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Rice-rape and rice-wheat rotations dominate the cropping patterns in the paddy upland rotation area in the middle and lower of the Yangtze River of China. The alternate drying and wetting process in the rotation tends to make the soil sticky and compact. The soil can also easily adhere to the soil-engaging components of the tillage machine in the actual preparation of arable lands, leading to low plowing efficiency and quality, as well as low traction efficiency but high power consumption. In this study, a barrier-type rotary anti-adhesion blade roller with a vibration crosspiece was designed to promote the quality and efficiency of the rotary blade roller caused by the soil adhesion during paddy field operation. The main purpose was also to realize the anti-adhesion of inherent components and the detachment performance of the crosspiece in the operation process. The rotation radius of the crosspiece was greater than the cutter shaft. A closed cylindrical area was formed to isolate the cutter shaft during the working process, in order to prevent the soil thrown by the rotary tillage blade from adhering to the cutter shaft. An opposite direction was set as the shear movement of the upper and lower crosspiece symmetrically installed on the blade roller driven by the vibration excitation device. As such, the soil adhered to the cutter shaft was sheared to break and then fall off. At the same time, the acceleration generated by the reciprocating motion of the crosspiece greatly contributed to preventing the soil from the crosspiece bar surface. Finally, the adhesion reduction and detachment were realized for the soil that entered the rotary blade roller via the comprehensive effect of barrier, shear and vibration of the crosspiece. The force states of soil particles were analyzed under the action of the vibration crosspiece and the structure of the vibration excitation device. After that, the structural parameters were determined in the vibration excitation device. A systematic analysis was made of the structure of the anti-adhesion blade roller, according to the throwing kinematics and dynamic process of the rotary tillage blade. Subsequently, the structural parameters of the anti-adhesion blade roller were designed to obtain the kinematic requirements for the separation of soil and rotary tillage blade. The key factors affecting the detachment performance of the anti-adhesion blade roller were determined as the cutting pitch of rotary tillage, blade roller rotary speed, and rotation radius of the crosspiece. Combined with the discrete element simulation, the Box-Behnken experiment was carried out with the number of contact between soil particles and crosspiece per unit time as the evaluation index in the detachment performance of the rotary blade roller. The optimal combination of parameters was determined as the cutting pitch of rotary tillage of 6.3 cm, the blade roller rotary speed of 260 r/min, and the rotation radius of the crosspiece of 140 mm. The simulation experiment was carried out to verify, according to the optimization parameters. It was found that the contact numbers between crosspiece and soil particles per unit of time were 127.89, with relative errors of 6.44%, which was basically consistent with the prediction of the regression equation. The structural parameters of the vibration excitation device were then optimized under the condition of optimal parameter combination. The motion characteristics of the crosspiece driven by the vibration excitation device were analyzed to obtain the structural parameters using the MATLAB software. Three paddy fields were selected as experimental sites, in order to verify the applicability and detachment performance of a barrier-type rotary anti-adhesion blade roller with the vibration crosspiece. The field experiments were carried out under the optimal parameters combination. The multi-field performance experiment and rotary tillage comparison showed that the improved device was suitable for mechanized seed bed preparation in most paddy fields. The soil adhesion of the rotary tillage anti-adhesion blade roller was also much less than that of the traditional. The average tillage depth stability coefficient, soil layer levelness, soil broken rate, adhesion mass, soil distribution uniformity, and straw buried rate were 92.02%, 15.21 mm, 81.81%, 2.63 kg, 10.99%, and 92.27%, respectively. All indexes fully met the design and agronomic requirements. The findings can provide the theoretical basis and technical support to design the adhesion reduction and detachment of rotary tillers in paddy fields in the middle and lower reaches of the Yangtze River. [ABSTRACT FROM AUTHOR]

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.)

Soft-soil surface in a paddy field is usually left with unevenly distributed rice stalks, uncut stubbles, and machine ruts after harvesting by combines. A common treatment of rice straws is rotary burying using tractor-hitched rotary cultivators in southern China. However, misses and overlaps inevitably occur, because human tractor drivers mainly perform the current operation under the complex conditions of field surface. It is greatly urgent to develop an automatic navigation system for better operational efficiency and accuracy. In this study, a Dongfanghong LX954 tractor with a hitched rotary straw returning cultivator was taken as the research object. An automatic navigation system was developed to replace the original tractor-rotary cultivator combined one, with a novel electronic proportional control and hydraulic steering. The main hardware of the navigation system included an onboard PC, an electronic-control proportional hydraulic valve, a steering angle sensor, and a dual-antenna RTK-GNSS. The navigation software was performed on the MATLAB platform in the Windows 7 operating system. The RTK-GNSS was used to measure the real-time lateral deviations and orientation errors of the tractor. The onboard PC was used to plan the operation paths, process the GNSS measurement data, calculate the steering angles using the designed control algorithms, and finally send control commands to the steering controller. Specifically, the steering controller was used to receive the control commands through a CAN bus, thereby controlling the opening and closing of the electronic-control proportional hydraulic valve, and finally realizing automatic navigation. An estimation model of slip angle was derived using the steering angle control of the tractor, and a variable gain single-neuron PID controller was designed, in order to reduce the great slippages from the complex conditions of field surface during rotary burying of straws. The slip angles of the front-wheel and rear-wheel were added into the model to accurately calculate the control angle more suitable for the actual operation. The variable gain single-neuron PID controller output the values of steering angle by learning the previous control effects from the neuron and the adjusted gain, according to the differences between the current heading and the target heading. As such, the navigation control rapidly adapted to the subsequent soil surface in the field. MATLAB simulations were carried out to compare the control effects of a conventional, a single-neuron, and the variable gain single-neuron PID controller. The results showed that the variable gain single-neuron PID controller behaved the fastest convergence, the smallest overshoot, and the best performance of signal tracking. A road test was performed to further verify the feasibility of the designed navigation system. When the operation speed was about 2 m/s, the variable gain single-neuron PID effectively improved the performance of path tracking, in terms of speed and accuracy for both straight path and curve tracking. Furthermore, the maximum lateral deviation was 0.026 m during straight path tracking. In the curve tracking for a half circle with a diameter of 12 m, the maximum lateral deviation was 0.382 m and the mean was 0.170 m. A field experiment was performed on the rotary straw returning under the designed navigation system. In straight path tracking, the maximum lateral deviation was 0.071 m, and the mean was 0.031 m when the operation speed was 1.15 m/s. Compared with the traditional and single-neuron PID controllers, the control accuracy of the maximum error and mean absolute error were improved by 53.08% and 51.72% respectively, and compared with single neuron PID controller, the control accuracy of the maximum error and mean absolute error were improved by 39.00% and 28.21% respectively, the developed navigation controller can significantly reduce the interference from the various soft-soil surface in a paddy field, thereby enhancing the adaptability and robustness of the navigation system, particularly with the higher accuracy of path tracking. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences 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.)

Cotton (Gossypium hirsutum) is one of the most important cash crops in China, The timely and effective removal of weeds in cotton seedling stage is an important measure to ensure high and stable yield of cotton. Nowadays, weed recognition based on machine vision is widely used. The fast and effective recognition of crop and weed in the field under natural illumination is one of the key technologies for the development of intelligent mechanization weeding pattern. In the one hand, cotton and weeds have similar color feature in the field. Feature presentation of the natural property of target is difficult to be obtained by the hand-engineered feature extractor. The spatial consistency of the obtained features is not good, and the real-time performance of recognition system is reduced for the complex feature extraction algorithm. On the other hand, the effect of image preprocessing has important influence on recognition results. In order to solve the main problems in the current research, we explored the way to improve the recognition accuracy, stability and real-time performance, and a recognition method of crop and weed based on Faster R-CNN．In this paper, cotton seedling at 2-5 leaves stages and weeding during the same stage were used as research objects under natural illumination. Weed identification from digital images taken under natural illumination at field level is still challenging in agricultural image processing applications, though a lot of research has been conducted related to this topic. To address this problem, images including cottons and weeds were taken vertically from top to bottom. A method based on Faster R-CNN convolutional neural network was proposed to identify weeds from cotton plants more accurately and quickly. The residual network was used to extract image features, with ReLU as the activation function and Max-pooling as the down-sampling method. In the region of proposal network, feature pyramid network was introduced to generate target candidate frame, and Softmax regression classifier was utilized to optimize the CNN network. The proposed methodology was implemented on 200 digital images taken under natural illumination. The experimental results demonstrated that, the average accuracy of weed identification reached 95.5%, and the average time for individual weed plant identification was 1.51 s, which was reduced to 0.09 s by using GPU. To test the efficiency of the proposed methodology, YOLOv3 method was also carried out on the same training and test datasets. The weed identification results were assessed by mean average precision and average precision. The experimental results showed that better performance was achieved by using our proposed methodology, and better identification accuracy was reached as well. This indicated that the proposed method had a good effect on weed detection under natural illumination, and it will greatly promote the development of precise weed control. [ABSTRACT FROM AUTHOR]

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 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.)

In order to improve the seeding performance of pneumatic cylinder-type precision direct seed-metering device for rice, the single factor and central composite experimental experiments were conducted in this paper. The effects of the main working parameters (rotational speed of seeding cylinder, vacuum degree in vacuum gas chamber, air-blowing velocity and clearing blockage positive pressure of chamber) on seeding performance of the direct seed-metering device were analyzed by means of the JPS-12 type performance test rig of metering device. The study object was “Huanghuazhan”, which was pre-germinated and its moisture was 21.65%-23.73% (wet basis). Qualified rate, miss-seeding rate, replay rate, average hole distance and variation coefficient of hole distance were regarded as the performance evaluation indexes. The result of single factor experiments showed that rotational speed of seeding cylinder, vacuum degree in vacuum gas chamber and air-blowing velocity had significant influence on the qualified rate, miss-seeding rate and replay rate of metering device, respectively. The clearing blockage positive pressure of chamber had no significant influence on qualified rate, miss-seeding rate, replay rate, the average hole distance and the variation coefficient of hole distance of metering device, respectively. So, it was only necessary to provide the positive pressure chamber with suitable strength of clearing blockage positive pressure to ensure the suction hole not be blocked during the metering device working. The three-factor and five-level quadratic regression rotation design optimization experiment of the 3 influence significant factors on metering device showed that the order affecting qualified rate was rotational speed of seeding cylinder > vacuum degree in vacuum gas chamber > air-blowing velocity, and the order affecting miss-seeding was vacuum degree in vacuum gas chamber > rotational speed of seeding cylinder > air-blowing velocity. The variance analysis of experimental results had a significant affecting of experimental factors on performance evaluation indexes. Through the analysis of effect of various factors on the metering device, the seeding performance of the metering device was better under the condition of low rotational speed of seeding cylinder, high vacuum degree in vacuum gas chamber and higher air-blowing velocity. The optimal combination working parameters of metering device were seeding cylinder rotational speed with 10 r/min, vacuum degree in vacuum gas chamber with 4.6 kPa and air-blowing velocity with 21.88 m/s. All of those were obtained by optimization solution of all factors by use of quadratic regression model equation of performance evaluation indexes in the range of experimental parameters constraints. The results of verification test were consistent with the results of optimization solution. Under the condition of the optimal combination working parameters, the qualified rate, miss-seeding rate, cavity rate and replay rate were 87.73%, 2.93%, 0.53% and 9.34%, respectively. Meanwhile, the seed breakage rate was 0.91%, the average hole distance was 200.07 mm (theoretical hole distance was 200.00 mm), the variation coefficient of hole distance was 4.75%, the apiece row consistency variation coefficient of seeding quantity was 3.07%, the stability variation coefficient of the full seeding quantity was 2.08%. This seeding quality met the direct seeding requirements of hybrid rice. The field sowing experiment of the direct seed-metering device was carried out in the modern agricultural science and technology experiment base of Huazhong Agricultural University. When the average forward speed was about 1.79 km/h of direct seeder, the average vacuum degree in vacuum gas chamber was about 4.6 kPa and the average air-blowing velocity was about 21.88 m/s, the qualified rate, miss-seeding rate, cavity rate and reseeding rate were 79.42%, 15.11%, 3.88% and 5.47%, respectively. Meanwhile, the average hole. [ABSTRACT FROM AUTHOR]

In transitory and busy farming season, the straw has to be buried in the field whether it’s paddy or dry land. In this study, we designed a straw burying rotary tiller, which can bury crop straw not only in paddy field, but also in dry land. It is suitable for tillage in middle and lower reaches of Yangtze River, where the principal crop rotation is paddy field rice after dry land crop annually. In order to improve the working quality of the cultivating roller for straw returning in paddy field and dry land, the experimental studies have been conducted in the fields. First, L9 (34) orthogonal experiment was conducted to research the influence factors of the performance of the cultivator for straw returning. The main influence factors for working quality of rotary tiller were tillage depth, rotary speed and forward speed. The tillage depth of 15.5, 18.5 and 21.5 cm, the rotary speed of 314, 330 and 360 r/min, and the forward speed of 0.43, 0.69 and 0.93 m/s were selected. The results showed that among the above 3 factors the influence order was tillage depth>forward speed>rotary speed. The tillage depth affected straw coverage extremely significantly, the forward speed affected straw coverage extremely significantly, and the rotary speed didn’t affect straw coverage obviously, but it affected soil crushing rate significantly. The better test conditions were shown as below: the forward speed was 0.43-0.93 m/s, the rotary speed was about 330 r/min, and the tillage depth was about 21.5 cm. Based on the better test conditions (the forward speed was selected as 0.43 m/s), the experiments on working performance of cultivator for straw returning in paddy field and dry land were conducted in the fields, and the wireless telemetry technology and the power output shaft torque sensor were used in the study. The results showed that the working qualities of cultivator which met the agro-technical requirement of rice sowing and transplanting were as follows: in paddy field, when the soil texture was clay loam, the soil water content was 42.6%, the height of straw was 78.9 cm, the tillage depth was about 150 mm and the soil compaction value was under 1 244.8 kPa, the vegetation coverage rate reached 94.3%, the tillage depth reached 20.8 cm, the stability of tillage depth was 92.3%, the field surface evenness was 0.9 cm, and the power consumption was 27.6 kW; in dry land, when the soil texture was loam, the soil water content was 25.8%, the height of wormwood was 97.2 cm, the tillage depth was 150 mm and the soil compaction value was under 2 310.5 kPa, the vegetation coverage rate reached 96.5%, the tillage depth reached 20.3 cm, the stability of tillage depth was 90.6%, the field surface evenness was 1.2 cm, and the power consumption was 31.2 kW. At the same time, the comparative tests between the combination blade roller and the spiral blade, the traditional rotary blade were also conducted, in which the new roller was in according with the national standard of the work quality. The results showed that the working quality of the combination blade roller was better than that of the spiral blade and the traditional rotary blade, and the power consumption of the combination blade roller was higher than that of the traditional rotary blade. Based on the above results, further research on the power consumption of the cultivator for straw returning in paddy field and dry land is needed. The results provide the basis for the structure optimization of the cultivator for straw returning and the improvement of its working performance, and also provide a suitable implement to achieve high stubble straw mulching and soil tillage in paddy field and dry land. [ABSTRACT FROM AUTHOR]