• TABLE OF CONTENTS
HIDE
 Front Cover
 Acknowledgement
 Title Page
 Table of Contents
 Introduction
 International trade and consum...
 The stem
 Tillering
 The eye
 The leaf
 The root system
 Elements of growth
 Vegetative propagation
 Breeding and selection
 Cultivation
 Chemical composition
 Nitrogen
 Phosphorus
 Potassium
 Other elements
 Foliar diagnosis
 Crop logging
 Factors affecting the growth of...
 Recent developments in the crop-logging...
 Tissue analysis--the basis of crop...
 Insect and rodent pests
 Diseases and disorders
 Maturity
 Maturity testing of sugarcane growing...
 Harvesting
 Payment regulations
 Processing
 Social aspects
 Table
 Figures
 Glossary of terms














Group Title: University of Florida. Agronomy monograph
Title: The Production of sugarcane
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00075699/00001
 Material Information
Title: The Production of sugarcane
Series Title: University of Florida. Agronomy monograph
Physical Description: 224 p. : ;
Language: English
Creator: University of Florida -- Institute of Food and Agricultural Sciences
Publisher: s.n.
Place of Publication: Gainesville
Publication Date: 1972
Copyright Date: 1972
 Subjects
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Contains bibliographical references.
Statement of Responsibility: Author: F. le Grand.
General Note: A contribution to the series of text books covering the field of tropical agriculture, prepared by the Department of Agronomy and sponsored by the Center for Tropical Agriculture, University of Florida, Gainesville, Florida.
 Record Information
Bibliographic ID: UF00075699
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 15374632

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Acknowledgement
        Acknowledgement
    Title Page
        Title Page
    Table of Contents
        Table of Contents
    Introduction
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
    International trade and consumption
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    The stem
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
    Tillering
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
    The eye
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    The leaf
        Page 31
        Page 32
        Page 33
    The root system
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
    Elements of growth
        Page 40
        Page 41
        Page 42
        Page 43
    Vegetative propagation
        Page 44
        Page 45
        Page 46
    Breeding and selection
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
    Cultivation
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
    Chemical composition
        Page 63
        Page 64
        Page 65
        Page 66
    Nitrogen
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
    Phosphorus
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
    Potassium
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
    Other elements
        Page 83
        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
    Foliar diagnosis
        Page 92
        Page 93
        Page 94
        Page 95
    Crop logging
        Page 96
        Page 97
    Factors affecting the growth of sugar cane
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
        Page 106
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
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        Page 116
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        Page 118
        Page 119
        Page 120
        Page 121
        Page 122
        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
        Page 128
        Page 129
        Page 130
        Page 131
        Page 132
        Page 133
        Page 134
        Page 135
        Page 136
        Page 137
    Recent developments in the crop-logging of sugar cane--phosphorus and calcium
        Page 138
        Page 139
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
        Page 145
        Page 146
        Page 147
        Page 148
        Page 149
        Page 150
        Page 151
        Page 152
        Page 153
        Page 154
    Tissue analysis--the basis of crop logging and crop control
        Page 155
        Page 156
        Page 157
        Page 158
        Page 159
        Page 160
        Page 161
        Page 162
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        Page 168
        Page 169
        Page 170
        Page 171
        Page 172
        Page 173
        Page 174
        Page 175
        Page 176
    Insect and rodent pests
        Page 177
        Page 178
        Page 179
        Page 180
        Page 181
        Page 182
        Page 183
        Page 184
        Page 185
    Diseases and disorders
        Page 186
        Page 187
        Page 188
        Page 189
        Page 190
        Page 191
        Page 192
    Maturity
        Page 193
        Page 194
        Page 195
    Maturity testing of sugarcane growing on organic soil of Florida
        Page 196
        Page 197
        Page 198
        Page 199
        Page 200
        Page 201
        Page 202
    Harvesting
        Page 203
        Page 204
        Page 205
        Page 206
    Payment regulations
        Page 207
        Page 208
        Page 209
    Processing
        Page 210
        Page 211
        Page 212
        Page 213
        Page 214
        Page 215
        Page 216
    Social aspects
        Page 217
        Page 218
        Page 219
        Page 220
    Table
        Page 221
    Figures
        Page 222
        Page 223
    Glossary of terms
        Page 224
Full Text






















ACKNOWLEDGEMENTS



Sincere thanks are due to Dr. Harry F. Clements, Senior Plant Pathologist

at the University of Hawaii, for his written permission to include three

reprints of his investigations about "Crop Logging" in this text.

















THE PRODUCTION OF SUGARCANE


F. le Grand, Associate professor for tropical crops











A contribution to the series of text books covering the field

of tropical agriculture. Prepared by the Department of Agronomy and

sponsored by the Center for Tropical Agriculture, University of

Florida, Gainesville, Florida.


September, 1972.












CONTENTS
Page

Introduction 1
International trade and consumption 7
The stem 13
Tillering 20
The eye 26
The leaf 31
The root system 34
Elements of growth 40
Vegetative propagation 44
Breeding and selection 47
Cultivation 57
Chemical composition 63
Nitrogen 67
Phosphorus 73
Potassium 78
Other elements 83
Foliar diagnosis 92
Factors affecting the growth of sugarcane 98
Recent developments in the crop-logging of sugar
cane phosphorus and calcium 138
Tissue analyses--the basis of crop logging and crop
control 155
Literature relating to crop logging of sugarcane 175
Insect and rodent pests 177
Diseases and disorders 186
Maturity 193
Maturity testing of sugarcane growing on organic
soil of Florida 196
Harvesting 203
Payment regulations 207
Processing 210
Social aspects 217
Table 221
Figures 222
Glossary of terms 224









CHAPTER 1


Introduction



This text will cover the growing of sugarcane for sugar, an important

commodity for numerous countries in the tropics. In general, growing sugar-

cane is rather easy as it is a deep rooting and sturdy plant. Growing

sugarcane for commercial sugar production, however, is difficult. With

the prevailing price structure and marketing arrangements for sugar, the

profit margin per unit produced is relatively small. It means that the

grower must obtain a high sugar yield per acre to remain competitive. To

optimize sugar production efficient application of modern agricultural

technology has become mandatory. This text will cover most of the aspects

of modern agricultural technology as applind to the production of sugarcane.



History


To aid in the understanding of the importance of sugarcane as a crop,

a historical review of its development will be presented.



Early Development


Domesticated tropical sugarcanes were selected and grown for chewing

purposes by the people of the Malayan Archipelago. During the last part

of the 19th century and the first part of the 20th century, expeditions to

New Guinea in the Netherlands East Indies collected noble canes, varieties

of S. officinarum. Other domesticated canes were collected around Coimbatore










in Northern India. It is unknown whether these domesticated canes originated

from the same area. There is also a lack of unanimity among the geneticists

about the expression "noble canes". Originally, this expression simply

meant that forms of wild S. spontaneum were improved by hybridizing these

varieties with S. officinarum. In more recent literature, nobilization

generally implies the increase in chromosome numbers for hybrids. To avoid

confusion, the canes collected during those expeditions should be called

"native" instead of "noble". During the last expedition in 1928, S. robustum

was added to the collection of native canes.

The soft S. spontaneum was dispersed to Indonesia, the Philippines,

Indochina, and to the area around the Bay of Bengal. Noell Deerr reports

in his historical studies that sugar made from sugarcane was known to the

soldiers of Alexander the Great when they returned from an expedition to

Western India in 325 B.C. By 1768 Tahiti became an important supplier of

cane seed to the "sugar colonies" of the New World.



Colonial Times


Sugar produced from cane is a non-perishable commodity, and was easily

transported by slow moving vessels between the colonies and the motherland.

The climatic and soil conditions of Indonesia and the Caribbean Islands are

ideally suited for sugarcane production. These areas became the sugar

suppliers for the major colonial powers of Europe, especially after the in-

troduction of slaves in the Caribbean provided a permanent labor force for

producing sugarcane.


". **9










During the Napoleonic wars, Europe was blockaded by England, thus

severing the sugar supply from the colonies. Sugar produced from sugar-

beet (Beta Vulgaris L.) then replaced the sugar produced from cane.

After the end of the hostilities, sugar production from the beet continued

in the countries of central Europe. Due to less demand, the amount of

sugar produced from cane was consolidated in the colonies.

Sugar consumption per capital was still low because of the relatively

small annual income. Widespread industrialization at the turn of the 20th

century changed this income. Demand for sugar from the colonies increased.

In exchange for raw materials, food, and fiber commodities, the colonial

powers supplied machinery to their colonies. This exchange provided the

means to establish in these territories a large sugar industry working

efficiently and marketing sugar at a reasonable price. Java, the Philippine

Islands, Cuba, and the Caribbean Islands became the "sugar bowl" for

Europe and North America.



The Great Awakening

After World War II, most colonies obtained their independence. During

this process, the land -- formerly managed by efficiently working but

foreign-dominated sugar companies -- was either expropriated or severe re-

strictions were applied to the management of these holdings. A fast-

declining production followed. For instance, Java exported in excess of

one million tons of sugar annually prior to 1940. During the sixties this

country, now called Indonesia, was forced to import sugar.

A second result of independence was the creation of a national sugar










industry in areas which did not produce sugar prior to World War II. India

thus has become one of the largest sugar producers of the world in just a

few decades. Judging from the growing conditions, which are sometimes mar-

ginally suitable for sugarcane, it appears that a sugar industry is often

established in a developing country as a result of national pride.

The change of ownership for land was not the only cause for declining

sugar production in the Caribbean. Sugarcane production in this area often

is associated with former slavery and colonialism by the younger generation.

The annual harvesting of sugarcane is a back-breaking and dirty task.

thesee conditions, together with the social stigma attached to sugar pro-

duiction, have caused the decline of employment in the sugar industry by

the present generation. Having enjoyed a more advanced education than

their parents, these people are now able to find alternative employment in

tourism and other small-sized industries in the West Indies. To counter-

act this trend, the sugar industry in the developing countries is faced

with an increasing need for field mechanization.



Future Aspects

Sugarcane will remain a very important agricultural commodity in the

future. On the average, this crop provides one of the highest yields per

acre in carbohydrates and this food is essential in the daily diet of man

and animal. The rapidly expanding world population calls for an ever-

increasing annual production of carbohydrates for its survival in the near

future.










The developing countries in the Caribbean and Asia may play an im-

portant role in feeding this future world population by virtue of the pre-

vailing soil and climate conditions which are well suited for sugar pro-

duction.

Governments of these areas should realize that total field mech-

anization must be encouraged in the future, in spite of the social hardship

that this may temporarily cause, to remain competitive in sugar production.

A modern sugar factory, being in the category of a heavy industry, can

be considered as a training ground for establishing other and light in-

dustries in developing countries. Emphasis in developing countries should

be placed on a vocational-technical training to meet the future challenge

for total field mechanization in cane sugar production.

A shift from areas now important in sugar production to other areas

which are presently less important also may occur. Countries such as

Australia with excellent climatic and soil conditions for a high sugar

production per acre is sparsely populated, have already taken advantage

of total field mechanization. During the past decade Australia has become

an important producer, supplying sugar at a moderate cost to Japan in

exchange for needed industrial production. Such a trend may continue;

countries having idle land resources available and having favorable

climatic and soil conditions may become important suppliers of agricultural

commodities through the application of modern field mechanization and

agricultural technology. These food commodities will be exchanged for in-

dustrial production by countries which have a scarcity in land resources.












The importance of the sugar industry for the Caribbean or other areas

may diminish unless modern agricultural technology is maintained. The

basis on which this technology is founded will be covered in the various

chapters of the text.



SELECTED READINGS:


1. Artschwager, E and E.W. Brandes, Sugarcane (Saccharum Officinarum L.),

Origin, Classification, Characteristics and Descriptions of Repre-

sentative Clones. USDA Agriculture Handbook No. 122, 1958.

2. Barnes, A.C. The Sugar Cane. Interscience Publishers, Inc., 1964.










CHAPTER 2

International Trade and Consumption


The world population consumes more than 70 million tons of sugar

annually. Of this quantity about 70% is consumed domestically in the

producing countries. Twenty percent of this world production enters the

international trade and is sold to markets which grant some form of pre-

ference. The remaining 10% constitutes the so called "world market" or

"free market".

England has arranged a quota system for its former Caribbean colonies

under which a substantial part of the annual sugar production can be sold

at a preferential price. Sugar produced by the French overseas provinces

is regarded as being grown in the motherland and receives the same price

advantage. Cuba, which practically had a monopoly to export sugar at a

preferential price into the United States during the past, now sells a

large portion of its annual production through barter rarngments to

the Iron Curtain countries.

The United States imports sugar at a preferential price from every

nation which has been granted a permanent import ouota by the Sugar Act.

Thirty-one nations are involved, among which are 20 areas on the South

American continent (Table 1). About 70% of the U.S. sugar consumption is

derived from sugarcane, whether grown domestically on the mainland, Hawaii

and Puerto Rico, or in foreign nations. A modern cane sugar refining in-

dustry has been established as a result. The remaining consumption is











derived from sugar-beets which produces a sugar quality directly suitable

for consumption.

The same price, based on the amount of raw sugar (970 polarization)

recoverable, is paid by the processor to the grower for his cane or beet

supply. In addition, the domestic grower receives a subsidy; this subsidy

is paid on a declining scale with increased sugar production per farm.

The federal government collects a tax on the refining of sugar, whether

from cane or beet, and partly distributes this revenue as a subsidy to

domestic growers. The subsidy is granted in exchange to the grower's

compliance with the regulations of the Sugar Act.

The Sugar Act requires the Secretary of Agriculture to estimate

during the last quarter of each year the sugar supply needed by the nation

for the following year. The Act further requires that the price for

sugar over the long period should relate to the Parity Index as the

average sugar price in 1957/59 did relate to the average parity index

of this period 1/.

The annual sugar consumption per capital in the United States remained

fairly constant during the past decades. Increase in the nation's annual

sugar consumption, therefore, is mainly caused by a larger population.

Hence, the once per year estimation of demand for sugar can be accurately

determined since short range population increase can be closely predicted.



1/ An index reflecting prices which farmers have to pay for production,

interest and taxes.











Holding the sugar price closely to the target price, which is relative

to the Parity Index is achieved with the help of the demand for sugar as

a known factor. When the sugar price remains below the target price for

a long period, the Department of Agriculture may revise and lower its

estimation for annual sugar consumption. As a result, less sugar will

be allowed for marketing and the price will eventually increase. The

reverse holds equally true. Persistent and large differentation between

the actual and target price for sugar will ultimately result in a change

in acreage quota for the domestic industry and a change in import quotas

for foreign suppliers. Small and temporary fluctuations in the sugar

price are corrected often by withholding or enlarging the quantity of

sugar allowed to be marketed during a specific period of the current year.

During the past, the Department of Agriculture has been remarkably

successful in maintaining the target price for sugar closely to the one

required by the Sugar Act. The system has provided an adequate sugar

supply at reasonable prices to the consumer, an orderly marketing for the

commodity, and reasonable returns to growers, domestic and foreign pro-

cessors, and refiners (Figures 1 and 2). The system was aided by the fact

that sugar was supplied by domestic industries and 31 foreign nations;

production deficits in the domestic areas are reallocated to foreign

countries while deficit in a particular foreign quota are assigned to

other foreign countries.

Only a few decades ago, two-thirds of all sugar sold in the United

States was used in the home kitchen while the rest was utilized by food











processors. Today only one-third enters the household kitchen and the

remainder is employed for curing hams, for the production of ketchup,

bread, and an infinite number of readily available food products. The

advent of convenience food products resulted in a major shift from con-

sumption in crystal form to the utilization of liquid sugar which product

is exclusively used by food processors.

As sugar is an important ingredient in many foods, the predictable

price has given stability to the production and price level of food

commodities. Hence, the price and supply stability as a result of the

Sugar Act has benefitted the consumer as well as the food processor in

general. It does not mean that sugar is provided at the lowest possible

price to the consumer.

Sugarcane and sugarbeet are subsidized crops in the United States.

The price of sugar is kept in accordance with a price level established

through the Parity Index, thus providing a fair return to the grower for

his funds and efforts expended. In addition, the federal government partly

returns to the grower the tax funds levied on refining of sugar as a sub-

sidy. Sugar is taxed by many nations when imported or refined. Unlike

the United States these nations utilize their revenue funds to provide

services to the population at large. Some persons claim that the price of

sugar in the United States could be lowered if all requirements would be

met by importation only. The nation now consumes close to 11 million

tons of sugar annually and total importation could disrupt the now constant

supply in times of international tensions.










Consumption


The world produces about 70 million tons of sugar every year. The

United States, although only representing a fraction of the world's

population, annually consumes close to 11 million tons of sugar or about

17% of the world's total production. Such a phenomena can only be ex-

plained by the sugar consumption per capital.

Sugar consumption per capital appears to be closely related to the

per capital disposable income. It follows that sugar consumption per

capital in developing countries is lower than in the developed countries.

As an example, the approximate annual sugar consumption per capital in

Haiti and India is 25 and 30 pounds, respectively, while for the United

States and Sweden is about 110 pounds.

Sugar may be regarded as a basic food commodity; it is cheap and is

the purest form of carbohydrates available on the market. People with

low incomes will first satisfy their total food requirements with car-

bohydrates because of price. When income increases, the purchase of car-

bohydrates will only increase to a certain level after which a change in

purchase is made in favor of foods having a protein base. Hence, the

normal sugar consumption is around 100 pounds of sugar per capital per year

in developed countries, and this amount remains fairly stable.

The population, especially in the developing countries is increasing

at a compounded rate. At the same time, the disposable income in these




I

I
countries is increasing, although more slowly than in developed countries.
Both factors will cause an accelerated need for greater sugar production
to fulfill future demand.
Whether new and suitable land resources in the developing countries
are still available for sugar production is an unknown factor. The
greatest potential seems to be in the development of far superior sugar
yields from acreage already devoted to sugarcane production. A significant
yield increase, thus, is the challenge for developing countries during I
the next few decades.
I
SELECTED READINGS:
I
1. A Background Discussion: The United States Sugar Act. Published
under the Sponsorship of 12 organizations, engaged in the production I
of beetsugar, cane sugar or refined sugar, not dated.
2. Special Study on Sugar; A Report of the Special Study Group on Sugar
of the U.S. Department of Agriculture. Committee print of 87th
Congress, Ist Session. U.S. Printing Office, Washington D.C., 1961.
I

I

I

I


I

I











CHAPTER 3


The Stem


The stem is economically the most important part of the sugarcane

plant. The root and leaf systems are responsible for the uptake of

nutrients and photosynthesis, respectively. The stem is the end result

of these processes; it is the plant part to be harvested for sugar.

Hence, tonnage harvested, together with the stored concentration of

sugar formed by photosynthesis, determines the sugar yield obtained per

cultivated unit. A second major function of the stem is to provide the

planting material for asexual propagation.


Morphology

The stem usually is tapering toward the bottom and top; maximum

stem elongation occurs when optimum climatic and other conditions prevail.

The bottom nodes are below the soil surface and gradually extend into

the root system. This part is high in sucrose content. The sucrose con-

tent in each successive joint declines towards the top of the stalk.

The average length and diameter of internodes is a varietal characteristic

but also depends on the prevailing growth environment. Conditions adverse

to optimum growth such as deficiency in nutrients, moisture, and low

temperatures, will cause short internodes and will reduce cane tonnage

at harvest. The position of the dwarfed internodes on a stalk is an in-

dication of the time when adverse growing conditions prevailed. Even under






optimum conditions, the elongation rate for internodes increases with

age till a maximum has been reached, after which further elongation de-

clines.

Depending on the photoperiod, the top part of the stem will change

from a vegetative to a reproductive stage. The growing point will cease

its vegetative development in favor of an inflorescence. Later, when

vegetative growth resumes, a certain number of nodes will be void of eyes.

The varietal characteristic of excessive flowering, therefore, is un-

desirable; specifically because the top part of the stem is used in many

countries as planting material since this part is of little value for

commercial processing due to its low sugar content.

The external color of the stem may vary as a varietal characteristic.

The observed color is caused by two basic pigments: Anthocyanin, a red

pigment predominant in the epidermal cells, and chlorophyll located in

the interior tissues. The intensity of color depends on the amount

of exposed sunshine and the altitude at which the cane is grown. It

follows that the coloration of the stems even within the same stool may

be different. Both pigments are extracted with the juice and are diffi-

cult to remove during juice clarification.

The entire stem, with the exception of the growth rings, is covered

by a wax layer. The thickness of this layer varies with the variety and

the color ranges from white to black. The latter color is caused by a

fungus. Numerous attempts have been made to recover this wax for commercial

sale. The present process in uneconomical; the type of wax recovered

after refining resembles carnauga wax which is often used in the production

of shoe polish and varnish. The interest in the economical recovery of










cane wax was greatly reduced with the discovery of synthetic waxes.

Longitudinal cracks sometimes appear in the outer tissues of the

internode. They are caused by a fast rate of growth, and appear when

growing conditions are very favorable. Moreover, some varieties are

more susceptible to the formation of cracks than others. The formation

of cracks is an undesirable characteristic since each opening forms

an entrance into the stalk for undesirable organisms.

The stem, in cross section, may vary in color, especially at the

internodes. This color may range from brown to green; the intensity

depends on the variety, and is caused by rapid action of oxidases. Hence,

an observed discoloration may be natural and not necessarily exhibit

a disease symptom.

A root band is located at the base of each internode. This band

is bordered by a growth ring on the top and scar tissue on the bottom.

The growth ring identifies the region of cell division and enlargement

which contributes to internode elongation. Auxins often cause the under-

side of a stalk to elongate more rapidly when in a horizontal position,

thereby causing a more erect position of the terminal internodes. This

characteristic is especially important for lodged cane, and enables the

stalk to "straighten" after wind damage. The root band also contains

several rows of root primordia, its number depending on the variety

employed. The largest root primordia are located on the upper part of

the band; the small ones located near the lower part are the most vigorous

ones and develop rapidly when the internode is planted.










Anatomy

In examining a cross section of the stem, three main layers of

tissue can be observed:

1. Epidermis

2. Rind (or cortex)

3. Vascular bundles which are embedded in soft tissue.

The epidermis consists of two major cell types; the so-called long

cells and short cells. The short cells are differentiated into cork

cells and silica cells. Relatively few stomata are located in the

epidermis.

The rind consists of several layers of cells, being mainly sclerenchymatous

(lign ified fiber cells), which give support to the stem. Some of the cell

layers contain red anthocyaninn) and green (chlorphyll) pigments.

The vascular bundles consist of a sclerenchymatous sheath which

encloses the xylem and phloem. A ground tissue is composed of thin-

walled parenchematic cells in which the bundles are embedded. The soft,

less lignified cells of the ground tissue are known in the trade as the

"pith" fraction of bagasse.

From the foregoing description some interesting conclusions may be

drawn:

1. The wax layer greatly reduces the loss of moisture after the

stalk has been harvested and therefore preserves the quality

of cane for processing. On the other hand, the wax layer enters

the processing and is difficult to remove during juice clarification.










The remaining wax adheres to the raw sugar crystal and forms

a significant obstacle for refining. For this reason, the

wax layer should be removed from the cane prior to milling in

order to prevent this material from entering the clarification

process.

2. The epidermis fraction is detrimental to sugar recovery. The

crushed cells absorb sucrose containing liquid during milling

and will actually reduce sugar recovery from cane. Moreover,

the inherent colors are difficult to remove during clarification

and form a nuisance for refining. The epidermis should there-

fore be discarded before cane is allowed to enter processing.

The rind fraction consists largely of lignified cells which give

the stalk its upright support. Sugar concentration in these cells is

low. Moreover, the purity of the juice extracted from these cells is

inferior, making undesirable the mixing of this juice with the one ob-

tained from the ground tissue having a much higher purity. The lignified

rind cells are valuable for further processing of fibrous by-products.

The quality of juice recovered from the ground tissue is excellent.

In contrast to the rind cells, the cells of the ground tissue are thin-

walled. These "pith" cells adversely interfere with the further pro-

cessing of bagasse.

Presently, cane is regarded as a major source for carbohydrates only.

On the average, this plant contains equal quantities of sucrose and fiber.

The latter is occasionally used for the production of paper or construction










board. The production of these commodities in the tropics is only

economically warranted when measures are taken to prevent the marketing

of similar materials produced at a lower cost elsewhere.

Bagasse as a raw material for paper making is expensive mainly

because the "pith" cells have to be separated from the vascular bundles

and the rind tissue. This separation process is cumbersome and only

partly effective, causing the chemical consumption for paper making

to be high and subsequently the cost of paper production from bagasse.

Annual requirements for paper and suitable building materials will

sharply increase in the developing countries during the next few decades.

The world's potential of 70 million tons of fiber per year is presently

wasted. Such a valuable resource may only be utilized effectively in the

future when the method of cane processing can he changed.

Sugar extraction from cane by milling has basically changed little

through past centuries. In the future, a new method for extraction should

be found to remove the wax and epidermis layers and to separate the rind

from the ground tissue fraction of cane prior to juice extraction. Total

sugar recovery from cane should be greater when these fractions are ex-

tracted separately. At the same time, the major portion of the "pith"

cells are kept separate from the lignified cells, thus making the portion

of bagasse derived from the rind more suitable for further processing.

Two challenges, therefore, are apparent for the future. First, an

increase in sugar yield per acre is needed in order to satisfy the demand

for carbohydrates by the ever increasing world population. Secondly, the










present method of juice extraction should be modified in such a manner

that the fiber resource from cane can readily be utilized for the economic

production of paper and building products. Succeeding with both challenges

will mean the maximum utilization of the sugarcane resource for the

benefit of mankind.



SELECTED READING:


1. Barnes, A.C. The Sugar Cane. Interscience Publishers, Inc., 1964.

2. Dillewijn, C. van. Botany of Sugarcane. The Chronica Botanica Co:

Book Department, 1952.










CHAPTER 4


Ti lering


The number of stalks or tillers formed by a particular cane stool

is primarily a varietal characteristic. Varieties producing stalks

with a large diameter generally produce less tillers per stool while

wild canes with a small diameter will tiller profusely. Hence, the

parentage of a variety will affect its tillering pattern.

In addition to being a varietal characteristic, tillering also

will be influenced by prevailing environmental conditions such as

altitude, light intensity, day length, temperature, nutrients, and

moisture. Varieties are mostly bred and selected for commercial pro-

duction in a certain area. When grown in other areas, the growth

characteristics often may be different. Varieties which tiller pro-

fusely in the original area may tiller sparsely in other areas.

Tillering is important because the number of stalks per stool

contributes to the final sugar yield per acre. Sugar yield is a

function of sucrose content in cane and tonnage per acre. In turn,

the latter is the result of several independent factors such as number

of tillers per stool, average diameter and length of internodes, and

the number of internodes suitable for processing. The sugar content

in cane depends on varietal characteristic, prevailing climatic and

soil conditions, and the average maturity of the stalk population.

Growers often believe that dense planting within the rows and narrow











inter-row spacings will produce a maximum of tillers, and consequently

tonnage per acre at harvesting. Early research in Java has proven that

such an assumption is not necessarily true.

Light intensity is a major factor governing tillering. Tillers

will be formed until light intensity accordingly becomes a limiting

factor; the cane crop is called "closed in" at that time. No new tillers

are normally formed after this period. Hence, an acre can support a

fixed number of cane stalks, the magnitude depending on the variety em-

ployed.

After the crop has "closed in", the existing stalks should be

allowed to elongate until maturity. Lodging of the cane will admit

additional light, and as a result will promote the formation of new

tillers. Tillers formed when the original stalks are already six months

or older are often called "water shoots" or "suckers". These late tillered

stalks are low in sucrose content when the original tillers are ready

for harvest, therefore, they can considerably lower the average sucrose

content for the crop.

As the number of stalks per acre is determined for each variety,

the grower should space the distance between rows so that the crop will

"close in" in about three months of a 12-month growing cycle. Likewise,

the tonnage of planting material employed should be such that no empty

spaces of more than two feet between stools within the row will occur.

Allowance for reduction in cane stand by insects, diseases and adverse

weather conditions should be made, therefore, when determining the










quantity of planting material needed, whether it be cane tops or stalks.

Normally 2 to 2L tons of planting material will achieve a uniform cane

stand within the rows and "closing in" of the crop at three months.

Rows 4- feet to 6 feet apart are commonly employed to obtain the

required stalk population. Experimentation in most parts of the world

has revealed that harvested cane tonnage is the same whether cane was

planted in rows 4- or 6 feet apart. This discovery is not surprising,

taking into account the foregoing explanation. With narrow rows, the

actual number of tillers present at the time of "closing in" will

exceed the optimum number which can be harvested. The excess of tillers,

therefore, will perish between the periods of "closing in" and harvesting

of the crop.

Temperature, together with available light and nutrients, are the

most important factors that govern tillering. For sub-tropical areas

such as Florida, temperature will significantly influence the formation

of tillers. With increase in temperature, the formation of tillers

also will gradually increase until a maximum is reached at about 300C.

Light-covering of the cane cuttings with soil after planting will pro-

mote tillering in these areas during winter.

Nitrogen, followed by phosphorus are the most important nutrients in

promoting tillering of sugarcane. The effect of phosphorus is apparent

only on soils which are deficient in phosphorus, while nitrogen applied

to mineral soils commonly stimulate profuse tillering, regardless of the

original nitrogen content of the soil.











Earthing up of the seed pieces is possibly the most effective tool

to control tillering./ The tillering of the plant crop is promoted by a

light soil cover over the seed piece. Under these conditions, new

tillers are quickly exposed to light.

Subsequent tillering can be governed by the timing and the degree

of additional soil applications. Small and infrequent soil applications

will continue to promote tillering, while heavy or frequent soil

applications will delay tillering. Excessive tillering should not be

allowed. As a rule, tillers to equal twice the number of stalks which

are present at harvest are desirable as an optimum cane stand.

Spacing between the rows and soil applications to cane in the rows,

therefore, are the most important variables affecting tillering, pro-

viding that no "gaps" are present within the row. Presently, the

variability in spacing between rows is limited by the need for mechanical

or chemical weed operations. To accommodate the machinery, a minimum of

5 feet, and preferably 6 feet between rows is recommended. This arrange-

ment leaves soil applications to cane as the only variable to control

tillering. Initial removal of soil from the space between rows should

be made as near as possible to the small cane plant as to avoid dis-

turbance of the root system. Also, the timing of split fertilizer applications

should coincide with earthing up in order to achieve optimum placement



2/ Earthing up, a commonly used term among sugarcane growers, means
the removal of soil from the inter-row spacing and the placing of
this soil on the cane stools in the row.











of fertilizers for growth of tillers. In this manner cultivation

practices can be combined into one operation to reduce cost. The

formation of a shallow furrow between rows should facilitate drainage

and later mechanical operations such as weeding and possibly harvesting.

The fact was mentioned that the ultimate number of permanent

stalks per unit of surface is fixed within fairly narrow limits for

each variety. Also, that under the same climate conditions, the final

cane tonnage at harvest is about the same, regardless of the amount

of cane planted per unit of row length or the distance between rows.

If so, why are soil applications necessary?

After planting, the sprouted eye will develop ultimately into the

so-called primary shoot which in turn, also carries eyes. When these

eyes sprout, secondary shoots will be formed. This process continues,

but each subsequent phase will originate closer to the soil surface.

Hence, for ridged anchoring of the stools and to reduce later "lodging"

of stalks, an effort should be made to allow the survival of primary,

secondary, and tertiary tillers only. The method of adding timed soil

applications to the row will achieve such a control.

The distance between rows and the quantity of planting material

used within the row are variables in planting of the crop. In contrast,

these variables are fixed for ratoon crops. The stools in ratoon

crops may expand in diameter, and thus compensate for a wide-spacing

between or within rows, by developing the desired number of stalks

per unit of surface area.











As in the plant crop, soil applications to ratoon crops are used

to limit the tillering to the formation of primary, secondary and

tertiary shoots only. Otherwise, the cane stool in a subsequent ratoon

will originate substantially nearer to the soil surface than the stool

grown during the previous crop. After a few years, the stools in the

ratoon appear to grow out of the soil. Failure to properly time and

supply soil applications to the cane, therefore, may limit the number

of ratoon crops which can be obtained economically.



SELECTED READINGS:

Dillewijn, C. van. Botany of Sugarcane. The Chronica Botanica, 1952.










CHAPTER 5


The Eye


The eye is a bud containing a small stem with leaves. The outer

leaves of this miniature stalk consist of scales. These scales contain

hair groups which shape is used as a reliable indicator in variety

identification. Also, the shape of the eye and the manner of implant

on the stalk serve as additional means for differentiation among varieties.

The eye is located in the rootband of the stalk, each node normally

contains one eye. Sometimes double or even triple eyes occur either

together enclosed or singly adjacent to each other. The characteristic

of multiple eyes usually is not permanent; multiple eyes may change into

singular ones during the next crop generation.

Germination is the development of the organs already present in an

embryonic stage. The rate and speed of germination not only depend on

climatic factors such as prevailing temperature or available moisture, but

also on the presence of growth regulators (auxins) and the metabolism

of different food compounds.

Went performed basic research on germination of cane at the turn

of the century. He found protein and starch present in meristematic

areas of the plant. In parts undergoing cell elongation (growth), glu-

cose was prevalent with starch and protein absent. These findings serve

as the basis for the modern diagnostic techniques.

Producers rarely grow cane specifically for seedcane production.











Seedcane is more likely chosen at random from commercial fields or from

abandoned fields. Experiments with seedcane have shown that germination

of seedcane markedly improves by heavy applications of nitrogen to

standing cane or even by placement of nitrogen within the seedpiece.

Also, soaking of seedpieces overnight in lime water or even plain water

has also been found to improve the speed and rate of germination. This

treatment may possibly have an effect on the metabolism and compounds

present within the seedpiece.

The eyes located near the base of the stalk are the oldest. The

factors which mainly influence the germination of these eyes are moisture,

nutrients, and growth regulating auxins. Nitrogen, moisture, and glu-

cose content in the stalks decrease with increasing distances from the

top while the reverse is true for the sucrose content. Starch formation

is the next step after invert sugars, and the highest concentration of

starch together with protein can be expected in the top part of the stalk.

This is one of the reasons why the eyes located in this stalk section

will easily germinate.

The eyes on a standing stalk normally remain dormant as long as the

growing point is intact. This phenomenon is called apical dominance.

The eyes nearest to the top of the stalk germinate when the growing point

is either removed or inactivated by insect or frost injury. These side

shoots, forming a kind of fan-like growth pattern, take over the function

of the growing point. In turn these shoots exert apical dominance over










the eyes lower on the stalk.

Apical dominance has an important effect on the stalk when used

as planting material. Only the topmost eyes germinate readily. The

germination of the eyes placed lower on the stalk will be delayed to

such an extent that they are an easy target for insect damage or bac-

terial rot. To secure an even cane stand, the cane stalk in the row

should be cut into lengths of two nodes each to eliminate the effect

of apical dominance on germination rate.

Cane elongation, root development and eye inhibition (apical)

dominance) are functions originating from growth-regulating sub-

stances. Two of these functions can be demonstrated as follows:

A section of cane stalk, consisting of a root band and one eye with

a length of internode left intact on both sides, is placed in a

vertical position. The growth ring will elongate and the roots will

develop when a mixture of heteroauxin (betaindoleacetic acid) and

lanolin is applied to the lower cut. Likewise, the roots will develop

on one side and the growth ring will only elongate on that side when

this mixture is applied to only half of the cut surface.

Elongation of the growth ring on one side will also take place when

the cane cutting is placed horizontally in the plant furrow, exposed

to climatic conditions without covering with soil. Only the roots in

contact with the soil surface develop while elongation at the growth

ring will take place at the lower side, causing the cane cutting to

curve upwards.











This curvature is very pronounced when whole stalks are used for

planting, causing both ends of the stalk to protrude above the soil

surface, even if this stalk is covered with soil at planting. There-

fore, cane should be planted in two-node lengths, not only to reduce

eye inhibition from apical dominance but also to avoid poor germination

from curvature. Planting of two eye cuttings will assure an even cane

stand while allowing for the possibility of loss of one eye. Cane tops,

discarded as having little value for sugar production at harvesting

time, can thus be made an excellent source for planting material.

At planting the seed material is subjected to rough handling. Eyes

are easily damaged resulting in an erratic cane stand during successive

years. For this reason the leaf sheaths, serving as a protective shield

for the eye, are left on the stalk. A leaf sheath which fits tightly

around the stalk can be regarded as a favorable characteristic for the

planting operation. In contrast, a leaf sheath is difficult to remove

from the stalk, even when burned prior to harvesting. These sheaths

increase the trash content in harvested cane, an undesirable characteristic

for commercial sugar production.

Most cane fields are burned prior to harvesting. The eyes of the

top part of the stalk, being well protected by the green leaf sheaths,

are not damaged by this quickly passing fire. When used as planting

material, the eyes of the top part will germinate faster after cane

burning than the eyes which were not subjected to this burning process.










The reason for this is still unknown.

Cane grown in the sub-tropics is sometimes subjected to freezing

temperatures which damage and even kill the eyes. Eyes are often

discolored when exposed to low temperatures. When cut diagonally, the

presence of the black and round discoloration inside the eye does not

signal the killing of the eye; these eyes produce a normal cane stand

after planting. Only eyes which are soft when touched must be re-

garded as having been killed by low temperatures.



SELECTED READINGS:


Dillewijn, C. van. Botany of Sugarcane. The Chronica Botanica, 1952.

Artschwager E. and E.W. Brandes. Sugarcane (Saccharum Officinarum L.)

USDA Agricultural Handbook 122, 1958.











CHAPTER 6


The Leaf


The leaf is truly the sugar factory. The building, widely referred

to as the sugar mill, is only an extraction plant processing the sugar-

bearing juice which yields raw sugar as final product. The sugars first

formulated by photosynthesis in the cane leaf are translocated to the

stalk and are either used for additional growth or temporarily stored.

These stored sugars will be utilized by the plant, if not harvested,

when favorable climatic conditions for further growth prevail.

The young leaves are located at the top and near the growing

point and are utilized for diagnostic purposes. Any deficiencies pre-

sent in these leaf blades and sheaths will be reflected in a reduced

rate of growth.

The leaves are alternately attached to the stalk. Each leaf

consists of a blade, the dewlap and liguie with the auricle, and the

sheath with its base. The leaves are small when the plant is young

and grow to a maximum length of 3 feet or more as the plant grows older.

Each stalk carries about 10 leaves after the crop has closed in. New

and small leaves formed in the plant top will replace the older leaves

below renovating the leaf surface while the stalk continues to elongate.

The width and length of the leaf, as well as the total active leaf

surface per plant, vary according to variety and prevailing climatic

conditions. No relationship has been found between the total active










leaf surface per plant and sugar content of the cane stalk. The total

green leaf surface of the cane crop equals about seven times the area

of soil surface utilized.

The blade is divided lengthwise with one distinctive midrib. The

sheath is broadest at the base and gradually tapers towards the tip.

The sheath envelopes the internode and often is covered with hair.

The blade and sheath join at a collar called the dewlap. The shape

of this dewlap helps to identify specific varieties. Also, the

position of the auricles and shape of the hair groups serve this pur-

pose.

Only the sheath, leaf, and dewlap can be distinguished in fully

developed leaves. Hence, only the leaf blade and often only partly

can be noticed on the young leaves while the sheath and dewlap are

still concealed within the "spindle", the embryonic part of the plant

top.

The blade and sheath will desiccate after the leaf matures. Finally

the leaf will fall, revealing a scar on the stalk where the sheath was

formerly attached. Often the dried sheath still envelopes the internode

after the blade from the sheath severs at the dewlap. Burning of cane

prior to harvesting only partly removes the dried sheaths, and the re-

maining part clings to the stalk as it enters the processing plant.

These sheath particles have a detrimental effect on sugar recovery from

cane. Therefore, self-shedding varieties, which drop their dried leaves

to the soil surface are preferable for high sugar recovery.










Finally the leaf blades can be used for visible diagnostic purposes.

Especially the fully developed leaves of the spindle tend to reveal

symptoms of any existing nutritional imbalance or of certain diseases

which may be present.



SELECTED READINGS:


Dillewijn, C. van. Botany of Sugarcane. The Chronica Botanica, 1952.










CHAPTER 7


The Root System


The root system performs two principal functions. First, it is

responsible for the uptake of moisture and nutrients. This uptake in

turn results either in growth or maturity processes, depending on the

prevailing moisture supply or temperature at a specific time period.

Secondly, the root system anchors the plant so that the leaf sur-

face can be exposed to maximum light intensity for optimum photo-

synthesis. This photosynthesis produces energy to be used in either

growth or sucrose accumulation. Hence, in the root system one may

distinguish two main types of roots: ones which have as primary

function the feeding of the plant and those roots which are principally

used to anchor the plant.

The root system has been extensively examined by growing cane in

boxes which contained wire netting stretched at different heights.

These boxes were buried in the soil and planted with cane. Later the

boxes were recovered and the soil adhering to the root system was care-

fully washed away leaving the root layers intact and supported by the

wire netting. The deep, penetrating roots, especially those important

for anchoring, were studied by careful excavations.

These studies revealed that 80 percent of the root system is lo-

cated in the first foot below the soil surface. This portion of the

root system serves mainly as feeder roots to the plant. The rest,









acting as anchor roots, may extend more than 10 feet below the soil

surface with the majority of these anchor roots located in the first

five feet below the soil surface.

Horizontally, the feeder root system extends nearly 10 feet, with

the greatest concentration within the first three feet from the plant.

With the cane rows 5-6 feet apart, the entire interrow space is solidly

penetrated with feeder roots. For this reason, fertilizers applied

to the subsoil in young cane fields should be placed in the center of

the interrow to avoid extensive injury to the root system.

The study also has indicated the desired depth of the free water

table. As feeder roots need adequate oxygen for proper functioning

and as the feeder roots are concentrated in the first foot below the

surface, it follows that the free water table should be kept below

this level.

Optimum depth of the free water table for cane has been a con-

troversial topic in areas like the Florida Everglades where this water

table can be controlled. Studies and practical experience suggest

that a constant, non-fluctuating free water table between one and two

feet below the soil surface is more important than the exact depth of

this water table.

A fluctuating water table will actually create conditions of pruning

off or new formation of the feeder root system. In areas with heavy

clay, as in Guyana, the topsoil layer becomes waterlogged by the rains

after a dry season. The sugarcane reacts by the leaves turning pale










green, a condition often associated with nitrogen starvation. The pale

color will disappear after water recedes without the need for artificial

correction, but the period of stress is permanently characterized by

shorter internodes formed during this time.

Most likely, the root system is pruned off during the time of water-

logging of the topsoil causing reduced uptake of elements. The formation

of new feeder roots corrected this imbalance during the period after which

no severe waterlogging took place. The free water table, therefore,

should be kept constant at a depth between 1l and 2 feet below the soil

surface by irrigation and drainage as needed.

When the free water table is maintained at a constant depth ranging

between 1' and 2 feet from the soil surface, the feeder root system,

concentrated in the first foot, must obtain its moisture requirement

through soil capillary action. This moisture supply is easily obtained

in soils containing a heavy loam or clay fraction and in organic soils.

To reduce surface evaporation and to increase the availability of this

moisture resource, shallow mechanical interrow cultivation should be com-

bined with chemical weed control.

The cane plant originated in the tropics on the banks of rivers

where it was frequently subjected to flooding. The rate of transpiration

by cane is low after planting, but increases rapidly until a maximum is

reached after six months. The relative transpiration (the ratio of

transpiration to evaporation) was measured by a Piche evaporimeter and

amounted to 0.36 for humid exposure and 0.19 for dry exposure, both expressed









in grams of water per square centimeter and per day for variety Co. 421.

Other investigations revealed that a 7-month old cane plant transpired

550 grams of water per day and addition of water immediately increased

this amount to nearly 1300 grams per day. It follows that the water

requirement for the feeder root system of cane may be in excess of 20

tons of water per day and per acre. This confirms the practical obser-

vation by the grower that an abundance of water is beneficial in obtain-

ing maximum cane tonnage.

Another expression by the grower is that "the cane crop can stand

wet feet". Indeed, cane will survive when subjected to prolonged flood-

ing, as is sometimes true when flood-fallow is practiced prior to re-

planting.

It is not surprising, therefore, that the anchor root system can

extend to a depth of 10 feet or more, and well below the free water

table. It appears that the cane plant has the ability to translocate

oxygen within its system. This may be the reason why the anchor roots

can survive under hostile conditions.

The deeply penetrating anchor roots are needed to support the portion

of the cane plant above the ground which often exceeds 12 feet in height

at the time of harvesting. A poorly developed root system will cause the

cane plant to topple. This is especially true for areas which are sub-

jected to damage by hurricanes and which grow cane in soil types of a

loose consistency like the organic soils of the Everglades region in Florida.

Finally some general remarks about the root system in ratoon crops.










When a new crop cycle is started, the root system develops from the root

primordia present in the growth ring of the planted cane cutting. When

this crop is harvested, the stubble (the part of the stool located in

the soil), if left in place, acts as the planting material for the

successive crop. The existing root system will perish and is completely

immobilized about three months after the previous crop. An entirely

new root system will take its place, originating from the root primordia

which are present in the stubble. Hence, every successive ratoon crop

will produce its own root system.

The yearly renovation of the root system provides important quantities

of organic matter to the soil. In the tropics the same fields are utilized

for cane production year after year without an appreciable change in

organic matter of the soil during the past century. The root and stubble

system represent nearly 17 percent of the total vegetative composition

of cane. Only 49 percent of the total vegetative crop is removed from

the field in the form of cane stalks to be processed. With a yield of

40 tons per acre a year of millable cane, about 20 tons per acre of

vegetative material is returned to the soil each year in the form of

roots, trash and tops. The root system and stubble play an important

role in recycling organic matter to the soil, which is especially impor-

tant in tropical areas.



SELECTED READINGS:


Evans H. The Root System of Sugarcane 1. Methods of Study. Emp. Jour.

Exp. Agric. 3, 1935.










Negi, O.P. et all. Root Studies of Outstanding Sugarcane Varieties

of Bihar, India. Proc. of the I.S.S.C.T., Louisiana (in press), 1971.


Exner, B. Anatomy of the Branch Roots of Sugarcane, Proc. of the

I.S.S.C.T., Louisiana (in press), 1971.










CHAPTER 8


Elements of Growth


The main function performed by the root system is to supply the

cane plant with nutrients and moisture, necessary for growth (the

formation of cane tonnage). In contrast, ripening of the cane calls

for partly inactivation of nutrient and moisture uptake through the

root system. During this period the energy from photosynthesis is stored

instead being utilized for further growth.

The root does not respond chemotropically to fertilizers (the

change in direction of root growth to locations where heavy con-

centrations of nutrients are present). The root system, however, is

able to vigorously branch out in locations with heavy concentrations

of nitrogen and potassium, thus, facilitating the uptake of these elements.

The ability of feeder roots to branch has important implications

for soil applications of nitrogen and potassium. A small application

should be given at planting time and placed in the furrow prior to

planting, followed by other split applications drilled into the topsoil

anywhere in the space between rows. Chances that a root will penetrate

the fertilized area are nearly guaranteed, while a rapid uptake of these

elements takes place by the subsequent branching of feeder roots. There-

fore, placement of nitrogen and potassium to accommodate the root system

is of minor importance.










Unfortunately, the same rule does not apply to the uptake of phos-

phorus. A heavy concentration of phosphorus does not stimulate branching

of feeder roots. The cane plant is able to secure an adequate supply

of this element only when as many as possible roots penetrate the phos-

phorus-containing area. It follows then that phosphorus should be applied

in a relatively wide band at a location having the greatest potential for

root penetration.

Experiments in Hawaii with radioactive P32 have revealed that only

a fraction of the required phosphorus is taken up by the cane plant

when applied as a top dressing. A somewhat greater quantity is utilized

when this element is applied as a side dressing. The major part of applied

phosphorus, however, was taken up when phosphorus was applied underneath

the plant.

The discovery is in accordance with the fact that greatest root

penetration at random takes place just below the plant. Phosphorus is

relatively immobile and does not readily move to deeper placed soil

layers; the cane receives its greatest benefit from a phosphorus application

when this element is applied in a wide band at the bottom of the furrow

prior to planting. As cane can be regarded as a perennial crop, place-

ment for optimum uptake by the root system can only be achieved once

per cycle, and the entire dosage of phosphorus for the plant crop as well

as all subsequent ratoon crops should be applied in bottom of the furrow

prior to planting.

Growth includes the process of cell elongation which is also associated











with the intake of moisture. Therefore, a close relationship should

exist between the cane tonnage to be harvested (growth rate over time)

and the quantity and distribution pattern of water available.

Seasonal changes from wet to dry take place in most tropical sugar-

producing countries. Cane ripening occurs most readily during the

dry season while the rainy seasons are optimum for vegetative growth.

Under ideal rainfall distribution, cane should be planted at

the end of the major dry season. Transpiration rate is relatively

low for the young plants and, therefore, only a limited amount of

irrigation is needed during a period when this commodity is often

scarce. During the following wet season enough rainfall should be

available to meet the heavy moisture requirements of fully grown cane

plants at a maximum rate of transpiration. By the end of this rainy

season, rainfall becomes often a limiting factor for maximum rate

of growth. At this time a large quantity of irrigation water should

be made available to sustain the maximum growth rate. Irrigation water

should be withheld about 4 weeks prior to the date of harvesting.

The date of planting, therefore, will have a significant influence

on the cane tonnage to be harvested, especially in areas having limited

or no irrigation facilities. Cane planted too early may die due to

lack of moisture. Cane planted too late may be severely reduced in cane

tonnage at harvesting due to lack of much needed moisture at a time when

the plant is at the point of maximum transpiration. In the tropics,

date of planting becomes less important in areas with adequate irrigation









facilities to supply the need for moisture during both critical periods.

Withholding moisture from the plant will reduce the rate of growth.

The root system becomes partly inactivated during the dry season, re-

sulting in the reduced uptake of nutrients. Photosynthesis continues,

however, and the photosynthate is stored as sucrose in the cane plant.

In essence this process represents cane ripening.

A drop in temperature also partly inactivates the root system and

therefore, will enhance cane ripening. The low temperatures often

experienced in the sub-tropics have the same effect on the maturing

process as drought in the tropics. A close relationship, therefore,

exists between prevailing day-degrees and rate of growth per time unit.

Finally, optimum moisture, temperature, and fertilizer placement

may not automatically guarantee the required functioning of the root

system and the rate of growth. Soil pH may significantly influence the

rate of uptake by the cane plant for needed nutrients, regardless of

whether adequate quantities of these nutrients and moisture were applied.



SELECTED READINGS:


Humbert, R.P. Basic Problems of Sugarcane Nutrition II. Applying

Basic Facts in Sugarcane Fertilization. Intern. Soc. Sugarcane Techn.

Proc. 8, 1953.


Halliday, D.J. The Manuring of Sugarcane. Centre d'Etude de L'Azote,

Geneva, 1956.












CHAPTER 9


Vegetative Propagation


Cane is propagated vegetatively by planting stalk cuttings in

commercial sugar production. This method normally should preserve

specific and favorable characteristics with the very infrequent

exception of spontaneous bud mutations. Theoretically then, cane

tonnage and sugar production will continue indefinitely at the same

rate once a superior yielding variety has been adapted for commercial

use.

In practice this statement is incorrect. Sugar production per

unit of surface will decline gradually and progressively. The cause

of this yield decline is not clear but is likely a combination of a

many related causes. Therefore, a commercial cane variety must be

replaced by a newly developed variety at least once every 10-15 years,

just to maintain the current level of sugar production per unit of

plant surface. Ideally, this new replacement would have yielding

abilities superior to the previous commercial variety.

Two-eye cuttings are preferably used for propagation on a commercial

scale. Such a cutting contains a large food reserve which, in turn,

promotes the speedy development of the root primordia and eye under

favorable conditions. Actually, only a small chip of the growth ring









containing at least one of the root primordia and the eye is needed

for the development of a cane plant. When being shipped over long

distances, these small chips sometimes are sent by air-freight to

save on transportation costs.

The cane cuttings are placed either horizontally in a furrow of

about 12 inches deep, or they are planted in a more slanted position.

The latter method often is used where weather patterns are unpredictable.

The theory behind this method is that the lower placed eye will germinate

well during dry spells but may perish during wet weather; the reverse

is true for the eye located near the soil surface. The method of

planting thus provides the best chance for uniform germination and sub-

sequent cane stand.

The method just described must be performed manually; because of

increasing scarcety and cost for labor, it is being replaced by plant-

ing cane cuttings horizontally in a furrow. Similarly, gaps in the

cane row formerly were planted by splitting and planting parts of

neighboring stools in the open row spaces. Planting short open gaps

in the cane row, whether in the plant or ratoon crops has been generally

abandoned because of high labor cost.

Presently, the only economical method of securing a full and even

cane stand is to plant an excess of cane cuttings horizontally in a

mechanically prepared furrow. The excess of shoots thus germinated

will be adjusted automatically when light intensity becomes a limiting

factor when the cane crop "closes in." The need for preparation of the











planting furrow by mechanical means will exclude the use of mountainous

terrain for growing sugarcane in the future.











CHAPTER 10


Breeding and Selection


Vegetative propagation of cane for commercial sugar production

is practiced to retain the favorable characteristics associated with

a variety such as disease resistance, tolerance to damage by insects,

favorable cane tonnage and high sucrose content.

Breeding is practiced to develop improved varieties. Desirable

characteristics for which selection is practiced include resistance

to diseases, improved tolerance against insect damage, and increased

tonnage and sucrose content in cane. Selection criteria are not

always chosen to increase sugar production. For instance, varieties

selected for stalk erectness to facilitate mechanical harvesting

usually result in an increase of fiber content in cane and, sub-

sequently, a lowering of sugar recovery and production per unit of

surface. Rejection of otherwise high yielding varieties because of

disease susceptibility must be mandatory; otherwise, the entire sugar

industry in a region may be annihilated.

At the turn of the century researchers in Java found that cane

could be multiplied through true seed. Since that time numerous

breeding programs have been established in prominent sugar producing

areas to provide cane varieties adapted to those areas.

The change from vegetative growth to florescence is dependent










on the day length. The flowering of S. Robushum and S. officinarum is

responsive to photoperiod; cane is known as a "short day" plant.

Therefore, the breeding program for the U.S. mainland is carried out

in south Florida, where the day length is more favorable to the

development of florescence. Under favorable circumstances every

cane variety is capable of producing bisexual flowers. Some varieties,

however, are unable to produce viable pollen.

Temperature influences cane breeding, especially in subtropical

areas like south Florida. Low temperatures adversely affect the

formation of viable pollen; a florescence, when normally capable of

producing viable pollen, will often become sterile when the pollen

production takes place below 60 degrees F. For this reason the plants,

selected for pollen production are placed in heated greenhouses during

cool spells in the subtropics.

Pollen is produced before the "boot" stage of the flower. At this

moment the viable pollen may be used directly for cross pollination with

prior selected varieties, or the mature pollen may be harvested and

stored in paper bags. Pollen will retain its viability for a long term

when these bags are placed in a deepfreezer. This storage technique

makes the timing of pollen production independent from the timing of

the selection for "female" arrows in the cross-breeding program.

The technique of cane breeding is rather simple. After determining

whether a variety produces viable pollen, selected varieties for breeding

may be planted side by side in the field. After the emergence of flowers,











the female and male arrows with viable pollen are placed in a type

of lantern, covered with cheese cloth to prevent cross pollination

by unwanted varieties. Cane stalks with the male arrow are shaken

at least once a day to facilitate the release of the viable pollen.

Since it gives a better control against low temperatures another

method is used specifically in south Florida. The base of the cane

stalk of both female and male varieties is packed in moss which, in

turn, is wrapped with plastic and the package is kept wet. The moisture

will cause development of the root primordia in contact with the moss.

Just prior to the full development of the arrow, the cane stalk with

its developed root system is cut from the stool and transferred to

a greenhouse. Here, the plant base including the root system remains

wrapped in moss and is placed in water, continuously aerated. The

arrows of the selected female and male plants are wrapped in a lan-

tern hood, again to avoid undesirable pollination.

The "male" and "female" flowers for crossing of selected varieties

may not necessarily mature at the same time for crossing purposes.

The flowering of certain varieties may have to be delayed for success-

ful pollination. In this case, the stools are grown in large containers

and are subjected to artificial light or darkness to increase or de-

crease the day lengths. The same effect can be obtained in the field

by using a photographic flash light close to midnight.

A successful pollination will produce a large number of viable

seed per female arrow. Under controlled conditions, with only one











or more "male" arrows of the same variety and one or more "female"

arrows from possibly different varieties per lantern, the percentage

of the true seed can be identified. Sometimes "male" arrows from

different varieties are placed in the same lantern to increase the

success of pollination. This is called a polycross and, of course,

only the "female" variety can be identified as a parent. The seed

obtained can be kept in cold storage for several years without sig-

nificantly losing its viability. This method guarantees a constant

supply of seed for use in the breeding program, even during years

when seed production is low due to wind damage or frost.

The technique for cross breeding cane varieties has been well

established and simplified. The choice of varieties for cross

breeding to obtain superior yielding offspring is much more difficult.

Cane varieties greatly differ in chromosome numbers. The basic

number for both S. officinarum and S. robustum appears to be 10.

Most forms, however, are polyploids and aneuploids. For instance,

in S. robustum chromosome numbers in many multiples of 10 have been

discovered while the majority has 2n = 80, in the form of octoploids.

The number of seeds with different characteristics but from the same

parents approaches infinity, due to the large range in chromosome

numbers and the magnitude of possible combinations. Hence, results

from cross breeding of cane varieties cannot be predicted with even

remote certainty; the discovery of a superior variety can, therefore,

only be regarded as a matter of chance. Random selection from pre-











determined cross breeding is the principle behind a sugarcane

variety improvement program.

The planting of large numbers of seedlings annually and carrying

these through an elaborate selection program is one method to improve

the chances for the discovery of a superior variety. For instance,

the USDA Sugarcane Field station in Canal Point, Florida releases

one variety for commercial production per 200,000 seedlings planted

and tested. To secure such a release once every 4 years it will be

necessary to plant and select through different stages at least

40,000 seedlings annually.

The release of a new variety does not necessarily mean a yield

increase per unit of surface. Varieties which appear to have a

better resistance against diseases or are better adapted to cultural

practices needed to reduce man-hour requirements also may be released

for commercial production, whether or not such a variety will yield

better than the standard commercial ones.

Improving the techniques presently employed in the program is

another way to increase the selection frequency. This approach is

difficult at least. Research has revealed a low correlation for

stalk diameter and length, erectness in stalk growth, and the number

of stalks per stool between the plant crop and ratoons when single

stools were selected. A somewhat better correlation was obtained

for the percent Brix in cane juice; even then, however, the factor

obtained was relatively low, suggesting that selection for Brix in









single stools should not be practiced rigorously. It is, therefore,

recommended that a liberal number of varieties be selected in an

effort to retain as many as possible of the valuable ones.

Failure to improve significantly the techniques for selection

may result in an ever increasing selection ratio. Each variety

released for commercial sugar production will augment the plateau

to be reached or surpassed by future releases.

In general, the following stages are present in a variety selec-

tion program:

Stage 1: Germination. Fuzz (a name specifically used for sugarcane

seed), either from cold storage or fresh from a recently completed

crossing program, is planted in flats. The flats contain sterilized

soil and are placed in a greenhouse. Prior to planting, a germination

test for each crossing was performed to estimate the number of seed-

lings to be processed annually. The flats in the greenhouse are partly

covered with a glass plate to retain the moisture during germination.

Cane seedlings need an abundance of light for successful development.

Seedlings are clipped several times in the flats to enhance a sturdy

development of the small stem.

The seedlings are transferred to the field when about 6 inches

high. They are planted in hills. Each hill is one foot apart in

rows with 5 feet between rows. Each hill may contain one to several

seedlings. The latter is called "bunch planting."

Bunch planting has the advantage that up to 5 seedlings can be

accomodated per hill, thus considerably reducing the area and manual









maintenance needed for the seedling program. In theory bunch plant-

ing may be regarded as a natural selection method; only the vigorous

growing seedlings will survive. On the other hand, this method greatly

favors the selection for optimum vegetation characteristics. Proof

is lacking whether these characteristics are also related with sugar-

producing qualities (sucrose content in cane). Furthermore, the re-

searcher is able to select only one stalk with certainty from seed-

lings planted in bunches. Every additional stalk may be either an

additional stalk from the same selection or a different seedling.

Selections made from singly-planted seedlings are not subjected to

this restriction.

Seedlings are mostly selected as plant crop. Selections are

made by visual observation on the basis of vigorously growing stools.

This disadvantage is somewhat reduced by selecting about 10 percent

of the seedlings for vegetative multiplication and observation during

the next stage.

Stage 2: First line tests. Selections from the seedling stage are

planted in rows 5 feet long. Visual evaluations are made when cane

is about 12 months old, when a Brix test by hand refractometer is

made. Again as much as 10 percent of the first line tests are selected

to avoid placing a too great emphasis on the Brix test. Selections

often are made during the plant crop as well as in the first ratoon.

All selections are carried into the next stage.

Stage 3: Second line tests. Selections from the first line tests

are planted in a random pattern in 20 foot lengths, replicated several

times. Selections are made in the plant crop and first ratoon for










growth habits, ratooning ability, and susceptibility to prevailing

climatic conditions, as well as juice yields generally obtained by

a milling test. For the latter, 10 stalks are harvested at random

and juice yields generally determined after extraction in a small mill.

Also, the milling test will reveal whether a variety is early,

medium or late maturing. Selections from this stage, about 5% of the

total planted in the second line tests, are multiplied vegetatively to

obtain sufficient planting material for testing in replicated variety

trials.

Stage 4: Replicated variety trials. Material from selected varieties,

together with a standard commercial variety, are planted in a formal

experiment for comparison of cane tonnage, juice quality, and yield

in the plant crop, and in the first and second ratoons. Plot size

is at least 1/20 acre. At harvesting the cane from each plot is

weighed, and a sample of 20 stalks from each plot is milled for the

determination of juice quality and yield.

Each variety is tested similarly at about 10 locations over a

wide area to eliminate the effects of different soil types and micro-

climate.

Stage 5: Testing for disease susceptibility and commercial use.

During the years of replicated testing, investigations also are

initiated to screen promising varieties for disease resistance.

Varieties not susceptible to major diseases and which have shown

superior qualities are released for limited trials on a commercial










scale.

Testing for a minimum of 10 years is required before a seedling

can be released as a commercial variety. Hundreds of acres are needed

for this purpose. The program is very costly since many man-hours

are required in the tasks of planting, transplanting and maintenance

of seedlings, replanting cane cuttings, drawing cane samples, and

milling these samples.

Visual observations are the only criteria for selection during

the early stages when the numbers of cane varieties is enormous.

An accurate and simple technique to test for juice quality during

these stages is needed that would allow the elimination of a large

portion of material now selected and carried throughout the program.

Failure to develop such a technique together with the ever-rising

yield plateau for commercial varieties, ultimately will cause cane

variety improvement programs to become too expensive.

Finally, varieties selected for commercial production carry

numbers instead of names. Examples are C.P. 50-28, B. 41-223 and

H. 37-1933. By international agreement, the letters in front designate

the place of origine for the clone; C.P., B. and H. designate Canal

Point (Florida), Barbados and Hawaii, respectively. The first set of

numbers denotes the year in which the crossing was made, while the

second set of figures designates the selection number of clones

during that year.





SELECTED READINGS:


Stevenson, G.C. Genetics and Breeding of Sugar Cane. Longmans, England,
1965. I
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CHAPTER 11


Cultivation


The methods employed for cane cultivation reflect the soil type,

climatic conditions, and local customs that prevail in a sugar-

producing area. Since World War II land reform has caused a shift

in ownership from large estates to small holdings. Ownership of

only a small acreage is not conducive to effective field mechanization.

The formation of cooperatives as common owner for field equipment

is contributing to the solution of this problem.

Most cane in the tropics is produced on flat, low-laying

land in need of drainage. Closely spaced drainage ditches are essential

and should be connected by culverts to main canals. The slope of the

ditches must be at least 1% to obtain an adequate flow. The short

distances between adjacent ditches result in small-sized fields

(often 10 acres or less). The necessity for an adequate drainage

system and the resulting short cane rows is not conducive to effective

field mechanization.

The Louisiana bedding system was invented to avoid these difficulties.

Beds are shaped by removing soil from the sides and depositing this soil

on the crown of the bed. The result is a shallow excavated area on

the sides, gently sloping and easily crossed by mechanical equipment.

The cambered bed also is sloping toward the sides and hap a width to

accommodate four or five cane rows, each at 6 feet apart. Soil is re-









moved from the inter-row space into the cane row several times per

year to further facilitate drainage. The entire system provides effective

drainage, even in heavy clay soil, with a minimum of idle acreage

and restrictions to full mechanization and cane transportation. The

shallow furrow between rows also promotes the effective use of har-

vesting machines.

Areas where drainage may prove to be a problem are gradually

adopting a type of Louisiana bed field lay-out. This lay-out also

allows surface application of irrigation water. Methods of irrigation

other than surface application by gravity are seldom used as the profit

margin per ton of cane normally will not justify the relative high

cost of irrigation by these methods.

Cane growth in areas with a sparse rainfall, like Peru, depends

entirely on surface irrigation. The cambered bed system is of little

use in this area. Surface irrigation is applied via each shallow

furrow between the bedded cane rows. Also, cambered beds would be of

little use in areas like Florida where cane is grown on organic soils.

Drainage is still obtained through a system of ditches, spaced far

apart. Irrigation is supplied by virtual absorption of water through the

porous soil from a water table maintained at constant depth. Lateral

movement of drainage and irrigation water is improved by mechanical

made mole drains spaced 12-15 feet apart and 11-2 feet deep.

If water supply permits, some countries inundate the fields for

several months successive crop cycles. This flood fallow will kill

most of the dormant weed seeds and will reduce the population of nematode









and insects built up during the previous crop cycle. When the flood

water is drained, a heavy oxidation of certain elements follows

which is beneficial for optimum cane growth during the next cycle.

This practice usually is limited to low laying and flat areas

where removal of the flood water often requires pumping.

After planting, or harvesting of the previous crop in ratoons,

the soil must be kept clear of weeds. Experiments during the early

thirties have shown that poor weed control is a false economy re-

sulting in severe reduction in cane tonnage. Weed control can be

practiced mechanically or chemically; a combination of both methods

is recommended.

Mechanical weed control is accomplished by means of a rototiller,

scratcher or interrow disking. Rototilling is especially recommended

for the first opercaion in ratoons as the equipment will cause the

pulverizing of plant material left on the surface from the previous

crop. Scratchers, using a set of tines, is especially effective in

light soils such as the organic soils of the Everglades. The operation

of off-set disking is used to add soil to the cane row to check tillering.

All operations are meant to reduce moisture loss through the soil

surface and to effectively control the weed population. Shallow inter-

row cultivation is practiced to prevent injury to cane roots. For

this reason, adding soil to the cane row must be carried out in several

operations. In heavy soils, an inter-row cultivation with heavy tines

up to two feet in length often is used in the middle of the inter-row










when the cane is young; this process creates a soil mulch which allows

adequate soil aeration that encourages better root development.

Two principles are employed for chemical weed control. In pre-

emergence application, the soil is sprayed with a herbicide which

ideally prevents the emergence of all weeds. Concentrations applied

are such that the chemicals do little harm to the emerging of cane

cuttings. Obviously this treatment is applied to the bare soil

surface just after planting.

Cane fields are past emergence after the cane has germinated.

Normally, the weeds have germinated prior to the emergence of the

cane. Grass weeds are the most difficult to control as they belong

to the same family as sugarcane. The herbicides presently used for

weed control almost invariably will destroy germinated broadleaf weeds,

and either severely damage or kill the emerged grass weeds. At the

same time these chemicals may reduce the growth rate of the emerged

cane when absorbed by the plant.

Several principles, apart from the type of herbicide used, are

important for success in chemical weed control.

1. When preemergence treatments are used, the chemical film on

the soil should remain undisturbed. Breaking this film by mechanical

inter-row cultivation will instantly destroy the effectiveness of the

application. Chemical weed control should always follow and never

preceded mechanical interrow cultivation.









2. A continuous and uniform film can be obtained only with equip-

ment suitable to perform such a task. Ground speed for application,

pressure under which the application is carried out, nozzle pattern

and concentration of mix are often as important as the type of her-

bicide used. Uniform coverage of the soil by the herbicide is achieved

by spraying as large a volume as possible. Reducing the volume of

water in the mix to save on cost of application is often false economy.

3. Spray nozzles should be shielded when applying herbicides which

are known to reduce the growth rate of cane. The shielding mechanism

should effectively prevent wetting of the cane leaf surface to pre-

vent the chemical from being absorbed by the plant.

4. Apply the chemicals at a dosage and frequency for which they

are recommended.

Mechanical as well as chemical weed control has severe limitations.

The need for effective weed control is greatest during the period prior

to closing in of the crop while the rainy season exists. During this

period it is difficult for machinery to proceed through the field.

Even then, mechanical weed control has the advantage of visible and

instant results. Results from chemical weed control depend on the pre-

vailing climate conditions in the future, and are revealed only on a

delayed schedule. Because of this factor, the results from chemical

weed control are at least uncertain of nature.






SELECTED READINGS:
Barnes, A.C. Agriculture of the Sugarcane. Leonard Hill, Ltd., London,
1953.
Humbert, R.P. The Growing of Sugar Cane. Elsevier Rublishing Company,
1967.















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CHAPTER 12


Chemical Composition


Only one percent of the fresh weight of cane consists of elements

other than hydrogen, oxygen and carbon. The application of these

other elements, so essential for cane production, represents the cost

of fertilization.

Research efforts have been directed toward the need, concentration

and distribution of these elements throughout the plant.

The mineral content after ashing of the plant decreases as the

internode grows older. The lowest ash content is found in the bottom

part of the cane while the highest mineral content can bg found in

the top, the most active tissue of the plant. The latter finding is

of importance to the sampling method adapted for the modern diagnostic

techniques.

Research findings also suggest that translocation of elements takes

place from the older to the younger tissues. Indeed, most nitrogen

and potassium are withdrawn from the old leaves before they die.

Necrosis starts at the tip and edges of the leaf blade aid resembles

acute potassium deficiency symptoms. The potassium content of the top

part of the stalk is about twice as high as the content :in the bottom

part.

Apart from the differentiation in mineral content between top

and bottom parts of the cane plant, it is also evident that this con-









tent decreases for every plant part with age. This finding was of

great importance for development of diagnostic techniques to determine

optimum mineral levels for growth at different ages of the plant.

Silica is the most concentrated component in the mineral con-

tent of fresh cane, accounting for more than 50% of the total. And

yet, the element is rarely found in short supply and the plant

rarely responds to applications of silica. Some of this element is

expressed with the juice and enters the sugar processing where it

forms a deposit on the evaporator tubes. The major part, however,

remains in the bagasse and forms a persistent, glass-like deposit

in the furnace of the boilers.

Mineral content in expressed juice is associated with the elements

available for uptake by the plant. The major mineral constituent of

expressed juice is potassium. This element is highly water-soluble

and difficult to remove by the clarification process. Hence, it

passes through the processing and forms an integral part of final molasses.

The latter often contains 20% potassium on a dry basis and is used

in some countries as a potassium fertilizer. A high concentration of

potassium in the juice is undesirable since it enhances molasses

formation with a consequent reduction in the recovery of sugar.

Uptake of potassium interacts with the uptake of calcium and mag-

nesium by the cane plant. Potassium content in juice is low when cal-

cium and magnesium content are high. The reverse also is true. A

high calcium and magnesium content in juice is undesirable as these

elements become insoluble in concentrated sugar solutions and are

deposited together with silica as heavy encrustations on the inside

of the evaporator tubes.










Juice should not contain less than 300 ppm of P205, below which

point adequate clarification of juice becomes difficult. Often

phosphoric acid is added to the extracted juice, deficient in this

element. A better method would be to supply phosphorus to the growing

cane plants, providing that the applied phosphorus remains available

for uptake by the plant and results in an increase in tonnage.

Concentration of elements in juice and fresh cane varies only

slightly between varieties grown in the same area and under the same

climatic and soil conditions. The concentration of these elements

in the same variety grown in different areas, however, may differ

markedly. Therefore, the values reported for different areas may

not be compared. Also, the effect of season on juice composition

may greatly differ from year to year and between plant and ratoon

crops. It appears that climatic and soil conditions are more impor-

tant to juice composition than the varieties employed.

A large proportion of the macro-nutrients ultimately is returned

to the soil in the form of decomposed roots, leaves, and tops. The

millable stalk is removed for the production of sucrose, bagasse,

and finally molasses. On the average about 80 pounds of N, 20 pounds

of P205, and 120 pounds of K20 per acre are removed yearly with the

millable cane.

Finally, the chemical composition and the concentration of each

element within the plant is dependent on the extent of root development

and numerous external factors. Uptake of nutrients to the plant may be










investigated by the following technique.

One stalk of a stool is cut about two inches above the ground while

the other stalks of the same stool are left standing. A tight fitting

rubber hose is placed over the stump of the cut stalk. The osmotic

pressure exerted by the still active root system forces the liquid

through the vascular bundles of the stump and into the rubber hose.

An aliquot can be collected and analyzed for type and concentration

of elements. This method may determine the effectiveness of the

root system for uptake of elements and the influence of soil pH on

the availability of certain elements to the plant without actually

disturbing the root system.



SELECTED READINGS:


Malavolta, E, Andall. On the Mineral Nutrition of Some Tropical

Crops. International Potash Institute, Berne, 1962.










CHAPTER 13


Nitrogen


The cost for nitrogen is a major factor in the fertilizer budget.

Familiarization with the interaction between nitrogen and other ex-

ternal factors, therefore is in order.

Nitrogen assimilation occurs under influence of light. During the

process the nitrogen is transported from the root system to the leaves

and stalk where it becomes a major constituent of protein compounds

mainly present in the cell protoplasm. Nitrogen assimilation may

occur in the absence of light, providing that carbohydrates are avail-

able at the same time. Hence, light which is essential for carbohydrate

assimilation, is a secondary and indirect requirement for nitrogen

assimilation.

Research with the isotope 15N showed that nitrogen was assimilated

within five days after application. Within the plant, most nitrogen was

located in the spindle and green leaves near the top. Also, nitrogen

was found in the older internodes in the area of the root bands, al-

though in lesser quantities.

As suggested by high concentration of accumulated nitrogen in

meristematic tissues, a close relationship seems to exist between

nitrogen available for uptake and that for growth. The nitrogen content

of the leaf blade in these tissues was about twice as large as that of

the sheath. This discovery implies that the leaf blade is a more useful










tissue than the sheath for diagnostic purposes.

The highest concentration of assimilated nitrogen is present in

the fully developed blades of leaves 1, 2, 3, and 4 when counting the

non-emerged spindle leaf as number zero. Nitrogen also can be

accumulated in the node directly under the root primordia and bud,

but this nitrogen content diminishes rapidly with aging. The older

node, therefore is a temporary storage space for nitrogen which can

be quickly translocated to other plant parts when needed. The top

parts have priority with regards to available nitrogen and moisture,

and will draw these materials from the lower tissues when shortages

exist. By the same mechanism the nitrogen in the older leaves will be

translocated to the younger ones. Therefore, symptoms of mild deficiency

for nitrogen will initially reveal itself in the older leaves.

Under favorable conditions the nitrogen absorbed during the initial

growth period of 90 days is stored and will afford an additional

growth period of 70 days without needed uptake of the element. Storage

capability and readily available nitrogen, especially when applied

even in split applications, will afford an adequate supply of this element

during the entire growth period of cane. Split doses of nitrogen can

be applied with a minimum risk for losses by leaching until the crop

"closes in", and then carry the crop until maturity.

The effects of nitrogen on plant behavior:

The cane plant needs macro-elements in decreasing order of nitrogen,

potassium, and phosphorus. Increasing quantities of nitrogen applied









result in higher nitrogen uptake by the plant. The concentration of

nitrogen in the plant, however, varies only slightly; therefore, the

increased uptake of nitrogen results in additional growth and dry

weight of the plant. Hence, a close relationship normally exists

between the uptake of nitrogen and the recovered dry weight of the

plant (growth).

Increased nitrogen available to the plant also will cause greater

succulence. The sugar recoverable is more diluted from plants at

maturity which received nitrogen applications. Nitrogen application

beyond the optimum rate, therefore, exerts an adverse effect on juice

quality. Likewise, the percentage of reducing sugar and sucrose is

affected by applications of nitrogen. As more nitrogen is applied,

quantity of reducing sugars in Juice increases and sucrose concentration

decreases. A close prritive correlation is apparent, then, among

reducing sugars, moisture content of the plant, and amount of nitrogen

applied; a negative correlation exists between these components and

sucrose content in cane. Also, increased nitrogen results in decreased

fiber content in cane.

Nitrogen applications have a limited effect on stooling out of

cane. In the plant crop, the number of millable stalks sometimes in-

creases with nitrogen apo ications. This advantage, however, ceases

in the subsequent ratoon crops when mortality of shoots is much greater.

Hence, the number of primary, millable stalks per unit of surface area

is influenced very little by nitrogen applications.

Nitrogen applications markedly increase total green weight, es-

pecially the leaves. Increasing amounts of nitrogen result in a wider









leaf and faster leaf formation. Also, experiments with water cultures

have shown that leaves of plants lacking nitrogen contained only half

the amount of chlorophyll as compared to normally developed plants

and their photosynthetic use of radio-active carbon was reduced to one

fifth of controls.

Nitrogen increases internode length and stalk size. Likewise, a

negative relationship exists between rate of nitrogen application and

fiber content in cane. Both conditions promote cane lodging.

Adequate moisture for the plant is essential to the efficient

utilization of nitrogen, since this element promotes succulence. Up-

take of nitrogen and hence, optimum growth is restricted when the average

day and night temperatures fall below 670F. Light intensity and number

of light hours per day have little effect on the utilization of nitrogen.

Types of nitrogen and symptoms:

The cane plant shows little difference in response to the type

of nitrogen supplied, whether in nitrate or ammonia form. The latter

can be directly absorbed by the root system, more rapidly than the

nitrate form. Conversion of ammonia to nitrate in the soil is not

essential for use by the cane plant.

The choice for type of nitrogen fertilizers, therefore, largely

depends on price per unit of N and soil pH. Sugarcane is adapted best

to a slightly acid soil, but relatively high tonnages are also obtained

from clay soils with pH 4.0-4.5. Accordingly, a continuous supply of









accidifying components like sulphate of ammonia is not objectionable.

Urea and liquid ammonia are used most commonly because of economy in

price. Both materials are drilled between rows to prevent losses of

nitrogen by evaporation.

Urea also is used for foliar application when needed after the

crop has "closed in". Dry application of 20 pounds per acre does not

burn the leaves; most of the urea granules rest in the top part of

the leaf sheath from where it will be readily absorbed when humidified

by dew.

To replace the nitrogen which is removed by the crop pr lost

through leaching, a normal application of 45 pounds and 90 pounds of

N to the plant and ratoon crops, respectively, is needed. The exact

amount varies among areas and can be determined only by foliar diagnosis,

a topic to be covered later. Normally, a plant crop requires about

one-half as much nitrogen as a ratoon crop especially where flood

fallow is practiced prior to replanting. The exact cause for the re-

duced need of nitrogen in the plant crop is unknown.

Sugarcane grown on organic soils does not respond to applications

of nitrogen. These soils are continuously subjected to oxidation,

which releases large amounts of nitrogen that is readily available to

the plants. In fact, the amount of available nitrogen is so great

that cane rarely reaches full maturity. Sucrose content ip cane grown

on organic soils is normally low while the large amounts of nitrogen

stimulates the promotion of a higher than normal cane tonnpge.










Finally, sugarcane grown on mineral soils with inadequate nitrogen

shows short internodes with pale green colored leaves. This color may

change to nuances of yellow, depending on the severity of nitrogen

deficiency. Much of this same discoloration on the lower plant leaves

often may be associated with aging.

With adequate nitrogen, the sugarcane leaf becomes dark green.

The intensity of this green color increases with increased nitrogen

application. Very heavy dosages of nitrogen may result in a blueish-

green color of leaves.



SELECTED READING:


Malavolta, E. and All. On the Mineral Nutrition of Some Tropical Crops.

International Potash Institute, Berne, 1962.









CHAPTER 14


Phosphorus


As with most other nutrients, the highest concentration of phos-

phorus may be found in the meristem parts of the cane plant. In con-

trast to nitrogen, the phosphorus content of the internodes increases

with the age of the cane.

The phosphorus concentration in the leaf, especially the sheath

portion is high. This is important for diagnostic purposes and will

be dealt with later. The notable presence of phosphorus is not sur-

prising as this element forms an integral part of every living cell,

especially the ones active in carbon assimilation. Most of the phos-

phorus harvested in the form of millable stalks is recovered in the ex-

tracted juice. Phosphorus translocates from the older leaves before

they become physiologically inactive.

The necessity for placement of phosphorus fertilizer below the

cane plant was mentioned already. Surprisingly, the sugarcane plant

is able to absorb its phosphorus requirements from very low concentrations

of this element in the soil. Experiments have indicated that concentrations

of 0.05, 0.2, 0.5, and 1.0 mg of phosphoric acid per liter of nutrient

solution resulted in the uptake of 20, 50, 78, and 96% of the maximum

possible, respectively.

At the same time speed and ability to absorb phosphorus is sig-

nificantly influenced by soil pH. At 4.5 pH, the rate of absorption

for phosphorus per unit of time is high and is little influenced by









concentrations of the element in the soil. At 6.0 pH, this absorption

rate follows a close relationship with the phosphorus concentration

in the soil. At pH 7.0 and 7.5 the -'bsorption rate per time unit is

markedly less than in acid surroundings, regardless of the prevailing

phosphorus concentrations.

These findings have important consequences. Phosphorus will he

assimilated by the plant at extremely low concentrations present in

the soil. Therefore, severe phosphorus deficiency rarely occurs in

acid soil. Further applications of a slowly releasing phosphorus

material, such as the cheao ground rock-phosphate, may Furnish adequate

amounts to the plant throughout the growing season, providing that the

soil pH is low enough to facilitate the uptake of this element.

The cane plant must be aided for adequate uptake of phosphorus

when the soil pH is approaching neutrality or is alkaline. Either

higher rates of application are essential, or the use of a more readily

available form of phosphorus such as the granulated form of triple

super-phosphate, will be required. The cane plant growing in an alkaline

medium may be able to absorb an adequate quantity of phosphorus from

very low concentrations in the soil if the particles surrounding the

root could be temporarily acidified by an application of granulated

sulfur. Also, the granulated triple super-phosphate serves two purposes

when applied: it will locally acidify the soil particles in contact

with the granule, and at the same time release a high concentration

of phosphorus readily avail-ble to the cane plant.









To raise the concentration of phosphate in the soil, very lara

applications of phosphate fertilizers should be avoided. High ap-

plication rates of granulated triple super-phosphate have significantly

reduced the cane tonnage on organic soils in the Florida EverqlpdHes,

Similar application of rock phosphate or basic slag did not have the

same effect. Whether the reduction in cane tonnage is simply a result

of high concentrations of available phosphorus in nearly neutral and

alkaline soils, or is due to an interaction in uptake of high phbs-

phorus and other nutrients, especially nitrogen or potassium, is still

unknown.

The uptake of phosphorus is markedly influenced by the availability

of moisture to the cane plant. Although the phosphorus content in

leaves does not materially change during the entire growth period,

temporary fluctuations do exist. A significant and positive correlation

has been established between the amount of moisture available to the

plant and the phosphorus content on a dry basis. It follows that a

relatively low phosphorus content in the plant prevails during the

dry seasons. The accumulation of phosphorus in the stem during the

first three months is small and increases to a higher and more con-

stant level thereafter.

Cane growing in soil deficient in phosphorus shows a marked re-

duction in the rate of tillering. Phosphorus application to soils,

not necessarily deficient in this element, will promote even tillering.

The number of tillers thus formed may easily exceed the optimum, and

from the discussion in a previous chapter does not result in an ultimate









increase in harvested tonnage. Also phosphorus deficiency may result

in short internodes and small stem diameter. Applications to soil

deficient in phosphorus increase the millable cane available to be

harvested.

The maturity of grain crops is enhanced by applications of phos-

phorus to deficient soils. Some beneficial effects in expediting

maturity also have been noticed occasionally for sugarcane, but these

benefits do not occur consistently. In general, it can be stated

that phosphorus applications have little or no effect on the ripening

of sugarcane.

Visual symptoms, of phosphorus deficiency, such as poor tillering

with short internodes and small stalk diameter, were already mentioned.

In addition, the cane leaf tends to become a blueish-dark green in

color when severe phosphorus deficiency occurs. The same discoloration,

however, is also associated with high applications of nitrogen fertilizers.

In practice, whether or not the cane plant is deficient in phos-

phorus can be determined only by analysis. Even then, deficiency

is difficult to correct due to the important role of soil pH and the

nature of phosphorus uptake by the plant. The latter conditions are

the main reason why phosphorus often must be added to the extracted

juice for satisfactory juice clarification during processing.

Approximately one pound of P205 is removed annually with every ton

of cane processed.










SELECTED READING:

Malavolta, E. and All. On the Mineral Nutrition of Some Tropical Crops.

International Potash Institute, Berne, 1962.










CHAPTER 15


Potassium


Potassium is used in sugarcane in association with photosynthesis

and protein synthesis, starch formation, and translocation of sugars,

as well as in transpiration. Since protein and starch play an important

part in germination of the eye and photosynthates the final crop pro-

duct, potassium is constantly needed throughout the crop life and cycle.

Potassium is completely soluble in water, making this element highly

mobile within the plant.

The highest concentration of potassium is found in the elongating

and meristematic plant parts. Next highest concentration is present

in the young leaf system while the lowest potassium concentration is

present in the active, older leaves. The fully formed internodes con-

tain the least amount of this element. The translocation of potassium

takes place in the same order: From the mature internodes to the active

leaves and from these parts to the stalk top. In the final stage,

most potassium removed with the juice from the crushed stalk is a com-

ponent of the final molasses.

As with other macro-nutrients, the greatest accumulation of po-

tassium takes place during the six months after planting or ratoon re-

growth. This suggests that all potassium applications should be made

to the cane prior to "closing in". Like many other plants, sugarcane










will enjoy luxury consumption of potassium when this nutrient is applied

at excessively high rates. Cane shows little preference for either

the chloride or sulphate form of potassium; because of the cost dif-

ference, muriate of potash is most commonly used.

Growth of sugarcane becomes depressed about 2-5 months after po-

tassium deficiency occurs. Deficiency symptoms include decreased

tillering and stalks with a small diameter which quickly taper towards

the spindle. These symptoms are less pronounced but somewhat similar

to those already discussed for deficiency from nitrogen or phosphorus.

The most pronounced characteristic for potassium deficiency can

be found on the leaf of sugarcane. With a moderate potassium deficiency,

a yellow discoloration occurs in a narrow strip along both sides of

the leaf blade. This discoloration commences at the tip of the blade

and extends in the form of an inverted letter "V" towards the middle.

In a more severe case, the discolored tissue at the top and edges of

the leaf blade will die, resulting in a brown top and inverted V along

the edges of the blade followed by an area of yellow discolored tissue.

At this stage a red discoloration also will appear at the surface of

the entire midrib of the leaf blade. The latter discoloration, however,

should not be confused with similar symptoms caused by borers or red

rot disease.

In a more advanced stage, necrotic areas will continually increase

in size on the leaf blade. This spotting, however, is similar to the

injury caused by Helminthosporium sacchari. Likewise, necrotic tips,









edges, and spots on the leaf blade should not be confused with the

normal aging process of the leaf surface. Hence, a leaf analysis

always should be carried out to confirm a deficiency of potassium. An

application of either muriate or sulphate of potash will quickly correct

the deficiency.

A deficient supply of potassium to the cane plant not only re-

duces cane tonnage, but also enhances an excessive uptake of other

elements. Nitrogen, phosphorus, and in particular, iron content in

cane is significantly increased due to potassium deficiency (also

called Kalimati disease). Iron in this case is accumulated in the

nodes and its presence in excessively great concentration may be de-

termined by the "Hoffer" test. The stalk is cut length-wise and a

few drops of a strongly acidified solution of 20 percent potassium

rhodamide are placed on the nodes. A deep reddening caused by the

formation of F(CNS)3 takes place, an indication of potassium shortage

to cane. Conversely, heavy applications of potassium may result in a

luxury uptake of this element by the cane plant which may prevent an

adequate absorption of other elements. Magnesium or calcium deficiency

may follow heavy applications of potassium to clay soils having pH of

about 4.0.

An application of potassium to cane deficient in this element has

several effects. It will reduce the concentrations of other elements,

particularly nitrogen, to a more normal level. As a high concentration of

nitrogen in the plant will inhibit maturity, it follows that an adequate










supply of potassium also plays an important role in the formation and

translocation of hexose and sucrose. A positive correlation has been

found, therefore, between the potassium content and sugar content of

the cane plant. As with nitrogen, an application of potassium promotes

uptake of moisture and will increase the succulence of cane.

Potassium has a distinct effect on the anatomy of sugarcane.

An adequate supply of the element reduces lignification and promotes

thickening of the cuticle. Injury from eye spot disease is reduced

by applications of potassium mainly because of the thickening of the

cuticle. This also may be the reason why applications of potassium

are claimed to reduce injury by freeze in the sub-tropics.

Sugarcane deficient in potassium shows a poor development of the

hairroot system. An adequate supply of this element promotes development

of a normal root system through which the uptake of nutrients and

moisture can contribute to higher cane tonnage per unit of surface

and to the succulence of the stalk. The better developed root system

also may explain the positive interaction in uptake of other elements

and potassium, which was mentioned already in the chapter concerning

nitrogen.

In general, about 2.5 pounds of potassium in the form of K20 is

removed with .every ton of cane harvested. About 100 pounds of K20 is removed

annually when assuming a crop of 40 tons of millable stalks. This

quantity of potassium and a certain amount which is lost due to

the physical properties of the soil during the year, must be added.












SELECTED READING:


Malavolta, E. and All. On the Mineral Nutrition of Some Tropical Crops.

International Potash Institute, Berne, 1962.













CHAPTER 16


Other elements


In most countries, cane is fertilized annually with nitrogen,

phosphorus and potassium, singly or in combination, to replace the

nutrients depleted by the removal of the crop. Exceptions are some

developing countries as Bolivia, Haiti, and India where either the

educational standard and standard of living, or excessive transportation

cost prohibit the use of inorganic fertilizers. Fields produce a

very reduced tonnage; the sugar yield is corrected somewhat, however,

by a higher than normal sugar content in cane due to the absence of

nitrogen applications.

In contrast to the macro-nutrients, the micro-nutrients are not

normally supplied to cane with the exception of a few areas where ah

application of certain micro-nutrients has proven beneficial or eveh

essential to cane growth, such as in south Florida. The following

elements may be classified as essential for cane production:

Calcium: The highest concentration is found in the meristematic

tissue. In severe calcium deficiency, the young cane leaf becomes

somewhat chlorotic, while the older leaves become rusty in appearance.

In extreme deficiency even the leaf spindle may die. In practice, leaf

symptoms associated with calcium deficiency are rarely noticed. It

appears that the extensive root system of the cane plant is able to

absorb an adequate amount of calcium to satisfy its growth requirement











even on very acid tropical clays.

Calcium may be applied to cane for a dual purpose. First, to

supply the necessary amount as plant food and secondly, to change the

chemical and sometimes physical soil properties, especially in very

acid tropical clays, by increasing the pH level. The former purpose

takes only a moderate application rate of calcium, mostly banded.

Many tons of calcium per acre, applied as a broadcast and disked into

the top soil layer, however, are needed to raise the pH of the soil

only moderately.

Raising a low soil pH only slightly may release enough elements

such as phosphorus or iron which formerly were unavailable, for ab-

sorption by the cane plant. Experimentation in the tropics has often

shown the beneficial effects from heavy calcium applications. Funds

spent for these applications should be regarded as long term capital

investment for improving the soil resource. Unfortunately, capital

funds are scarce in most tropical areas and hence, cane must often be

produced in soils with 4.0 pH or even lower. Permanent improvement of

soil pH may have a significant influence on future sugar yield in such

areas.

About 20 pounds of calcium in the form of CaO is removed per 40

tons of cane crop harvested annually.

Magnesium: This element is one of the essential components in the

chlorophyll chain. Magnesium behaves similarly to calcium in its

effect on the cane plant. Even the deficiency symptoms, the rustlike











appearance on the leaves is identical. Results from plant analyses

will only indicate whether calcium or magnesium need to be supplied

for correction of the symptoms. About 30 pounds of magnesium in the

form of MgO is removed per 40 tons of cane crop harvested annually,

Iron: The element is also essential in the chlorophyll chain

and it is present throughout the cane plant with the greatest con-

centration located in the spindle portion. Iron is rather immobile

within the cane plant. In contrast to most other elements, iron in

the older plant parts is not readily translocated to the meristematic

part when shortage occurs. Symptoms due to iron deficiency will show

first on the leaves of the spindle and will later extend to the older

leaves.

When iron is deficient, the normal green color disappears between

the vascular bundles of the leaves. The deficiency is characterized

by a pale striping extending over the entire length of the leaf blade.

In severe and prolonged iron deficiency, these stripes may convert

into a uniform chlorotic leaf blade and ultimately into pure white

leaves. Sometimes a sudden unavailability of iron to the plant may occur

when the plant crop or ratoon is germinating. One or more shoots in the

same stool may appear as pure albinos while other shoots of the same

stool develop a normal, although a somewhat, pale green color.

Iron deficiency frequently occurs in heavy tropical clay soils and

lateritic soils having a low pH. Under this condition phosphorus com-

bines with iron into compounds which make the iron unavailable for ab-











sorption by the cane plant. Additional fertilizer applications with

iron will not correct this condition.

Iron deficiency is efficiently corrected by foliar applications.

About 10 pounds of iron sulphate or iron oxide per acre applied in

a large volume of water to secure an optimumcoverage will quickly

correct the deficiency within 48 hours; a small green island will

develop at the spot where the spray droplet struck the leaf blade.

This island will enlarge rapidly until the entire leaf blade has

returned to a healthy green color. This method of recovery once

more suggests the slow mobility of iron in the cane plant. The spray

application should be repeated every 4-6 weeks to insure an adequate

supply of iron to the cane plant as long as soil conditions remain

unfavorable for uptake of iron through the root system.

Manganese: Deficiency symptoms caused by a shortage of this

element are similar to the ones already described for iron deficiency.

One main difference, however, is apparent. Manganese is perfectly

mobile within the cane plant. Hence, deficiency symptoms will be-

come evident first on the older leaves as the manganese from that

section is translocated to the younger plant parts. To distinguish

between deficiency symptoms caused either by manganese or iron, one

has to observe the location at which the leaf discoloration occurs.

Confirmation, however, should be obtained from the results of foliar

analysis.

Manganese deficiency in sugarcane is always associated with a












soil pH of about 7.0 or higher. Manganese is relatively unavailable

to most plants.

A foliar spray with 10 pounds of manganese sulphate or oxide

may be applied to alleviate the influence of high soil pH. Sugarcane

responds equally well to both the sulphate and oxide forms; manganese

oxide is used most frequently for foliar sprays because of its low

price.

As an additional precaution, manganese fertilizer applied to the

soil frequently is premixed with 400 pounds of granulated sulphur to

counteract the adverse effect by high soil pH on the absorption of

manganese by cane. The sulphur granules will dissolve slowly and

acidify the surrounding soil particles, and thereby manganese remains

available to the plant.

Manganese deficiency frequently occurs in cane grown on organic

soils in the Florida Everglades region. Roads serving the cane fields

are topped with crushed lime rock. Run-off from these roads causes

a high soil pH and subsequently, cane bordering these roads frequently

show acute signs of manganese deficiency, despite an adequate soil

application of this element in conjunction with granulated sulphur.

The symptoms associated with manganese deficiency in cane are

sometimes confused with similar symptoms caused by a disease and known

in Hawaii as Pahala blight.

Copper: This micro-nutrient has gained special importance for











cane grown in the Florida Everglades region. An application of 25

pounds of brown copper oxide to the virgin, just drained, organic

soil is essential to avoid a total crop failure and normal develop-

ment of cane during the initial few months after planting.

Cane planted without an application of copper to the virgin

soil will germinate normally, but will soon stagnate in growth;

very short internodes and shoots with a small diameter will result.

The plant usually dies when about 3 months old and one foot in

height. The cane cutting itself likely contains enough copper

to sustain plant life during the initial weeks after planting.

The cane plant may still show a decreased rate of growth at about

5 months old, in spite of the copper application to the soil.

Inclusion of zinc together with copper in the fertilizer dosage,

however, has produced a normal cane crop at maturity.

A banded application of copper in the furrow of virgin organic

soil was not effective. An initial and one-time broadcast application

of 25 pounds of brown copper oxide or sulphate, properly mixed

with the first.foot of top soil by frequent diskings, provided

for the maximum absorption of copper by cane. After the initial

heavy broadcasted application, the copper fertility level in these

organic soils is maintained by the inclusion of 4 pounds of CuO in

the form of brown copper oxide in the fertilizer applied to each

plant or ratoon crop. It appears that feeder roots do not speci-

fically branch at areas in the soil having a heavy concentration of









copper. The uptake of copper by the cane plant can, therefore,

be compared with the reaction of cane to an application of phos-

phorus to the soil.

The copper application to the soil fails to increase the

concentration of this element within the plant tissues. Hence,

tissues of plants suffering from copper malnutrition show the same

concentration as tissues from normally developed cane plants.

The amount of copper removed by the crop, which is many times

greater for normally developed plants than for plants stunted

by lack of copper, is the only reliable criteria for judging

whether or not a soil is deficient in this nutrient.

Copper deficiency symptoms on the leaf blade consist of a

pale yellow leaf with small islands of perfectly healthy, dark

green colored tissue. mI an advanced stage these islands will

disappear, leaving the leaf blade chlorotic and similar in appear-

ance to the one caused by nitrogen deficiency.

The reverse process takes place when 5 pounds of copper sul-

phate per acre is applied to the foliage. First, small green islands

will appear on the chlorotic leaf blade where the droplet of the

copper solution adhered. Next, these islands will enlarge until

finally the whole leaf blade shows a healthy green color. All

leaves of the plant show copper deficiency at the same time, sug-

gesting that copper is relatively mobile within the cane plant.










Zing: Symptoms produced with the help of water cultures show

light yellow streaks between the veins of the leaf blade. In prac-

tice these symptoms do not appear when cane is produced commercially.

The most pronounced symptom caused by zinc deficiency' is a severe

reduction in cane tonnage at harvest. This reduction in stalk

elongation starts when the cane is about 5 months old in the plant

crop, Deficiency is easily prevented by the inclusion of about

4 pounds of zinc oxide or zinc sulphate per acre into the fer-

tilizer applied to the plant and ratoon crops.

Molybdenum; Sporadically molybdenum deficiency is mentioned

and then mainly associated with acid soils having a pH of well below

4. In these soils molybdenum deficiency often occurs in conjunction

with calcium or magnesium starvation. Heavy applications f ground

limestone to raise the soil pH will usually make enough molybdenum

available for normal cane growth.

Finally, aluminum, sodium, strontium, boron, and lead are.

known to be essential for cane production. Minute quantities of

these elements are present in the plant. The soil in cane pro-

ducing areas appears to contain an adequate reserve of these elements,

as little and only localized response in cane growth to soil applications

of these elements have been reported to date. The role of the large

concentrations of silica in the cane plant is still largely un-

known. Some response to fertilization in Hawaii was recently re-









ported. Conclusive evidence, however, is still lacking in general.


SELECTED READINGS:


Malavolta, E. and All. On the Mineral Nutrition of Some Tropical

Crops. International Potash Institute, Berne, 1962.










CHAPTER 17


Foliar diagnosis


Sugarcane, being a very competitive crop with only a small pro-

fit margin per unit produced, should produce optimum yields for

economic survival. Yield will have declined below profitability

long before deficiency symptoms become apparent. For this reason

certain fertilizer mixtures, mostly based on prior cropping ex-

perience, are applied to plant and ratoon crops. Foliar diagnosis

often is used to establish these levels of fertilization.

Sugarcane is a crop for which modern diagnostic techniques

are used to their fullest extent. An intensive processing plant

is needed, and fertilizers are comparatively expensive in the

tropics because of the long hauling cost..

The spindle of the cane, having the highest level of physio-

logical activity in the plant, is used for the collection of tissue.

Counting the spindle as number zero, the youngest leaf with a visible

dewlap is designated as number one. Blades and sheaths of leaf

numbers one through four are collected from 10 stalks each taken

at random throughout the cane field. Mostly one set of 10 stalks

is taken for every 10 acres of cane. To facilitate collecting the

tissue, the entire top of each cane stalk is harvested. By removing

the joints, one at a time from below, each successive sheath with









the attached blade can be carefully separated from the enveloped

internode. Each of the four sheaths and blades so collected from

each stalk is now separated at the dewlap.

The midrib of each blade is discarded.! Only a section of the

green tissue measuring between 10-12 inches in length serves as

the sample for future chemical analyses. The leaf sections are

dried at 800C to a constant weight prior to pulverization in a

Wiley mill. The leaf sheaths are used for other determinations

to be discussed in the next chapter.

Results from chemical analyses of sugarcane tissues differ

with different countries and soil types. Also, they may differ

slightly among varieties, and between plant and ratoon crops

within the same region. The following table reports average

acceptable analytical values in elemental form for sugarcane leaves :

Table 2. Percentage of different elements in sugarcane leaves to

obtain optimum yield at harvesting.


Element Index or percentage Remarks
of element in leaf
blade, dry basis


Nitrogen 2.5-2.6% of N when cane is 2 The critical period for
months old; maintaining the nitrogen
2.0% of N when cane is 3 index is between the
months old; second and sixth month of
1.75% of N when cane is 4 cane growth. Failure to
months old; maintain the levels of
1.65% of N when cane is 51 N will result in a severe
months old. reduction of cane tonnage
at harvest. The nitrogen
index is reduced with
inadequate or excessive
rainfall.









Index or percentage
of element in leaf
blade, dry basis


Phosphorus









Potassium








Calcium


o.2-0.22% of P.









1.20% of K.








0.17% of Ca.


Timing of application
is not as critical as
for nitrogen. The avail-
ability of phosphorus for
the remainder of the growing
period can be assumed
as adequate when the
reported index is reached
for 2 and 4 month old cane.

The critical periods
occur when cane is 3 and
6 months old. Leaf sam-
ples, therefore, should
be taken and analyzed
at least twice to correct
a possible deficiency
for this element.

An adequate fertiliza-
tion program with nitro-
gen will facilitate the
uptake of calcium and
reach the suggested index.


Magnesium

Micro-elements


0.10% of Mg.


ranging
ranging
ranging
ranging
ranging
ranging


between
between
between
between
between
between


210 and 250 ppm.
10 and 100 ppm.
5 and 15 ppm.
2 and 100 ppm.
10 and 110 ppm.
0.02 and 0.80 ppm.


The analytical results from leaf samples are used for numerous reasons,

ranging from applied research to improving commercial yields. For in-

stance:

---Fertilizer dosage and type of mixture to be routinely applied to




94


Remarks


Element









cane can be determined, based on correlations between soil analyses,

leaf analyses, and final sugar yields.


---Nutrient deficiencies, either by visual or suspected symptoms, may

be confirmed by foliar Inalyses.


---Interaction between the uptake of two or more elements by cane

can be studied or confirmed, and can be correlated with sugar yield.


--The influence of chemical and physical soil properties on nutrient

uptake and sugar yield may be studied and appropriate steps may be

taken to correct adverse influences.


---The role of soil pH, moisture, and frequency of application and

placement of fertilizers on the uptake of nutrient by the cane

plant and sugar yield may be studied.


As a next step, the results from leaf analyses may be used for cor-

relating the efficiency for uptake of nutrients with growth indices

and, in turn, correlate these growth indices with the final sugar

yield. Such a step-wise correlation will achieve the guidance towards

optimum growth and sugar yield by human effort through manipulations of

nutrient and moisture applications. This, then, is the principle

behind the "crop logging" system to be discussed in the next chapter.




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