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Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

"Who will farm" and "how to farm" would be one of the common problems in agriculture all over the world in the future. Modern agriculture is the development direction for agriculture, and it is an effective way to solve the problem of "who will farm" and "how to farm". Smart agriculture has been the promising development direction in modern agriculture. Among them, the unmanned farm is one of the most important ways to realize smart agriculture. South China Agricultural University first constructed the unmanned rice farm in Zengcheng, Guangzhou, Guangdong Province of China in 2020. This unmanned rice farm has broken through four key technologies, including (1) Digital perception for the accurate perception of the operating environment, working objects, and machinery information of unmanned farms; (2) Intelligent decision-making for land reclamation, tillage, planting, sowing, field management, and harvest programs; (3) Precision operation for the automatic navigation and precision of agricultural machinery; (4) Intelligent management for crop growth, agricultural machinery operation, and farm management. Five functions were achieved, including (1) Full coverage production links of tillage, planting, field management, and harvesting; (2) Automatically transferring from the garage to the field; (3) Automatic obstacle avoidance and parking for safety; (4) Real-time monitoring of crop production, and (5) Intelligent operation with the decisionmaking precision. Remarkable economic, social, and ecological benefits were also achieved in this unmanned rice farm. The yield of the Simiao rice variety was 9934.35 kg/hm² in the unmanned rice farm in Zengcheng, Guangdong Province of China in 2021, 32% more than the local average yield of the same rice variety. The yield of ratoon rice was 17 988 kg/hm² in an unmanned farm in Qianshanhong Town of Yiyang, Hunan Province of China in two seasons of 2023. Therefore, the crops were planted well in the unmanned farm. 30 unmanned farms were constructed in 14 provinces in China by the end of 2022, including rice, wheat, corn, and peanuts unmanned form. The unmanned farm can provide the great potential to solve the "who will farm" and "how to farm" in the future. In order to further promote the development of unmanned farms, the following recommendation were proposed: (1) Enlarge the agricultural farmland scale and agricultural management scale, strongly support the agricultural cooperative, agricultural leading enterprises and large farm landowners to enlarge their farmland scale to suited the construction of the unmanned farm. (2) In light of the basic requirements of unmanned farm for lager farmland, flat field, continuous planting, and convenient farm track path and irrigation and drainage channel, land improvement and develop high-standard farmland should be strengthen . (3) Explore suitable unmanned farm models for different area, different agrotype, different crops, different cropping systems, and different production models. It is necessary to promote the construction of unmanned farms according to the local modern agricultural industrial parks. (4) Explore various talent training for unmanned farm. For example, it would be a good propose to train technicist and manager working for unmanned farm in vocational school. (5) It is necessary to speed up the formulation of relevant policies to promote the construction of unmanned farms, especially the financing of construction funds. To mobilize the enthusiasm of the government, enterprises and society to invest in the construction of unmanned farms, and appropriately increase the purchase subsidy amount of intelligent agricultural machinery should also be considered as soon as possible [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modern rice drilling needs to meet the increasing requirements of different rice varieties, high speed operation and large seeding rate for direct seeding farmland in China. In this study, a kind of centralized pneumatic rice seeding machine with high precision was developed for dry land, including uniform distributing unit, seeds metering unit, pneumatic tube line conveying unit, synchronous transmission unit, large size integrated seed box, ditching, soil covering and compacting unit, supporting and suspension unit. The distributing mechanism and uniformity of the pneumatic centralized distributor were investigated according to the rice varieties, working speed, and seeding rate of seeding machine. The theory of airflow conveying was utilized to evaluate the movement trajectories of seeds in the distributor under continuous air flow in terms of physical characteristics of different rice varieties. A groove-wheel metering device was designed to adjust the seeding rate, in order to meet the requirement of large tailoring speed of seeding, where the groove shape was arc-shaped, and a dual ground wheels driving was used to ensure the synchronization between seeding rate of seed metering device. Variable speed transmission devices were utilized to increase adaptability of high-speed working for the seeds metering unit. A centralized-pneumatic rice seeding machine was trail-produced and tested, and the comparison study was conducted to explore the movement behavior and field seeding effects by using varieties of indica and japonica rice in the direct seeding process. The test results showed that the seeding rate of rice seeding machine was 75-375 kg/hm², the maximum working speed was 14 km/h, the working width of the 10 rows was 2 m and 20 rows was 4 m, and the coefficients of variation of sowing quantity per row were 4.89% and 5.06%, respectively. The broken rate of rice seeding in paddy field was 0.46%. In 2017, the rice yield of japonica Fu Yuan No. 4 was 10 372.5 kg/hm² in Ningxia, the rice yield of indica Yue Nong Si Miao was 7 074 kg/hm² in Guangdong. The production results demonstrated that the developed centralized pneumatic rice seeding machine for dry land could reach the design goal and meet the working requirements for direct seeding farmland in China. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shenyang Agricultural University is the property of Journal of Shenyang Agricultural University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Precise localization is an important premise of autonomous navigation for agricultural vehicles. We propose a localization algorithm based on monocular camera. After features are detected and tracked through multiple frames, vehicle poses are estimated based on 3D-2D correspondences. Furthermore ,the translation absolute scale is calculated based on the assumption that the ground patches are locally flat and the camera is moving at a known and fixed height over the ground. Finally, the poses are refined by the pose threshold filter. Compared with the RTK GPS data, the average relative position errors of the three different experimental terrains are 5. 459 9.%，8. 373 1% and 6. 443 94M ? and the average heading errors are 7. 717 7°, 5. 738 9° and 3. 438 3°. The results show that the algorithm is feasible for agricultural vehicles localization. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to better realize the combination of agricultural machinery and agronomy, the design of precision rice hill-drop drilling machine was further optimized and tested. The precision rice hill-drop drilling machine that was powered with high speed transplanter chassis was composed of frame, furrowing and ridging device, height and horizontal profiling mechanism system, power transmission system, seeding device and hydraulic lifting frame. It could meet the rice direct seeding agronomic requirements which are furrowing and ridging synchronously, adjustable sowing rate and hill space, optional row space, profiling seeding mode and stubble burying before seeding. The combined hole-type metering device included small and big type holes was used for the precision rice hill-drop drilling machine, so that it could meet the sowing rate requirement of conventional rice and hybrid rice simultaneously and adjust the seeding rate quickly. On the basis of the combination of agricultural machinery and agronomy as well as the experimental verification, the frame, reduction gearbox, horizontal profiling mechanism, height profiling system and installation angle of slide plate were optimized. The new frame could protect the main bar from being bended. The new reduction gearbox made the hill space to match the speed of the chassis more accurately and also could change the rotation direction to fit different kinds of chassis. The height and horizontal profiling mechanism made the seeding machine more floatable, so it could adapt more complicate ground. Furthermore, the related experiments proved that profiling system is conducive to the seedling emergence of rice. The seedling emergence rates of the rice varieties XS134 and PZTF, which were seeded by the precision rice hill-drop machine with horizontal profiling mechanism, were 7.8% and 8.7% higher than that without horizontal profiling mechanism, respectively. In order to protect the atmosphere environment, the government introduced the relevant policies and laws to prohibit the burning of straw, and promoted the comprehensive utilization of crop straw. Many farmers returned straw residue to field to improve soil fertility and reduce environmental pollution, but it could be more difficult for the direct seeding machine and rice transplanter working in the field as well. To overcome this difficulty, the stubble-burying seeding was studied. The angle of the slide board was confirmed as 4° by the experiment result, while the efficiency of stubble burying was 91.6% and the furrowing and ridging effect under 4° was relatively better than that under other degrees. In this paper, some verification tests involved the main technical indices of the seeding machine and its reliability. Results showed that, the pure work efficiency was 0.67 hm2/h, the qualified rate of hill space was up to 100%, the variable coefficient was as low as 2.5%, the qualified rate of the seeds number per hill reached 95% and the cavity rate was 0; furthermore, the variable coefficient of the consistency of seeding quantity per row and the stability of total seeding quantity were 3.8% and 1.5% respectively; after seeding with horizontal profiling mechanism, the height difference between the left and the right field surface was about 2.0 cm; more important, the average of assignment before first-time fault (MTTFF) was 30.4 hm2/h, and the validity reached up to 98.2%. Therefore, on the basis of these results which all meet the national standard and the requirements of the combination of agricultural machinery and agronomy, and the reduction gearbox makes the machine+ more universal. The performance of the optimized precision rice hill-drop drilling machine is reliable and has exciting application foreground. [ABSTRACT FROM AUTHOR]

Since 1978, great progress has been achieved in Chinese agriculture. However, the problems still exist in the development process, such as low labor productivity, high production cost, low land productivity, low yield, low rate of resource utilization and lacking international competitiveness of agricultural products. One important reason for these problems lies in the low agricultural mechanization level in China. The informationization of agricultural machinery is a fundamental way to enhance agricultural mechanization level. In order to keep the sustained growth of agricultural mechanization level and accomplish the agricultural sustainable development in China, it is critical to take full advantages of advanced information technology to improve the design, manufacturing, operation and management of agricultural machinery, and then to enhance the level of agricultural mechanization. This paper mainly introduced: 1) The key information technologies for agricultural machinery design: parametric design, agricultural machinery product design based on knowledge engineering, and concurrent and collaborative design based on product data management; 2) The key information technologies for agricultural machinery manufacturing: flexible manufacturing, computer integrated manufacturing, and virtual and network manufacturing; 3) The key information technologies for agricultural machinery operation: agricultural information acquisition, agricultural machinery navigation, and field management; 4) The key information technologies for agricultural machinery management: agricultural machinery management, and agricultural machinery scheduling. The deficiencies of current information technologies were analyzed, the development trend was summarized for the countries all over the world, and the core issues of enhancing the agricultural mechanization level in China for present information technologies were proposed. In order to further enhance the level of agricultural mechanization by using information technology, some suggestions are proposed in this paper: 1) To make the breakthrough in key technologies of digital design of intelligent equipment, coordinated control of auto-navigation and fieldbus technology of agricultural equipment; 2) To strengthen the innovation of major precision production equipment, such as precision production equipment for field operation and facilities agriculture, orchard production and livestock, and poultry and aquaculture production; 3) To construct the precision operating system for modern agricultural machinery, and to research and develop a series of major technical products, such as precision operating system of water, fertilizer and pesticide, automatic feeding system and automated processing production line of livestock, poultry and aquaculture. [ABSTRACT FROM AUTHOR]

A precision rice hill-drop driller powered by a wheeled tractor will leave wide and deep wheel tracks in the field surface, which destroy the mud surface roughness and seriously affect sowing quality. A spiral filling approach with variable thread pitch and equal diameter was proposed in this paper. An opposed spiral filling device that is installed on a precision rice hill-drop drilling machine and powered by a Dongfanghong ME304 wheeled tractor was designed to solve the problem. When working in the field, the spiral filling assembly is powered through an independent hydraulic power system, and is driven by a hydraulic motor for rotation. The depth of the spiral blade into the mud is adjusted by the hydraulic lift rod through the tractor’s three-point linkage. The rotating spiral blade pushes the surface mud in paddy field along the spiral axial to the wheel tracks that are formed by the tractor to eliminate the tracks. Taking soil particles as the research objects, stress analysis and motion analysis on soil particles were carried out in order to find kinetics and kinematics models during mud transportation process. The mathematical model was then established for the mud transportation capacity of the spiral filling assembly combing the tractor’s working speed, parameters of tractor wheels, and automatic self-filling factor of the wheel track. The models helped for the determination of the spiral parameters. The spiral parameters were determined through the empirical formula of spiral design. Relationship curves between mud transportation speed and spiral radius and pitch were drawn with Matlab software to verify the rationality of the spiral parameters. After theoretical calculation and optimization design, key parameters of the spiral, the outer diameter, the inner diameter, and the maximum pitch were finally determined to be 250, 80 and 200 mm, respectively. The rotating speed of the spiral and the walking speed of the tractor should be adjusted according to the actual situation in the field. A spiral speed of 200 r/min and a tractor walking speed of 1 m/s were selected for field track filling tests based on the experimental field conditions in South China Agricultural University. Results show that with the tractor’s automatic self-filling factor larger than 0.6, the spiral speed of 200 r/min and the tractor’s forward speed no more than 1 m/s, the designed wheel track filling assembly is able to fill tracks of no deeper than 250 mm and less than 400 mm wide with smooth soil surface in order to provide excellent working environment for future sowing operations. The filling assembly has reasonable design and excellent operating performance. It is able to eliminate the wheel track and meet the actual production requirements. The study provides useful reference for further research and design of tractor track filling devices. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although great development has taken place in agricultural mechanization since reform and opening up, China still faces the big challenge in improving agricultural resource utilization as well as promoting the sustainable development of agriculture at present. As we all know, it is mainly the 5 factors, i.e. water, soil, fertilizer, pesticide and seed that affect sustainable development in the construction of China’s agricultural modernization. The overall development of agriculture in China will be impeded if the resource utilization stays low. There exist some phenomena: 1) the irrigation water use is 360 billion m3 each year, while canal-system water use efficiency is only 0.4~0.6; 2) high-quality cultivated land is lacking; 3) nitrogen use efficiency is about 30%~35%, which is 20% less than developed country; 4) pesticide utilization is merely about 30%, while leads to severe environmental pollution; 5) the demand of seeding quantity is high while there are shortage of high-quality seeds and serious waste of seeds. Accordingly, several technologies and machines in PA (precision agriculture) were put forward in this article so as to meet the requirement of agricultural sustainable development: precision irrigation, precision plow, precision fertilization, precision spraying, and precision sowing. By reviewing the researches at home and abroad, the current situation of PA was analyzed and thus the methods to achieve the 5 mentioned key technologies were presented. Meanwhile, some other suggestions were proposed to push the agricultural mechanization to play a greater and more important role on the utilization of agricultural resource and agricultural sustainable development: 1) further strengthen the combination of agricultural machinery and agronomy as well as the basic study of related theory; 2) carry out in-depth studies on key technologies of maximum utilization of agricultural resource, especially in precision irrigation, precision plow, precision fertilization, precision spraying, and precision sowing; 3) enhance the capacity of independent innovation, namely, the capability of equipment design and manufacture related to PA; 4) accelerate extensive application of precision agricultural machine and equipment. Above all, this paper has provided a scientific guide and policy direction for improving utilization of agricultural resource, promoting agricultural mechanization and agricultural sustainable development. [ABSTRACT FROM AUTHOR]

Cutting diagram is an important means of performance analysis of reciprocating cutter. The evaluation of working performance of reciprocating cutter principally depends on the size of 3 featured areas (repeated cutting area, area failing to cut and once cutting area), which can be observed from the cutting diagram. Drawing cutting diagram by the traditional manual tracing method has the disadvantages of low efficiency and imprecise result. Meanwhile the system of cutting diagram drawing and analyzing which is based on the MATLAB and other homemade programs cannot carry on the continuous analysis of parameter. Aiming at the inconvenience of the traditional methods, a cutting diagram analytic system was developed based on visualization platform. This paper took the standard ordinary I type reciprocating cutter as main research object, performed the kinematic analysis to cutting blade and obtained the moving-track curve of featured points. Method to calculate the 3 featured areas was deduced based on the kinematic analysis of the cutting blade. Moreover, 3 special situations which may happen during the calculation process were analyzed, and the respective solution for each situation was proposed. The software was developed based on VISUAL STUDIO 2008. The main interface of this system mainly consists of cutter parameter configuration zone, working property feature analyzing zone and cutting diagram drawing zone. After inputting the cutting parameter by user, system can draw corresponding cutting diagram and calculate the area of featured areas. The drawing of cutting diagram uses Picturebox control and GDI+ (graphics device interface plus) technology, and it can carry on the coordinate conversion to the actual dimension of cutting blade depending on the dimension of drawing zone. In order to adapt the calculation characteristics of computer, it uses the numerical analysis method in calculation process, including obtaining the coordinates of key points through the dichotomy solution to single-variable equation and calculating the area of featured areas by using the trapezoidal method to do definite integral calculation. The main content of working performance analysis is calculating the proportional relationship among the 3 featured areas under different working parameters, thus to find the best working parameters. Traditional method is to carry on comparative analysis by drawing many cutting diagrams, however, it has the shortages of hefty workload and imprecise result. This paper proposed a working performance analytical method depending on stepping calculation, which used the steeping method to automatically calculate and analyze the areas of 3 feature regions according to the cutter dimension parameters specified by users, and generated the corresponding curve graphs in set working parameter range. This provided the basis for users to analyze working properties of cutters and determine the best working parameters. The analysis of the standard ordinary I type reciprocating cutter showed that there was no area failing to cut when the rotator width was less than 44 mm, and no repeated cutting area when the rotator width was greater than 94 mm, moreover, when the rotator width equaled 61 mm, the area proportion of once cutting area reached the highest value which was 88%. Application result showed that the software had the advantages of convenient use, independence of the third platform and precise calculation result, which provided an efficient mean to optimize the operation of the reciprocating cutter. [ABSTRACT FROM AUTHOR]

The wireless sensor network (WSN) technology has been evolving very quickly in recent years. Sensors are constantly improved in their sensing, processing, storage, and communication capabilities. In a larger scale hilly land agricultural environment monitor WSN, a pure multi-hop approach to route the data all the way along the network, which can extend for hundreds or even thousands of kilometers, can be very costly from an energy dissipation point of view. In order to significantly reduce the energy consumption used in data transmission and extend the network lifetime, we presented a three-tier framework for monitoring agricultural environment using TUFSN（Three-tire Unmanned aerial vehicle Farmland Sensor Network）where data collection and transmission were done using Unmanned Aerial Vehicles (UAVs) in South China. In the system, we defined three types of nodes, which included: sensor nodes, relay nodes, UAVs. In the sensor nodes, a classic WSN one-hop or multi-hop routing approach to transmit their data to the nearest RN was used, which acted as a cluster head for its surrounding sensor nodes. Then, an UAV was moved along the pre-defined route or optimizing route that transported the data collected by the RNs to the data center. The TUFSN was divided into three layers, which included: the lower layer for acquisition data based on relay node and sensor node, the middle layer of relay transmission based on sensor node and UAV, and the upper layer for moving aggregation based on UAV and data center. This architecture led to considerable savings in node energy consumption, due to a significant reduction of the transmission ranges by use of a one-hop or the least hop between sensor node and relay nodes and the transmission to communicate the data by use of a one-hop from the relay nodes to the UAV. Furthermore, the strategy provided reduced interference between the relay nodes that can be caused by hidden terminal and collision problems, which would be expected if a pure multi-hop approach was used at the relay node level. We evaluated the performance of the architecture by some simulation. Our simulation of investigating the impacts on some parameters included: flying speed, flying height, flying time, relay node buffer size, UAV buffer size and relay node communication radius. Simulation and test results showed that, 1) when flying at the speed of 1 m/s, UAV should fly much lower to get enough time for communication with relay node; 2) when the communication radius of relay node was higher than 30 m, UAV could have more than 45s for communication; 3) when the buffer size of each relay node increased, UAV needed to fly more slow or fly more lower; 4) when relay node communication radius increased, UAV could fly more high or fly more quickly; and 5) when the transition ratio was 2000 bps, the range of relay node's cache was 3-13kB. We hoped that our simulation provided some guidelines on large scale hilly country farmland data collecting systems. A set of experiments were carried out in the Teaching and Research Farm of South China Agricultural University in April 2015, with the purpose of demonstrating the effectiveness of the proposed system. The experiments were limited to eight relay nodes which were separated from each other at a distance of 150 m. There were two or three sensor nodes surround every relay node. It should be highlighted that sensor nodes can only communicate with the closest relay node. The eight rotors of the UAV attached mobile node flied at a speed of 1 m/s and 15 meters altitude in the experiment. Statistical results indicated that the average communication time for UAV and each relay nodes were 26 seconds. [ABSTRACT FROM AUTHOR]