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Sugarcane Under Moisture Stress Conditions
- Moisture stress varying degrees is experienced at one
stage or the other of the crop growth in almost all the sugarcane
growing regions of the country.
Important causes for moisture stress are:
1. Limited availability of irrigation water in lift irrigated
areas.
2. Canal closure during summer in many of the canal irrigated
tracts.
3. Droughts which occur in a cyclic manner.
- The extent of damage to sugarcane yield and quality depends
upon the crop stage and duration of stress.
- In most of the areas, the crop experiences moisture stress
during the formative phase of growth, affecting germination
and tillering, thus leading to reduced stalk population and
reduced initial stalk growth.
- In the early planted cane, moisture stress coincides with
the ground growth phase of the crop, thus affecting stalk
elongation and stalk growth.
- In the case of late planted crops, moisture stress affects
the formative phase as well as maturity and ripening phases.
- Thus initial crop stand gets affected and also there could
be disruption in the sugar synthesis and accumulation under
severe stress during the ripening phase.
- However, limited stress during ripening helps improve percent
sugar content in cane.
- In India moisture stress usually coincides with the hot weather
period.
- Therefore, the situation gets aggravated due to higher evaporative
demand and direct high temperature effect on the crop.
Moisture stress also aggravates certain pest and disease problem.
- Sugarcane can withstand certain degree of moisture stress
without any serious yield or quality loss as it has remarkable
ability to recover and put up normal growth arc released from
stress either through rainfall or irrigation.
- However, under severe stress the yield loss may go upto 60-70
per cent.
- Average yields of cane in moisture stress areas are less by
30-50 per cent as compared to canes growth with required irrigation.
- With suitable management practices substantial yield improvements
are possible.
- Some of the proven techniques to mitigate moisture stress
are given below.
Early planting:
- A grown up crop can withstand moisture stress better than
young crop.
- In the case of an early planted crop the formative phase largely
is not affected thus the initial plant population does not
suffer.
- In the tropical belt November-January planting would be better
than March-April planting to overcome the problem of moisture
stress
- In the subtropics too early spring planted crop can withstand
moisture stress better than a late or summer planted crop.
Seed rate and spacing:
- Higher seed rate with closer row spacing of 60 to 75 cm
facilitates to establish a higher stalk population to make
up growth loss of individual stalks.
Trash mulching:
- Spread of trash as a mulch reduces evaporation from soil
surface, moderates soil temperature, consumes soil moisture
aids in improving germination, better tiller survival and
growth and checks weed growth.
- The mulched trash may be incorporated into the soil while
earthing up both in plant and ratoon crops.
- Whenever, trash mulching is practiced, there could be termite
problem which could be easily overcome by the application
of gamma HCH 10% dust at 25 kg/ha.
- Mulching reduced the water requirement of crop and also adds
large quantities of organic matter to the soil.
Fertilizer management:
- Basal manuring of phosphorus followed by an early N and
K top dressing is desirable with an aim to develop a deeper
root system and adequate tillering before drought setts in.
Foliar application of fertilizers:
- Lack of moisture affects root growth as well as uptake
of nutrients. Under such situation foliar application is advantageous.
- Urea is the most common and useful fertilizer which can be
fed through foliage at 2.5% concentration(2.5 kg in 100 litres
of water)
- Along with urea, muriate of potash (kcl) at 2.5% concentration
spray helps in maintaining cell turgidity.
- Best spraying time is early hours in the morning and late
hours in the evening.
Soaking setts in lime water:
- Soaking setts in lime water (dissolving 80 kg kiln lime
in 400 litres of water) before planting not only enhance germination
but also gives ability to crop to withstand drought considerably.
Protective irrigation:
- Irrigating the crop in alternate furrows reduce the water
application by 50 per cent.
- Skipped irrigation combined with mulching alternate furrows
and irrigation only non-mulched alternate furrows.
Deep trench system of planting:
- In deltaic condition where early drought and late water
logging common, the deep trench system is highly advantageous.
Use of tolerant/resistant varieties:
- Usually high tillering varieties with fast initial growth
rates having ability to produce deep root system, relatively
thin stalked with narrow and erect leaves are able to tolerate
moisture stress.
- The leaves of such varieties can maintain a higher leaf water
potential.
- Some of the relatively moisture stress or drought tolerant
varieties are Co 8202, Co 86011, Co 85007, Co 85004, Co 7717,
CoC 90063, Co 8362, Co 87263, Co 8145, Coc 85061, Co 6806,
Coc 671.
Integrated moisture stress management practices:
1. Choosing appropriate variety
2. Soaking the setts in saturated lime water
3. Choosing appropriate planting method
4. Close row spacing while planting
5. Basal manure application
6. Pre-stress manuring and irrigation
7. Trash mulching
8. Protective irrigation if available
9. Appropriate post-stress crop management
10. Urea and potassium spray.
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Sugarcane Under Water Logged conditions
Losses of Water Logging in Sugarcane
- Excessive moisture in the soil is injurious to growth
- Prolonged flooding causes difficulty in recovery of sugar
as it increases invert sugar, total colloids, gums, pectins,
non-protein and ash
- Sugarcane grown in waterlogged areas shows poor results in
terms of yield per unit area and also percentage of sugar
recovery.
- Waterlogging at germination is the most damaging to the establishment
of the crop leading to total loss.
- If waterlogging occured at the tillering stage the loss is
relatively less but still severe.
- Grand growth phase the loss is relatively low.
- At maturity, the loss is more pronounced on quality of the
crop rather than yield.
- Waterlogging caused about 25 per cent reduction in yield and
23 per cent loss in per cane weight on the yield.
Effects of Water Logging in Sugarcane
- Flood-survived canes showed remarkable improvement in
brix. But there was a reduction in sucrose and an increase
in glucose.
- Waterlogged canes had high percentage of phosphate and low
content of nitrogen.
- The effect of waterlogging may also be aggravated by the predisposing
cultural environment like drought and lack of irrigation,
water-transmissible diseases like red-rot or in the post-waterlogging
phase by cyclones.
- The effect of waterlogging is to induce anaerobic conditions
in soil. This, in turn, adversely influences the function
of roots and also induces flowering and ageing.
Symptoms of Water Logging in Sugarcane
- The first visible effect of waterlogging on standing cane
is aerial rooting, specially on the lower nodes,
- Leaves tend to become yellow.
- There is rapid moisture loss in the cane
- Concomitant pithiness, increase in fibre, early reduced flowering
and increase in non-sugars.
- The deterioration actually starts faster after the water recedes.
- There is also nutrient loss specially of nitrogen from the
soil resulting in chlorosis having uniformly pale yellow colour
of leaves.
- On the other hand, the availability of iron and phosphate
increases as is common with all soils after submergence.
- Toxicity, due to production of sulphides, has seldom been
reported under field conditions.
- The general loss in the vitality of roots, besides adversely
affecting uptake of nutrients and water also reduces the anchorage
of the plants.
- The crop becomes vulnerable to lodging and uprooting with
strong winds in the subsequent phase after waterlogging.
- Some promising varieties which can survive waterlogging BO.11,
Co 453 and X 3861 at Pusa (Bihar).
Cultivation Practices for Crop Under Water Logged Condition
- The technologies which enhance early growth of cane in
a manner that it attains considerable height and vigour by
the time flooding occurs, would hold good here.
- Techniques which prevent lodging and lodging-resistant varieties
are also advocated for adoption in waterlogged conditions.
Cultural Practices
- Varieties : Co 1007, Co 1157, Co P1 and Co. P2 are the
varieties which can withstand waterlogging for quite some
time. B.O. 24 ,B.O. 91 is doing well in waterlogged areas
of north Bihar and eastern Uttar Pradesh.
- CoS 510 and CoS 416, the former was more suited for waterlogged
areas B.O. 91 and CoS 8118 were found superior than the rest.
- CoS 8118 is performing well in the flood affected areas.
- Under waterlogged conditions, although the yield is badly
affected even then CoS 837 is becoming popular
- Superior performance of SES 334 and SES 340, two Saccharum
spontaneoum clones under artificially created waterlogged
conditions. CB 4013, H 59-3775, H-49-3553 and PT. 4352 showed
good performance for yield, quality and utilisation of their
potential in breeding as parents to evolve varieties resistant
to waterlogging.
- Eight sugarcane varieties suitable for water logging conditions
viz B.O. 70, B.O. 89, B.O. 91, CoS 767, CoS 796, CoS 802,
CoS 837 and UP 1
- Cane maturity was delayed under waterlogging.
Planting Time
- Early planting is beneficial.
- Crop planted in first week of February gave higher yield than
the crop planted in March or April.
- Autumn planting is more beneficial than spring planting as
by the time flooding starts, autumn crop would have attained
sufficient vigour and height.
- It is suggested that sets should be planted deep and earthingup
should be done as the crop grows.
- Ring sysetm of planting where sets are placed deep in pits
and soil covering is done gradually as the crop grows, serves
both these purposes.
- Trench method proved superior than the other methods because
cane roots in trench system penetrated deep into the soil
which prevented lodging.
- Lodging was less under raised-beds and ridges than the flat-beds.
- Planting systems should be selected on the basis of nature
and extent of waterlogging.
- Seed Rate and Row Spacing Normally 38 to 40 thousand healthy
three-bud setts/ha are used for planting. This amounts to
5 to 6 t/ha seed rate.
- The row-to-row distances should be widened to 135 cm to make
drainage channels in between them at the time of waterlogging.
- Nitrogen application helps in tillering of sugarcane. Therefore,
for profuse tillering heavy application of Nitrogen is to
be applied.
- Heavy Nitrogen doses will not be of much help unless split
2 or 3 times. Split application helps in minimising nitrate
leaching, the chances of which are more under water-logging.
- It is believed that spray application of 5 per cent urea during
waterlogging increases the yield of cane.
- Soil application of nitrogen after waterlogging increased
sugarcane yield significantly.
- Application of potassium and phosphorus along with nitrogen
causes greater root proliferation and stiffness of cane. This
makes the cane disease and lodging resistant.
- All the operations which help in the early growth of sugarcane
should be performed.
- Control of weeds is very essential in formative phase of sugarcane.
- Hoeing should follow irrigation. Apart from weed control,
hoeing creates soil aeration which helps in better root growth.
- Earthing is an essential operation in waterlogged areas. It
should be done in first week of July. By earthing-up operations
the inter-row spaces are converted into drainage channels.
- Wrapping and popping helps the cane to withstand lodging.
It should be performed to minimise the losses in cane yield
due to lodging.
- Pest Management High humidity and poor drainage conditions
make the environment congenial for diseases and pest development.
Precautions should be taken to avoid the attack of diseases
and pests.
- Seed should be selected from a moist hot air treated nurseries.
Setts should be treated with chemicals
- Application of Carbofuran are essential to prevent the attack
of pyrilla and topborer.
- During waterlogging period in August-September, infestation
of white fly increases. To keep them under control, cultivation
of resistant varieties is suggested.
Harvesting
- The sucrose content in case increases suddenly after receding
of water and drops again a few days.
- It has also been observed that canes of waterlogged areas
start drying at a faster rate after receding of water in comparison
to normally grown canes.
- It is, therefore, revealed that sugarcane matures earlier
in waterlogged areas. So, cane should be harvested as early
as possible after water recession so that maximum amount of
sucrose is obtained.
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Water Management
- Number of irrigations required varies widely with varying
rainfall patterns.
- Only two irrigations are required in the extreme northern
districts while 22 to 25 are required in the southern districts
- Further it was also observed that 20 irrigations at an interval
of 12 days are required during the rainless period.
- When the average rainfall is 1000 mm ,the optimum soil moisture
regime 25 to 100 percent .
- The moisture levels during maturity period, caused no different
in yields or quality.
- Light and frequent irrigations gave higher yield per unit
of water than heavy irrigations at longer intervals.
- About 110 mm rainfall, 680 mm of water applied at 40mm each
time, was adequate to obtain good yields
- For restricted irrigation facilities, a most sensitive period
for water requirement in sugarcane was third order of Tillering.
- When water for only one irrigation is available, it should
be given at third order of tillering. With the availability
of two irrigations, second and third orders of tillering were
the most responsive stages.
- Irrigations given at 80% sheath moisture produces the highest
yield.
- Irrigations given when 0.7IW/CPE ratio was obtained or 50%
available soil moisture was achieved, produced significantly
higher yield .
- Plant character, therefore was judged as an efficient parameter
for scheduling irrigation in sugarcane. where as the choice
of parameters of scheduling irrigation depends on the facilities
available for such an use.
- Skip-furrow Method of Irrigation where in one row is skipped
and irrigation is given on alternate rows by which limited
water could be used for irrigating larger areas.
- Trash Mulching besides conserving soil moisture, it can prevent
or lessen soil erosion, ensure greater absorption of rainfall,
reduce temperature changes and accordingly modify biological
activities including changes in availability of nutrients
particularly nitrogen and phosphorus to plants.
- Trash mulching keep temperature levels and enhances the microbial
activities which ultimately result in mineralisation of nutrients
in the soil.
- Adjustment of planting dates represented one of the possibilities
for avoiding the high evapo-transpiration in pre-monsoon period.
- Generally, longer the crop duration, higher is the evapo-transpiration.
Delayed planting reduces the length of pre-monsoon desiccating
period, thereby cutting down the water requirement during
that period.
- To maintain 75 per cent ASM in February-planted crop, 8 irrigations
are required whereas April-planted crop needs only 5 irrigations
to attain the same moisture level.
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- When Jalashakti
was used to increase irrigation efficiency of sugarcane
in All India Coordinated Research Project it was revealed
that Jalshakti might increase cane yield at the same
level of water application
- Scheduling of irrigation needs to be scheduled either
at 80% sheath moisture or 60% ASM or 75 mm cumulative
pan evaporation.
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- Sugarcane requires to be irrigated at about 10-12 days
in summer and 20-25 days in winter.
- Longer period of anerobic conditions around root zone are
more harmful to a certain extent as compared to water stress.
Conventional flood system of irrigation has the following disadvantages
- Low irrigation efficiency ranging between 30-40%.
- Uneven distribution of water in fields due to uneven gradient
resulting in poor crop yields.
- Exposure of crop to cyclic changes of water and air stresses
disturbing physiological activities, ultimate result being
decreased yield and quality.
- Decrease in effective area of land by 10 to 15% which is used
for irrigation layouts.
- Gradual build up of water logging and salinity, making soils
unsuitable for agriculture.
- Loss of nutrients due to deep percolation and seepage resulting
in higher use of fertilizers and irrigation
- Difficulty in regulating the application of fertilizers leading
to low fertiliser use efficiency.
- Slow and gradual change in soil physical and chemical properties
due to top soil erosion at fields of higher elevations and
unwanted silting at low levels.
- Cyclic changes in wetting and drying of soil particles around
root zone leading to disturbance in root activity of the crop.
- Undesirable weed growth. To avoid all these problems, irrigation
systems are available which provide regulated water to the
crop.
Micro-irrigation system
Drip irrigation
- Higher water saving in sub-surface drip may be due to
higher application efficiency and less evaporation.
- Surface as well as subsurface drips with daily irrigation
techniques and paired (double row) planting of sugarcane are
more effective in saving water to the tune of 50-60%.
- Surface drip system with pressure compensating drippers also
appears more advantageous .
- The pipes are usually buried about 15 to 20 cm deep to prevent
rodent attack.
- The integrated drippers are highly resistant to mechanical
damage, and the special positioning prevents sediments from
settling in the dripper when the system is not in use.
- The system facilities use of fertilisers and selective plant
protection chemicals along with the irrigation water.
- Another advantage offered by this system over conventional
drip is that the lateral lines can travel longer distances
with only a minor variation in the quantity of water discharged
in the first and the last drippers.
- Once laid, the laterals serve well for one planted crop and
two or three ratoons for three to four years.
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