Introduction
Crop planting operation is the art of placing seed in the soil to obtain good germination and crop stands.
A perfect sowing gives
Correct amount of seed per unit area.
Correct depth of sowing
Correct spacing between row-to-row and plant to plant.
Correct seed rate
Unit 4_Part 1 CSE2001 Exception Handling and Function Template and Class Temp...
Agricultural machinery chapter 3 sowing machine
1. BAHIR DAR UNIVERSITY
BAHIR DAR INSTITUTE OF TECHNOLOGY (BiT)
FACULTY OF MECHANICAL AND INDUSTRIAL
ENGINEERING
Course Title: Agricultural Machinery Technology(AEng5161)Course Title: Agricultural Machinery Technology(AEng5161)
CHAPTER THREE
Sowing Machine
By
Solomon Tekeste
(Lecturer)
7/11/2018 1
2. Sowing Machines
Introduction
• Crop planting operation is the art of placing seed in the
soil to obtain good germination and crop stands.
• A perfect sowing gives• A perfect sowing gives
1. Correct amount of seed per unit area.
2. Correct depth of sowing
3. Correct spacing between row-to-row and plant to plant.
4. Correct seed rate
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3. Seed Rate & Spacing
• The primary objective of any planting operation is to
establish an optimum plant population and plant
spacing, the ultimate goal being to obtain the
maximum net return per unit area.
• Population and spacing requirements are influenced
by:
– Type of crop
– Type of soil
– Fertility level of the soil
– Amount of moisture available
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4. Methods of Planting
• Broadcasting: random scattering of seeds over the
surface of the field.
• Drilling : Drilling consists of dropping the seeds in
furrow lines in a continuous stream and covering them
with soil. The spacing between the seeds is not
uniform.uniform.
• Hill dropping: placing groups of seeds at about equal
intervals in rows.
• Precision planting: accurate placing of single seeds at
about equal intervals in rows.
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5. Methods of Planting in Ethiopia
• Most Ethiopian farmers normally spread seeds
manually or by hand or by broadcasting.
• But, in manual seeding, it is not possible to achieve
uniformity in distribution of seeds. A farmer may sowuniformity in distribution of seeds. A farmer may sow
at desired seed rate but inter-row and intra-row
distribution of seeds is likely to be uneven resulting
in bunching and gaps in field. In addition there will be
a poor control over depth of seed placement, these
results in poor emergence of the crop. This again
leads to low productivity.
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6. Planting Systems
• Planting may be done on the flat surfaces of the
field, in furrows or on beds.
Furrow Planting (or Lister Planting)
• This planting method is widely practiced under semi-
arid conditions for row crops such as corn, cotton and
grains because this system places the seed down in to
the moist soil and protects young plants from windthe moist soil and protects young plants from wind
and blowing soil.
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8. Planting Systems
Flat planting
• This type of planting generally predominates where
natural moisture conditions are favourable
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9. Functions of Seed Planter
• With the exception of broadcasters, a seed planter is
required to perform all the following mechanical functions.
1. To carry the seed
2. Open the seed furrow to the required /or proper /
depth
3. Meter the seed3. Meter the seed
4. Deposit the seed in the furrow in acceptable pattern
5. Cover the seed and compact the soil around the seed
to the proper degree for the type of the crop
involved
• When accomplishing these functions, the planter should
not damage the seed enough to appreciably affect
germination.
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10. SEED CUM FERTILIZER DRILL
• Seed drills fitted with fertilizer dropping attachments are
called seed-cum-fertilizer drills.
• They deliver both the seeds and fertilizers simultaneously
in an acceptable pattern.
• Suitable for small grain soybeans, oats, wheat, barley, teff
Manual Seed Cum Fertilizer Drils
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11. SEED CUM FERTILIZER DRILL
Animal Drawn Seed Cum Fertilizer Drils
Tractor Drawn Seed Cum Fertilizer Drils
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12. Components of seed cum fertilizer drill
• The seed cum fertilizer drill machine consists of
– seed box
– fertilizer box
– seed metering mechanism
– fertilizer metering mechanism– fertilizer metering mechanism
– seed tubes
– furrow openers
– Seed covering device
– seed rate adjusting lever and
– transport cum power transmitting wheel
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13. Seed Metering Device
• The mechanism which picks up seeds from the seed box and
delivers them in to the seed tube is called seed metering
mechanism.
• Both mechanical and air systems are used to meter seed.
Mechanical metering
• The seed enters cells in the edge of a flat, circular plate that
rotates in the bottom of the seed box. The plate then carries
the seed to the knockout tube where it falls down to thethe seed to the knockout tube where it falls down to the
furrow opener.
Air system
• Use the flow for air through a carefully sized hole in a moving
seed plate to trap and hold a single seed until it is released to
the seed tube. As the plate turns counterclockwise, the seed is
picked up from the supply pool, is transferred to where the
vacuum is cut off, and dropped into the seed tube.
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14. Types of Seed Metering Mechanism
• Seed metering mechanism may be of several types:
– Fluted feed type
– Internal double run type
– Cup feed type
– Cell feed type– Cell feed type
– Brush feed type
– Auger feed type
– Picker wheel type and
– Star wheel type.
• Usually seed metering mechanism is provided at the
bottom of the box.
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15. Seed Metering Mechanism
Bulk Flow Metering Devices
• Bulk flow metering devices deliver more or less a
continuous flow of seeds. The most common type of
bulk flow metering device is the fluted wheel type.
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16. Seed Metering Mechanism
Fluted Roller
• These types of metering
devices are used to a limited
extent on row crop planters
but their main application is
on grain and grass drills.
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18. Precision Planters
• Characteristics of a precision planters
– Individual row units
– More precise metering system (in most cases, each
seed is individually metered)
– Row spacings from 380mm to 1000mm– Row spacings from 380mm to 1000mm
– Usually have markers to help keep row spacing
consistent
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19. Functional Processes
Meter
Store/Convey
Seed
(hopper)
1. Open a furrow
2. Meter the seed
3. Place the seed
4. Cover the seed
5. Firm the seedbed
Row Crop Planting
Meter
Seed
Open
Furrow Cover
Seed
Firm
Seedbed
5. Firm the seedbed
Seed Transport/
Placement
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20. Seed Metering Mechanism
Devices for Metering Single Seeds
• Row planters are distinguished from grain drills in
that they deposit seed in rows spaced to permit
inter-row cultivation and they usually have single seed
metering.
• Devices for metering single seeds usually have cells
on a moving member (plate or rotor) or anon a moving member (plate or rotor) or an
arrangement to pick up single seeds and lift them out
of a seed mass.
• Plates/rotors may be horizontal or vertical.
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24. Furrow Openers
• The optimum depth of planting varies widely with
different crops and influenced by soil moisture conditions,
soil temperature, time of the year, etc. some seeds are
rather sensitive to environmental conditions and require
careful control of planting depth, whereas others can
tolerate a considerable range of conditions.
• Furrow openers can be either fixed or rotary type.• Furrow openers can be either fixed or rotary type.
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25. Furrow Openers
Rotary Type
• They are disk type
openers. They are
suitable for trashy or
relatively hard ground.
• Single disk permits
good soil penetration
Fixed type :
• They are hoe type and
used when good
penetration and release
trip are needed
• When they are quipped
with springs, they are
suitable for stony or root
• Single disk permits
good soil penetration
and excellent trash
clearance. Double disk
gives more uniform
placement of seeds in
the soil that is well
worked and trash free.
with springs, they are
suitable for stony or root
infected soils. They are
also used for deep
placement of seeds if
the soil is relatively free
of trash.
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27. Seed Tubes
• Seed tubes receive the seeds from the metering
devices and supply to the furrow. Rubber or plastic
seed tubes are in common use. They will bend easily
when the furrow openers are lifted and are not
corroded by fertilizers. Spirally wound metal seed
tubes are flexible but they will rust and are easily
damaged.
Covering DevicesCovering Devices
• Covering devices are used to cover the seed after it
is placed in the furrow. Thus, they are used for the
last stage of the planting operation. A covering device
should place a moist soil to have firm contact around
the seeds, cover them to the proper depth and yet
leave the soil directly above the row loose enough to
minimize compaction or crusting and promote easy
emergence. A firm soil is needed to ensure moisture
transfer to the seed.7/11/2018 27
28. Covering Devices
1. Drags
• Link or drag chains, drag bars, scraper blades are
used to cover the seed and level the soil. This casual
coverage furnished by dragging a large ring chain,
bars or scraper blades over the seed row is
acceptable if the moisture supply is adequate.
2. Press Wheels2. Press Wheels
• Steel or rubber wheels come in many shapes and size
to meet specific seedbed needs. Rubber covered
presswheels are good to flex-off soil buildup. A small
diameter, narrow wheel may be used to press the
seed to the bottom of the furrow before soil
coverage.
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30. Basic Methods of Planting
• Broadcast Seeder
– Seed is usually thrown on top of
the ground
– Generally used on smaller seeds,
fertilizer, pesticides, or other
small granular material
– Seeding rate is controlled by a
variable orifice at bottom ofvariable orifice at bottom of
hopper
– Spinning disk at bottom
accelerates material horizontally
away from machine
– Coverage width depends on many
variables including size, shape,
and density of seeds
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31. Basic Methods of Planting
Hopper
Orifice
Spinner, Beater, Spinning Disk
Beater Drive Motor, usually
electric or hydraulic7/11/2018 31
33. Procedure for Design of Sowing Machines
1. Define the functional requirements of the seed
drill/planter
2. Depending on the available the available power,
determine the size of seed cum fertilizer drill.
3. Design the seed and fertilizer box.
4. Take tentative assumption for the diameter of
ground wheel and transmission ratio. (The groundground wheel and transmission ratio. (The ground
wheel can also be designed by considering obstacle
size, to be safe larger ground wheel diameter is
better, > 600mm).
5. Design the metering mechanism.
6. Design the power transmission system
7. Design the attachment to the power unit ( handle,
hitching system)
8. Design the furrow openers
34. Design of Metering Mechanism
1. Define the functional requirements of the seed drill/planter
• Select type of seed and for the selected seed collect the
following information.
– Seed rate, Rs
– Fertilizer rate, Rf
– Row spacing, S
– Spacing between seed, X– Spacing between seed, X
– Bulk density of the seed & fertilizer, ρb
– Density of seed & fertilizer, ρ
– Angle of repose of the seed, α
• Source of power
– Available power for planting, P
– Speed of operation, V
• Other operating condition, such as field condition (Clog size….)
35. Design of Metering Mechanism
2. Take tentative assumption for the diameter of ground
wheel and transmission ratio. (The ground wheel can also
be designed by considering obstacle size; to be safe
larger ground wheel diameter is better, > 600mm).
• Diameter, D
• Transmission ratio, i• Transmission ratio, i
36. Design of Metering Mechanism
3. Design the metering mechanism.
A. Determine the flow rate of seeds from the metering unit
• where
– Rs = seeding rate, kg/ha or seeds/ha
– Q = flow rate of seeds from the metering unit, L/s
– ρb = seed bulk density, kg/L or number of seeds/L
– S = spacing between rows, m
– V = travel speed of planter, m/s
Knowing the flow rate is very important to determine the seed
hopper volume
37. Design of Metering Mechanism
3. Design the metering mechanism.
B. Determine number of revolution of the ground wheel per
minute.
• Where
• N= number of revolution of the ground wheel per minute
• D=diameter of the ground wheel
38. 3. Design the metering mechanism.
C. Determine the number of cells in a drum
• Where
• n = number of cells in a drum
• X = spacing between seeds
• i = transmission ratio,
39. 3. Design the metering mechanism.
D. Determine the cell volume
• where
• Q = volumetric flow rate, L/s
• Vc = cell volume = volume of each cell, mm3
• n = number of cells on periphery of fluted wheel or internal run
• Nd = rotational speed of fluted wheel or internal run, rev/min
40. 3. Design the metering mechanism.
E. Determine the diameter of seed roller
• dr = diameter of seed roller, cm
• Vr =Peripheral velocity of roller, this can be assumed or can
be taken from standard book not to cause seed breakage,
(for cereals like wheat, Vr can be 0.2 m/sec for minimum
seed breakage)
41. 3. Design the metering mechanism.
F. Determine the width of roller and shaft diameter
depending on the conventional design process.
G. Repeat the same procedure for fertilizer too.G. Repeat the same procedure for fertilizer too.
42. Calibration of seed drill
• The procedure of testing the seed drill for correct seed
rate is called calibration of seed drill.
• It is necessary to calibrate the seed drill before starting
the actual operation so as to adjust to the desired seed
rate.
• In doing so, the following steps of calibration will be
employed.employed.
Calibration Procedure:
1. Determine the nominal width (W) of seed drill
Where,
• M = Number of rows
• S = Spacing between rows, m
43. Calibration of seed drill
2. Find the length of the strip (L) having nominal width
(W) necessary to cover 1/25 ha (1/25 x10000) = 400m2
3. Determine the number of revolutions (N) of the3. Determine the number of revolutions (N) of the
ground wheel of the seed drill required to cover the
length of the strip (L)
44. Calibration of seed drill
4. Raise the seed drill keep in a platform prepared for
test purpose so that the ground wheels turn
freely. Make a mark on the drive wheel and a
corresponding mark at a convenient place on the
body of the drill to help in counting the revolutions
of the ground wheel.
5. Fill the selected seed in the seed hopper. Place a5. Fill the selected seed in the seed hopper. Place a
container under each boot for collecting the seeds
dropped from the hopper.
6. Set the seed rate control adjustment for maximum
position and mark this position on the control for
reference.
7. Engage the clutch and rotate the ground wheel for
N = 400/ x D x W, revolutions.
45. Calibration of seed drill
8. Weigh the quantity of seed collected in the container
and record the observation.
9. Calculate the seed rate in kg/ha
10. If the calculated seed rate is higher or lower than
the desired rate of selected crop, repeat the process
by adjusting the seed rate control adjustment till the
desired seed rate is obtained.
46. Reference
1. Ajit K. Srivastava et. al. 2012. Engineering Principles
of Agricultural Machines. Second Edition. American
Society of Agricultural and Biological Engineers.
2. D. N. Sharma and S. Mukesh. 2010. Farm Machinery
Design Principles and Problems. Second Edition.
Pusa Agri-Book Service, IARI, New Delhi.Pusa Agri-Book Service, IARI, New Delhi.
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