The use of plastic film for mulching cultivation is an important agricultural production technology, which plays an important role in achieving agricultural yield increase and farmers’ income increase. China’s use of plastic mulch ranks first in the world, and China is also the country with the most severe residual plastic mulch pollution in farmland. It is of great significance to have a comprehensive understanding of the use and resource recycling of plastic mulch in China. As a result, this article reviews the recent advances in the use and recycling of plastic mulch in China. First, the types and characteristics of commonly used agricultural plastic mulch are introduced. Then, the development process and application situation of plastic mulch in China are mainly summarized, and the problems of farmland soil and environmental pollution caused by residual plastic mulch are discussed. Finally, the current situation, main practices, and existing problems of waste plastic mulch recycling in China’s farmland are explained in detail from the perspectives of government policy formulation and farmer practice. The research in this article will play an important role in further solving the problem of plastic mulch pollution in farmland soil in China and can also provide a reference for other countries.

Mulching technology has created a major problem of agricultural plastic pollution. This is because the mulch is severely degraded by UV (ultraviolet) irradiation and the mechanical properties deteriorate, which makes mechanical recycling or manual recycling difficult. This study was conducted on m-LLDPE (metallocene linear low-density polyethylene) mulch films. The difference in mechanical properties of specimens in the TD (transverse direction) and PD (parallel direction) was investigated, and the changes in the mechanical properties after UV irradiation were compared. Finally, an initial mulch mechanical property evaluation model was developed to adapt to different recovery machines and crop agronomic requirements. The results suggest that the mechanical properties of m-LLDPE mulch films were strongly influenced by the film thickness, and also showed directional differences in tensile and tear properties. After UV irradiation, the mechanical properties of the specimens were enhanced after a short period of time, but the overall trend was a non-linear decay which gradually slowed down with time.

To address the gap in research on the mechanical properties of peanuts in the harvesting period, the mechanical properties of peanut seedling vines, pods, and peduncles were studied during the peanut harvesting period. The moisture content of peanut pods, peduncles, and seedling vines was measured, yielding values of 36.03%, 66.76%, and 77.95%, respectively. The tensile characteristic parameters between the pods and peduncles, peduncles and peduncles, and the seedling vines and peduncles during the harvesting period were determined using an electronic universal testing machine at three different loading speeds: 10 mm/min, 20 mm/min, and 30 mm/min. The test results indicated that the peduncle–peduncle, peduncle–pod, and peduncle–seedling vine detachment forces were 19.91 N, 17.41 N, and 8.62 N. The mechanical properties of peanuts during the harvesting period differed from those of peanuts that were excavated and sun-dried. Peanut-digging and turning machines should be designed based on the detachment force required to separate the peduncles from the pods, which, at a loading speed of 20 mm/min, is 17 N. This examination of the mechanical properties of peanuts during the harvesting period could have significant practical implications and a lasting influence on enhancing the efficiency and quality of peanut harvesting, refining harvesting machinery design, and advancing agricultural modernization.

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.

The soil during the sowing period of wheat after rice stubble cannot be accurately described by existing models and parameters with DEM because of its high moisture content and strong viscosity. The purpose of this study is to conduct an overall simulation of high-viscosity paddy soil and to analyze the accuracy of the model. Based on the results of an unconfined compression test and shear test, the range of bond parameters is preliminarily determined by a simulation test. Through the P-BD test and RSM test, the parameters with significant influence are determined to be normal stiffness per unit area (S_N), shear stiffness per unit area (S_S), and critical shear stress (C_S), and an optimized combination of these parameters is obtained. Based on the optimized model, the error range and error generation mechanism of the model are analyzed under different operating parameters. The results show that the optimal parameter combination is S_N of 1.07 × 10⁷ N/m³, S_S of 0.70 × 10⁷ N/m³, and C_S of 0.35 × 10⁵ Pa, corresponding to a compression force of 120.1 N and a shear force of 7.70 N. With an increase in forward speed or seeding quantity or a decrease in rotary plowing speed, the model accuracy tends to increase, and the range of relative errors was found to be from 8.8% to 28.4%. The results can provide a research basis for the study of the motion state of seeds under soil. It can also further enrich parameter data of soil discrete element simulation models and provide a reference for related research studies.

This study proposes a negative-pressure fruit-soil separating device for peanuts cultivated in hilly and mountainous areas after combined harvesting, and the mechanism of the movement of the material in the process of material screening, fruit-soil separating, and pneumatic conveying of the device was analyzed. In addition, a four-factor, three-level Box-Behnken regression design test was used to explore the optimum operating parameters of the peanut fruit-soil separation device. The results showed that the best fruit-soil separation effect was achieved when the wind speed of the blower was 13.58 m/s, the height of the suction nozzle from the screen surface was 27 mm, the length of the suction port was 64 mm, and the feeding rate was 600 kg/h. Validation tests demonstrated that the impurity rate of 0.16% and the peanut pod loss rate of 0.2% exceeded the industry standard, indicating superior performance.