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To solve multiple problems, such as the poor seeding process stability in the conventional finger-clip precision corn seed metering device and the inability to monitor the seeding effect, a long-belt finger-clip precision seed metering device was optimized and designed. The overall structure and working principle were described, and the mechanism of smooth transport and delivery was analyzed. A diffuse reflection photoelectric sensor and rectangular optical fiber sensor were used to monitor the number of corn seeds in the seeding process, and the states of multiple and miss seeding were calculated. A corn seeding quality monitoring system was designed. In this study, the seed metering performance of the long-belt finger-clip precision seed metering device was compared to that of the conventional finger-clip precision corn seed metering device. It was shown that the reseeding index, the miss-seeding index and the coefficient of variation can be effectively reduced with increasing seed metering tray speed. At the maximum speed of 65r/min, the qualified index increased from 75.75 to 84.70%, the reseeding index decreased from 13.66 to 8.49%, the miss-seeding index decreased from 10.59 to 6.81%, and the coefficient of variation decreased from 20.69 to 6.83%. The variations of these four evaluation parameters with the seed metering tray rotating speed were analyzed. Furthermore, the effects of the seeding frequency and seeding speed on the four evaluation parameters were studied through single factor and variance analyses. The results showed that the relative errors of the qualified index, the reseeding index, the miss-seeding index and the seeding amount increased gradually with the increase in the seed metering tray rotating speed, and the monitoring accuracy of the sensor decreased gradually. The accuracy of sensor monitoring decreased with increasing seeding frequency and seeding speed. This study provides an optimized scheme for the smooth delivery and movement of conventional seed metering devices and provides a technical reference for the development and design of monitoring systems with multiple index and the miss-seeding index of seed metering devices.

This paper aims to solve the problems of the low quality and shallow depth of the traditional straw return method. According to the requirements of the new furrow burial and return agronomic model, a corn straw ditch-buried returning machine was designed that could simultaneously complete the processes of picking, conveying, ditching, soil-covering and pressing. Key components were theoretically analyzed and designed, such as the pickup device, ditching device and straw-guiding soil-covering and pressing device. Based on a field experiment, the main factors influencing the effects of straw picking, soil ditching and straw return were studied. Both forward speed and pickup device speed significantly affected the straw picking rate. The ditching area, ditching width consistency factor and ditching depth stability factor gradually decreased with increasing forward speed and gradually increased with increasing trenching device speed. There was a significant interaction among the forward speed, pickup device speed and ditching device speed. At a forward speed of 1.68 m/s, the picking device speed was 330 r/min, the ditching device speed was 290 r/min, and the highest straw return rate was 93.65%.

The bruising of fruits occurs at various stages, including picking, transportation, and sale. For fruits with large kernels that occupy a significant portion of their overall volume, considering the impact of the kernel is crucial in elucidating the mechanisms of bruising and controlling bruise formation. This study employs reverse engineering to develop a composite finite element model of loquat peel, flesh, and kernels. Bruise formation during collisions is analyzed from the perspectives of contact force, equivalent stress, energy, bruise volume, and bruise susceptibility, aiming to reveal the significant role of the fruit core in the bruise formation process. In this paper, we propose the use of 3D printing technology to accurately quantify bruise measurement for fruits with large kernels. The results showed that the maximum contact force, equivalent stress, and internal energy between loquat and steel/wood were essentially consistent, but all exceeded those observed when using rubber. Due to the blocking of stress transmission by the kernel, the susceptibility of loquats to bruising increases with height before decreasing. This study elucidates the mechanism of bruise formation in fruits with large kernels and provides methods and ideas for the research and precise measurement of complex fruit bruising characteristics.

In order to accurately establish a discrete element model for the whole plant flexibility of upright rice during the harvesting period, several physical characteristics, such as geometric features, moisture content, and density, of the entire rice plant were measured, along with frictional properties, such as the static and rolling friction coefficients, and mechanical properties, including the elastic modulus and restitution coefficient. A flexible and upright discrete element model of the rice plant was established using the DEM method based on the Hertz–Mindlin (no slip) and Hertz–Mindlin with bonding mechanical models. The parameters were optimized through Plackett–Burman screening experiments, steepest ascent experiments, and Box–Behnken optimization experiments to accurately determine the discrete element model parameters of each component of the rice plant. The calibration process of the contact parameters between rice grains and steel was analyzed in detail as an example, resulting in a calibration error of 0.68% for the natural repose angle. Taking the calibration of the contact parameters between the main stem and steel as an example, a detailed analysis of the calibration process was conducted. The calibration resulted in a calibration error of 2.76% for the natural repose angle and 2.33% for deflection. This study lays the foundation for understanding the mechanical response of rice and machinery when they are coupled together. Additionally, it provides valuable references for establishing discrete element models of plant species other than rice.

The modeling accuracy of rice straw remains limited, and discrete element method (DEM) simulations of its compression are computationally intensive. To address these challenges, this study systematically investigated the physical characteristics of rice straw and proposed an innovative DEM and parameter calibration approach. Uniaxial compression tests were conducted on individual straw stalks, and key DEM parameters were systematically calibrated using Plackett–Burman experiments, steepest ascent trials, and Central Composite design. The calibrated parameters were validated against single-straw compression tests, showing a relative error of only 1.9% between simulated and measured peak loads, indicating high model fidelity. Building on this foundation, vibration-assisted compression bench tests were performed on bulk straw, further validating the scaled-up DEM and its parameters. The evolution of normal forces and porosity during compression was analyzed by comparing experimental results with simulations, confirming the model’s accuracy in capturing straw compaction behavior. Finally, a comparison of computational efficiency between the scaled-up and original DEMs revealed that the scaled-up model reduced computation time by approximately 67.4% and 65.2%, respectively, significantly improving simulation efficiency. This study provides a robust methodology for modeling flexible agricultural fibers and establishes a foundation for efficient numerical simulation of straw compression.

This study focuses on enhancing the comprehensive utilisation of rice straw by proposing a vibration-assisted compression technology, with the aim of resolving inherent issues in traditional baling, such as uneven compression and low density. This study designed a multi-point vibration-assisted compression test rig and established a vibration-enhanced compression mechanical model based on the physical properties of rice straw. By integrating discrete element method (DEM) simulations with bench testing, the optimal length-to-width ratio of 1:1 was identified for achieving superior compaction quality. A systematic analysis was conducted to evaluate the effects of vibration point configuration, frequency, and amplitude control on straw bale integrity. The results of the DEM simulations demonstrated that vibration-assisted compression significantly enhanced the compaction uniformity and stability of rice straw. The dimensional stability coefficient and pressure transmission rates of the straw bales reached 88.25% and 58.04%, respectively, validating the efficacy of the vibration-assisted compression technique. This study provides innovative concepts and theoretical foundations for optimising the design of straw baling and in-field collection equipment. It holds critical significance for advancing the resource-efficient utilisation of agricultural residues and promoting sustainable agricultural practices.

Selecting an appropriate disc coulter is crucial for reducing the power consumption of no-till seeders, preventing straw from being pressed into seed furrows, improving the soil penetration performance of the disc coulter, and thus minimizing the weight of no-till seeders. This study utilized the quadratic regression orthogonal rotation central composite approach. With the application of EDEM and RecurDyn software, a virtual simulation model of the interaction between a toothed disc coulter and soil was developed. The angle of front serration δ, the angle of rear serration θ, and the number of serrations n were taken as experimental factors. The draft Fv and penetration resistance FN were selected as performance evaluation indicators for parameter combination optimization simulation tests. The results indicated that δ, θ, and n have significant influences on Fv and FN (p < 0.05). When the optimized parameter combinations δ, θ, and n were respectively determined as 16°, 39.1°, and 13, both Fv and FN reached their minimum values. A comparative experimental study was conducted with the optimized toothed disc coulter and six existing disc coulters; under the working conditions of 14.4 km·h−1, both the draft and penetration resistance of the toothed disc coulter are minimized. The draft was 227.5 ± 8.9 N and the penetration resistance was 415.9 ± 5.3 N. Meanwhile, the toothed disc coulter had the highest ratio of soil disturbance area to draft, indicating better soil loosening effects.

To address the challenges of missed and false detections in citrus fruit detection caused by environmental factors such as leaf occlusion, fruit overlap, and variations in natural light in hilly and mountainous orchards, this paper proposes a citrus detection model based on an improved YOLOv5 algorithm. By introducing receptive field convolutions with full 3D weights (RFCF), the model overcomes the issue of parameter sharing in convolution operations, enhancing detection accuracy. A focused linear attention (FLA) module is incorporated to improve the expressive power of the self-attention mechanism while maintaining computational efficiency. Additionally, anchor boxes were re-clustered based on the shape characteristics of target objects, and the boundary box loss function was improved to Foal-EIoU, boosting the model’s localization ability. Experiments conducted on a citrus fruit dataset labeled using LabelImg, collected from hilly and mountainous areas, showed a detection precision of 95.83% and a mean average precision (mAP) of 79.68%. This research not only significantly improves detection performance in complex environments but also provides crucial data support for precision tasks such as orchard localization and intelligent picking, demonstrating strong potential for practical applications in smart agriculture.

To solve the problems of poor quality mechanical weeding and no obvious plowing effect in complex paddy field environments, the burying weeding operation mode was proposed. The height and force acting on the weeds were the main factors that altered the effectiveness of burying. The structure of the rake teeth weeding wheel was designed and matched with appropriate power, and the rake teeth weeding device was optimized. To verify the rationality of the designed device, the forward speed of the machine, rotating speed of the weeding wheels and weeding depth were selected as the experimental factors, and the inter row weeding rate was selected as the experimental index. A quadratic orthogonal rotation combination experiment with three factors and five levels was designed and optimized. The results showed that when the forward speed was 0.64 m/s, the rotational speed of the weeding wheel was 140 r/min, the weeding depth was 56.8 mm, the inter row weeding rate predicted by the model was 88.43%, and the inter row weeding rate was determined by a confirmatory experiment to be 87.06%, which met the weeding requirements for modern agronomy. To intuitively analyze how the soil was disturbed by the weeding wheel, the explicit dynamic analysis software LS-DYNA was used to build a fluid–solid coupling simulation model of the weeding wheel and water soil. The soil density and coupling stress were used to analyze the plowing state of paddy soil when the weeding wheel was operated. This study provides references for the design and development of paddy field weeding components and for mechanical and soil coupling simulation in paddy fields.

It is difficult to determine the coefficient of restitution accurately due to the small size, light weight, and complex influencing factors of rice grain. In the study, the experimental principle of restitution coefficient was described by the impact method, and the restitution coefficients of four typical rice varieties in Northeast China were measured. According to the orthogonal experiment, the primary and secondary factors affecting the restitution coefficient of rice grain were collision material, spring compression (initial collision velocity), moisture content, and rice variety. A single factor test was carried out for the significant factors, and the results showed that: The restitution coefficient of rice grain to a Q235 steel plate, plexiglass plate, seed plate, and rubber plate decreased in turn, and the restitution coefficient gradually decreased with the increase of spring compression (initial collision velocity), and with the increase of water content. The restitution coefficient was obtained by a bench test and simulation test, and the results were 0.429 and 0.423, respectively. The reason for the error was discussed and analyzed, which effectively verified the validity of the measurement of the restitution coefficient of small grain size. This study provides a method for the determination of the restitution coefficient of small grain, and provides a reference for the optimization design of threshing and a cleaning device of the combine harvester and high-speed precision seeder.