Search

Copyright of Journal of Jiangsu University (Natural Science Edition) / Jiangsu Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Jiangsu University (Natural Science Edition) 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.)

Wheat is one of the main grain crops in China. It has a great significance to ensure its sustained high and stable yield for maintenance food security in China. Studies have shown that the traditional wheat drill sowing technology is not suitable for the requirement of high and stable yield due to the bareness between rows, the insufficient utilization of land resources, the crowding between rows and plants, and the competing for water and fertilizer. Wide-boundary sowing was a new planting type of wheat, which can effectively improve the utilization rate of light, heat, water, fertilizer and land, it is meaningful to develop mechanized wide-boundary sowing technology. Wide-boundary sowing device is a core component of the technology. Structure and parameters optimization of wide-boundary sowing device were studyed based on the discrete element simulation technology, soil tank test and orthogonal test in this paper. The mathematical structure model of seed separated plate was established, spherical radius, installation angle and span were 3 key structural parameters of mathematical structure model. The discrete element simulation platform for wide-boundary sowing device, which mainly consists of particle factory, seed tube, cover plate for protect seed, side plate for support, seed separated plate and seedbed was set up. Taking the coefficient variation of wheat transverse uniformity as evaluation index, the influence of 3 key structural parameters on the performance of wide-boundary sowing device was analyzed, and the structure of seed separated plate was optimized according to the simulation results. The results of single factor simulation test showed that wide-boundary sowing device had relatively small coefficient variation of wheat lateral uniformity when spherical radius, installation angle and span at 130-150 mm, 30°-40° and 80°-100° respectively. According to the results of single factor experiment, the quadratic orthogonal rotation combination simulation experiments were conducted, and the regression equations of 3 key structural parameters and coefficient variation of wheat lateral uniformity were established. The orthogonal results showed that the main and secondary factors affecting coefficient variation of wheat lateral uniformity were installation angle, spherical radius, span, interaction between installation angle and span, and there was a certain interaction between installation angle and span. When spherical radius, installation angle and span were 141.26 mm, 35.53° and 90.72° respectively, coefficient variation of wheat lateral uniformity was minimum. in this case, the coefficient variation of wheat lateral uniformity of theoretical calculation value and simulation test value were 10.58% and 9.21%, respectively, and the deviation was only 1.37%, the regression model was accurate and credible. In order to validate the regression model established by simulation test and the optimization effect of structure parameters, a bench test of wide-boundary sowing device with the structure parameters optimization combination of seed separated plate was carried out. The results showed that the average coefficient variation of wheat lateral uniformity was 13.40%, and the deviation with simulation experiment results was 4.19%, which less than 5%, and considering there may be some errors in the bench test, so it was believed that the results of bench test was basically consistent with simulation test. This paper proved that the discrete element method was feasible to optimize the structural parameters of seed separated plate, the research results could provide references for optimizing the structural parameters of seed separated plate of wide-boundary sowing device and improving the performance of the wide-boundary sowing. [ABSTRACT FROM AUTHOR]

Application of chemical fertilizer is an important part in the process of crop production management. The research showed that precise application of chemical fertilizer had great significance to improving the utilization rate of fertilizer and reducing the amount of fertilizer application. The outer fluted roller fertilizer apparatus is the key carrier in the process of precise variable rate fertilization. In order to optimize the fertilizer performance of the existing outer fluted roller fertilizer apparatus comprehensively, the discrete element simulation technology, orthogonal test and 3D rapid prototyping technology were used in this paper. The straight flute wheel structural was taken as research object, and influence regularity of 4 key structural parameters such as groove wheel radius, groove numbers, effective working length and groove section on fertilizer performance was analyzed. A discrete element simulation platform was set up in this paper for outer fluted roller fertilizer apparatus, which mainly consists of fertilization bin, fertilization box, the outer groove roller, fertilization tongue, fertilization pipe, soil ground and fertilizer particles. In the simulation test, the advancing speed of outer fluted roller fertilizer apparatus was 0.5 m/s, the working height was 500 mm, and the rotation speed of outer fluted roller was 20 r/min. The coefficient of variation of the fertilizer was selected as the performance evaluation index of outer fluted roller fertilizer apparatus. The test results of the interaction of 3 factors showed that there was no interaction between groove wheel radius and groove numbers, and between effective working length and groove numbers, there was a certain interaction between groove wheel radius and number of the grooves. The L18（37) standard orthogonal table was selected according to the result of interaction. The orthogonal result showed that factors affecting fertilizer performance, from importance to secondary, mainly include groove numbers, groove wheel radius, effective working length, interaction between groove wheel radius and groove numbers, and groove section. The groove numbers had very significant influence on fertilizer performance. The groove wheel radius had significant influence on fertilizer performance. The effective working length, interaction between groove wheel radius and groove numbers, and groove section had no significant influence on fertilizer performance. The optimum combination of parameters is that the groove numbers is 7, the radius of grooves is 30 mm, the effective working length is 20 mm, and the groove section is circular-arc, and the coefficient of variation of the uniformity of fertilizer for this type of outer fluted roller fertilizer apparatus is 1.75%. In order to test the simulation structure parameters optimization results of outer fluted roller fertilizer apparatus, a bench test was carried out under the optimal combination of structural parameters. The bench test mainly consisted of fluted roller fertilizer apparatus, power motor of conveyor belt, power motor of external groove, control box, conveyor belt and ruler. The experimental results showed that the coefficient of variation of fluted roller fertilizer apparatus is 5.48%. Considering that there may be some errors in the bench test, the results of the bench test were basically consistent with the simulation results, which proved that the discrete element method is feasible to optimize the structural parameters of fluted roller fertilizer apparatus. This research results can provide references for optimizing the structural parameters of fluted roller fertilizer apparatus and improving the performance of the fertilizer [ABSTRACT FROM AUTHOR]

Winter wheat is the most important crop in China, which has a large planting area, a high per unit area yield and a high total output. This is important to the maintenance of national food security. Base-fertilizer application is an important process of winter wheat production, which directly affects the yield of crops, and reasonable and effective use of chemical fertilizer can improve the yield of crops. At present, base-fertilizer of winter wheat is applied to the surface of farmland by manure spreader or laborers. Then the rotary tiller or moldboard plow is used to bury the fertilizer underground. The method has the problems of disordered fertilizer, excessive fertilizer delivery and low utilization efficiency. The depth-setting fertilizer application for winter wheat is an ideal way of fertilization. It can carry out a uniform fertilization to the winter wheat’s underside position with a certain depth, which can reduce fertilizer amount of 10%-20% compared with the traditional fertilization operation. It is a fertilization technique with high output, stable yield and low cost. Combined with the characteristics of rotary tillage fertilizing of winter wheat in Huanghe-Huaihe-Haihe (HHH) zone of China, this paper proposes a precise depth-setting fertilizer application method based on principle of rotary tillage. From the kinematics analysis of rotary blade and soil block respectively, the mathematical model of the positions of fertilizer outlet orifice of steel pipe and the target depth of fertilization was established. In order to validate this mathematical model, a precision rotary tillage fertilization test platform was set up. The test platform includes tractor, depth-controlled component, rotary tillage device, fertilizer ejecting device, precision hydraulic control system and press device. The fertilizer ejecting device is the key part of the test platform. It includes longitudinal beam, fastening bolt, steel pipe of fertilizer ejecting, U-shaped bolt and sleeve. The steel pipe of fertilizer ejecting can be adjusted longitudinally and laterally according to the requirements of the test. In order to accurately validate the mathematical model, 2 groups of progressive experiments were designed and conducted at the National Experiment Station for Precision Agriculture in Xiaotangshan Town, Beijing City in October 2017. After testing, the hardness, humidity and temperature of soil in the test area at the depth of 0-10 cm were 615.0 MPA, 10.9% and 17.6 °C, respectively. In the experiment, the IT245 rotary blade cutting operation parts were selected, and power transfer mechanism used John Deal 1204 tractor. The tractor was controlled at the speed of 1.5 m/s, the rotational speed of rotary blade was stable at 180 r/min, and the rotary tillage depth was set to 200 mm in the verification test. The experiment selected blue fertilizer as the application object. Target fertilization depth was set as 80, 100, 120, 140, and 160 mm, respectively, for the precision fertilization field test, and the actual depth of fertilization was 73, 92, 111, 132 and 151 mm, respectively. The maximum offset deviation of fertilization depth was 9 mm, and the maximum deviation ratio of fertilization depth was 8.75%, which could meet the requirement of the actual production. The results of these experiments show that the mathematical model of the positions of fertilizer outlet orifice of steel pipe and the target depth of fertilization established is trustworthy. The results can be a theoretical basis for design and development of rotary tillage and fertilization equipment. [ABSTRACT FROM AUTHOR]