• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.401-410
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• 1997

Scattering of seeds is one of the problems in the hill- dropping planters with a roller-type metering device. For crops like rice, corns and beans, the hill-dropping is own better for a high yield than the drill planting. The roller type metering device has been used for the drill planters and has many advantages. However, it has a problem of scattering of seeds when they are placed on rows. In this study a method was developed to design the roller type metering device fir the precision hill-droppings. Design parameters were derived to configure completely the geometries of the roller and brush. The method was applied to the design of the metering device of the rice seeding machines. The field test showed that the metering device designed by the method made a better performance of seed placement than that made by the precvious one. The method also can be applied to the design of metering devices for the precise hill-droppings of other crops.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.303-310
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• 2018

Purpose: This research was conducted to determine the design factors of a seed-metering device for the development of a seeder. The device allows the seeder to sow precisely one to three seeds of foxtail millet and sorghum. To obtain fundamental information regarding the design of the seed-metering device, examination of the physical properties of foxtail millet and sorghum was conducted. Methods: Based on the results of an adaptability test using an existing seeder with foxtail millet and sorghum, an experimental roller-type seed-metering device was made. The seeding factors considered during the experiment were the width, length, and depth, as well as the shape of the groove in the seed-metering roller. By adapting an analysis of variance, the experimental results of the seeding factors were analyzed. Results: The measured results of the respective lengths and widths of the seeds were 2.11 and 1.64 mm for foxtail millet, and 3.68 and 3.32 mm for sorghum, respectively. The weight of 1,000 seeds was 2.43 g for foxtail millet and 17.5 g for sorghum. The seeds were of an elliptical shape, considering the length and width. A sieve analysis showed that the size distribution of foxtail millet was quite regular whereas that of sorghum was irregular. Conclusions: The seeding results showed that the rates of incorrect planting were low when the groove of the roller-type metering device is an elliptical type. To sow one to three seeds, the groove of roller-type metering devices $2.0mm{\times}4.0mm{\times}1.5mm$ ($width{\times}length{\times}depth$) for foxtail millet, and $4.0mm{\times}8.0mm{\times}3.0mm$ and $4.5mm{\times}8.0mm{\times}3.0mm$ ($width{\times}length{\times}depth$) for Sorghum.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.261-267
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• 2005

In order to save labor and cost, direct seeding has been considered as an important alternative to the machine transplanting in rice cultivation. As current seeders for direct seeding of rice seeds drill irregular amount of seeds under various operating conditions, conventional drilling should be turned to precision planting which enables accurate placement of proper amount of rice seeds at equal intervals within rows. In this study, design, construction and performance evaluation of a precision seed metering device for planting of rice seeds were carried out. As prototype, the conventional roller type seed metering device was modified for planting: increasing diameter of metering roller, setting 2 or 4 seed cells on metering roller, adding seed discharging lid and its driving cam mechanism. Through performance tests for prototype and the current seed metering device, number of seeds in a hill, planting space and its error ratio, coefficient of variation of planting space (planting accuracy), and seeding length of $90\%$ of seeds in a hill divided by planting space (planting precision) at setting planting spaces of 15, and 20cm, seeding heights of 10, and 20cm, and seeding speeds of 0.1, 0.2, and 0.5m/s were investigated. Prototype showed better seed planting performance than the current seed metering devices. When setting planting space of 15 cm and seeding height of 10cm, prototype with 2 seed cells showed that variations of planting space and seeding lengths of $90\%$ of seeds in a hill at up to seeding speed of 0.5m/s were within 0.9cm, and 3.6cm, respectively.