双腔气力式水稻精量水田直播机设计与试验

杂交水稻分蘖能力强，产量高。为满足杂交水稻水田直播需求，该研究以3～5粒/穴为播种目标，设计了一种双腔气力式水稻精量直播机。介绍了双腔气力式水稻精量直播机主要工作部件结构，并对负压风力系统进行选型与设计。以杂交稻甬优4949为试验对象，以吸种负压与直播机前进速度为影响因素进行了田间试验。试验结果表明：当吸种负压为3.2 kPa、直播机前进速度为0.2～0.4 m/s时，10行排种器平均播种合格率（3～5粒/穴占比）为91.04%，0～2粒/穴占比2.23%，大于5粒/穴占比6.73%，各排种器之间的播种合格率变异系数为1.24%，满足杂交稻田间播种作业要求，为水田精量直播提供了参考依据。

Development and experiment of double cavity pneumatic rice precision direct seeder

Abstract: Rice is one of the main food crops in China, and it is also the staple food for more than 50% of the world''s population. Rice mechanized direct seeding technology was mainly divided into broadcast seeding, drilling and hill seeding. The seeding precision of broadcast seeding was low, the distribution of rice seeds was irregular in the field, and the uniformity of seedling emergence was poor, which was not conducive to the field growth and management. The field distribution regularity of drill seeding was better than that of broadcast seeding, but it was mainly suitable for conventional rice because of its large seeding rate, which could not meet the needs of hybrid rice seeding. At present, about 50% of the rice planting area in China is hybrid rice. Compared with conventional rice, hybrid rice has stronger tillering ability and higher yield. When mechanized direct seeding is adopted, only 3~5 seeds / hill is needed to form high-yield structure. In order to meet the requirement of hybrid rice direct seeding in the field, a double cavity pneumatic rice precision direct seeder was designed with the seeding rate of 3~5 seeds / hill as the goal. The seeder was mainly composed of double cavity pneumatic rice precision seed metering device, Gasoline fan, negative pressure pipeline, furrow opener equipment, transmission system, etc. The seed metering device was introduced and the transmission system of the seeder was designed. According to the negative pressure of seed metering device, the fan was selected, and the pipeline was designed to provide negative pressure air flow for the double cavity pneumatic rice precision direct seeder. The hybrid rice Yongyou 4949 was selected as experimental materials, the field experiments were carried out under the conditions of different seed sucking negative pressure and different forward speed of seeder (Namely, different rotation speed of seed sucking plate). The effects of seed sucking negative pressure and the forward speed on seeding precision of double cavity pneumatic rice precision seeder were studied. The results showed that: when the seed sucking negative pressure was 3.2 kPa and the forward speed of seeder was low (0.2~0.4 m/s), the average seeding qualified rate (probability of 3~5 seeds / hill) of the seeder was 91.04%, the probability of 0~2 seeds / hill was 2.23%, the probability of >5 seeds / hill was 6.73%, the average number of seeding in a hill was 4.16, and the variation coefficient of seeding qualified was 1.24%. The results of field tests were lower than those of laboratory tests. The main reasons that the field seeding environment was complex, the field work of seeder would be affected by the uneven mud surface. This would lead to the mechanical vibration of the seeder and the performance of seed sucking was affected. At the same time, due to the uneven distribution of the negative pressure, when some of the seed metering devices reached the optimal negative pressure of seed sucking, the others would not be able to achieve the optimal negative pressure of seed sucking, and the seeding precision of seeds metering devices will be affected. Therefore, the above two factors led to that the seeder field seeding qualified rate was lower than the laboratory. From the field test results, the probability of 0 seed/hill was 0%. Compared with the original single cavity single sucking plate seeder, the double cavity pneumatic rice precision direct seeder could effectively improve the probability of 0 seed/hill. The overall seeding precision could meet the requirement of direct seeding of hybrid rice in the field. In this paper, a new type of double cavity pneumatic rice precision direct seeder was designed according to the requirement of direct seeding of hybrid rice in the field. The main working parts of the seeder were designed and analyzed. The field experiments were carried out and the best working parameters were obtained, which provided reference for the precision direct seeding technology and equipment of hybrid rice.