Transcript Module Module8: 8:Seeds Seedsand andSowing Sowing Virtual Academy for the Semi Arid Tropics Modules Lessons Lesson 3: Sowing of Sorghum After completing this lesson, you have learned to answer: 1.

Module
Module8:
8:Seeds
Seedsand
andSowing
Sowing
Virtual Academy for the Semi Arid Tropics
Modules
Lessons
Lesson 3: Sowing of Sorghum
After completing this lesson, you have learned
to answer:
1. Describe the practiced systems of sorghum
sowing?
2. Which system of sorghum sowing you
recommend and why?
3. What are the different methods followed in
sorghum sowing?
4. What are the implements used in sorghum
sowing?
5. What criteria should be followed in
determining the amount seed required for
sowing?
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Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of sorghum
After completing this lesson, you have learned
to answer:
6. What plant populations are recommended,
for sorghum cultivation?
7. What are the steps involved in estimating
the required seed to establish a given plant
stand?
8. How do you determine the spacing to be
followed in sorghum cultivation?
9. How do you determine the suitable
conditions for carrying out sorghum sowing
in your field?
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Three systems of sorghum sowing are followed:
• sowing on a flat surface,
• sowing on a ridge-and-furrow system,
• sowing on a broadbed-and-furrow system.
Sowing on flat surface
Ridge and furrow system
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
When seeds are sown using ridge and furrow
system, the seeds are either sown at the bottom
of the furrow or on the side or top of the ridge.
Planting on the side or top
of the ride is practiced in
heavy rainfall areas and
under irrigated conditions.
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Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
The broadbed-and-furrow (BBF) system has an
advantage over flat sowing in
• draining off excess water,
• providing more soil aeration for plant growth,
• greater in-situ moisture conservation.
• easier for weeding and mechanical harvesting.
Broad-bed and Furrow
BBF sown crop
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Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
The seeds are sown either by
•
sowing by broadcasting seed manually,
•
Sowing behind country plough using pora,
•
using an improved seed drill which may or may
not be fitted with hoppers for fertilizer
application,
•
Using mechanical seed drills attached to a
tractor.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Manual sowing by broadcasting the seed is
practiced when the area to be sown is
small.
After broadcasting, the seeds are covered
by running a brush harrow.
The germination my not be uniform in hand
sowing, and so one has to use a higher seed
rate to get the optimum plant stand in the
field.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
A country seed drill called
pora i.e. a wooden hopper
attached to a hollow bamboo
(Fig.) is used to sow the
seeds in the shallow furrows
opened by the tines of a
country plough.
A larger area can be covered
with this method of sowing.
Country seed drill
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
The best method is to sow the
hardened seeds of sorghum at
5 cm depth with seed cum
fertilizer drill to ensure
uniform depth of sowing and
fertilizer application before the
onset of monsoon as detailed
Seed cum fertilizer drill
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Seed rate
The amount of seed required per unit area
depends on:
• Optimum plant stand required per unit
area
• Plant type i.e. tall or short plants
• Weight of seed
• Quality of seed in terms of germination.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Seed rate
Seed rate should be determined based on the
optimum number of plants required in unit
area (acre or hectare or sq ft or sq m) for good
yields.
The optimum plant population for sorghum can
vary between 150,000 to 250,000 plants/ha.
If the plant population is on the higher side of
150,000 plants, the reduced panicle and seed
size is compensated by the higher number of
panicles per unit area.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Seed rate
The recommended plant stand for sorghum
under normal conditions is 180,000 plants per
ha or 15 plants per sq m or 72,000 plants per
ac.
Under irrigation or high levels of management
on highly productive soils, a population of
225,000 plants/ha (100,000 plants per ac) is
recommended.
On extremely sandy, droughty soils, a
population of about 90,000 plants/ha (40,000
plants per ac) is desirable.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Seed rate
For rabi crop, the optimum population should
be between 90,000 - 1,35,000/ha (36,00055,000/ac).
In case the soil moisture is low, it is advisable
that the population should be 92,000 per
hectare (36,000 per acre) and when the
moisture is optimum the plant population
should be 1,35,000/ ha (55,000/ac).
Under irrigated conditions for summer crop, the
optimum plant population should be 1,80,000
plants/ha.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Estimation of seed quantity per hectare:
Given: Sorghum seed with 75% germination, 100seed mass of 2 g, and the required plant population is
150,000 plants per ha.
Step 1
Since the germination percentage is 75, we need to
adjust for this deficiency.
Number of seeds needed to get 100 seedlings
100 x 100
------------ = 134 seeds
75
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Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Estimation of seed quantity per hectare:
Step 2
To get 100 seedlings, 134 seeds are required, then,
the number of seeds required for 150,000 plants:
150,000 x 134
----------------- = 201,000 seeds
100
Thus, 201,000 seeds are needed to establish 150,000
plants per ha.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Estimation of seed quantity per hectare:
Step 3
The quantity of seeds(seed rate) required for
201,000 seeds, based on 100 seeds weight of 3 g.
201,000 x 3 g
------------------ = 6030 g or 6 kg
100 seeds
Thus, 6 kg of seeds are needed per ha to establish
150,00 plants per ha.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Estimation of seed quantity per hectare:
If germination % of seeds is not known, then the
seed rate is determined by adding additional 20% of
seeds to cover any seed germination problems.
Example: Given: Sorghum 100-seed mass of 3 g, and
the required plant population is 150,000 plants per
ha.
Step 1
Based on 100 seed mass of 3 g
3 g X 150,000 plants
------------------------- = 4500 g or 4.5 kg
100 seeds
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Estimation of seed quantity per hectare:
If germination % of seeds is not known, then the
seed rate is determined by adding additional 20% of
seeds.
Step 2
Based on 20% more seed requirement for any
seed germination problem i.e 120% required
120 X 4.5 kg
--------------------- = 5.4 kg of seed
100
Thus, 5.4 kg of seeds are needed per ha to take care
of any seed problem and to establish 150,00 plants
per ha.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Seed rate
The seed rate varies from 6 to 15 kg/ha.
But the weight of seed planted is not a
good measure of population since seed
weight varies considerably i.e. 2 to 4 g per
100 seeds among various hybrids and
improved varieties.
Establishing optimum plant population in
unit area is more important than the seed
rate.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Sowing distance
The distance between row to row of
plants, and plant to plant within a row
can be varied depending on the method
of sowing.
However it should be remembered that
the sowing distance determines the
optimum plant stand requirement.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Sowing distance
In general, if ridges are formed 45 cm apart,
then the plants should be 15 cm apart
within a row.
If broad bed and furrow method is adopted,
then the plant rows will be 60 cm apart on
the bed and the distance between plants
should be 10 cm to get the optimum
population
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Sowing time
The sowing time of sorghum is important
aspect in increasing the crop yield.
This sowing time is also related with soil
moisture and soil temperature, as well as
incidence of shoot fly.
The rainy season crop (kharif) should be
sown immediately after commencement of
monsoon and after having adequate moisture
in the soil.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Sowing time
The sowing should be completed before 7th
July.
Early sowing helps in minimum incidence of
shoot fly and less damage to the crop.
Delayed sowing after first week of July
results in reduction of yield due to heavy
attack of shoot fly.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Sowing time
The seeds should be sown when there is
moisture in the soil up to a depth of 5 to
7.5 cm.
If irrigation facility is available, irrigating
the field for sowing just before the onset
of rainy season and thus advancing the
sowing substantially increases sorghum
yield.
Course on Insect Pests of Groundnut
Module 8: Seeds and Sowing
Virtual Academy for the Semi Arid Tropics
Lesson 3: Sowing of Sorghum
Sowing time
Rabi crop is sown between 25 September
and 15 October.
Late sowing beyond October may result
in poor germination and plant stand due
to low soil temperatures. Also, further
growth of sorghum plants will be slowed
down at low temperatures.
Course on Insect Pests of Groundnut
Module
Module8:
8:Seeds
Seedsand
andSowing
Sowing
Virtual Academy for the Semi Arid Tropics
With this, the Lesson 3 on Sorghum
Sowing Practices, and also this Module on
Seeds and Sowing of Sorghum concludes.
If you want to check your understanding
about seeds and sowing in sorghum,
please click “Exercise” button given
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