For achieving higher yields under a set of soil conditions, soil-plant
relationships have to be understood from planting time itself upto harvesting
stage and corrections for any defects, excesses or deficit have to be
made immdiately.
Sugarcane is a management responsive crop and produces maximum biomass
by making best use of sunlight under a set of management practices.
Soils differ considerably in their fertility and productivity.
By adopting suitable soil, fertilizer and crop management practices,
it is possible to raise productivity levels of a given soil.
Usually, this is done by improving the physical and biological conditions
of the soil through proper drainage, aeration, aggregation of soil particles,
adding enough quantity of bulky organic matter and applying fertilizers
by proper placement in balance from based on soil test values.
The soil-plant relationship centres around changes in soil moisture
which in turn depends upon the irrigation practices adopted and the
soil type in which the crop is allowed to grow.
The nutrient supply position of the soil is influenced by the level
of organic matter in the soil, degree of microbial activity, changes
in soil pH and status of soil moisture.
It is emphasised that efforts should not be concentrated only on to
increase soil fertility but in building up soil productivity through
preventing the development of conditions like salinity, alkalinity,
compaction, infestation with weeds and deficiency of micro nutrients.
Soil requirement of Sugarcane
Sugarcane can be grown an all types of soils ranging from sandy loam
to clay loam.
It, however, thrives best on well drained soils.
It can also be raised successfully on lighter soils provided there
is adequate irrigation facilities and on heavy clays with proper drainage
and addition of organic matter.
Saline, alkaline and acidic soils are not at all suitable for sugarcane.
For cultivation of sugarcane, the soils should be viewed both by their
physical and chemical characteristics.
Physical characteristics
Physical characteristics of soil determines the water holding capacity
and draining capacity of soil, aeration, soil temperature, root growth,
availability of nutrients, microbial growth etc.
In light textured soils, the problem is poor water holding capacity
and this can be improved by the addition of organic matter as well as
soil amendments like tank silt.
Very frequent irrigations are required.
Sugarcane is not a suitable crop for light soils unless otherwise
irrigation sources are available.
Heavy soils, though having very high water holding capacity, the problem
is ill-drained conditions.
These soils can be beat utilized by providing proper drainage.
The soils best suited for any crop including sugarcane are medium
textured soils.
They are equally good in water holding and draining characteristics.
Management of Sugarcane soils having sub-surface hard pans
The soils having the sub-surface hard pan occurred in the clay loam
(Regur) soils in Nizam sagar Ayacut area at the depth of 22-40 cm.
The sub-surface hard pan may be developed due to formation of plough
sole on medium textured soils where sugarcane is taken in rotation with
puddled paddy; use of heavy machinery on moist soils, accumulation of
clay in B horizon under sub-humid conditions; presence of kankar layers
and shallow depth cultivation for longer periods.
The sub-surface hard pans are relatively impervious with the result
that water stagrates on the soil surface after heavy rainfall or irrigation
and the cane crop turns yellow due to oxygen stress.
The hard pans reduce infiltration rates, increase the run off, reduce
the water storage capacity of the soil.
The pans restrict root growth into deeper layers and increase the
lateral spread of roots. Shallow root system makes the plant drought
prone during dry spells and promotes lodging during unusually wet conditions.
Ultimately the hard pans restrict the water and nutrient supply and
there by reduce the yield and quality of sugarcane crop.
The problem of sub-surface hard pan formation in clay loams can be
solved by deep tillage and soil amendments.
The root penetration, juice quality and cane yield can be improved
by deep ploughing (sub-soiling ) to break the pan and reduce the bulk
density.
The beneficial effects of deep ploughing are expected to last atleast
for three years as the deep and strong root system of sugarcane does
not allow the compaction to develop.
The effect of the treatment began to diminish after third year and
the effect of loosening of soil showed least persistence in soil with
silt content, low clay content, low pH, inadequate drainage and higher
proportions of kaolinite.
The problem of formation of sub-soil hard pan can be tackled by tillage
or chiselling at 90 cm intervals upto 30 cm depth and by incorporation
of gypsum @50q/ha or FYM @250q/ha.
Management of Sugarcane soils having surface crust
The impact of high intensity rain drops breakdown the soil aggregates
over the soil surface.
The dispersed soil particles go into suspension, coarse particles
start to settle out but fine ones remain in suspension.
As the water drains or evaporates, clay settle on the top of coarse
particles, forming a crust on drying.
Formation of crust is a common feature in many soils particularly
in the red sandy loam soils (Alfisols) locally called "Chalka"
soils.
Surface crust are thin (2-3 mm) and are characterised by greater
bulk density, finer pores and lower saturated conductivity than the
underlying soils.
The thickness of the crust depends on the amount and type of clay
and silt present in the soil.
Presence of kaolinite clay tends to form a thin crust which curls
and breaks on drying but the montmorillonite type of clay tends to form
a thick and hard crust.
The thickness of the crust increases with the increase of clay content.
It is to be noted that surface soil layers consists of 60 to 70 per
cent coarse and 30-40 per cent fine fractions a proportionate optimum
for crust formation when organic carbon is less than one per cent.
The surface crust allows to reduce the rate of infiltration, increase
the run off, reduce the water storage capacity of the soil, increase
the bulk density, and slows the soil-atmosphere gas exchange.
The crust restricts root spread and nutrient uptake, interfere with
cane germination leading to poor initial crop stand thereby lower the
cane yields.
The problem of surface crusting in sandy loam soils of A.P can be
solved by frequent intercultivation, frequent light irrigations; mulching
with straw or sugarcane trash after planting of cane., application of
chemicals like phosphorus @80 to 200 kg/ha for 4 to 5 years and gypsum
@3t/ha., incorporation of regur soils or tank silt in chalka soils.,
incorporation of slow decomposed organic materials like paddy husk,
powdered groundnut shells and FYM in the soil and deep ploughing.
Some of the chalka soils in A.P. have some what shallow soils with
surface crusts.
As cane is a deep rooted crop, these soils need deep ploughing for
better root spread, water storage, juice quality and cane yields.
The deep ploughing should not, however, involve soil inversion which
is likely to bring the infertile sub-soil /morrum to the surface thereby
reducing the yield.
Salt concentration in Soils (pH)
Soil pH plays a major role in cane cultivation.
The salt concentra-tion of a soil is expressed in terms of electrical
conductivity (EC) and this should not exceed 4 m.mhos/cm.
Under such high concentration of soil salts the plant will not get
and cannot absorb sufficient soil moisture though there is sufficient
water available in soil.
In addition, if the sodium content is more in the soil the availability
of potassium and magnesium to plant is drastically reduced leads to
lower yields.
Sugarcane grown on alkali soils or irrigated with water having high
concentration of salts, will have juices with low sucrose and they give
trouble in processing for Jaggery making or sugar manufacture.
Internodal elongation and tillering were reduced in acid soil (pH=5.6).
In alkaline soils (pH=8.0) growth and tillering were poorer than in
the neutral soil but better than in the acid soil.
Young shoots do not develop normally in saline soils and leaves are
generally yellowish in tinge.
In extreme cases, the leaves become whitish with black patches of
dead tissue, canes are stunted in growth and thin.
The clumps can be easily pulled out with their mass of short dead
roots.
High salinity and compactness of soil leads to diseased roots as well
as chloritic and stunted shoot growth with poor quality cane.
In general, sugarcane crop requires a well prepared, well structured
and adequately aerated soil profile to a depth of atleast 40 to 60 cm
without compaction, hard pan, lime band or salt zone in the sub soil.
Ikisan - Suiatble Climate for Sugarcane cultivation
Climate
Sugarcane is a tropical plant. It grows more successfully in those
regions where the climate is more or less tropical but it can grow in
sub tropics too as in north India.
Influence of Climate on Sugarcane
Climate playing an important role in the productivity of any crop
particularly sugarcane, since the crop is on the field for almost one
year.
Because of its long standing on the field, the crop has to face the
changing climatic parameters of all the seasons in a year.
Hence, the climate is certainly influence the crop stand, growth,
yield, quality of juice and finally sugar recovery.
Sugarcane needs speicfic weather conditions during different growth
phases.
During active growth phase the weather conditions should be favourable
for vegetative growth, which during ripening phase weather should be
favourable for more sucrose accumulation.
An ideal climate for sugarcane should have two distinct weather conditions
viz., (1) a growing season which is long and warm with adequate rainfall
or irrigation, long hours of bright sun shine and higher relative humidity
which permits rapid growth to build up adequate yield (more tonnage),
(2) a ripening season of around 2-3 months duration having warm days,
clear skies, cool nights and relatively a dry weather without rainfall
and higher difference in day (maximum) and night (minimum) temperatures
for build up of sugar.
However, such ideal conditions are not found in all sugarcane growing
areas.
In order to get suitable climatic conditions during different physiological
phases of sugarcane as mentioned above, the planting will be done in
February, though the young and tender crio has to face higher temperatures
during the following summer months.
If there are summer showers the crop establishment is extremely good.
A crop which is put up the required growth and drymatter by May can
only best utilise the climatic conditions existing in June-July to September-October
and such crop will give higher cane yield coupled with higher sugar
recovery.
Weather parameter - cane growth and yield
Temperature
Optimum cane growth is achieved in temperatures between 24 and 300
C.
A temperature less than 50 C is harmful even to resistant
varieties.
Temperatures above 380 C reduce the rate of photosynthesis
and increase respiration.
At temperatures above 350 C cane appears wilted irrespective
of water supply.
During the active growth period, a minimum mean temperature of 200
C is required.
However, cane variety, irrigation and cultural practices can modify
the influence.
Fluctuations in temperature have profound influence on sucrose accumulation.
A mean day temperature of 12 to 140 C would be highly
desirable for proper ripening.
At higher temperatures reversion of sucrose into fructose and glucose
may occur besides enhancement in photorespiration thus leading to less
accumulation of sugars.
Rainfall
In India sugarcane is grown in areas ranging in rainfall of about
600 mm to 3000 mm.
The crop can survive normal variation around a mean of 1200 mm. for
obtaining higher yields, a rainfall of 2000 to 2500 mm per annum, evenly
distributed is considered ideal.
During the active growth period rainfall encourages rapid cane growth,
cane elongation and internode formation.
But during ripening period, it is not desirable as it leads to poor
juice quality, encourage vegetative growth, formation of water shoots
and increase in the tissue moisture.
It also hampers harvesting and transport operations.
Humidity
The relative humidity does not have much influence, if water supply
is not limiting.
Moderate values of 45 to 65 per cent coupled with limited water supply
is favourable during the ripening phase.
However, high humidities coupled with warm weather favour vegetative
growth.
About 7 to 9 hours of bright sunshine is highly useful both for active
growth and ripening.
Areas with short growing period benefit from closer spacing to intercept
higher amount of solar radiation and thus get higher yields.
But in areas with long growing season wider spacing is better to
avoid mutual shading and mortality of shoots.
Frost
In some parts of the N-W Indian the problem of extreme cold weather
conditions are confronted.
Severe cold weather inhibits bud sprouting in ratoons and arrests
cane growth.
At temperature -10 to 20 C the cane leaves and
meristem tissues are killed.
Wind
High velocity winds exceeding 60 km/hour are harmful to grown up canes
leading to lodging and cane breakage.
Also leaves get damaged even at early stage.
Winds enhance moisture loss from the plants and thus aggravates the
ill effects of moisture stress.
Sugarcane yields and sugar recovery in relation to climate in the
country.
The sugarcane productivity and juice quality are profoundly influenced
by weather parameters during the various growth phases of cane.
Data from three cane growing states (U.P, Maharashtra and Tamil Nadu)
indicates that Maharashtra records higher recoveries than the other
two states.
In Maharashtra the period from November to March (the main crushing
period) is dry with very less rainfall and low humidity and a lower
daily mean temperature, the nights are cooler and the sunshine hours
are greater.
The diurnal variations in temperature are also fairly wide.
These conditions favour higher sugar accumulation.
The latitudes between 150 and 200 north or south
where ideal climatic conditions are met with record higher sucrose levels
than the other latitudinal positions.
Maharashtra is situated in third position and thus achieves the highest
recovery in the country.
Both Tamil Nadu and U.P are not in the favourable latitudinal positions.
In Tamil Nadu, the mean temperatures throughout the year are more
favourable for vegetative growth and thus the yield are the highest
in the country.
The ripening phase has a higher mean temperature, the diurnal temperature
variations are narrow, the relative humidity is higher and the duration
of sunshine is less.
These factors are not favourable for higher sugar build up.
In U.P, weather extremes are observed, very cold winter period follows
very hot summer months.
The length of growing season is very much restricted to South-West
monsoon and autumn months (June-November).
The restricted growth phase results in lower yield levels. Very low
temperatures restricts sugar accumulation also.
This is why productivity levels are much less in sub-tropics. Therefore
thermo insensitive varieties, if could be developed, are highly useful.
Sugarcane yields and Sugar recovery in relation to Climate
in the State
Climatologically our state is located in the tropics between 12.60
and 19.80 N. latitude and 76.80 to 84.80
East longitude.
But even within this range, sugarcane is cultivated in areas differing
widely in rainfall, temperature and soils.
This mostly accounts for differences in sugar recovery and the yield
of cane per Ha. in different parts of the state.
Out of the 15 essential cane growing districts, 8 lie along the East
Coast with sugarcane being cultivated within distances ranging from
15-25 miles from the coast.
The coastal areas are exposed to strong winds, frequent cyclonic
storms and fairly high rainfall through both the S-W and N-E monsoons.
Being proximal to the sea, the region records high humidities.
The topography in these districts is mostly plain, rendering surface
drainage of excess rain water difficult.
Sugarcane is cultivated in 5 out of these 8 coastal districts is
mostly by flow irrigation while in other 3 districts, sugarcane receives
uncertain irrigations from seasonal flow in the rivers.
Heavy rains during S-W/N-E monsoon in the period July to November
coupled with copious flow irrigation from the river channels and the
practice of rotating paddy crop with sugarcane, expose the crop in these
coastal districts to ill-drained conditions over considerable areas
leading to low yield of cane and sugar recovery.
Twenty four out of 32 sugar factories in the state are located in
these districts and the sugar recovery tends to be low, ranging between
8.5 to 9.75 %, and occasionally exceeding 10%.
Lack of sharp winters and prevailing high humidities tend to keep
the crop growing without allowing it to store sufficient sugar.
In addition, the crop is subjected to cyclonic winds during October-December
cause lodging leads to low quality juice and poor sugar recovery.
Of the remaining seven cane growing districts, three (Nizamabad, Medak
and Karimnagar) are located in the north-western region of the state,
far remote from the coast.
Rainfall in these districts is mostly limited to S-W monsoon period
and from October onwards cool, dry weather prevails.
The soils in this area are better-drained. Though rainfall is high
the region is not exposed to strong winds or cyclonic storms.
Major area irrigated by flow irrigation and also by lift from open
wells and also filter points, but ground water resources are also not
adequate.
Because of early onset of dry cool weather there is cessation of growth
from early in October leading to better sugar accumulation.
Sugar recovery in this area is between 10.0 to 11.5 %.
The rest of the area under cane is concentrated in the South-Western
districts in the state (Chittoor, Anantapur, Cuddapah and Kurnool).
This area is also far remote from the coast and the climatic conditions
are almost intermediate between the other two regions.
Rainfall is sparce upto August-September and most rains received in
the N-E monsoon period and at times it extends upto Dec-Jan.
This enables continued growth but affects recovery.
There is no major river valley project to ensure irrigation to the
crop and they have to entirely depends upon rainfed tanks with uncertain
supplies or on the sparce ground-water supplies.
The crop gets inadequate irrigations in summer and is drought affected.
The sugar recovery is around 9.0 to 10.0 %.
In almost all the regions, summer irrigation to cane crop (May to
Mid June) is a problem as in canal fed areas also, canals are closed
for maintenance works.
In areas dependant on ground water, underground water supplies gets
depleted.
Based on climatic conditions prevailed and types of soils
and irrigation resources existing:
Coastal regions tend to keep the crop growing
(moretonnage) without allowing it to store sufficient sugar (less sucrose
per cent)
In Telangana region where cane is grown, there
is cessation of growth from early in October (less tonnage) leading
to better sugar accumulation (high sucrose per cent)
In Rayalaseema region the crop enables continued
growth (if sufficient irrigation is available) and also for sucrose
accumulation. But due to increased temperature from March onwards cause
reduction in sucrose content of cane.Cane yield and sugar recovery depends
on rainfall, humidity, temperatures and light. However, temperature
and duration of light controls several metabolic activities of sugarcane
as follows:
Bud germination
For maximum bud germination the optimum soil temperature should be
in between 34-380 C.
There is reduction in bud germination upto 190 C and absolutely
no germination is seen if the soil temperature touches 100
C.
In Telangana districts normally at the time of planting the soil temperatures
are low and hence, deep planting of sugarcane setts is necessary (atleast
5 cm soil layer should be there on the planted setts) for better germination.
Root development
Optimum soil temperature for better root growth and spread is about
300 C. If the temperature falls to 120 C and below,
there is drastic reduction in root growth.
Crop which exposed for more period of sun shine showed better root
spread over shaded plants.
Tillering
Intensity and duration of light affects tillering.
If the intensity reduced the tillering will be decreased.
Atmospheric temperature around 300 C encourages better
tillering.
Soil temperature below 150 C cause reduction in tillering
and the most optimum soil temperature for tillering is around 300
C.
Transpiration
There is gradual reduction in transpiration when the soil temperature
falls below 280 C. though there is sufficient moisture in the soil.
This means the plants cannot take the soil moisture in required quantities.
Hence, light and frequent irrigations should be given in December-January
to maintain optimum soil temperature and for higher transpiration rates
for the winter transplanted crops.
Transpiration rate is drastically reduced on cloudy days which in
turn reduced the uptake of nutrients.
Cane growth
Cane growth rate is higher from June to October because of intermittant
rains coupled with higher temperatures and less growth was observed
from November onwards due to reduced temperatures.
The rate of growth is higher during nights over day time.
If the air temperature is below 210 C the rate of growth
is minimum.
Plants which receives bright solar radiation for a longer period thick
canes with broader and dark green leaves.
Plants received less solar radiation produce lean, long canes with
narrow leaves and the stems contain more moisture.
Regions of more cloudy days recorded low cane yield, less sucrose
per cent in juice, poor quality juice, less recovery.
In addition, more period of cloudy conditions increase the nitrogen
and potash contents in juice.
Sugarcane plants cannot utilize the applied nitrogen and potash fully
when the intensity as well as duration of light reduced.
Application of nitrogen during cloudy period enhance the bad effect
on the plants.
Flowering
Duration of light determines the flowering in cane.
Quality of Juice
Cool and dry climate favours in increasing sucrose per cent in juice.
Higher sucrose content and quality of juice can be obtained when
the night temperature are low for 2-3 months before cutting.
Reduction in duration of light reduce the accumulation of sucrose
in cane.
Reduction in night temperatures over day temperatures helps in more
sucrose accumulation.
This means if there is wider differences between day (max) and night
(min) temperatures there is more sucrose accumulation in cane.
Utilization of solar radiation - cane yield
Yields of several crops including sugarcane depends on interception
and utilization of light. interception of light depends on leaf area
and leaf arrangement of the plant.
This means the interception and unilization of light depends on LAI,
Leaf area duration.
In sugarcane the maximum interception and utilization takes place
when the LAI approaches five and beyond five the increase is limited.
The interception and utilization is almost double in sugarcane when
compared with other crops like rice, wheat etc.
This is one of the reasons for high drymatter production in sugarcane.
Yield of any crop depends on efficiency of solar energy utilization
(Eu) and efficiency of conversion of absorbed energy (E). E values of
sugarcane and paddy are 2.41 and 2.55 respectively. This means Efficiency
of conversion of absorbed energy in sugarcane and paddy is almost same.
But efficiency of solar energy utilization (Eu) in sugarcane is 1.39
whereas for paddy is 0.825.
This means sugarcane utilized maximum solar radiation but not low
efficiently it utilized the intercepted energy.
However, there is need to develop the cane varieties having higher
values of both E and Eu.
Insects - diseases
Light and temperature helps in plant growth. similarly both the climatological
parameters influence the pest, disease outbreak and their spread as
well as their control.
Optimum soil temperature for initiation of smut on sugarcane is 250
C and for its spread 25-300 C air temperature is very optimum.
At tillering stage if the air temperatures are high, the spread of
smut is also high.
Similarly the spread of red rot disease is higher at higher temperatures
(37-400 C) when all other conditions are similar.
Rust incidence is high when the minimum temperatures are drastically
reduced.
Shoot-fly incidence is maximum in summer when the air temperatures
are very high.
Also higher shoot fly incidence was observed when the difference between
maximum (day) and minimum (night) temperature are low.
Ikisan - Management of Sugarcane in salt affected soils
Management of Sugarcane in salt affected soils
Sugarcane is under cultivation in about 7-8lakh hectares of salt affected
soils.
Since, sugarcane is some what tolerant to salinity and alkalinity.
Salt problem is experienced both in irrigated soils as well as in
semi arid areas.
Specific effects on sugarcane
Germination failures
Reduced germination, delayed germination.
Reduced crop growth
Poor tillering, leaf burning and curling, reduced internode
length, poor root growth and pithiness
Cane yield reduction even upto 50% or some times more.
Poor juice quality
Soluble salts accumulate in juice, reduce sugar content
and thus lower recovery, milling problems like scaling in the evaporators.
Ratoon failures
Due to poor sprouting and subsequent growth.
Integrated reclamation methods
Physical amelioration
Deep ploughing, subsoiling, applicatin of sand, profile
inversion, promotion of drainage.
Chemical amelioration
Adding suitable amendments to replace sodium with calcium,
and removes carbonates and bicarbonates with sulphate, common amendments
used are gypsum, basic slag, phosphogypsum, press mud and pyrites.
Biological amelioration
Use living or dead organisms, organic matter, green
manuring.
Adding agricultural water
Groundnut shells, safflower hull, coir pith waste, rice
husk etc.
Agronomic practices
Higher, seed rate to ensure adequate initial population,
trench planting, additional nutrition (25% extraN) and its proper method
of application.
Using of varieties suitable for salt affected soils
Soil and Climate
