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The mechanical transplantation of large rice seedlings severely inhibits yield; however, studies on the impacts of mechanical transplantation are relatively scarce. Root–stem coupling damage is the main form of damage in mechanically transplanted large seedlings. Here, 40-day-old rice seedlings served as subjects for pot experiments conducted under two conditions, with and without a root–stem coupling damage treatment. Changes in root characteristics, leaf SPAD values, and stem structure were observed at 12 days after transplantation. Additionally, a transcriptome analysis was conducted on the seedlings 6 days post-transplantation. The root–stem coupling damage significantly inhibited rice growth. By 12 days after planting, the root length, root surface area, root volume, number of root tips, and SPAD values in the treatment group decreased by 44.4%, 53.1%, 61.5%, 31%, and 23%, respectively, compared with the control (non-treatment) group. The heart leaf growth rate decreased by 49.5% between the 9th and 12th days after transplantation. Transcriptome sequencing data indicated that mechanical transplantation enhanced rice disease resistance and structural strength but slowed the growth rate. Adjustments in gene expression may help rice resist the physical and biological stresses encountered during mechanical transplantation. This study provides important references for the design of rice transplanters and the selection of suitable varieties for mechanical transplantation.

To address the inefficiency and instability of automatic transplanting machines, a dual-row seedling pick-up device and its corresponding control system were developed. Existing seedling end-effectors are primarily mechanically controlled, and the seedling needles can easily cause damage to the interior of the bowl. In order to reduce the damage inflicted by the end-effectors to the bowl, this paper conducted a mechanical analysis of the end-effector. At the same time, a buffer optimization analysis was conducted on the operation of the end-effector, and a flexible pneumatic end-effector for seedling picking was designed. The control system combined the detection of multiple sensors to monitor the process of seedling picking and throwing. By coordinating the lifting cylinder and clamping cylinder, the system effectively reduced seedling pot damage while improving seedling picking efficiency. By setting the operating parameters of the servo motor, the goal of low-speed and high-efficiency seedling picking was achieved. To evaluate the performance of the control system, the linear displacement sensors and acceleration testing systems were used to analyze the performance of the seedling throwing. The results showed that the seedling picking efficiency could reach 180 plants min−1, with no significant difference between the actual measured moving distance and the theoretical setting distance. The positioning error remained stable between 0.5 and 0.9 mm, which met the requirements for seedling picking accuracy. The buffer optimization design reduced the peak acceleration of the end-effector from −22.1 m/s2 to −13.4 m/s2, and the peak value was reduced by 39.4%, which proved the significant effectiveness of the buffer design. A performance test was conducted using 128-hole seed trays and 33-day-old cabbage seedlings for seedling picking and throwing. When the planting frequency reached 90 plants/row·min−1, the average success rate of picking and throwing seedlings was 97.3%. This indicates that the various components of the designed seedling pick-up device work in good coordination during operation, and the control system operates stably. Technical requirements for the automatic mechanical transplanting of tray seedlings were achieved, which can provide reference for research on automatic transplanting machines.

【Objectives】 Nitrogen loss from agricultural soils is an environmental concern worldwide and the purpose of this paper is to investigate the impact of the types of nitrogen fertilizers and planting methods on reducing nitrogen loss from surface runoff and ammonia volatilization from paddy field. 【Method】 The experiment was conducted in a field with the rice established either from machine transplanting (MTR) or direct drill (DSR). Added to these were four nitrogen fertilizations: conventional fertilization (FFP), slow-controlled fertilizer combined with urea (CRF) and seaweed polysaccharide nitrogen fertilizer (HTN), with no nitrogen application as control (CK). In each treatment, we measured nitrogen loss from the surface runoff and ammonia volatilization. 【Result】 Nitrogen lost from surface runoff was dominated by ammonium nitrogen (NH4+-N), with the loss from the drainage prior to the planting accounted for approximately 52% of the total nitrogen loss from the surface runoff. The impact of fertilizers on total nitrogen loss from the surface runoff was ranked in the order of FFP > HTN > CRF, the same as the loss rate and intensity of ammonia volatilization (AV) for both MTR and DSR. Compared with FFP, CRF and HTN each in combination with MTR reduced the AV loss during the whole growth season by 12.5% and 4.3% respectively, with their associated AV intensity reduced by 43.1% and 17.8% respectively; when combining each with DSR, they reduced AV loss rate by 23.2% and 12.2% respectively, with their associated AV intensity reduced by 53.3% and 26.8% respectively. Compared with FFP, CRF and HTN increased the yield by 9.31% and 4.70%, respectively, for rice planted using MRT, and 9.25% and 4.91%, respectively, for rice planted using DSR. 【Conclusion】 During the whole growth season, planting rice using DSR increased the AV flux, nitrogen loss rate and AV intensity than planting with MTR. The impact of fertilizers on nitrogen loss from the surface runoff was ranked in the order of FFP > HTN > CRF. When the amounts of all applied nutrients were the same, selecting an appropriate nitrogen fertilizer with a rational combination with basal fertilization and tillering-stage dressing can not only reduce nitrogen loss, but also improve nitrogen use efficiency and ultimate yield.

To better meet the requirements of mechanized transplanting of pepper plug seedlings, this study explores the seedling picking mechanism of a fully automatic pepper transplanting machine. It introduces a novel “eagle beak” type trajectory for seedling picking and designs a probe-type mechanism for pepper plug seedling retrieval. We establish a kinematic theoretical model and delineate the composition and operational principles of this probe-type mechanism. Additionally, we develop an auxiliary optimization software tailored based on Visual Basic 6.0 visual programming software for this mechanism. It employs a blend of manual fine-tuning and a “parameter guidance” optimization algorithm, enabling the determination of 11 optimal target parameters. Our comparative analysis between the theoretical model, optimization software, and high-speed camera experiments reveals a strong correlation in the motion trajectories, and the maximum error of the pose angle is 1.2°. To validate the mechanism’s design, we conducted a seedling retrieval experiment. In this test, the success rates of the seedling harvesting mechanism at speeds of 30, 40, and 50 r/min were 96.4%, 94.3%, and 91.4%, respectively, thus demonstrating its practical feasibility.

Wheat and Paddy are the new focuses in farming where still, relatively few scientists and makers take an interest. This field faces a few issues, for example, how to boost the benefit, how to build efficiency and how to diminish the expense. In India, two sorts of horticultural gear are utilized, manual strategy (ordinary technique) and motorized sort. Automation includes the utilization of a gadget between the work and power source. Transplantation is the on the extensive labor processes in agriculture, where in cultivation field the workers need to work in stooping position which creates the physical ailments to labors. In this work, to eliminate the difficulties in rice cultivation design of semi-automatic rice transplanting machine by cost effective method was discussed. This machine helps the farmer to improve the productivity and efficiency. Machine was designed and fabricated by using the available materials. Compare to the commercial machines the project has more economic. Investigation of the machine performance indicate that it significantly reduces the effort of labors and translation time.

A structural optimization scheme for the prototype is proposed to improve the driving performance of tree transplanting machines operating in hilly and mountainous environments. Through theoretical analysis of the tree transplanting machine’s stability and passability, we determined the relationship between the center of gravity offset distance and overall performance when climbing slopes and crossing steps and trenches. This analysis determined the optimal parameter for the center of gravity offset distance. Subsequently, the prototype structure was optimized, and the center of gravity position was adjusted accordingly. The stability and passability of the prototype were simulated using the multi-body dynamics analysis software RecurDyn V9R4. Finally, the driving performance of the optimized prototype is evaluated through extensive tests. The test results revealed that the optimized prototype achieves the maximum lateral travel and longitudinal climbing angle of more than 30°, the maximum height over steps of 330 mm, and the maximum width across trenches of 890 mm. The outcomes of the real-vehicle tests are largely consistent with the simulation results, and the test outcomes meet the driving performance requirements for transplanting operations in hilly and mountainous terrains.

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 <1.2% and >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.

To address problems caused by rice machine transplanting such as injury to the seedlings and recovery period that extend growth period, this study explored the effects of different machine transplanting methods on the physiological and yield characteristics of late rice in China, and determine the appropriate machine transplanting method for late rice, which was expected to provide a basis for high-yield and high-efficient cultivation of machine-transplanted late rice. Hybrid indica rice Taiyou 398 and conventional indica rice Jing Gangruanzhan were selected as the research objects, and large-pot carpet seedling machine transplanting (M1), conventional pot carpet seedling machine transplanting (M2) and ordinary carpet seedling machine transplanting (M3) were adopted respectively to analyze their effects on seedling quality, population physiological characteristics, yield and its components and economic benefits of late rice. The results showed that compared with M2 and M3, M1 achieved higher seedling quality, showing significant advantages in the early stage despite average root entwining force that met the requirement of machine transplanting. The seedlings transplanted using M1 had shorter recovery period after mechanical transplanting, with earlier tillering, earlier peak seedling, and slower declining of stems and tillers in the late stage; the peak seedling number was not high, but the effective tiller number and earbearing tiller percentage were significantly higher than those achieved by the other two machine transplanting methods. Also, M1 achieved stronger photosynthetic capacity of flag leaves before HS, with more photosynthetic products in stems and leaves transported to panicles and more efficiently after HS. Compared with seedlings transplanted using M2 and M3, the recovery period of those transplanted using M1 was shortened by 3 and 5 d, the heading stage (HS), and maturity stage (MS) were advanced, which effectively reduced the risk and impact of \"cold dew wind\" on machine-transplanted late rice. M1 had significant yield increase advantage and economic benefit, with better grain maturity, and \"larger panicles, more panicles, more and fuller grains\". M1 achieved an average yield increase of 10.31%-l 1.10%, 20.67%-25.10% in 2 years, and an average income increase of 18.65%-131.06% and 62.85%-323.78%, respectively. Therefore, vigorously developing Ml is the key to the high-yield and high-efficient cultivation of machine-transplanted late rice in China.

Mounting labor shortages and rising operational costs are threatening the sustainability of mechanized rice production in Southern China, underscoring the urgent need for innovations that reduce labor inputs during nursery preparation and transplanting. To address these challenges, this study developed an innovative double-blanket seedling tray measuring 120 cm in length—twice that of a conventional tray. Based on this design, experiments were conducted to identify suitable lightweight substrates capable of producing cohesive and structurally stable double-blanket rice seedling mats. Two lightweight substrates—crop straw boards and matrix cotton—were evaluated in comparison to traditional nursery soil. Results demonstrated that, when combined with the nutrient solution “Miao Zhuang Feng”, both lightweight substrates significantly improved seedling quality, transplanting performance, and final yield. Notably, the fresh weight of double-blanket seedlings grown on lightweight substrates was comparable to single-blanket seedlings cultivated in soil while being 47.46% lighter than double-blanket seedlings raised with soil. To optimize double-blanket seedling mat formation and transplanting quality, five seeding densities (300, 360, 420, 480, and 540 g/tray) and four seedling ages (10, 15, 20, and 25 d) were tested using crop straw board as the substrate. The results revealed that optimal combinations varied by condition: 480 and 540 g/tray were suitable for 15-day-old seedlings, 420 g/tray for 20-day-old seedlings, 360 g/tray for 20~25-day-old seedlings, and 300 g/tray for 25-day-old seedlings. Compared with single-blanket seedlings, the double-blanket approach reduced the number of trays required per hectare and the total seedling cultivation and transportation cost by 57.97% and 16.67%. Furthermore, increasing the seeding density from 300 to 360, 420, 480, and 540 g/tray led to additional reductions of 16.31%, 26.24%, 34.75%, and 41.13%, respectively—substantially lowering labor requirements for tray handling and seedling feeding during transplanting.

Transplanting rice pot seedlings without damaging the roots, which promotes early tillering, is an effective measure to enhance rice yield and quality. This study aimed to obtain the mechanized-transplanting trajectory and attitude of rice pot seedlings by utilizing non-circular planetary-gear trains, focusing on the three key actions of rice pot-seedling transplanting: seedling picking, conveying, and planting. A lightweight and simplified rice pot-seedling transplanting machinery was designed, referring to the motion characteristics of artificially transplanting rice pot seedlings by first pulling them out and then planting them. Key technologies such as non-circular gear trains, the rice seedling supply system, the transmission system, and the rice seedling-picking device were studied, and their key components were designed and manufactured, resulting in the creation of two physical model machines: an ordinary ride type and a high-speed type. The seedling-picking test and field-transplanting test showed that the rice pot-seedling transplanting mechanism can accomplish the rice pot-seedling picking, rice conveying, and planting actions. The designed operation efficiency yielded a planting-depth qualification rate of over 92%, a seedling injury rate of less than 1.2%, and a missed-transplanting rate of less than 2%.