| Rice is the most important food crop in China.In the process of growth,scientific application of fertilizer can improve rice production efficiency and ensure food security.The traditional rice fertilization operation mainly relies on artificial fertilization,and the uniformity of fertilization is poor,which not only reduces the utilization rate of fertilizer,affecting the yield and quality of rice,but also leads to ecological and environmental problems such as eutrophication of paddy soil.Fertilization mechanized deep application technology can reduce fertilizer volatilization and significantly improve the utilization of nitrogen,phosphorus and potassium in fertilizers.Fertilization distribution apparatus in paddy field nowadays generally adopts the method of combining groove-wheel fertilizer apparatuses with wind.Because groove-wheel fertilizer apparatuses has high requirements on the physical characteristics of the solid granular fertilizer,and the wind fertilizer is easy to be affected by the field environment such as water and weeds.Therefore,the phenomenon of fertilization blockage often occurs.Therefore,it is necessary to study scientific,rational rice fertilization techniques and equipment to achieve multiple effects such as fertilizer reduction,production increase and environmental protection.In this paper,according to the agronomic requirements of rice fertilization,the research on the side-deep fertilization device in the paddy field was carried out for blockage and poor uniformity.The physical properties of common solid granular fertilizer were tested and analyzed.Based on the advantages of fertilizer and fertilizer deep application technology,the overall structure of the two-stage spiral driven fertilizer and deep fertilization device(hereinafter referred to as paddy field fertilizer and deep fertilization device)was developed.The displacement and deepening of paddy field was simulated by discrete element method.The structural parameters and working process of the first-stage fertilization spiral and the second-level deep fertilization spiral of the key components of the fertilizer application device;Fertilizer distribution and deep application apparatus in paddy field were developed,The fertilization performance test was carried out.The specific work is as follows:(1)In order to solve the problems of fertilizer clogging and poor uniformity of different types of solid granular fertilizers in rice fertilizing machinery,the physical properties of common solid granular fertilizers were studied.The density,size and shape of three kinds of fertilizers:domestic urea(Luo Feng Shan),domestic compound fertilizer(Ba Tian)and Russian compound fertilizer(AKANG)were determined.The crushing force and water content of three fertilizers under different water content and particle size were studied.The law of self-made static friction coefficient is obtained,and the static friction coefficient law of fertilizer and body with different water content is obtained.The results show that the density of domestic urea,domestic compound fertilizer and Russian compound fertilizer are 1.256 g/cm~3,1.670 g/cm~3 and 1.776g/cm~3,respectively.The sphericity of all three fertilizers is more than 90%,which can be approximated as spherical particles.The moisture content and particle size of the fertilizer have an important influence on the crushing force,especially the water content more.The crushing force of the same variety of fertilizer decreases with the increase of water content,and increases with the increase of the particle size.The static friction coefficient of the same variety of fertilizer and the body increases with the increase of water content.(2)According to the agronomic requirements of rice fertilization,the research on the overall structure of fertilizer distribution and deep application apparatus in paddy field was carried out.On the basis of comprehensive analysis of the existing technical problems of fertilization machinery in paddy field,combined with the advantages of spiral fertilizer and deep application technology of fertilizer,a paddy field row consisting of a first-stage fertilizer fertilization mechanism and a second-stage deep fertilization spiral deep fertilization mechanism was developed.The first-stage fertilization spiral agitates the fertilizer in the fertilizer tank to ensure the fluidity of the fertilizer;the second-stage deep fertilization screw forces the fertilizer into the soil to complete the lateral deep fertilization operation.(3)The structural parameters and working process of fertilizer apparatus based on EDEM are studied emphasisly.By funnel method,combining the actual measurement of the stacking angle with the simulation test,the discrete element simulation parameters of the domestic compound fertilizer is calibrated.The discrete element method was used to determine the first-order fertilizer heaving spiral and the second-level deepness of the key components of fertilizer distribution and deep application apparatus in paddy field.The optimal structural parameters of the fertilization helix;the first-order fertilization spiral outer diameter,the first-stage fertilization spiral inner diameter,and the first-order fertilization spiral pitch are the experimental factors,and the coefficient of variation of the fertilizer discharge stability of the first-stage fertilization screw discharge mechanism is Test indicators,three-factor three-level orthogonal simulation test;two-stage deep fertilization spiral outer diameter,two-stage deep fertilization spiral inner diameter,two-stage deep fertilization spiral pitch as test factors,uniform fertilization with paddy field fertilizer and deep fertilization device.The coefficient of variation of sex is the experimental index,and the orthogonal simulation test of three factors and three levels is carried out.The simulation test results show that when the first-stage fertilization spiral outer diameter is50mm,the first-stage fertilization spiral inner diameter is 20mm,the first-stage fertilizer fertilization spiral pitch is 35mm,the second-stage deep fertilization spiral outer diameter is30mm,and the second-level deep fertilization spiral inner diameter is 16mm.When the fertilization pitch of deep fertilization is 26mm,the fertilization performance of paddy field fertilizer and deep fertilization device is the best.(4)Developing water field fertilizer and deep fertilization equipment,and conduct fertilization performance test.Three kinds of commonly used solid granular fertilizers,such as domestic urea,domestic compound fertilizer and Russian compound fertilizer,were used to carry out bench test of paddy field fertilizer and deep fertilization device.The test results show that when the equivalent speed is 1.38～1.67m/s and the fertilizer discharge rate is159.45～465.51 kg/hm~2,the fertilization stability coefficient is less than 7.8%when the fertilizer is discharged from the paddy field and the deep fertilization device.The fertilization performance meets the requirements of the fertilizing machinery industry standard.The device can be installed on the rice transplanter and the paddy field tractor to realize synchronous deep fertilization or topdressing operation,which lays a foundation for the development of the whole machine fertilizing equipment. |
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