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Precision fertilization is one of the key technologies to control non-point source pollution in agriculture. Fertilizer reduction and efficiency technology can greatly contribute to green and sustainable agriculture in the rice-oil rotation region in the mid-lower reaches of the Yangtze River. Among them, fertilizer apparatus s have been focused mainly on the performance and optimization of structural devices. It is relatively lacking in the high speed and precision of fertilizer apparatus for rapeseed in real time. It is a high demand to optimize the precision fertilizer discharging for the reference value. The performance of fertilizer apparatus can depend directly on the accuracy of working components, in terms of uniformity and rational fertilization. However, the existing fertilizer apparatus cannot fully meet the range of direct seeding rapeseed of high-speed machines, due to the jam, low stability and distribution, as well as the serious crushing of particle fertilizer. In this study, an extrusion fertilizer apparatus for rapeseed was designed with a centrifugal cavity disc with high speed and precision. According to the agronomic requirements of high-speed direct seeding, the movement analysis of fertilizer particles was combined to determine the key parameters, such as fertilizer inlet, centrifugal cavity disc, fertilizer outlet, and power system. The discrete element software (EDEM) was used to establish the simulation model of fertilizer discharging. A systematic investigation was implemented to clarify the influence of the speed of the fertilizer apparatus on the torque of the centrifugal cavity disc, the average load, and the crushing rate of fertilizer particles. The results showed that the torque of the centrifugal cavity disc increased, whereas, the average load of fertilizer particles in the cavity disk decreased gradually, and the crushing rate increased below 0.80%, with the increase of the speed of fertilizer apparatus. The performance test showed that the speed of the fertilizer ejector was 30-120 r/min, and the displacement was 15.0-58.1 g/s, fully meeting the demand of high-speed direct seeding when the maximum fertilization amount was 600 kg/hm2. The coefficient of variation was less than 8.58% for the consistent displacement in each row of fertilizer discharging, less than 6.45% for the stability of the displacement in the same industry, and the crushing rate was less than 0.89%; Specifically, the coefficient of variation was below 8.72% for the displacement consistency of each row shall under normal field operation with 0°~5° inclination. The comparative test showed that compared with the spiral perturbation, the fertilizer discharging with a centrifugal cavity disc was suitable for high-speed operation, where the crushing rate was reduced by 63.82%. There was no fertilizer jam when discharging fertilizer at high speed and large displacement. The field test showed that when the operation speed was in the range of 4.1-10.1 km/h, the coefficient of variation was not more than 6.72% for the consistent discharge in each row of the fertilizer ejector, while the coefficient of variation for the stability of the same row during fertilizer discharging was not more than 4.84%, and the relative error between actual and theoretical fertilizer discharging was less than 4.54%. The fertilizer discharging shared a wide range of displacement, smooth and stable operation, in order to effectively avoid the fertilizer sticking and the crushing rate in the process of fertilizer discharging. The fertilizer apparatus also fully met the demand for the high-speed direct seeding and precision fertilizer discharging of rapeseed. [ABSTRACT FROM AUTHOR]

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Precision agriculture can play an important role in the development of intelligent agricultural machinery, due to fertilizer saving, low labor intensity, and high work efficiency. Among them, the amount of fertilizer discharge can directly dominate the crop yield. Nevertheless, the fertilizer discharge device was in a closed state during the live broadcast operation. Therefore, the detection of particle fertilizer discharge has been one of the development trends of intelligent and precise operation. Various approaches have been developed to replace granular fertilizers in recent years, such as the rotational speed, doppler effect, dynamic weighing, photoelectric, visual, and electrostatic ones. However, the low accuracy of detection has limited in the rapeseed mechanical direct seeding, due mainly to the large and disordered flow of fertilizer particles. There is a high demand for the real-time detection of high-throughput granular fertilizers during high-speed operations. In this study, the high-throughput particle flow dispersion and diversion serialization of "collision dispersion +sieve diversion +spiral tube constraint" were proposed to fully meet the agronomic requirements of fertilization and high-speed operation in rapeseed direct seeding operation. The high detection accuracy was also obtained under the large and disordered flow of fertilizer particles. A parallel detection device was designed for the diversion order of granular fertilizer using the discrete diversion order mechanism. The key parameters were then determined for the sensing detection structure, uniform fertilizer tube, sieve diversion structure, and spiral tube. A multi-channel signal synchronous acquisition system was also designed for the detection device of rapeseed live broadcast granular fertilizer, according to the multi-channel parallel detection and sensing. A test bench was constructed using a spiral disturbance cone centrifugal fertilizer feeder. The device performance tests were conducted to verify the effectiveness of discrete diversion serialization. The results showed that there was a gradual decrease in the coefficient of variation for each channel diversion of the detection device in an inclined state, as the speed increased when the speed of the fertilizer discharger was 100-130 r/min (fertilizer discharge frequency 361.80-631.60 Hz). The coefficient of variation exceeded 6.08% for each channel diversion under normal field operation with an inclination of 0°-5°. Once the discharge frequency of single-channel fertilizer was 30-80 Hz, the accuracy of the detection device with the spiral tube increased by 7.3 percentage points, compared with the straight tube. The detection accuracy was not less than 90.11% within the speed range of 100~130 r/min after displacement compensation, which was 9.3 percentage points higher than before. The experiment of vibration fertilizer discharge showed that the low-frequency vibration (0-30 Hz) significantly improved the discretization of granular fertilizer and detection accuracy. There was a stable detection accuracy of intermediate frequency vibration (30-110 Hz). High-frequency vibration (110-150 Hz) broke the serialization constraint of granular fertilizer for low detection accuracy. There was no significant impact of different vibration frequencies on the uniformity of the flow distribution in the detection device. The coefficient of variation exceeded 4.98% for each channel diversion. Field experiments showed that there was no significant impact of the light, vibration, and dust on the detection device under normal field operating speeds of 4.3-7.0 km/h. The detection accuracy of the device was not less than 90.05% when the speed of the fertilizer discharger was 100-130 r/min. The detection device can be expected to detect the fertilization operation of the equipment, in order to improve the quality of fertilization operation [ABSTRACT FROM AUTHOR]

A seed metering device is closely related to the sowing quantity and crop yield in the planting process. Various detection methods have been used to improve the seeding performance for corn, and soybean precision seeding in recent years, such as photoelectric sensor detection, high-speed photography, and capacitance sensing. However, it is difficult to accurately count the high-frequency seed flow in the process of high-speed wheat sowing. In this study, a set of multi-channel parallel detection device was designed for the wheat seed flow with thin-surface light refraction. A "LED lamp beads + narrow slots" method was also proposed to generate the thin-surface light layer, in order to combine the convex lens refraction for the large effective detection area. According to the physical characteristics of wheat seeds, the seed stream shunt structure and the thin-surface LED narrow slot size were designed to determine the convex lens focal length and the key parameters of the sensing components. The multi-channel parallel detection and sensing were utilized to develop a multi-channel signal synchronous acquisition system for the multi-channel parallel detection device of the wheat seed flow with thin-surface light refraction. The seeding accuracy rate and frequency test was conducted to improve the detection accuracy. Among them, the error rule of the detection device was analyzed to construct the accuracy compensation model. The bench test showed that the normal seeding frequency range was 52.10~321.55Hz in the field, and the detection accuracy was not less than 96.68%, when the rotation speed of the seed metering device was 80~180r/min. The comparison test showed that high reliability was achieved with a detection accuracy of not less than 96.64%, when the seeding frequency was not more than 32.75Hz. The detection accuracy rate of the single-channel detection device decreased significantly in the frequency range of 49.40~320.75Hz during seed metering in the field, with the increase of seeding frequency. There was a stable detection accuracy rate of the multi-channel parallel detection device. Specifically, the minimum detection accuracy rates were 26.67%, and 96.53%, respectively, for single and multi-channel parallel detection devices. It infers that the multi-channel parallel detection improved the detection accuracy rate of wheat seeds after shunting. The field sowing test showed that the normal seeding frequency in the field was 67.65~323.95Hz at the operating speed of 2~9km/h, and the detection accuracy was higher than 95.28% in the detection device. Consequently, the detection device can be expected to detect the seeding frequency of the seeding device, the seeding amount of each channel, and the total seeding amount in real time. There was no influence of mechanical vibration, strong light, and soil dust on the detection device in the normal field wheat sowing. The detection device can provide effective support to accurately detect the high-frequency seed flow for the missed seeding detection and reseeding in high-speed wheat sowing. [ABSTRACT FROM AUTHOR]

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.)