In order to quickly dry the peanut pods and effectively reduce the mildew on peanut pods in rainy weather, this paper analyzed the research status of peanut digging and inverting technology in China and abroad, combined with the peanut two-stage harvesting mode. The orthogonal experiment was carried out by using the peanut digger-inverter to study the different forms of upright type, taking the rate of vines inverting, the rate of buried pods, and the rate of fallen pods as the evaluation indexes, and taking the traveling speed of the tractor A, the line speed of the conveyor chain B, and the line speed of the inverting roller C as the experimental factors. The results showed that, in the states of unpressed vines and pressed vines, the order of influence of the peanut digger-inverter on the evaluation indices was A > C > B. The optimal horizontal combination of unpressed vines was A₂C₃B₂, when the traveling speed of the tractor is 1.06 m/s, the line speed of the inverting roller is 2.12 m/s, and the line speed of the conveyor chain is 1.02 m/s; the rate of vines inverting was 71.07%, the rate of buried pods was 0.2%, and the rate of fallen pods was 0.22%. Under the condition of vines pressing, the best horizontal combination is A₂C₂B₂, when the travelling speed of the tractor is 1.01 m/s, the line speed of the inverting roller is 1.88 m/s, and the line speed of the conveyor chain is 1.02 m/s; the rate of vines inverting was 74.29%, the rate of buried pods was 0.14%, and the rate of fallen pods was 0.33%. The paired t-test was carried out by the peanut digger-inverter under the state of pressed and unpressed vines. There was little difference in the influence of each factor on the rate of fallen pods and the rate of buried pods, but there was a significant difference in the influence on the rate of vines inverting. The rate of inversion of vines under the state of pressed vines was higher than that under the state of unpressed vines. The research results will provide certain technical support for the late optimization of the peanut digger-inverter and create a hardware foundation for the intelligence and information harvesting of peanuts.

As an important oil crop in China, peanuts require mechanized sowing to enhance production efficiency. This paper analyzes the influence of peanut seed physical characteristics on the design of seed metering devices and systematically introduces the working principles, advantages, and disadvantages of mechanical (internal cell-fill, cell-wheel, and spoon-wheel types) and pneumatic (air suction, air pressure, and air-blowing types) seed metering devices. This paper reviews the development status of peanut seed metering devices and provides examples of these devices mounted on sowing machines. It is found that European and American researchers mainly conduct research on high-speed pneumatic seed metering devices, and, though China’s peanut seed metering device development has made progress and resulted in products with different technical levels, they still fall short of international advanced products in terms of high-speed seeding capability and seeding accuracy. In the future, research should be strengthened in areas such as the in-depth development of pneumatic seed metering devices, the adaptability of mechanical seed metering devices to high-speed operation, and intelligent monitoring and control systems.

To enhance the operational performance of green manure sowing, seed harvesting, and processing equipment, as well as to obtain the physical characteristic parameters required for equipment simulation analysis, it is necessary to carry out the seed physical properties such as dimensions, bulk density, and frictional characteristics. This study focuses on the main cultivated varieties of green manure in China—milk vetch, hairy vetch, and sesbania—and innovatively proposes three low-cost, convenient, and high-precision experimental methods of geometric size for small-sized seeds. The measured results show that geometric dimensions of the seeds for milk vetch were 2.60mm-3.40mm in length, 1.90mm-2.40mm in width and 0.71mm-0.97mm in height, the pod dimensions of hairy vetch were 23.03mm-32.83mm in length, 7.39mm-9.74mm in width, 4.06mm-6.15mm in height, and seed diameters were 3.04mm-4.10mm, the seed dimensions of sesbania were 3.81mm-4.29mm in length, 1.98mm-2.37mm in width, 1.85mm-2.08mm in height. Using Python programming language and open-source AI algorithms, we innovatively developed an image-based seed counting experimental method. This cost-effective approach requires no specialized instruments while significantly saving time and labor. Based on the counting results, the thousand-seed weights of milk vetch, hairy vetch, and sesbania seeds were determined to be 3.40g, 26.50g and 15.58g, with respective seed moisture contents of 7.18%, 9.81% and 8.73% at the time of measurement. The instruments and methods for measuring bulk density and angle of repose of green manure seeds were defined. The bulk densities of milk vetch, hairy vetch, and sesbania seeds were determined to be 732 g/L, 761 g/L and 845 g/L, by using the electronic grain densitometer. Meanwhile, the angles of repose of milk vetch, hairy vetch, and sesbania seeds were determined to be 31.66°, 28.15°and 29.82°, by using the angle of repose tester. Based on the principle that the indexing head can accurately determine the angle, the sliding friction angles of milk vetch, hairy vetch, and sesbania seeds were determined to be 25.85°, 23.55°and 24.03°, by using the di-viding head. The testing methods developed in this study, along with the results of measuring the physical properties of green manure seeds, provide valuable reference data for the measurement of the physical properties of small-seeded crop (e.g., green manures) as well as other small or irregularly-shaped particles.

To improve the performance of green manure sowing and processing equipment, it is necessary to investigate the physical properties of seeds, including their dimensions, bulk density, and frictional characteristics. Focusing on the main cultivated varieties of green manure in China—milk vetch, hairy vetch, and sesbania—this study proposes three low-cost, convenient, and high-precision experimental methods to measure the geometric size of small seeds. The measured results show that the milk vetch seeds were 2.60–3.40 mm in length, 1.90–2.40 mm in width, and 0.71–0.97 mm in height. The hairy vetch pods were 23.03–32.83 mm in length, 7.39–9.74 mm in width, and 4.06–6.15 mm in height, and the seeds were 3.04–4.10 mm in diameter. The sesbania seeds were 3.81–4.29 mm in length, 1.98–2.37 mm in width, and 1.85–2.08 mm in height. The thousand-seed weights of milk vetch, hairy vetch, and sesbania seeds were 3.40 g, 26.50 g, and 15.58 g, with moisture contents of 7.18%, 9.81%, and 8.73%, respectively. The bulk densities of milk vetch, hairy vetch, and sesbania seeds were 732 g/L, 761 g/L, and 845 g/L. The angles of repose of milk vetch, hairy vetch, and sesbania seeds were 31.66°, 28.15°, and 29.82°, measured using an angle-of-repose tester. Sliding friction angles of 25.85°, 23.55°, and 24.03° for milk vetch, hairy vetch, and sesbania seeds were obtained using a dividing head. These methods and results provide valuable references for the measurement of the physical properties of small-seeded crops (e.g., green manures) as well as other small or irregularly shaped particles.