There are approximately 36.7 million hectares of saline alkali land available in China. To enhance the comprehensive utilization value of coastal saline alkali land and boost crop yields in such areas, it is essential to conduct research on optimizing the operational performance of high-performance soil contact components in light of the soil characteristics of coastal saline alkali land. Discrete element simulation can be employed to investigate the operational mechanisms of various key components. Nevertheless, at present, there is a dearth of discrete element models for the key physical parameters and soil structure of coastal saline alkali land soil. In this article, typical coastal saline alkali field soil was sampled, and the physical properties of the saline alkali soil, including salt content, moisture content, particle size distribution, and particle size, as well as intrinsic parameters such as soil compaction, density, Poisson’s ratio, and shear modulus, were measured. The Hertz Mindlin with Bonding contact model was employed. Physical experiments on soil accumulation angles at different depths were carried out using the cylindrical lifting method. Subsequently, by means of the discrete element method and the BBD experimental design method, a response surface model was established, and an optimization analysis was performed on the optimal parameters for the soil–soil collision recovery coefficient, static friction coefficient, and dynamic friction coefficient at each depth. Test benches for measuring the collision recovery coefficient, static friction coefficient, and rolling friction coefficient of saline alkali soil at -65Mn were set up, calculation formulas for each parameter were derived, and the contact parameters between soil at different depths and 65Mn were obtained. The results of the sliding friction angle test on different depths of saline alkali soil at -65Mn were further verified using the discrete element method, with a maximum error of 3.11%, which falls within the allowable range. This suggests that the calibration results of the discrete element simulation parameters for the interaction between soil and contact components are reliable, providing data and model support for future research on enhancing the operational performance of high-performance contact components.

Aiming at the current peanut pickup combine harvester seedling vines crushing mechanism operation qualified seedling length rate is low, the impurity rate is high, and the seedling vines crushing mechanism is optimized design. On the basis of the material characteristics of peanut seedling vines, taking the crushing mechanism as the research carrier, the interaction mechanism of the seedling vine mechanism was analyzed. Establish the mechanical model and motion trajectory model in the crushing process, simulate the peanut seedling vines crushing process based on the discrete element method, analyze the influence of the cutter shaft rotational speed, movement speed, and bending angle on the crushing of peanut seedling vines, and establish the regression model, and the results of the research show that the influence factors in the main order of priority are: knife shaft speed > movement speed > bending angle The optimal parameter combination is knife shaft speed 2171.94 r/min, movement speed 0.79 m/s, and bending angle 45°. According to the field test conditions, it is determined that the knife shaft rotational speed of 2170 r/min, movement speed of 0.8 m/s, and bending angle of 45° can make the peanut seedling vines crushing mechanism of the work performance to achieve a qualified seedling length rate of 97.292%, the rate of impurity content of 2.746%, and the error with the predicted value is less than 2%, which indicates that this study can provide a reference for the optimal design of the seedling vines crushing mechanism of the peanut pickup combine harvester.

Design and test of a dual-axis layered rotary tillage stubble exterminator in saline-alkali land based on discrete elements

In order to facilitate the peanut plot breeding process, a seed discharger for peanut plot breeding was designed and optimised. Two single stroke cylinders were used for seed replacement and to avoid confusion between different varieties of seeds. The working performance of the seed discharger was simulated by the CFD-DEM method. The simulation results showed that the seed suction hole could adsorb the seeds stably, the adsorption force at the seed suction hole was about 0.02 N, and the seed-clearing time was 0.31 s. When the rotation speed of the seed discharge cylinder was 25 r/min, the diameter of the seed suction hole was 6 mm and the working negative pressure was −5.5 kPa. The developed seed discharger was installed on the test bench to carry out the central composite design experiment, and the test results were analysed and optimised by Design-Expert software. The final parameters of the seed discharger were obtained as follows: rotational speed of the seed cylinder is 25 r/min, the diameter of the seed suction hole is 6 mm, and the working negative pressure is −6 kPa. This indicates that the design of the initial parameters is reasonable. Finally, the seed discharger was tested in the field. The results shown that the 95% confidence intervals for seeding pass rate, multiple-seed rate, and seed missing rate were (88.9557%, 93.1777%), (3.8137%, 6.4597%), and (2.1157%, 5.4777%), respectively, which met the requirements of peanut plot seeding.

A seed discharger for peanut plot breeding was designed and its seed supply, seed carrying, seed discharge and seed clearing processes were analysed. Two single stroke cylinders were used for seed replacement and to avoid confusion between different varieties of seeds. The working performance of the seed discharger was simulated by CFD-DEM mothed. The simulation results showed that the seed section hole could adsorb the seeds stably, the adsorption force at the seed suction hole was about 0.02N, and the seed clearing time was 0.31s, when the rotation speed of the seed discharge cylinder was set to be 25r/min, the diameter of the seed suction hole was set to be 6mm, and the working negative pressure was set to be 5.5kPa. The developed seed discharger was installed on the test bench to carry out the central composite design experiment, and the test results were analysed and optimized by Design-Expert software. The optimal parameters of the seed discharger were obtained as follows: rotational speed of the seed cylinder is 24.38 r/min, the diameter of the seed suction hole is 5.73 mm, and the working negative pressure is -6.15 kPa. Finally, the seed discharger was tested in the field, and the result shown that the seed spacing pass rate was more than 90%, the multiple seeds rate was less than 6%, the seed missing rate was less than 4.5%, and the seed clearing rate was always 100%, which met the requirements of peanut plot seeding.

In China, there are approximately 36.7 million hectares of available saline–alkali land. The quality of land preparation significantly influences the yield of crops grown in saline–alkali soil. However, saline–alkali soil is highly compacted, and, currently, the market lacks land-preparation products specifically tailored to the unique characteristics of saline–alkali land. The soil crushing performance of existing power harrows fails to meet the requirements for high-quality land preparation, thus affecting crop planting yields. Consequently, it is imperative to conduct research on the design and performance improvement of the soil crushing components of power harrows for saline–alkali land. This paper centers on the key soil crushing component, the harrow blade, and conducts research from the perspectives of kinematics and dynamics. Initially, the ranges of key structural and motion parameters are determined, such as the angle of the harrow blade cutting edge, the thickness of the of the harrow blade cutting edge, and the ratio of the circumferential speed to the forward speed. Subsequently, through simulation tests integrating the Discrete Element Method (DEM) and the Box–Behnken Design (BBD), the optimal parameter combination is identified. The impact of the forward speed and the rotational speed of the vertical-shaft rotor on soil disturbance is analyzed. The relationship between soil disturbance and soil heaping is explored, and an optimal forward speed of around 6 km/h is determined. Field tests are conducted to verify the cause of soil heaping. The test results show that the soil crushing rates are all above 85%, with an average soil crushing rate of 88.66%. These test results have achieved the predetermined objectives and meet the design requirements.