Experimental Study on Working Performance of Rice Rope Direct Seeding Machine

Structure and sowing principles of rice rope direct seeding machine are introduced. In order to test the machine＇ s working performance, such as compacting effect, sowing depth, influence of sowing device to rice rope, etc., field experiments were conducted. It is concluded that mean slip ratio of compacting wheel 1 is 4.44%, wheel 2 is 5.58%, wheel 3 is 7.81%, and wheel 4 is 6.96%; mean depth of planting is 29.72 mm, and mean variability coefficient of planting depth is 6.39%. Maximum variability coefficient of planting depth is 8.40%. Rice rope＇s snapping is closely related with the machine＇s speed and guide thread wheel by sowing device orthogonal experiments. Test results show that the machine has a rational design, safe work and meets to the requirements of planting. This study has laid the foundation for further studying the project.

Chemical Weeding in Dry Direct Seeding Fields of Single Cropping Middlelate Rice

Chemical weeding in dry direct seeding fields of single cropping middle-late rice was studied in Huida vegetable farm of Huizhou City in 2012. The main treatment was herbicide（ pretilachlor ＋ bensulfuron-methyl,Yangguo and butachlor）,and the sub-treatment was application method（ soil treatments,seedling treatment and integrated treatment）. The results showed that 80 g pretilachlor ＋ bensulfuron-methyl（ 36% pretilachlor ＋ 4% bensulfuron-methyl） diluted with 50 kg water could be sprayed or 200 g Yangguo（ 23. 9% butachlor ＋ 1. 1% bensulfuron-methyl） mixed with 15 kg sandy soil could be broadcasted per 667 m2 on the sowing day or the second day under moist condition of soil,which could effectively control weeds in dry direct seeding fields of single cropping middle-late rice.

Virtual simulation analysis and verification of seed-filling mechanism for dipper hill-drop precision direct rice seeder

In order to improve the seeder’seed-filling ability of the dipper hill-drop precision direct rice seeder,and to meet the mechanization requirement of high speed operation,the self-designed seeder was taken as the objective to explore its seed-filling mechanism and the movement status of rice seed in seed box from the perspective of mechanics.The force models of seed-filling process by dipper were established,and the influential regularity of its rotation speed to compressive resistance of seed population was analyzed as well.The image processing Module-Clipping of discrete element simulation software EDEM was used in the virtual simulation analysis for the process of the seed filling into the dipper,and the velocity relation curve and the force changing curve between rotation speed and seeds were obtained.According to the virtual experiment,the composite filling force of seeds,i.e.the qualified rate on filled rice seed amounts was the largest when rotation speed was at 40 r/min.The performance test bed of seeder was used to verify the simulation results,in which the qualified rate on scooped rice seed amounts was taken as the index,and six rotation speeds of seed-filling dipper were also selected for analysis of seed-filling ability of the device.The results are as follows:with the increase of working speed,the qualified rate on filled rice seed amounts fluctuated with a trend of cosine curve,the largest value was 94.16%occurred when the rotation speed of seed-filling dipper was at 40 r/min.The variation trend of simulation value was approximately consistent with that of verification value.The study can provide a reference for the research and development of mechanical seeder.

Development of UAV-based shot seeding device for rice planting

In order to realize the high-quality row seeding operation with unmanned aerial vehicle(UAV)in paddy field,a shot seeding device that can sow five rows of pelleted rice seeds at the same time was designed.The shot seeding device mainly consists of an external grooved wheel seed metering device and five shot seeding modules.The designed external grooved wheel seed metering device can take the seeds out of the seed box and divide the seeds into five parts.The shot seeding module can accelerate the pelleted rice seeds to reduce the impact of the UAV wind on the direction of seed movement.Furthermore,an angle adjustment mechanism for the shot seeding module was used to change the row spacing.The seed metering device test verified that when the speed of the seed metering wheel was 15 r/min,the coefficient of variation of the discharge rate of each row(C.V1)and total seed discharge rate stability(C.V2)were 1.70%and 1.04%,respectively.Image processing technique was used to test the UAV seeding performance.The distribution characteristics of seeds on the ground showed that the number of seeds in each row gradually increased from both sides to the middle in the width direction.According to the statistics,there were 60%-70%of the seeds in each row in the 100 mm width range.The field test showed that when the working height was 1.5 m and the seeding quantity was 38.56 kg/hm^(2),the performance of sowing in rows was obvious,the deviation rate of seeding quantity was 1.89%.After 16 d of sowing,the seeds’emergence rate was stable,and the average emergence rate was 82.63%and the yield was 6775.50 kg/hm^(2).