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• Established and calibrated a Soil-Straw composite model. • A vertical active rotation straw cleaning method has been proposed. • Designed a vertical stubble cleaning and soil crushing device. • Structural parameters were optimized through DEM-MFBD. Strip tillage is a necessary technical means to solve blockage problems during the no-tillage sowing process under the condition of total straw return to the field. However, the large amount of straw on the surface, thick stems, and slow decomposition make it difficult for the traditional straw wheel structure to effectively clean the straw out of the operating area. Based on the distribution of straw and soil characteristics on the no-tillage surface, a Soil-Straw composite model is established using the discrete element method (DEM) for undisturbed soil under straw coverage conditions. The relative error of its bonding parameters is 7.9 %, which can accurately predict the mechanical behavior of soil contact components. A vertical rotation-based straw strip cleaning and soil tillage method is proposed, and three vertical straw strip cleaning and soil tillage devices combining spring teeth (ST) and rake teeth (RT) were designed. The reasonable operating parameters are determined through trajectory analysis, with a forward velocity of 1.67 m/s and a rotational velocity of 300 r/min. Based on the Soil-Straw composite model, the combination of three ST and RT types is studied using DEM-MFBD coupled simulation technology. Regarding the straw cleaning rate, the straw cleaning rates of ST b -RT b and ST c -RT c are 96.66 % and 96.99 %, respectively, meeting the operational requirements. The field test results showed that the straw cleaning and soil fragmentation rates of the ST c -RT c combination were 97.7 % and 96.4 %. The bench test and field test verification show that the DEM-MFBD coupled simulation technology based on the Soil-Straw model can predict the operating quality and deformation stress of the machine. This study provides a new solution for a wide range of straw cleaning in straw-covered areas. [ABSTRACT FROM AUTHOR]

In this study, the manure block model is established by the discrete element method through the combination of uniaxial compression physical test and simulation test. The model optimizes the propeller blade structure. Finally, the device is processed and tested. The purpose of this study is to solve the problems of the lack of numerical simulation models of solid organic fertilizer, the overhead of the traditional chain fertilizer delivery device in the process of fertilizer transportation, and the poor quality of subsequent fertilization due to the difficulty in effectively breaking the fertilizer blocks. [Display omitted] • The HMB model of organic fertilizer is established and calibrated. • A method of transporting and crushing fertilizer by PB is proposed. • Based on the fertilizer model, the parameters of the PB device are optimized. In organic fertilizer application, it is difficult for existing chain-type fertilizer transport devices to cut and break organic fertilizer blocks during operation. The fertilizer transport process does not effectively disturb the fertilizer group, and it is easy to cause fertilizer overhead, which makes the subsequent fertilizer spreading and deep application process unable to operate normally. In addition, the lack of a solid organic fertilizer numerical simulation model restricts the innovation of organic fertilizer application equipment. Because of the above problems, based on the physical characteristics of the manure, this paper establishes a simulation model of a manure block through the Hertz-Mindlin with bonding (HMB) contact model in the discrete element method (DEM), calibrates the bonding parameters of the organic fertilizer by combining the uniaxial compression physical test and the simulation test, and verifies the calibrated bonding parameters by the load–displacement test and the deformation test of organic fertilizer. Through parameter optimization, the unit normal stiffness (UNS) is 11.27 × 107N/m3, unit shear stiffness (USS) is 4.17 × 107N/m3, critical normal stress (CNS) is 3.40 MPa, critical shear stress (CSS) is 1.25 MPa, and bonding radius (BR) is 2.80 mm. The relative error of the maximum load (ML) is 8.7%, and the relative error of the displacement is 3.2%, as verified by the bench test. This paper proposes a propeller blade (PB)-type organic fertilizer crushing and transporting device, and the structural parameters of the PB are simulated based on the calibrated organic fertilizer model. The optimal parameter combination after the optimization of the PB is obtained as follows: the blade inclination angle is 42°, the blade spacing is 227 mm, the blade speed is 89 r/min, and the blade height is 205 mm. The machine is processed, and the field test is carried out. The results show that the average oil pressures of the stable fertilizer crushing process under the half-speed and full-speed modes are 11.06 MPa and 12.01 MPa, respectively. The minimum oil pressure is 8.89 MPa and 10.90 MPa, respectively, the average energy consumption is 2.71 kW and 5.42 kW, respectively, and the proportion of the particle size of the organic fertilizer after crushing is more significant than 92.4%. The quality of the crushed fertilizer is high and can be used in crushed fertilizer applications. [ABSTRACT FROM AUTHOR]

Because of the problems that the current solid organic fertilizer is easy to agglomerate in the fermentation and stacking process, the fertilizer efficiency is brutal to release, and the strip application is difficult to discharge, this paper proposes a solid organic fertilizer crushing strip application method combining propeller blades and differential speed rollers. A solid organic fertilizer crushing and strip applicator were designed and developed through theoretical analysis and discrete element simulation experiments. Finally, it was verified by field experiments. The research results provided a new scheme and technical support for the broken strip application of solid organic fertilizer in cultivated land. [Display omitted] • Solid organic fertilizer breaking strip applicator was designed and developed first. • Propose crushed fertilizer combining propeller blades and differential speed rollers. • The structure of the furrow fertilizing device was optimized based on EDEM. • The machine is processed and experiments are conducted to verify its performance. Because of the problems that the current solid organic fertilizer is easy to agglomerate in the fermentation and stacking process, the fertilizer efficiency is brutal to release, and the strip application is difficult to discharge, this paper proposes a solid organic fertilizer crushing strip application method combining propeller blades and differential double roll. This article clarified the structure or installation parameters of the double roll fertilizer crushing, paddle fertilizer screw and trench covering device. The simulation test of the fertilizer tank compares the performance of three paddle fertilizer transport devices' fertilizer crushing and fertilizer transport and selects the symmetrical arrangement of the paddle combination. The discrete element software is used to simulate the operation process of the solid organic fertilizer crushing strip, and the influence of the ditching and fertilizing shovel tip into the soil, entirely into the soil, and stable ditching complete operation process on the movement state of soil particles were analyzed. A quadratic orthogonal rotation test is designed, and the optimal parameter combination is obtained as follows: the operating speed of the machine is 6.37 km/h, the angle of the shovel tip is 72.83°, the angle of the overburden is 19.56°, and the coefficient of variation of the optimized fertilization uniformity is 9.30 %. Finally, The average coefficient of variation of fertilization uniformity in the ground spreading experiment and the field strip fertilization experiment is 11.32 % and 13.87 %, respectively; both experiments are close to the simulation results. The research results provided a new scheme and technical support for the broken strip application of solid organic fertilizer in cultivated land. [ABSTRACT FROM AUTHOR]