In view of the problems of the difficulties faced in horizontal planting; high labor intensity, poor operation quality and low economy in the existing sweet potato bare seedling transplanting technology and equipment, combined with the agronomic requirements of sweet potato planting and transplanting, a sweet potato bare seedling horizontal transplanter is designed, which can realize multiple processes such as rotary tillage and ridging, ditching and transplanting, covering soil and standing seedlings. The main parameters affecting the working performance and operation effect of the whole machine are analyzed, determining the relevant position and motion parameters, taking the forward speed of machines and tools, spacing of the ribbons and spiral speed as the influencing factors of the performance test, selecting the qualified rate of plant spacing as the evaluation index, and designing a three-factor and three-level orthogonal test. The test results show that the primary and secondary order of the significance of the qualified rate $Z$ of plant spacing is $B$, $A$ and $C$. The better horizontal combination of influencing factors is that the forward speed of machines and tools is 0.17 m·s⁻¹, the spacing of the ribbons is 110 mm, and the spiral speed is 170 rpm. The field test results showed that the average $Z$-value of plant spacing qualification rate under the optimal factor level combination was 91.87%, which met the relevant technical standards and agronomic requirements.

The operation of the semi-automatic pepper pot seedling transplanter has the problem of a low frequency of manual operation. We designed a new automatic transplanting mechanism based on a clamping stem. Through the movement law of a double-crank connecting rod mechanism, the static trajectory of beak shape and the dynamic trajectory of N shape were designed to meet the requirements of backward transplanting. The kinematics equation of the seedling picking mechanism was established and the mechanism parameter optimization program was developed based on MATLAB. The effect of the mechanism parameter changes on the seedling movement trajectory was analyzed. A group of parameter combinations that met the requirements of seedling picking and planting were optimized. After optimization, the trajectory height was 220.8 mm, the picking angle was 21.03° and the planting angle was 64.15°. The plant spacing was 260 mm, which meets the agronomic requirements of pepper transplanting. Through the combination of theoretical analysis and prototype tests, the test results showed that the theoretical trajectory was basically consistent with the actual trajectory, verifying the feasibility of the mechanism design. In this study, pepper pot seedlings in the suitable planting period of 60 days were selected and planted at the rotation speed of 60, 70 and 80 r/min, respectively. The success rate of seedling selection was more than 91.1%, the success rate of planting was more than 78.5%, the qualified rate of erect degree was 94.9%, and the coefficient of variation of plant spacing was stable below 14.1%. The results show that the integrated automatic transplanting mechanism for pepper pot seedlings was effective.

In order to meet the sowing demand of the hybrid rice plug seedling, a horizontal rotary precision seed metering device was proposed. The key structure parameters were designed, the kinematics analysis of the seed-filling process was carried out, and the main influencing factors of the seeding performance evaluation index were determined. Taking motor speed, the eccentric distance of the disk, and seed layer thickness as test factors, and the taking qualification rate, repetition rate, and miss-seeding rate as seeding performance test indexes, the quadratic regression orthogonal rotation combination test was carried out, and the relationship between the test factors and evaluation indexes was approached by a quadratic polynomial. On the basis of discussing the influence of the test factors on the performance index, the regression surrogate mathematical model between the main performance index and the influencing factors was established. The value of the evaluation index of correlation degree p between the model variables was less than 0.01. Based on the regression surrogate mathematical model, the response surface of the qualified rate of the seeding performance evaluation index was established, and the test data were analyzed by multiple regression analysis. The rapid prediction of qualified rates under the influence of test factors was realized, and the optimum test parameters were obtained as follows: motor speed 165 r/min, an eccentric distance of disk 22 mm, seed layer thickness 28 mm, qualification rate 98.55%, miss-seeding rate 1.45%, and repetition rate 0%. According to the best combination of test parameters, the performance evaluation index test of the prototype was carried out, and the qualification rate, miss-seeding rate, and repetition rate were 98.34%, 1.66%, and 0%. The experimental results were in good agreement with the theoretical analysis, indicating that the horizontal rotary precision seed metering device can meet the agronomic requirements of hybrid rice. The research results could provide some reference for the design of a precision seeding device for industrialized plug seedlings.

Research on precision seeders operated in the dry field shows that an electric driving system used for a seed meter can significantly improve the planting uniformity. The measuring method for forward speed greatly affects the control accuracy of the electric driving system. However, the performance of an electric drive system for precision seeders operating in wet fields, such as paddy, is still unclear. The operating conditions of dry and wet fields are quite different, and it is necessary to study the effects of an electric driving system and corresponding speed measuring methods on a wet-field operating seeder. In this paper, field experiments were carried out by using a wet direct planter of rice under three driving methods for seed meter, including classic mechanical driving system (MDS), electric driving system with speed acquiring from an encoder (EDSE), and electric driving system with speed acquiring from the global positioning system (EDSG), at forward speeds of 4.62, 5.81, and 7.23 km·h⁻¹. The seeding uniformity (seeding rates, coefficient of variations) and the slippage (slippage rate, broken strips) were investigated. Results showed that the EDSG exhibited more qualified operation performance compared with the MDS and the EDSE. For both the MDS and EDSE, the seeding rates significantly decreased and deviated from the desired value as the forward speed increased. The negative slippages of MDS and EDSE were 3.47–31.72% and 2.13–7.7%, respectively, and they significantly increased when the forward speeds increased from 4.62 to 7.23 km·h⁻¹. Analysis of the seeding uniformity and slippage presented that the EDSG exhibited a more qualified operation and is recommended for the wet direct seeder of rice.

The intelligent control of precision planting can detect and regulate the operation quality of the planter in real time, which plays an important role in improving the operation quality of the planter and the yield of the corn. In this paper, the control system of a corn precision planter is designed to realize the operating quality monitoring and electric driving of the seed-metering device. The planting quality is calculated by the time interval between the neighboring falling seeds, instead of the plant spacing, to improve the operational efficiency of the system. At the same time, the forward speed of the planter is obtained by radar, which is used to accurately match the speed of the seed-metering device with the forward speed of the planter. The velocity error of the radar is analyzed, and the relevant relationship of the radar output frequency and forward speed is established. Comparative test results of this system and the JPS-12 test bench show that the detection performance of the system is reliable, and the maximum detection error of the quality parameters is less than 2.88%. Field experiments were carried out to verify the operational performance of the control system. Two speed sensors, radar and GPS, were chosen to study the effect of speed measuring on the performance of the control system. We found that speed measuring has a significant effect on planting performance. The qualified parameters of radar were significantly higher than those of GPS, at a forward speed of 6–12 km/h. The qualification feeding index (QFI) of radar was 0.51%, 0.67%, and 2.05% higher than that of GPS at speeds of 6, 8, 10, and 12 km/h. The precision index (PREC) of radar was 17.60%, 5.44%, 16.81%, and 17.30% lower than that of GPS. Therefore, the control system based on the radar speed measurement developed in this paper can significantly improve the operating quality of the planter.

Deep tillage is a conservation tillage method that aims to break the plow pan layer. It provides significant benefits, including enhanced root development, improved soil quality, and substantial increases in crop yields. The depth of tillage is a crucial factor in assessing the effectiveness of deep tillage operations. Accurate regulation of tillage depth in deep tillage equipment is vital for ensuring the high-quality and efficient execution of these practices. The distribution of mechanical resistance within the soil can effectively indicate the location of the plow pan layer and serves as the main reference for setting the tillage depth for machinery. This paper examined the current state of research on tillage depth control technology for deep tillage operations. It focused on three main technical areas: soil mechanical resistance detection, tillage depth measurement, and tillage depth regulation. The report discussed the working principles of various technologies and compared the existing methods. Additionally, the paper analyzed the challenges faced in the development of tillage depth control technology in China and offers recommendations for future advancements. It highlighted that leveraging information and digital technologies to determine the distribution of the soil plow pan layer, along with the integration of efficient and intelligent control technologies for precise tillage depth regulation, represented a key direction for the future development of deep tillage operations.