Seed metering devices

This presentation consists of descriptions regarding different types of metering devices with appropriate figures.

1. Seed metering devices Vijitha Vikneshwaran Lecturer(Temporary) Faculty of Technology University of Jaffna

2. Introduction Seed metering devices will meter the seeds at their desired depth desired location desired pressing It can be classified into Bulk seed-metering device Single seed hill metering device 2

3. Bulk seed-metering device It draws seeds in bulk, delivers them at the desired rate in seed tube for sowing There are 4 types 1. Stationary orifice with agitator Low cost Size of the orifice is controlled by sliding plate Consequently the seed rate also will be controlled 3

4. 2. Flute roller Widely used in seed drills Made of cast iron, aluminum or plastic Handles wheat, gram, green gram, soybean and sorghum seeds Seed rate is controlled by exposure length of roller Bulk seed-metering device, cont … Fluted roller Figure 01: Fluted roller metering device 4

5. Bulk seed-metering device, cont … Seed entry Seed exit Drive shaft Seed dropper housing Adjustable flap Sliding cut-off Sliding the shaft adjusts roller exposure to the seed Fluted roller Figure 02: schematic diagram of fluted roller metering device 5

6. 3. Stud type roller Widely used in European design seed drill Studs are present on the periphery Application rate is changed by multi speed gearbox Bulk seed-metering device, cont … Figure 03: Stud type roller type metering device 6

7. 4. Rotating drum with orifice type Popular for paddy crop Consists of a horizontally positioned cylinder drum The drums have rows of closely spaced holes punched along the periphery Seed rate depends on the size of holes in the drum Bulk seed-metering device, cont … 7

8. Bulk seed-metering device, cont … 8 Figure 04: Rotating drum with orifice type metering device

9. Seeds are soaked prior to sowing And then soaked seeds are put into the drums Then the seeds are allowed to fall on the field which posses some amount of moisture (muddy condition) Therefore the seeds can be positioned perfectly at same row to row spacing It is possible to get more yield through this device This is an effective method compare to energy spent in transplanting Any how seed weed growth is slightly high in this method Bulk seed-metering device, cont … 9

10. Single seed hill metering devices Design to maintain uniform seed spacing There are 06 types 1. Vertical roller with cell metering device Good for very small seeds like mustard and jute Rotor is positioned vertically at the base of the seed hopper Seeds are picked up into the cells and are dropped one by one 10

11. The vertical plate will have small holes on the periphery As this rotates the seeds will be picked up within the cup Then the seed delivery will take place 11 Single seed hill metering devices, cont … Seed delivery tube Vertical plate Seeds Seed box Figure 05: Vertical plate metering device

12. 2. Horizontal plate-metering devices Commonly used for maize Wide range of plates with varying size and number of cells are provided for different seeds Single seed hill metering devices, cont … 12 Figure 06: Horizontal plate-metering device

13. Plate has seed holding cups or seed holding locations and that rotates The outer ring carries a cut-off devices and a knock out devices Cut off device will brush up the extra seeds Knockout device will knock the seeds exactly at the location where it has to go into the seeding tube. Single seed hill metering devices, cont … 13

14. 3. Inclined plate metering device Commonly used for sowing of legumes, sorghum and peanut Easy construction The inclined plate rotates at an angle of about 60 ̊ with the horizontal Inclined structure provides smooth movement of seeds Seeds are picked in the cells and dropped on the top of inlet of seed tube Single seed hill metering devices, cont … 14

15. Single seed hill metering devices, cont … 15 Cell Hopper Base plate Bevel gear Sliding baffle Seed metering plate Seed tube Chain drive Ground wheel Figure 07: Inclined plate metering device

16. 4. Belt with cell-type metering device Metering hole is provided at equal spacing on an endless belt. Once the seed is trapped and comes to the location, it will be knocked off at that place in the seed tube. The belt can be changed according to the seed type. Seeds from the main hopper enter a small chamber above the metering belt and remain at controlled level. Then the seeds are delivered in the furrow close to the ground with small terminal velocity to achieve appropriate spacing. Single seed hill metering devices, cont … 16

17. Single seed hill metering devices, cont … 17 Metering belt Figure 08: Belt with cell-type metering device

18. 5. Cup feed metering device It is used where seed damage due to rough mechanical handling is not desirable It is applicable for planting of garlic, cloves and sugarcane buds Size of the spool depends upon the size of seed Seed rate depends on number of spool and rotational speed. Size of the cup can be changed depending upon the size of the seeds. Single seed hill metering devices, cont … 18

19. Single seed hill metering devices, cont … 19 Figure 09: Cup feed metering device Cup-feed type metering mechanism Metering chain

20. Single seed hill metering devices, cont … 20 Figure 10: Schematic diagram of cup feed metering device Hopper Shutter Cup disk Delivery tube

21. 6. Pneumatic metering device Uses air suction for picking the seeds Aspirator blower is used to create a pressure of 3-5 kPa in the blower inlet chamber. Blower inlet chamber is connected to the vacuum disc of the planter unit. Seeds are moved up and released when the pocket pass a baffle that cut the vacuum and drop seed into furrow by gravity. Single seed hill metering devices, cont … 21

22. Pneumatic metering device has, 99-100 % cell fill efficiency 99-100 %single seed picking efficiency Less or no damage of seeds 22 Single seed hill metering devices, cont … Figure 11: Pneumatic metering device

23. Calibration of seeders 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 operating in the field to get a predetermined seed rate of the machine. The following steps are to be followed for calibration Step 1: Determine the nominal width (W) of seed drill . Where, M - Number of furrow openers S - Spacing between the openers (m)   23

24. Step 2: Find the length of a strip (L) having nominal width (W) Step 3: Determine the number of revolutions (N) the ground wheel has to make to cover the length of the strip (L) π rpm Where, D - diameter of ground wheel (m)   Calibration of seeders, cont … 24

25. Step 4 Raise (Jack) the seed drill in such a way 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 drive wheel  Step 5 Fill the selected seed in the seed hoppers. Place a sack or a container under each boot for seeds Rotate the twenty revolution of ground wheel 25 Calibration of seeders, cont …

26. Step 6 Replicate the same procedure minimum three times Calculate the mean weight of seeds collected into the container Step 7: Calculate the seed required (kg/ha ) Seed rate = (N/20)* mean weight of seed collected in 20 revolution 26 Calibration of seeders, cont …

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