After completing one lesson in this Module, you have learned to:

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Module 12 Sweet Sorghum
Virtual Academy for the Semi Arid Tropics
Modules

• After completing one lesson in this Module, you
  have learned to
• Recognize the uses and importance of sweet
  sorghums as value added cultivation of sorghum.
• Understand good agricultural practices to grow
  sweet sorghum.

Course on Sorghum Production Practices
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Sweet sorghum is a type of sorghum. Sweet
sorghum provides grain but also the stem can be
used for sugar, alcohol, syrup, jaggery, fodder,
fuel, bedding, roofing, fencing, paper and
chewing. Sweet sorghums have also been widely
used for the production of forage and silage for
animal feed
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Sweet sorghum stalks are juicy and rich in
fermentable sugars, as high as 15-18 , and has
potential for stalk yield of 40 t/ha or more.
Sweet sorghum is also energy rich crop as it
produces up to 7,000 liters of ethanol per
hectare. The crop varied uses makes it highly
attractive for many developed and developing
countries.
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Cultivation of sweet sorghum
Climate and soil requirements Sweet sorghum is a
warm-season crop that matures earlier under high
temperatures and short days. It tolerates
drought and high-temperature stress better than
many crops, but it does not grow well, under low
temperatures. It can be grown on soils ranging
from heavy clay to light sand. Loam and sandy
loam soils generally allow the best syrup
production.
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Cultivation of sweet sorghum
Climate and soil requirements Sweet sorghum is
ideally shown during June, coinciding with the
south - west monsoon. Rainfall of 500 600 mm
distributed ideally across growing period is the
best, unless the soil can hold much water (deep).
The crop does not prefer high rainfall as high
soils moisture or continuous heavy rain after
flowering may hamper sugar increase.
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Cultivation of sweet sorghum
Climate and soil requirements If irrigation is
available, sowing can be done before June so that
the crop does not face heavy rains after
flowering and more so during the last half of
grain maturing period. Sowing during rabi or
summer season may result in low biomass and sugar
yield.
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Cultivation of sweet sorghum
All India Coordinated Sorghum Improvement Project
by the National Research Center for Sorghum at
Hyderabad has released SSV 84, a sweet stalk
variety. SSV 84 has average yielding ability of
40.4 t/ha green cane, 1.38 t grain, and 12-13
sucrose. It is able to produce 15 fermentables
at 50-60 recovery and can yield up to 2000 l/ha
ethanol.
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Sweet sorghum varieties

• SPV 422
• A high yielding variety for cultivation in
  post-rainy season
• Flowers in 90 to 95 days and matures in 25
  to 130 days, grows to a height of 2.6 to 3.0
  m
• Juicy stalks with 19 sugar
• Produces millable cane yield of 40 t/ ha
• It gives a grain yield of 3.0 to 3.2 t/ ha
  with pearly white bold grains
• Resistant to leaf diseases.

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Sweet sorghum varieties

• NTJ 2
• A high yielding variety for cultivation in
  post-rainy season
• Flowers in 68 to 75 days and matures in
  110 to 115 days and grows to a plant height
  of 2.0 to 2.5 m
• Flowers in 70 to 75 days and matures in
  105 to 110 days with a plant height of 2.0
  to 2.5 m in the post-rainy season
• Stems are thick and juicy with 18.5 sugar
  
• Produces millable cane yield of 50 t/ ha
• It gives a grain yield of 3.5 to 4.0 t/ha
  with creamy white bold grains
• Resistant to leaf diseases.

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Sweet sorghum varieties

• SPV 1411
• A high yielding variety for cultivation in
  post-rainy season
• Released as Parbhani Moti for post rainy
  season
• Flowers in 79 to 85 days and matures in
  120 to 129 days and grows to a plant height
  of 2.0 m
• Stems are juicy with 21 sugar
• Produces millable cane yield of 30 t/ ha
• It gives a grain yield of 3.0 to 4.0 t/ha
  with pearly white lustrous bold grains
• Tolerant to shoot fly, stem borer and leaf
  diseases.

SPV 1411
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Sweet sorghum varieties

• ICSR 93034
• A high yielding variety for cultivation in
  post-rainy season
• Flowers in 75 to 80 days and matures in
  110 to 115 days during post-rainy season
• Matures late in 120 to 125 days during
  rainy season
• Grows to a plant height of 2.0 to 2.8 m
• Stems are juicy with 18 sugar
• Produces millable cane yield of 43 t/ ha
• It gives a grain yield of 3.0 to 3.4 t/ha
  with lustrous and bold grains.

ICSR 93034
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Sweet sorghum varieties

• ICSV 93046
• Flowers in 75 to 80 days and matures in
  115 to 120 days during post-rainy season
• Matures late in 120 to 125 days during
  rainy season
• Grows to a plant height of 2.0 to 2.5 m
• Stems are juicy with 15 sugar
• Produces millable cane yield of 43 t/ ha
• It gives a grain yield of 3.2 to 3.5 t/ha
  with lustrous and bold grains.
• Stays green even after physiological
  maturity
• Tolerant to shoot fly, stem borer and leaf
  diseases.

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Sweet sorghum varieties

• ICSV 700
• Flowers in 80 to 85 days and matures in
  120 to 125 days during post-rainy season
• Matures late in 120 to 125 days during
  rainy season
• Grows to a plant height of 3.0 to 3.2 m
• Stems are juicy with 18 sugar
• Produces millable cane yield of 40 t/ ha
• Lustrous, creamy and small sized grains.
• Resistant to stem borer.

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Cultivation of sweet sorghum
Seed rate A good crop may have about 1,00,000 to
1,20,000 plants/ha. This can be achieved with 8
kg seed/ha. Sowing Sowing can be done on
ridges or in furrows at a spacing of 60 cm
between rows and 15 cm within rows. Three to four
seeds are dibbled in each hill/planting hole and
the seedlings are to be eventually thinned to one
per hill. If a planter is used, then the existing
seed rate will be reduced.
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Cultivation of sweet sorghum
Fertilizer application Like other crops, sweet
sorghum needs adequate nutrients to produce good
yields. Fertilization practices may also affect
syrup quality. Soil testing should be used to
determine the need for lime, phosphorus,
potassium, calcium, and magnesium.
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Cultivation of sweet sorghum
Fertilizer application Recommended dose of
fertilizer for sweet sorghum in soils with normal
fertility levels is 80kg of nitrogen, 60 kg of
phosphorous and 40 kg of potassium. Half of N
and whole of P and K are applied as basal.
Remaining N is top-dressed during 25-35 days
after germination, following weeding and
inter-cultivated.
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Cultivation of sweet sorghum
Fertilizer application Excessive nitrogen
reduces syrup quality. So, recommended amounts
of nitrogen should not be exceeded. When sweet
sorghum is grown immediately after a legume crop,
the nitrogen application rate can be reduced or
eliminated without harming yields
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Cultivation of sweet sorghum
Crop Protection Shoot fly and Stem borer are
major pests. Shoot fly infestation occurs soon
after germination and up to 30 days. Shoot fly
attack can be noticed by the dead hearts and
profuse tillering by the plant. Shoot fly can
be managed by the soil application of Carbofuran
3G at 8 to 10 kg/ha.
Observe dead hears and tillering of the plant due
to shoot fly attack.
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Cultivation of sweet sorghum
Crop Protection The first indication that a
sorghum plant is infested by the stem borer is
the appearance of small elongated holes in young
whorl leaves (Left Fig.).
Windows due to stem borer attack.
Subsequently larvae bore into the stem and
shot-holes appear (Right Fig.).
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Cultivation of sweet sorghum
Crop Protection Consequent to eating the central
stem portion, the growing point is killed and
dead heart symptoms appear in whorl leaves (Left
Fig.). A large number of predators attack this
pest. Chemical control is required only when the
infestation is very severe. 2 to 3 granules of
Carbofuran 3G are placed in the leaf whorls
immediately after observing the shot holes on the
leaves to prevent stem tunneling.
For more information on shoot fly and stem borer,
please review the course on sorghum Insect Pests
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Cultivation of sweet sorghum
Harvesting Most of the sweet sorghum varieties
mature between 115-125 days during rainy season.
The highest-quality syrup is produced when the
sorghum is harvested before the mature or ripe
seed stage. Sucrose percentage and syrup yields
generally increase as the stalk matures to the
ripe seed stage.
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Cultivation of sweet sorghum
Harvesting To obtain high-quality syrup and high
yields, the crop should be harvested when the
seed is in the soft dough stage. Stalks can be
harvested either along with the grain, or 4-5
weeks after the grain harvest. The ear-head and
peduncle (between the base of the seed head and
the top node) should be removed before processing
the stalks. Ear-heads may be dried and threshed
so the seeds can be used for the next year's
crop.
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Cultivation of sweet sorghum
Harvesting Excellent-quality syrup can be made
without removing (stripping) the leaves.
However, the stalks should not be crushed while
the leaves are still wet. Delay milling for 3 to
5 days. This delay will allow the leaves to dry
out, the stalks to lose some water, and natural
enzymes within the stalk to invert some of the
sucrose. These changes will make the syrup easier
to cook and less likely to crystallize.
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Cultivation of sweet sorghum
Harvesting A crop yielding 40 t fresh stalk/ha
and 60 extractability would yield about 3 t
jaggery and 3.5 t syrup. The same stalk in
fermentation may yield 2500 l of ethanol. The
stalk residue left over after processing is about
12-15 t/ha, which may be used either as fuel or
feed.
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Module 12 Sweet Sorghum
Virtual Academy for the Semi Arid Tropics
Modules
Exercise
End

With this, Module 12 on Sweet Sorghum, and
also this course on Sorghum Production Practices
concludes. If you would like to check your
understanding about harvesting sorghum, please
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Course on Sorghum Production Practices