1989. Incidence of Bacillus popilliae in

different life stages of Florida sugarcane grubs (Coleoptera: Scarabaeidae).

J. Entomol. Science. 24:526-530.

Cherry, R., F. Coale, and P. Porter. 1990. Oviposition and survivorship of

sugarcane grubs (Coleoptera: Scarabaeidae) at different soil moistures. J.

Econ. Entomol. Accepted for publication.

Coale, F., and R. Cherry. 1989. Effect of white grub Ligyrus subtropicus

(Blatchley) infestation on sugar cane root: shoot relationships. Journal

of American Society of Sugar Cane Technologists. 9:52-55.

Coale, F., and R. Cherry. 1989. Impact of white grub (Ligyrus subtropicus

(Blatchley)) infestations on sugarcane root: shoot relationships. J. of

Plant Nutrition. 12:1351-1359.

Hall, D. 1987. Seasonal flight activity of adult sugarcane grubs in Florida.

J. Amer. Soc. Sugar Cane Tech. 7:39-42.

Jannson, R., S. Lecrone, and R. Cherry. 1988. Comparative toxicities of

fonophos and phorate to different populations of Melanotus communis

(Gyllenhal) (Coleoptera: Elateridae) in southern Florida. The Canadian

Entomologist. 120:397-400.

Raid, R., and R. Cherry. 1990. Pathogenicity of Metarhizium anisopliae to the

sugarcane grub Ligyrus subtropicus (Coleoptera: Scarabaeidae). J. of

Agricultural Entomology. Accepted for publication.

Samuels, K., D. Pinnock, and P. Allsopp. 1989. The potential of Metarhizium

anisopliae (Metschnikoff) Sorokin (Dueteromycotina: Hyphomycetes) as a

biological control agent of Inopus rubricips (Macquart) (Diptera:

Stratiomyidae). J. Aust. Ent. Soc. 28:69-74.

Samuels, K., D. Pinnock, and R. Bull. 1990. Scarabaeid larvae control in

sugarcane using Metarhizium anisopliae. J. Invertebrate Pathology.


Sosa, 0. Jr., and D. Hall. 1989. Mortality of Ligyrus subtropicus (Coleoptera:

Scarabaeidae) by entomogenous nematodes in field and laboratory trials. J.

Econ. Entomol. 82:740-744.


Frank J. Coale, Extension Agronomist
Modesto F. Ulloa, Agronomist


The Florida sugarcane industry is potentially subject to

damaging freezing temperatures each year. Freezing temperatures

kill the young growth of early-planted plant cane and early-

harvested ratoon crops. Typically, this type of crop damage

results in delayed crop development that the farmer/manager can

do little to alter. Freezing temperatures also damage mature

cane prior to harvest. The occurrence of this type of damage is

also largely beyond the control of the farmer/manager but the

magnitude of yield loss may be quite manageable.

Fortunately, the Florida sugarcane producing area has

experienced only a few damaging freezes in the past 15 years. We

are also fortunate to have had a continuous influx of new

alternative varieties introduced into our production system. It

is widely known that sugarcane varieties differ in their

susceptibility to pre-harvest freeze damage. Unfortunately, a

large proportion of the unharvested acreage that was damaged by

the freezing temperatures of 24-26 December 1989 was planted with

varieties that have not been extensively evaluated for post-

freeze deterioration. The rate of yield loss following the

freeze was obviously variety specific. However, for most

recently released varieties, the rate of yield loss was not

predictable. The objective of this study was to evaluate the

post-freeze deterioration of eight popular sugarcane varieties.


Thirty-eight hours of sub-freezing temperatures were

recorded at the Everglades Research and Education Center weather

station between December 24 and December 26, 1989. Beginning

December 26 and continuing at seven day intervals until February

13, 1989, sugarcane stalk samples were harvested from each plot

of a replicated variety trial growing as first-ratoon cane at

Closter Farms (TWP:43S, RNG:37E, SEC:12N). The experiment design

was a randomized complete block with eight varieties and four

replications. The varieties were CP70-1133, CP72-1210, CP72-

2086, CP75-1553, CP78-1247, CP78-2114, CP80-1557, and CP80-1827.

At each sampling date, five randomly selected stalks from each of

the 32 plots were cut at the soil surface and topped at the

uppermost hard node. The harvested samples were weighed and

crushed with a three-roller mill (2500 psi pressure). The

crusher juice was weighed, sub-sampled and analyzed for Brix by

laboratory refractometer, polarization after clarification by the

aluminum chloride-calcium hydroxide procedure, pH, and titratable

acidity. Titratable acidity was determined by titrating 50 ml

pure crusher juice with 0.1N NaOH to a pH of 8.4. Crusher juice

sucrose, purity, and sugar yield per ton of cane were calculated.


Sugar yield per ton of cane is the most critical parameter

associated with quality deterioration following exposure to

freezing temperatures. The eight varieties monitored in this

study divided into two distinct groups with respect to decline in

sugar per ton following the freeze. Three varieties, CP72-2086,

CP78-1247, and CP80-1827, exhibited declining sugar yields after

two weeks and five varieties, CP70-1133, CP72-1210, CP75-1553,

CP78-2114, and CP80-1557, exhibited declining sugar yields after

three weeks post-freeze (Figure 1). Once sugar/ton began to

decline, the rate of decline in sugar yield ranged from non-

significant for CP80-1827 and CP72-1210 to 23.3 pounds sugar/ton

per week for CP70-1133 (Figure 2).

Declining crusher juice Brix (Figure 3) and percent sucrose

(Figure 4) contributed equally to declining sugar yield for six

of the eight varieties and, therefore, calculated purity did not

shift with deterioration (Figure 5). Two varieties, CP70-1133

and CP80-1557, exhibited a significant decline in purity as

deterioration progressed.

Crusher juice pH decreased (Figure 6) and titratable acidity

increased (Figure 7) as deterioration progressed, but neither

were as satisfactory in determining declining juice quality as

were sugar/ton calculations.



270 -




0 1 2 3 4 5 6 7

CP70-1133 CP72-1210 CP72-2086--- CP75-1553
X CP78-1247-- CP78-2114- CP80-1557-- CP80-1827













CP75- 1553
CP70- 1133




2 3 4 i



CP70-1133-- CP72-1210 CP72-2086-- CP75-1553
- CP78-1247- CP78-2114 CP80-1557H CP80-1827



1 2 3 4 5 6 7



CP70-1133 CP72-1210 CP72-2086-- CP75-1553
- CP78-1247 CP78-2114 CP80-1557- CP80-1827




0.7' 1
0 1

2 3 4 f




- CP70-1133 CP72-1210 CP72-2086-- CP75-1553
-- CP78-1247- CP78-2114-- CP80-1557- CP80-1827



1 2 3 4 5 6 7







CP70-1133 CP72-1210 CP72-20868- CP75-1553
- CP78-1247 CP78-2114 CP80-1557 CP80-1827



ml 0.1N NaOH/50 ml

4 1 I I I I I
0 1 2 3 4 5 6 7

CP70-1133 CP72-1210 CP72-2086--- CP75-1553
CP78-12470 CP78-2114- CP80-15576 CP80-1827

Effects of the December 1989 Freeze on Juice Quality
at 3 locations

J. D. Miller, Research Geneticist
Peter Y. P. Tai, Research Geneticist
Modesto F. Ulloa, Agronomist


Following the December 1989 freeze we decided to sample three tests, the

mechanical harvester variety test at Belle Glade (BG) and the historical nursery

plots at New Farm (NF) and South Florida Industries (SFI). The test at BG was a

replicated variety trial with 3 replications of 3 rows of 12 varieties. The

tests at NF and SFI had a total of 31 varieties planted in single 4 row plots.

Samples were taken each Thursday starting on December 28 for 9 weeks, stored at

Canal Point inside a shed and milled the next day. Ten stalk samples were

collected from BG but only 5 stalk samples were collected from NF and SFI.

Results were analyzed by SAS. Since there was no true replications at NF & SFI

the interaction term Rep (Var Loc) was used as the error term in the overall



There were significant main effect differences for locations and varieties,

and significant location x variety interactions. Table 1 shows the overall

analysis by variety, with CP 72-1210, CP 72-2086, CP 80-1827, CL 61-620, and CP

74-2005 not being significantly different. However, CP 70-1133 and CP 73-1547

being significantly lower than the previous group. CP 70-1527 and CP 78-2114

were intermediate in average sugar per ton values.

The average deterioration rate was different at the various locations.

Belle Glade had the least amount of damage (however there was no green in any

leaves) followed by NF and SFI, which suffered the most damage.

Table 3, shows the break down of just the 12 varieties in the test at BG.

The only real differences are those between CP 70-1133 and CP 73-1547 and the

rest of the group.

When the data are examined by regression analysis to measure the slope of

the regression line a different equation is calculated for each variety at each

location, Table 4. This information could be utilized to predict the sugar per

ton of cane for any time up to 9 weeks after the freeze by pluging the number of

weeks into the equation for x and then solving it. For example at BG the

expected sugar per ton of cane for CP 80-1827 four weeks after the freeze would

be Y = 241.0 -(3.0)(4.0) or Y = 241.0 -12.0 or Y = 229.0. Thus if you could

estimate the intensity of the freeze damage and knew your starting sugar per ton

values you could utilize these tables to help determine your harvest schedule

following freezes of differing intensities.

Table 5 and 6 give these same type of values but only for the average of

the NF and SFI locations. The group of varieties with the highest average sugar

per ton of cane values averaged over the entire sampling period include some old

standards as well as some of the newer varieties. CL 59-1052, CL 61-620, CP 63-

588, CP 72-1210, CP 72-2086, CP 80-1557, CP 80-1827, and CP 81-1254. The group

of varieties with the lowest average sugar per ton at these locations were: CR

74-250, CP 62-374, CP 70-1133, CP 73-1547, CP 78-2114, and CP 75-1632.


The main lesson from all of this is that risks must be balanced to provide

the grower with optimum returns per acre. This would be simple provided we had

a perfect variety of cane to work with but we don't so it is a complex decision.

Ideally from this data we would say that the acreage of CP 70-1133 and CP 73-

1547 should be limited to that than can be harvested within 2 3 weeks after a

freeze. However this is complicated by the fact that these are two of the

highest-tonnage best-ratooning varieties we have. Ideally we would like to have

all of the acreage remaining to be harvested after a freeze planted in freeze

tolerant varieties. In the past this may not have been possible, but with some

of the newer varieties showing up with at least some freeze tolerance it is a

goal to work toward.

Table 1. Mean Brix, sucrose, purity and Ibs sugar/ton of cane for 9 varieties
averaged over 3 locations and 9 sampling dates after the December 1989

Variety Brix Sucrose Purity Sug/ton

CL 61-620 18.3 b1 15.7 abc 85.7 ab 218.5 ab

CP 70-1133 17.1 d 13.3 f 77.2 de 174.5 e

CP 70-1527 18.1 bc 14.9 cd 82.0 bc 202.0 bc

CP 72-1210 18.9 a 16.4 a 87.0 a 230.0 a

CP 72-2086 18.3 b 16.0 ab 87.3 a 223.5 a

CP 73-1547 18.2 bc 13.9 ef 75.7 e 180.0 de

CP 74-2005 18.4 b 15.5 bc 83.8 abc 212.9 abc

CP 78-2114 17.9 c 14.5 de 81.0 cd 195.7 cd

CP 80-1827 18.1 bc 15.7 abc 86.9 a 220.0 ab

IMeans within columns followed by the same letter are significantly different
at the 5% level according to Duncan's Multiple Range Test.

Table 2. Average Ibs sugar/ton of cane for
varieties at the Belle Glade, New

9 sampling dates averaged over 12
Farm, and South Florida Industries


12/29/89 240.6 al 243.3 231.0

1/5/90 249.2 a 227.4 222.6

1/12/90 249.7 a 227.9 220.3

1/19/90 192.9 d 183.4 182.2

1/26/90 227.7 b 202.6 188.8

2/2/90 219.6 b 187.4 167.8

2/9/90 180.5 e 153.6 148.0

2/16/90 201.2 cd 185.8 172.1

2/23/90 206.5 c 179.1 165.6

IMeans within columns followed by the same letter are significantly different
at the 5% level according to Duncan's Multiple Range Test.

Table 3. Means for Brix, sucrose, purity and lbs. sugar per ton of cane for 12
cultivars in the first ratoon crop at Belle Glade sampled nine times at weekly
intervals after the December 1989 freeze.

Variety Brix Sucrose Purity Sug/ton

















































83.1 ab

87.7 a

77.6 bc

83.5 ab

88.3 a

87.6 a

74.4 c

86.6 a

88.2 a

85.9 ab

82.0 ab

87.1 a













IMeans within columns followed by the same letter are significantly different
at the 5% level according to Duncan's Multiple Range Test.

Table 4. Regression equations that predict the Ibs of sugar per ton of cane at 3 locations for 12
varieties after the December 1989 freeze.

Variety Belle Glade New Farm South Florida Ind.

Y = 248.3

Y = 235.7





















-4. 1x







-101. 1x



Y*= 268.4

Y*= 216.3

Y = 254.6

Y = 233.1

Y = 238.4

Y*= 259.9

Y*= 223.2









































+ 77.8x





Y = 235.5 -9.1x

*Slope of regression equations significantly different from zero at the 5% level.

-20.5x2 + 1.3x3

+ 25.6x2 -2.2x3

Y = 240.8

Y*= 246.5

Y = 240.4 -4.2x

_ __

Y =






Table 5. Mean values for Brix, sucrose, purity and Ibs sugar/ton of cane of
30 varieties in plant cane at New Farm and South Florida Industries
when sampled nine times at weekly intervals after the December 1989

Brix Sucrose Purity Sug/ton

CL 54-378 18.4 abcd1 15.2 abcdef 82.5 cdefg 206.9 bcde

CL 59-1052 18.4 abcd 16.0 a 86.6 ab 222.9 a

CR 67-400 17.8 bcdef 14.1 defghij 79.1 ghijk 187.6 ghij

CR 65-185 16.9 fg 14.0 efghij 82.1 cdefgh 190.5 fghij

CR 74-250 16.0 g 12.8 j 79.7 gfhijk 171.2 kl

CP 56-59 16.9 fg 14.4 bcdefghi 84.3 abcd 198.1 defghi

CP 62-374 17.0 efg 13.0 hij 76.2 k 169.7 1

CP 63-588 17.6 bcdef 15.3 abcdef 86.6 ab 213.4 abcd

CP 65-357 17.5 bcdef 14.7 abcdefg 84.0 abcde 202.0 cdefgh

CP 68-1026 18.3 abcde 14.7 abcefg 80.4 efghij 197.7 defghi

CP 75-1082 17.3 bcdef 14.5 bcdefgh 83.4 bcdef 198.2 defghi

CP 75-1553 18.4 abcd 14.6 abcdefg 79.0 ghijk 193.8 efghi

CP 75-1632 17.4 bcdef 13.5 ghij 77.0 ijk 177.1 jkl

CP 77-1776 19.4 a 15.3 abcdef 78.3 hijk 201.8 cdefgh

CP 78-1628 17.1 defg 14.6 abcdefg 85.0 abc 202.2 cdefg

CP 80-1557 17.7 bcdef 15.4 abcde 86.9 ab 215.2 abc

CP 80-1743 18.5 abc 14.6 abcdefg 79.0 ghijk 194.4 efghi

CP 81-1254 18.5 ab 15.6 abc 84.4 abcd 214.6 abc

CP 81-1302 17.1 defg 14.8 abcdefg 86.1 abc 205.5 bcdef

CP 82-1172 17.2 cdef 13.9 fghij 80.2 efghij 185.9 hijk

CP 78-1247 17.2 cdef 14.7 abcdefg 84.7 abcd 203.1 cdefg

1Means within columns followed by the same letter are significantly different at
the 5% level according to Duncan's Multiple Range Test.