In order to solve the problems of high impurity rate and large loss rate in the whole fresh peanut harvesting and production process in hilly areas of China, the method of computational fluid dynamics (CFD) and discrete element (DEM) coupling is used to examine the gas–solid two-phase simulation of the cleaning device of the crawler fresh-peanut-picking combine harvester. In addition, the Box–Behnken test method is used to analyze the influence of different parameters on the impurity content and loss rate of materials in the cleaning process by taking the fan speed, feed amount, and air inlet angle as the test factors, and the optimal combination of working parameters is sought. The simulation results show that when the fan speed is 2905.07 r/min, the feed rate is 0.80 kg/s, the air inlet angle is 43.14°, the impurity content is 7.32%, and the loss rate is 4.78%. Compared with the simulation test results, the impurity content is increased by 0.68%, and the loss rate is increased by 1.24%, which verifies the reliability of the simulation model, and the research results provide some technical support for the improvement of the cleaning device in the later stages.

Addressing the issue of complex terrain and small field plots in hilly and mountainous regions where large combine harvesters are not suitable, this paper presented the design and development of a semi-feed self-propelled peanut combine harvester. This harvester is characterized by its small size and flexible steering. Theoretical calculations were used to determine the structural parameters of the main working components. A three-factor, three-level orthogonal experimental design was implemented, focusing on forward speed, vibration frequency and picking roller rotational speed, as these parameters significantly influence operational performance. Through this experiment, regression models were established between the total loss rate, the broken pod rate, and these three above mentioned factors. Through multi-objective optimization, it was found that when the forward speed is 0.44 m/s, the picking roller rotational speed is 350 rpm, and the vibration frequency is 6.4 Hz, the total loss rate and broken pods rate of the harvester are the lowest. Validation experiments were conducted under this parameter combination, with the total loss rate and broken pods rate being effectively reduced to 3.21% and 0.85%, respectively. The experiments proved that this harvester meets the requirements for mechanized peanut harvesting in hilly and mountainous regions.

In recent years, there have been many studies on the calibration of soil simulation parameters; however, there are few soil parameters for wheat grown after rice that have been calibrated in the lower reaches of the Yangtze River, and the data from such calibrations remain inaccurate. Therefore, using the soil of Jiangsu as our research object, a soil parameter calibration was carried out based on the EEPA (Edinburgh elastoplastic adhesion) model and using the discrete element software EDEM (2020, DEM-Solutions, Edinburgh, UK). The depression depth measured via a uniaxial compression test and the maximum crushing force measured via an unconfined compression test were taken as indexes. The Plackett–Burman test was used to screen seven influencing factors (recovery coefficient, static friction coefficient, rolling friction coefficient, surface energy, contact plastic deformation ratio, tensile exp, and tangential stiff multiplier). The recovery coefficient and static friction coefficient were analyzed using a central composite test with depression depth as an index. The surface energy, plastic deformation ratio, and tangential stiffness factor were analyzed via a Box–Behnken test, with the maximum crushing force as the index. Taking the measured depression depth of 3.36mm and the maximum destructive power of 210 N as the target, the following final data were obtained—recovery coefficient: 0.322, static friction coefficient: 0.676, rolling friction coefficient: 0.5, surface energy: 17.158, contact plastic deformation ratio: 0.358, tensile exp: 2, and tangential stiff multiplier: 0.8. Finally, the simulation value and the actual value of the parameter group were verified and compared. It was found that the mismatch coefficient R² of the actual value and the simulation value is 93.509%. The mismatch coefficient R² between the actual and simulated values of unconfined compressive test is 94.2%. This shows that the curves obtained from the real test and simulation test have a high similarity. This study can provide technical support for the simulation and optimization of growing wheat after rice seeding equipment in the lower reaches of Yangtze River in China.

Plastic film mulching technology occupies a prominent position in China’s agricultural production and plays an important role in improving crop yields, which can increase farmers’ income and ensure national food security. As the current residual film recycling mechanism is incomplete, the accumulation of residual film in the soil has gradually increased, and the problem of residual film pollution has posed a serious threat to agricultural production and the natural environment. Ridge mulching cultivation is one of the main planting patterns for grain and oil crops, such as peanuts, potatoes, and maize, in China. In this paper, the planting patterns, mulching conditions, characteristics, and distribution of residual film of the typical ridge mulching crops, such as peanut and potato, were analyzed. The merits and demerits of various kinds of residual film recycling machines and the application status and operation quality of peanut and potato residual film recycling machines are summarized. Problems and suggestions for the mechanized recycling of residual film were raised. This study may provide ideas for the development of residual film mechanization recycling of ridge mulching crops. The aim of this study is to propose practical solutions by analyzing the current status and existing problems of mechanized residual film recovery in order to reduce residual film pollution, protect the environment, and achieve sustainable agricultural development.