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In order to solve the problems of poor hole-filling performance and the high seed-breakage rate of conventional rice bud seed precision hole direct seed-metering devices, a side-filled rice precision hole direct seed-metering device was developed, and the mechanism and force analyses for seeding operations were carried out. The key factors affecting seeding quality were determined: rotation speed, seeding angle and seeding height. By coupling the discrete element method (DEM) and multi-rigid body dynamics (MBD), the seed breakage rate and seeding performance at different rotation speeds were analyzed. Single-factor bench testing was used to analyze the effect of a duckbill unit on seeding performance under different factor levels. The three-factor and five-level quadratic regression orthogonal rotation center combination test methods were used to obtain the optimal working parameter combination. The test results showed that when the rotation speed was 47 r/min, the seeding angle was 19°, and the seeding height was 180 mm, the qualified index of seeding was 92.03%, the hole diameter qualified index was 91.62%, and the hole distance variation index was 7.17%. This study provides a reference for the research of mechanical rice sprouting seed-metering devices. [ABSTRACT FROM AUTHOR]

No-tillage seeding is of great significance for adjusting and improving soil structure in Northeast China. The conventional no-tillage seeder faces several issues with its row cleaner, such as a low straw cleaning rate and a high working resistance. To address these problems, this paper utilizes the bionic design method and develops a bionic elastic row cleaner inspired by the motion behavior of mole excavation. The bionic structure includes bent teeth and a torsion spring for lateral throwing. The MBD–DEM coupled simulation technology is proposed as the experimental optimization method, and it analyzes the interactions between different row cleaners, straw, and soil. The results indicate that a bionic elastic row cleaner with curved teeth and a torsion spring for lateral throwing (BA-T) had a higher straw cleaning rate and total kinetic energy of straw. It also had lower working resistance. The field test results indicate that the BA-T improved the straw cleaning rate by 13.04% and reduced the working resistance by 39.24% compared to a flat row cleaner. This outcome also validates the accuracy of the simulation experiments. This study contributes to the design of new and efficient row cleaners suitable for maize straw mulching and no-tillage conditions, thereby promoting the adoption of conservation agriculture practices. [ABSTRACT FROM AUTHOR]

Preharvest threshing is a harvesting method that focuses on collecting rice grains while leaving the rice straw unharvested. Investigating the interaction mechanism between the machine and rice during the operation process and its correlation with harvest losses is crucial for enhancing harvest quality. In this study, structural design and operational mechanism analysis of the combs was conducted through theoretical analysis. By extracting the relevant parameters of rice plants, a model of entire-plant rice during the harvesting period was established based on the discrete element method (DEM). Numerical simulation studies were conducted to clarify the interaction mechanism between the machinery and rice at different operating stages and under various operating parameters, as well as the impact of this interaction on operational quality. The simulation results revealed that various operating parameters had a significant impact on the sliding-cut effect between the combs and rice. A higher cylinder rotation speed enhanced the effect, whereas increased forward velocity hampered it. Additionally, the effect initially improved and then decreased with a higher threshing height. In the bench test, high-speed cameras were used to verify and further analyze the comb–rice interaction mechanism and explore the optimal working parameter combination. The results showed that at a rotation speed of 616 r/min, a forward velocity of 0.91 m/s, and a threshing height of 792 mm, the grain loss rate was 1.997%, and the impurity rate was 4.073%. The harvesting losses were effectively reduced, validating the effectiveness of the study on the interaction between the machinery and rice. [ABSTRACT FROM AUTHOR]

Successive years of straw mulching and returning straw to the fields in Northeast China have made strip-tillage necessary, and reasonable strip-tillage operations can create conditions for crop growth. However, there are limited research studies on the related equipment applicable to this area. In this paper, an automatic control strip-tillage machine is designed. According to the conventional planting pattern of maize in this region, the operative processes of the machine were determined, and a suitable strip seedbed structure could then be constructed under straw mulching conditions. The type of coulters and the structural parameters of the V-type soil-crushing wheel were determined through theoretical analysis. Based on the air spring and electric linear actuator, the plowing depth control system and the straw width control system were developed, respectively, so as to improve the stability of the machine operation. Field tests showed that when the forward speed, tillage depth, and theoretical width were 6–12 km/h, 6–12 cm, and 18–24 cm, respectively, the straw clearing rate, soil crushing rate, and tillage depth and breadth stability were higher than 90%, and the soil flatness was less than 2 cm. All the indexes satisfied the agronomic and technological requirements of corn cultivation. The results of this study can provide equipment and technical support for the further popularization of conservation tillage technology. [ABSTRACT FROM AUTHOR]