Shouyin Hou

Selecting an appropriate disc coulter is crucial for reducing the power consumption of no-till seeders, preventing straw from being pressed into seed furrows, improving the soil penetration performance of the disc coulter, and thus minimizing the weight of no-till seeders. This study utilized the quadratic regression orthogonal rotation central composite approach. With the application of EDEM and RecurDyn software, a virtual simulation model of the interaction between a toothed disc coulter and soil was developed. The angle of front serration δ, the angle of rear serration θ, and the number of serrations n were taken as experimental factors. The draft F_v and penetration resistance F_N were selected as performance evaluation indicators for parameter combination optimization simulation tests. The results indicated that δ, θ, and n have significant influences on F_v and F_N (p < 0.05). When the optimized parameter combinations δ, θ, and n were respectively determined as 16°, 39.1°, and 13, both F_v and F_N reached their minimum values. A comparative experimental study was conducted with the optimized toothed disc coulter and six existing disc coulters; under the working conditions of 14.4 km·h⁻¹, both the draft and penetration resistance of the toothed disc coulter are minimized. The draft was 227.5 ± 8.9 N and the penetration resistance was 415.9 ± 5.3 N. Meanwhile, the toothed disc coulter had the highest ratio of soil disturbance area to draft, indicating better soil loosening effects.

To address issues such as slow soil temperature recovery and delayed sowing periods caused by straw mulching in the cold regions of northern Heilongjiang Province, this study designed a straw crushing and scattering device compatible with the 2BMFJ series no-till planters, aiming to achieve moderate straw fragmentation and uniform distribution. By establishing mathematical models for the straw pick-up, crushing, and scattering processes, key parameters affecting the device’s performance were determined. Utilizing the discrete model of EDEM 2018 software virtual simulation experiments were conducted based on response surface methodology. The test factors included the blade angle of the crushing long blade, the edge thickness of the crushing long blade, the weight of the crushing long blade, and the rotational speed of the crushing long blade. The performance evaluation indicators were the straw pick-up rate, straw crushing rate, power consumption, and inter-row straw coverage consistency. The optimal parameter combination was identified to be a blade angle of 25°, an edge thickness of 1.25 mm, a weight ranging from 0.35 to 0.41 kg, and a rotational speed between 1400 and 1750 r/min, resulting in a straw pick-up rate of 83%, a straw crushing rate of 84%, power consumption of 6.8 KW, and a straw cleaning consistency between rows of 75%. Field test results indicated that the straw pick-up rate reached 87.2%, the straw crushing rate achieved 81.5%, power consumption was 7.7 kW, and the straw cleaning consistency between rows attained 79.3%. The deviations from simulation results were within acceptable limits. This equipment can effectively complete straw crushing and scattering operations, thereby creating favorable seedbed conditions.

: To improve the efficiency of rhizobial inoculation operations and address the current situation of rhizobial inoculation being labor-intensive, a spraying and control system for variable rate application (VRA) of liquid rhizobia was developed. The system can accurately regulate the spraying rate of liquid rhizobia according to the desired rate of rhizobia by incremental Proportional Integral Derivative (PID) closed-loop control algorithm, making it particularly suitable for precise spraying with small amounts. In the laboratory experiment of precise flow control, variation coefficient of spraying nozzle from 0.10 MP to 0.20 MP pressure were no more than 1.2%. A clear linear relationship was observed between the spraying rate and pressure. The maximum response time was 1.93 seconds, while the average response time was 1.62 seconds when controlling the spraying system for small amounts. Field trial was conducted in Heilongjiang Agricultural Xianghe Farm of China. Average seeds number and 100-seed weight of soybean plant with rhizobia inoculation treatment were better than control group, and average yield of spraying liquid rhizobia agent with full base fertilizer increased by 232.5 kg/hm2, representing a significant 7.4% improvement over the control group. The results of these trails clearly showed the positive effect of the spraying and control system for liquid rhizobial inoculation, which has superior to existing inoculation manners, and provides an important technical support for the widespread adoption of rhizobia technology.

Aiming at precise evaluation of the performance of soybean seed metering devices, a photoelectric sensor-based real-time monitoring system was designed. The proposed system mainly included a photoelectric sensor module for seeding signal collecting, Hall sensors speeding module, microcontroller unit (MCU), light and sound alarm module, human–machine interface (HMI), and other parts. The indexes of miss, multiples, flow rate, and application rate were estimated on the basis of seeder speed, seed metering disk rotation rate, photoelectric sensor signals, and clock signals. These real-time statistics of the seeding process were recorded by seeding management system. The laboratory results showed that the detection errors of seeding quantity of both big- and small-diameter soybeans were less than 2.0%. Miss and multiples index estimated by this system were 0.4% and 0.5% than that of seeding image monitoring platform (SIMP), respectively. In field tests, miss and multiples index can be used to evaluate the performance of seed metering device, and big-diameter seeds can be detected more precisely than small ones by these photoelectric sensors. This system can provide support for evaluation of working performance of seed metering devices and have a positive effect on seeding monitoring technology.

After corn mechanical harvest in autumn in the cold region of northeast China, straw mulching leads to high soil topsoil water content and slow ground temperature rise in the spring sowing season, which may result in a no-tillage planter being unable to operate in time, delayed sowing date, poor seedling emergence quality, and low grain yield. Based on the problems of high moisture content and low temperature in soil topsoil in the spring sowing season in conservation tillage with straw mulching, an experimental study on timely sowing in the spring sowing season was carried out from the perspective of combination optimization of attribute parameters of straw mechanical treatment. Taking the four mechanical treatment attributes as experimental factors, including straw length, straw shape, mulching form (surface covering, inter-ridge covering, and inter-ridge mixed soil covering), and stubble height after corn harvest in autumn of 2019 as experimental factors, and soil topsoil moisture content and temperature during spring sowing in 2020 as evaluation indexes, a field plot experiment was carried out by four factors and three levels of orthogonal combination test method. The results showed that all the factors had significant influence on soil topsoil moisture content and soil topsoil temperature (p < 0.05). It is helpful to reduce the moisture content of soil topsoil and increase the temperature of soil topsoil by increasing the length of corn stalk, breaking the stalk moderately, covering the stalk between ridges, and increasing the stubble height of stalk. Design-Expert software was used to optimize the parameters. The results showed that when the length of straw was 150 mm, the shape of straw was half-cut (dividing straw into two parts evenly along the axis), the mulch was between ridges, and the stubble height was 600 mm, the moisture content of soil topsoil was 22~24% and the temperature of soil topsoil was higher than 8 °C during spring sowing. After corn harvest in autumn of 2021, corn stalks were treated in that year according to the results of parameter optimization combination. The soil topsoil moisture content and temperature were measured to be 24.4% and 8.2 °C, respectively, in the spring sowing season of 2022, which proved that the optimization results in this experiment were credible. The experimental results provide a technical reference for the implementation of conservation tillage with straw surface mulching in the cold region of northeast China.

Aiming at the problems of large soil disturbance, high power consumption and strong vibration during the operation of the 2BMFJ series straw clearing and mulching no-tillage precision planter with rigid teeth, an elastic tooth type lateral straw clearing roller was designed and the key parameters and values affecting the operation performance of the device were determined through theoretical analysis. Orthogonal test method was adopted to implement parameter combination improvement test with the length of tooth rod, the clearance of roller center from ground, the circumferential number of elastic teeth and the angular velocity of roller as test factors and straw clearing rate, power consumption and vibration intensity as performance evaluation indexes. The results showed that: all the factors had extremely significant effects on the straw clearing rate and power consumption performance evaluation indexes, except the clearance of roller center from ground had no significant effect on the vibration intensity performance evaluation indexes, the other factors have significant effects. Parameter optimization combination: At the planter forward speed of 7.2 km/h, the length of toothed rod was 270 mm, the clearance of roller center from ground was 360 mm, the circumferential number of elastic teeth was 8, the angular velocity of roller was 52 rad/s and the performance evaluation indexes were as follows: straw clearing rate was more than 90%, power consumption was less than 1.7 kW and vibration intensity was less than 85 m/s². Through the comparative test of the elastic tooth and rigid tooth type lateral straw clearing roller, there was no significant difference in the straw clearing rate between the two, but there were significant differences in the power consumption and vibration intensity. The elastic tooth type lateral straw cleaning roller reduced power consumption by 63.3% and vibration intensity by 43.2%.