Experiment of precision rice pneumatic seed metering device on the thickness of seed layer

摘要

Due to high tillering capacity and preventing the risk of low seedling emergence rate in the field, generally, 3-4 seeds are required for each hill when the hybrid pregnant rice seeds were direct seeded to the field by drilling machine. Because the seeds were sprouted and their bud length were less than 3 mm with high moisture content, they were low liquidity and irregular shape, it is quite difficult to meet the requirement. In order to solve the problem, a novel precise pneumatic metering device was designed with group sucking holes plate in seed metering device, by which 3-4 seeds can be sucked and dropped at the same time.According to improving the precision of the pneumatic seed metering device which has grouped holes, the thickness of seed layer was experimented in this paper. Seeds of rice varieties were Indie hybrid Y-Liangyou 1 pregnant rice seed, and the 33orthogonal experiments were conducted to investigate the suck characteristic of the device on the seeding test-bed under the thicknessof seed layer, vacuum, and the rotary speed of seed sucking plate. The results showed that the sucking precision was affected by them, the order affecting the <2 sucked seeds per hill and >5 sucked seeds per hill both were the rotate speed of seed sucking plate > vacuum >the thickness, the order affecting the (3-4) sucked seeds per hill was the thickness>vacuum>the rotate speed of seed sucking plate, but the opposite influence were brought by them on different level to the ￡2 sucked seeds per hill and￡5 sucked seeds per hill .Base on the production aim of the field, the optimization condition were that the thickness was 25mm, the vacuum was 2.6kPa, and the rotary speed of seed suck plate was 30 rpm. Under the conditions of Y-Liangyou 1 pregnant rice seed which moisture content was 23.93%~24.4%, the percentage of i2 sucked seeds per hill was 16.41% ,the (3-4) sucked seeds per hill of the pneumatic seed metering device was 63.24%, and the 5 sucked seeds per hill were 20.35%, the (2-5) sucked seeds per hill were 92.12%, The results were better than the orthogonal experiments results and showed improving the precision of the pneumatic seed metering device from controlled the thickness of seed layer.