| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 102 === The Adzuki bean is one of the important economic crops in the southern part of Taiwan between autumn and winter. The major places where Adzuki beans are planted are Kaohsiung and Pingtung, and most of them are sold in the domestic market in Taiwan. After Taiwan joined the WTO, the price of Adzuki beans became unsteady and the price has become higher than imported Adzuki beans. Therefore, the issue now is how to reduce cost and increase planting accuracy. For reducing the cost of seeds per area and manual operation, the sowing device in this study was operated according to the non-tillage dibbling method, with row space of 30 cm, seed space of 21 cm and two seeds in each group. The original sowing device tested and improved in this study was provided by a domestic agricultural machinery factory. The lab test focuses on seeding quantity, sowing accuracy, missing rate, and multiple sowing rate, and observes the effects of different discs: the original disc with a thickness of 7 mm and an improved disc with a thickness of 3 mm, at each working speed: 4 km/h, 5 km/h, 6 km/h, 7 km/h,8 km/h and 9 km/h. In the test, a belt was placed under the device to catch the beans, and an AC motor was used for driving the belt and the device. Gears between the belt and the motor allowed the sowing device to drop beans each time when the belt moved forward about 21 cm. After Adzuki beans were distributed on the whole belt, we measured the seeds spaces manually and calculated the results using MATLAB software.
The result indicated that the installation of a retaining board, scraping brush and agitator are needed to allow this device to work normally. In the test of seeding quantity, the device with the original disc sowed excessive seeds. The seeds sowed by the improved disc corresponded more closely with the ideal total. However, when the working speed increased, the total seeds sowed deceased to 1~2 seeds in a group. The test of seeds distribution showed that the improved disc achieved better accuracy of up to 70%. Compared to the 20% of accuracy of original disc, the improved disc indeed had a better performance. Moreover, the test of the multiple sowing rate showed that multiple sowing could be reduce from 80% to 30%, making it possible to save more seeds. When the working speed reached 9 km/h, the missing rate with the improved disc reached 7%, however. Therefore, this study recommends the use of a retaining board, scraping brush and agitator when this device was driven. In addition, with a non-tillage two seeds dibbling method, the use of the improved disc with a thickness of 3 mm is a better choice, and if the working speed is kept under 8 km/h, near ideal seed distribution conditions can be obtained.
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