China is the largest vegetable producer in the world, and vegetable production is more geographically concentrated in the Huang-Huai-Hai region and the Yangtze River Basin. There are significant challenges ahead for increasing the average yields of the vegetables in this region. The effects of a cultivation system, a mulched ridge with a double row (MRDR), were evaluated by using the 2ZBX-2A vegetable transplanter newly designed in this paper. The key parameters of the equipment were designed and optimized by using the human–computer interaction method and the discrete element method according to agronomy requirements. Compared with the traditional ridge (TR) system on two typical solanaceous vegetables (eggplant and capsicum), the uniformities of the plant spacing and the planting depth in the MRDR system were significantly improved. Finally, the fresh fruit yield in the MRDR system increased significantly (p < 0.05) by 40.8% and 35.3% compared with that in the TR system for eggplant and capsicum, respectively. In addition, the water use efficiency (WUE) was also 54.9~59.7% higher under the MRDR system than under the TR system. All the results indicate that the MRDR system has the potential to improve the yields and WUE of solanaceous vegetables in the Huang-Huai-Hai Plain of China.

China is the world’s biggest producer of sweet potato (Ipomoea batatas (L). Lam.), and approximately 55% of the global supply is from China. Raised beds (RB) and raised beds mulched with plastic film (RBF) are the two main sweet potato cultivation systems now widely used in northern China. Planting placement of multiple nodes buried in shallow soil layers is additionally required for the sweet potato cultivation to achieve higher yields and reduce pests and diseases in this area, which increases the difficulty of transplanting mechanically. Therefore, a 2CGFS-2 compound sweet potato transplanter was developed, and the key parameters of slips transplanting apparatus were designed in this paper. Furthermore, its performance was investigated over two years under four treatments with different sweet potato varieties (Jishu 26 and Pushu 32) and cultivation systems (RBF and RB). The results showed that the missing seedling rate and qualified rate of transplanting population for each treatment by using 2CGFS-2 compound transplanter were 95.0% in both 2020 and 2021, while the mean values of the plant spacing variation coefficient and the qualified rate of transplanting depth during 2020–2021 were 4.53% and 96.28%, respectively. The length of the sweet potato slip inserted into the soil by the 2CGFS-2 compound sweet potato transplanter was almost the same, ca. 195 mm. The accurate placement of the sweet potato slips reduced the differences in tuber weight per plant caused by manual transplanting. These results are of considerable importance for RB and RBF sweet potato cultivation systems.

The sweet potato transplanters of diverse transplanting configurations have been shown to produce various planting properties in relation to different raised bed cropping systems, thus affecting crop growth and yield in sweet potato cultivation. In Shandong Province, a field experiment assessed the effects of three treatments (RB1, mulched raised beds with a finger-clip type transplanter; RB2, bare raised beds with a finger-clip type transplanter; and RB3, bare raised beds with a clamping-plate type transplanter) on soil temperature, plant growth, yield, and economic benefits. With the lowest coefficient variation of plant spacing and planting depth, the RB1 with the finger-clip type transplanter had 6.4% and 6.0% higher temperature at 5–10 cm soil layer by using the plastic-mulch for rapid early slips growth as compared with the RB2 and the RB3, respectively. Consequently, the leaf area index in the RB1 was increased by 5.6% and 6.4% as compared to the RB2 and the RB3, separately. This finally contributed to 57.5–70.8% greater fresh vines weight and 23.8–33.8% higher tubers yield in the RB1 compared with both the RB2 and the RB3 treatments, respectively. In general, in the mulched raised bed system of the Huang-Huai-Hai region of China, the finger-clip type transplanter could be a suitable option for the transplanting of sweet potato slips. In the bare raised bed system, meanwhile, the clamping-plate type transplanter has the potential to increase the production of sweet potatoes.

A Gas–solid two-phase flow coupling simulation is widely used to study the working process of pneumatic seed dischargers. Due to the demand for deterministic particle orbit numerical calculation models, seeds are mostly modeled using the particle aggregation method, where the seed model is formed through particle aggregation bonding without overlapping. The smaller the radius and the more filled ball particles used in this method, the closer they resemble the real morphology of the seed. However, this results in the over-consumption of simulation computational resources and simulation time growth. In this study, we used wheat seeds as the research object, studied the effect of seed models with different filled ball radii on the kinetic response characteristics between the particles, and searched for the optimal number of filled ball particles for the seed model. With the help of three-dimensional scanning and inverse fitting methods to obtain the seed profile, we used different radii (0.2 mm, 0.24 mm, 0.28 mm, 0.32 mm, 0.36 mm, and 0.4 mm) to fill the ball particles, and formed a wheat particle bonding model for a gas–solid coupling simulation. We used a combination of real tests and simulation measurements of bottomless cylinder-lifting and slip-stacking. The interspecies static and dynamic friction factors in seed models with different radii of filled spherical particles were first calibrated using the angle of repose as an index. Then, the parameters were verified using bottomless cylinder lifting and slip stacking tests, which used the coefficient of variation for the simulation test’s angle of repose as an index. Our results show that the smaller the radius of the filled ball, the closer the simulation results were to the real value. Validation was conducted using a gas–solid coupling simulation of an air-blown wheat seed discharger, with the seed filling rate as an index. Our results showed that the simulation length and simulation accuracy were optimal when the radius of the filling particle was 0.32 mm.

The mechanized transplanting of sweet potato slips onto mulched raised beds in China’s Huang-Huai-Hai region faces significant challenges due to fragmented smallholder farms and the specific agronomic requirement of “boat-shaped” horizontal planting. To address this gap, this study aimed to develop a compact, cost-effective transplanter that meets the “boat-shaped” planting agronomy and adapts to small plots. We designed the 2CGX-1 mini wheel-driven transplanter coupled with a tractor. This machine features a compact chassis ( ¥800/ha), this transplanter achieves a daily operational efficiency of ~0.35 ha/day (calculated by 0.55 km/h speed × 0.8 m working width × 8 h daily working time). Meanwhile, the consistency of its key planting indicators and the planting qualification rate are significantly superior to those of manual planting, while improving operational quality and significantly reducing labor cost input. Deviations in individual indicators mainly stem from planting positioning deviations induced by terrain undulations in hilly test areas, and sweet potato seedlings’ tendency to fall off during clamping due to mechanical vibration. However, these errors are within the acceptable agricultural operation range and do not compromise the machine’s overall compliance with agronomic requirements. The transplanter effectively meets agronomic requirements while offering a cost-effective, adapted solution for small-scale sweet potato production systems, significantly advancing mechanization capabilities for mulched cultivation.