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As is well known, intelligence and efficiency are important development directions for modern agriculture. The harvesting header, as key components of crop harvesters, have significant implications for achieving intelligent control of their working height, which has a notable impact on reducing harvest loss. To understand the current state of intelligent control technology for the working height of a crop harvesting header, and to explore their application potential, this article provides a relatively systematic literature review. Firstly, we analyzed the structure and principle of the harvesting header of typical grain and oil crops such as rice and peanuts. Secondly, we briefly described the current methods for controlling the working height of the harvesting header. They mainly use two methods: mechanical profiling and electro-hydraulic profiling. Thirdly, we focused on researching and analyzing the measurement methods and control algorithms for the working height of the harvesting header. Finally, we pointed out the problems in the current height control of the harvesting header. These problems mainly include insufficient measurement accuracy of working height in complex terrain, slow response and large delay of working height hydraulic control system, incompatibility between working height control models and strategies, and relatively single working height measurement methods.

Given the problem that traditional garlic cultivation patterns in China have difficulty in achieving comprehensive mechanized production, an experimental investigation on mechanization-friendly cultivation agronomy was conducted. In this study, an orthogonal experimental method was used to conduct continuous tracking experiments for three years in three major garlic production regions of China. All the experiments were used to verify the impacts of sprout orientation, planting mode, planting density, and row spacing on garlic bulb yield per hectare. For every impact, nine experiments were processed. The results indicated the following: (1) planting density influenced the garlic bulb yield per hectare extremely significantly, followed by row spacing, planting pattern, and sprout orientation; (2) the combination of sprout orientation (1–45°), planting pattern (large ridge), a planting density (42.75)/10,000 plants per hectare, and row spacing (26 + 10) led to the largest garlic bulb yield per hectare, which means this combination was the best form of cultivation agronomy. This study will provide a valuable reference for China’s farmland suitability for agricultural machinery operation (FSAM) production program.

Tractors are widely used self-propelled power machinery. Electrification is one of the main directions for the green and low-carbon development of tractors. Currently, electric tractors have become one of the main research hotspots in countries around the world. This study provides a comprehensive review of the research progress on electric tractors in China. Firstly, a brief analysis is conducted on the development history of electric tractors, the current research status in other countries around the world, and the situation regarding China’s tractor industry. Secondly, the classifications and characteristics of electric tractors are summarized. We focused on the research progress of electric tractor motors and their drive transmission systems, batteries, and energy management technology, as well as other key technologies. Finally, some opportunities and challenges faced by the development of electric tractors in China are pointed out from the aspects of market demand, national policies, and standard setting.

Background Seed germination and young seedling growth are important agricultural traits for developing populations of both irrigated and directly seeded rice. Previous studies have focused on the identification of QTLs. However, there are few studies on the metabolome or transcriptome of germination and young seedling growth in rice. Results Here, an indica rice and a japonica rice were used as materials, and the transcripts and metabolites were detected during the germination and young seedling growth periods on a large scale by using RNA sequencing and a widely targeted metabolomics method, respectively. Fourteen shared transcripts and 15 shared metabolites that were continuously differentially expressed in the two materials were identified and may be essential for seed germination and young seedling growth. Enrichment analysis of differentially expressed genes in transcriptome expression profiles at different stages indicated that cell wall metabolism, lipid metabolism, nucleotide degradation, amino acid, etc., were enriched at 0–2 days, and most of the results are consistent with those of previous reports. Specifically, phenylpropanoid biosynthesis and glutathione metabolism were continuously enriched during the seed germination and young seedling growth stages. Next, KO enrichment analysis was conducted by using the differentially expressed genes of the two materials at 2, 3 and 4 days. Fourteen pathways were enriched. Additionally, 44 differentially expressed metabolites at 2, 3 and 4 days were identified. These metabolites may be responsible for the differences in germination and young seedling growth between the two materials. Further attention was focused on the ascorbate–glutathione pathway, and it was found that differences in ROS-scavenging abilities mediated by some APX, GPX and GST genes may be directly involved in mediating differences in the germination and young seedling growth speed of the two materials. Conclusions In summary, these results may enhance the understanding of the overall mechanism of seed germination and young seedling growth, and the outcome of this study is expected to facilitate rice breeding for direct seeding.

China’s carrot planting area and total output rank first in the world, but China’s mechanized carrot harvesting level is relatively backward. There are many problems in the existing machine operation process, among which the problems of a high leakage rate and high damage rate are the main difficulties faced. In order to study this problem, a test platform composed of clamping and pulling devices and conveying devices is designed, and it can complete the experiments of clamping, pulling and conveying carrot plants and collecting carrot stalks at one time. During the test, the clamping speed was divided into four test levels: 0.40 m/s (T1), 0.85 m/s (T2), 1.30 m/s (T3), and control test (CK), and each test level was carried out three times at different forward speeds. Finally, the leakage rate and damage rate were statistically analyzed. The results show that the average damage rate of Xiahong2 is 6.13%, 3.53%, and 9.36% and that of Sanhong is 6.22%, 3.76%, and 9.88% under the clamping and conveying speeds of T1, T2, and T3 in two years. The average carrot missed-pulling rate of two consecutive years corresponding to two carrot varieties, Xiaohong2 and Sanhong, was 3.68% and 4.14%, respectively. The carrot missed-pulling rate of CK in the control group of two carrot varieties, Xiaohong2 and Sanhong, was high and stable at 96.2% to 97.5%. At the same time, T1, T2, and T3 had similar overall trends of high carrot leakage rates for two carrot varieties at different clamping and conveying speeds. This control experiment also proves that the experimental arrangement is scientific and accurate. The average carrot leakage rate of T1, T2, and T3 for Xiahong2 is 3.91%, 3.42%, and 6.22%, and that of T1, T2, and T3 for Sanhong is 4.06%. The research results can provide a theoretical basis and reference for the optimization and improvement of carrot clamping and conveying devices, and this research can provide a reference for how to reduce the harvest loss of carrot combine harvesters in China.

In order to clarify the mechanism of tiller–soil interaction in the process of strip rotary tillage, this paper conducted a simulation and experimental research on four blade configurations composed of three rotary blades (bent C, straight and hoe) at three rotation speeds (280, 380 and 510 rpm). The study found that the soil throwing characteristics of the blades are the key factors affecting the quality of tillage. The increase in the rotation speed not only improved the soil breaking effect, but also enhanced the phenomenon of soil throwing and then led to a reduction in the soil backfill. In the BC configuration (combination of four bent C blades), the bent C blades showed the best soil throwing characteristics and created the best soil fragmentation. However, due to the obvious side throwing of the soil, the backfill effect of soil fragmentation was the worst. The backfill rate was only 8% when the rotation speed was 510 rpm and could not allow reaching the required seed–soil contact during sowing. The hoe blades in the HC configuration (combination of four hoe blades) could collect part of the soil fragments and throw them towards the direction of the machine during the cultivation process, which led to a good soil breaking effect and a low soil side throwing rate. When the rotation speed was 510 rpm, 36% of the soil was backfilled into the seedbed. In the SC configuration (combination of four straight blades), the straight blades could well control the scattering of the side-thrown soil fragments. At a super-high rotation speed (510 rpm), the side throwing rate was only 70%, and the backfill rate was as high as 60%. However, the soil fragments created by the blades were too large (average soil block diameter > 40 mm) and could not form a loose and finely broken seedbed environment. The MC configuration (combination of two straight blades and two hoe blades) benefited from the combination of straight blades and hoe blades, offering outstanding advantages for backfill and soil fragmentation. Therefore, under the condition of a centralized configuration of field surface straw, it is recommended to use the MC configuration of the wheat rotary strip–till planter for cohesive paddy soil.

IntroductionRoot cutting is an important process in garlic field harvesting but is the weakest link in the full mechanization of garlic production. To improve the current situation of technological backwardness and poor operational quality of mechanized garlic root-cutting in the main garlic-producing regions of China, this study combined the physical characteristics and agronomic requirements of garlic plants, and proposed an innovative floating root-cutting technology for garlic combine harvesters that enables the top alignment of bulb, adaptive profiling floating of cutter, and embedded cutting of roots.MethodsThrough the kinematic analysis of the floating cutting process, the coordinate equations of the initial contact point of the bulb, the mathematical model of the floating displacement of the cutting component. Using computer simulation techniques, the dynamic simulation study of the floating cutting process was carried out in the rigid-flexible coupling numerical simulation model of root-cutting mechanism and garlic plant. The influence law of garlic conveying speed, extension spring preload force and stiffness on the floating displacement of the cutting component and the angular velocity of swing arm reset and its formation causes were analyzed by a single-factor simulation test. The key operating parameters of the root-cutting mechanism were optimized through the computerized virtual orthogonal test and fuzzy comprehensive evaluation.Results and discussionThe significance of the factors affecting the floating cutting performance decreased in the following order: extension spring preload force, garlic conveying speed and extension spring stiffness. The optimal parameter combination of the root cutting mechanism obtained from the optimization were as follow: extension spring preload force was 16 N, garlic conveying speed was 0.8 m/s, and extension spring stiffness was 215 N/m. Tests conducted with the optimal parameter combination yielded a root excision rate of 92.72%, which meets the requirements of Chinese garlic field harvesting quality. This study provides computer simulation optimization methods for the optimal design of the root-cutting mechanism, and also provides technical and equipment support for the full mechanization of garlic production in China.

In response to the dust pollution issue during the harvesting operations of peanut pickup combines, this study involved conducting bench tests to explore the variation patterns of dust emission parameters and harvesting operation indicators under diverse working parameter conditions of the combine’s working components. A multi-factor mathematical model was established to predict both the dust emission rate of peanut pickup combines and the quality of harvesting operations. The model was utilized to identify the optimal combination of operation parameters for achieving high-quality and low-emission performance. The optimal parameter combination was determined as follows: a pod threshing roller speed of 313 r/min, a cleaning fan speed of 2535 r/min, a vine crushing roller speed of 1970 r/min, and a lifting fan speed of 1604 r/min. Under these conditions, the theoretical dust emission rate was calculated to be 10,603 mg/s, with a pod loss rate of 4.73% and a pod impurity rate of 5.21%. Compared to previous settings, the optimized operation parameters effectively reduced the combine’s dust emissions by 9.95%. Notably, the harvesting operation quality still complies with the industry standards for peanut harvesters. These research findings offer theoretical insights and robust technical support for minimizing dust pollution during the whole-feed harvesting of peanuts, contributing to more environmentally friendly and efficient peanut harvesting practices.

In a previous transcriptome analysis of early response genes in rice during Magnaporthe oryzae infection, we identified a CONSTANS-like (COL) gene OsCOL9. In the present study, we investigated the functional roles of OsCOL9 in blast resistance. OsCOL9 belonged to group II of the COL protein family, and it contained a BB-box and a C-terminal CCT (CONSTANS, COL and TOC1) domain. OsCOL9 was found in the nucleus of rice cells, and it exerted transcriptional activation activities through its middle region (MR). Magnaporthe oryzae infection induced OsCOL9 expression, and transgenic OsCOL9 knock-out rice plants showed increased pathogen susceptibility. OsCOL9 was a critical regulator of pathogen-related genes, especially PR1b, which were also activated by exogenous salicylic acid (SA) and 1-aminocyclopropane-1-carboxylicacid (ACC), the precursor of ethylene (ET). Further analysis indicated that OsCOL9 over-expression increased the expressions of phytohormone biosynthetic genes, NPR1, WRKY45, OsACO1 and OsACS1, which were related to SA and ET biosynthesis. Interestingly, we found that OsCOL9 physically interacted with the scaffold protein OsRACK1 through its CCT domain, and the OsRACK1 expression was induced in response to exogenous SA and ACC as well as M. oryzae infection. Taken together, these results indicated that the COL protein OsCOL9 interacted with OsRACK1, and it enhanced the rice blast resistance through SA and ET signaling pathways.

Stones in farmland soil affect the efficiency of agricultural mechanization and the efficient growth of crops. In order to solve the problems of traditional stone pickers, such as large soil disturbance, high soil content and low picking rate, this paper introduces the Archimedean curve with constant radial expansion characteristics into the design of the core working parts of the drum picker and designs a new type of drum stone picker. The key components such as spiral blades, rollers, and scrapers were theoretically analyzed, the structural parameters of the main components were determined, and the reliability of the spiral blades was checked using ANSYS Workbench software. Through the preliminary stone-picking performance test, the forward speed of the stone picker, the rotation speed of the drum, and the starting sliding angle of the spiral blade were determined as the test influencing factors. The picking rate and soil content of the stone picker were determined as the test indicators. The response surface test was carried out in the Design-Expert13.0 software. The results show that, when the forward speed of the stone picker is 0.726 m/s, the drum speed is 30 rpm, and the initial sliding angle of the spiral blade is 26.214°, the picking rate is 91.458% and the soil content is 3.513%. Field tests were carried out with the same parameters, and the picking rate was 91.42% and the soil content was 3.567%, with errors of 0.038% and 0.054% compared with the predicted values, indicating that the stone picker meets the field operation requirements. These research results can provide new ideas and technical paths for improving the performance of pickers and are of great value in promoting the development of advanced harvesting equipment and the efficient use of agricultural resources.