الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This study was conducted to develop metering device suitable for planting many seeds of different size and shape. We note that mechanized planting has an advantage over manual planting in terms of saving in the quantity of seeds used in planting and also in time, in addition to having the advantage in distributing seeds in more regularly. To achieve the goal of the study, three types of seeds of different size and shape were selected. The choice was taken into account to be from legumes, such as sunflower seed, as an example of large-sized seeds, and cowpeas as an example of medium-sized seeds, and from aromatic plants such as blackseed as an example of small-sized seeds. The metering device was developed and manufactured based on theoretical engineering studies in terms of the diameter of land wheel, the motor speed, the speed reducer device, the number of metering disc cells and the diameter of the metering disc to obtain an appropriate forward speed and speed of the metering device commensurate with the number of fallen seeds as recommended in planting distances. The metering device was manufactured in a mechanical workshop in the village of Mit Ali, Mansoura, Dakahlia Governorate, during year 2020, and the manufacturing took into account that most of materials used were locally made, available and low cost. Experiments were carried out for measurements of selected seeds (sunflower, cowpea, and black seed), where the angle of repose, shape index, weight of a thousand seeds, seed size, crushing forces and moisture content were measured. The results of these measurements were used as a basis when manufacturing planting machine with the developed metering device. For example, the values of the angle of repose (Ra) for the seeds were (40-30-15 degrees) for the seeds of black seed, sunflower and cowpea, respectively, and therefore the appropriate slope of the seed hopper and the angle of inclination of the tubes were designed. The seeds should be larger than this angle so that the seeds can slide into the machine to reach the planting furrow. The measurements also had another importance in determining the optimal design of the planting machine, such as the shape factor, in order to determine the shape of the holes on metering disc. The study was conducted using: •Three different revolutions of the land wheel (30 - 45 - 55 rpm).• Using three different reduction ratios from the ground wheel to the feed disc (0.5-0.3-0.25). • Three different types of seeds (cowpea – black seed - sunflower). The machine with develop metering device was tested in the laboratory in order to determine the best performance rate of the machine in terms of revolution speeds of the land wheel and the speed of the metering disc device. Measuring the percentage of visible seed damage, percentage invisible seed damage, total percentage of seed damage by summing up the two previous percentages, feeding rate, quantity of seeds falling within a distance of 10 meters to determine the uniformity of seed distribution, lateral scattering of fallen seeds and percentage of germination (by planting in dishes). The most important results of study: -1.The highest total seed damage of the sunflower seeds was 4.1% at the highest ground wheel 55 r.p.m (when using a reduction ratio of 0.25). 2. The highest total seed damage of cowpea seeds was 3.9% at the highest ground wheel 55 r.p.m (when using a reduction ratio of 0.25). 3. The highest total seed damage of blackseeds was 3.1% at the highest ground wheel 55 rpm (when using a reduction ratio of 0.25). 4. Increasing the metering shaft speed causes more damage of the seeds. 5. The best feeding rate for sunflower seeds at a distance of 10 meters was 51 seeds at the revolutions of the land wheel 30 r.p.m and at a reduction ratio of the metering device (0.3-0.5). 6. The best feeding rate of cowpea seeds at a distance of 10 meters was 66 seeds at the revolutions of the land wheel 30 r.p.m and at the reduction ratio of the feed device (0.5). 7. The best feeding rate of black seeds at a distance of 10 meters was 170 seeds at the revolutions of the land wheel 30 r.p.m and at the rate of reduction of the metering device (0.3). 8. As the land wheel revolutions increases from 30 rpm to 55 rpm the lateral scattering of the seeds increases, due to the increased vibration of the machine at high forward speed. 9. Increased seed weight reduces seed scattering around the midline because heavier seeds are more balanced. 10. The highest value of the lateral scattering was for black seeds at the speed of the ground wheel 55 rpm and the reduction ratio of the feeder was 0.25. 11.The lowest value of the lateral scattering was for cowpea seeds at the speed of the ground wheel 30 rpm and the reduction ratio of the feeder was 0.5. 12. The best germination rate of sunflower seeds was 99.9% at the revolutions of the ground wheel 30 rpm at a reduction rate of for the feeder 0.5. 13. The best germination rate of sunflower seeds was 99.9% at the revolutions of the ground wheel 30 r.p.m at the rate of reduction of the feeder 0.5. 14. The best germination rate of sunflower seeds was 99.9% at the revolutions of the ground wheel 30 r.p.m at a reduction rate of for the feeder 0.5. 15. The percentage of germination of the three seeds increases as the revolutions of the ground wheel decreases, as well as the revolutions of the metering disc, due to the vibration of the machine decreases at slow speeds, which leads to a reduction in the percentage of seed damage.