Design and Test of the Clearing and Covering of a Minimum-Tillage Planter for Corn Stubble

Conservation tillage technology can reduce wind erosion and soil erosion, improve soil fertility, avoid straw burning and relieve ecological pressure. It is an important measure to achieve sustainable agricultural development. In northeast China, there is a large amount of straw covering the ground after the corn machine harvest, which can easily lead to the blockage of the soil-touching parts during no-tillage seeding, affecting sowing quality and crop yield. In order to solve the above problems, the clearing and covering of a minimum-tillage planter for corn stubble was developed. The machine can complete multiple processes, such as seedbed preparation, seeding, fertilization, covering and suppression, straw covering, etc., in a single entity. This paper focuses on the design of the straw cleaning device and uses discrete element method software (EDEM 2018, Altair Engineering, Troy, MI, USA) to establish the straw cleaning device–straw–soil discrete element simulation model. The quadratic-regression orthogonal center-of-rotation combination test method is used to optimize the parameter combination of the machine, using the operating speed, the speed of the knife roller and the penetration depth of the knife as the test factors and using the rate of cleaning straw and the equivalent power consumption as the evaluation index. The results show that each factor has a significant influence on the performance evaluation indices, and the order of influence of each factor on the rate of cleaning straw is operation speed > penetration depth of knife > speed of knife roller, and the order of influence of each factor on the equivalent power consumption is penetration depth of knife > speed of knife roller > operation speed. The optimal combination of parameters is a 5.5–6.2 km/h operation speed, a 500 rpm speed of the knife roller, a 40 mm penetration depth of the knife, a straw-cleaning rate of more than 90% and an equivalent power consumption of less than 8 kW. This study provides technical and equipment support for the promotion of conservation tillage technology in Northeast China

Parameter Combination Optimization of the Lateral Straw Clearing and Throwing Knife Based on Discrete Element Simulation

In order to explore the laws of corn straw lateral moving and throwing, it is necessary to identify the main factors that restrict improvements in the quality of straw clearing and reductions in power consumption and then optimize the knife parameter combinations; in this paper, the kinematic analysis of single-stage lateral moving and throwing of corn straw was carried out, and the mathematical model for the collision process between the knife and straw is established. Key factors affecting the lateral moving and throwing efficiency of straw were determined according to the model analysis. A parameter combination optimization test was conducted with three-factor and five-level quadratic regression orthogonal rotation center combination test methods and discrete element virtual simulation, taking into account the edge angle of cutting, the rotation radius of the knife, and the rotation speed of the knife roller as test factors and the straw clearing rate and power consumption as performance evaluation indexes. The test results showed that at a travel speed of 7.2 km/h when the edge angle of cutting was 65°, the rotation radius of the knife was 420 mm, and the rotation speed of the knife roller was 538~600 rpm, the straw clearing rate was ≥85%, and power consumption was ≤1.5 kW. The field test was carried out to verify the optimized results, and the test results showed that the test values of the performance evaluation indexes were all in the ranges of the optimized interval. These research results lay down the foundation for the design of lateral straw clearing and throwing knives

Experiments on the Influence of Corn Straw Morphological Combinations on Timely No-Tillage Sowing Soil Temperature and Moisture in Cold Regions

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

Design and Test of Elastic Tooth Type Lateral Straw Clearing Roller Based on the Straw Clearing and Mulching No-Tillage Precision Planter

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%

The Sliding Frictional Properties of Untreated and Extrusion-Exploded Wheat and Rice Straw

Knowledge about the frictional characteristics of materials is required for equipment design, either to exploit the friction or to overcome it. This paper deals with studying the coefficients of sliding friction of non-treated and extrusion-exploded wheat straw and rice straw on mild steel and aluminum surfaces and the effects of several factors, including the moisture content (at five levels 35, 45, 55, 65, and 75%), normal pressure (at the following five levels: 2, 4, 6, 8, and 10 kPa), and length (at the following five levels: 30, 60, 90, 120, and 150 mm). Through the use of a statistical analysis method, we found that the moisture content, normal pressure, and interactions between them had statistically significant effects on the coefficient of sliding friction (p < 0.01). The coefficient of sliding friction was much larger than that of rice straw on both contact surfaces, and the coefficient values of both straw samples on the aluminum surface were notably higher than those on mild steel. A significantly higher value was found for the coefficient of sliding friction of extrusion-exploded straw compared with that of untreated straw on both surfaces. As the normal pressure increased from 2 to 10 kPa, the coefficient of sliding friction decreased first, and then increased sharply, finally fluctuating slowly for both kinds of straw and on both tested surfaces, with the maximum value was observed at a normal pressure of 6 kPa. When the length increased from 30 to 150 mm, a slightly linear upward trend was observed for the coefficient of sliding friction of untreated wheat straw, and the coefficient of sliding friction of untreated rice straw initially increased and then decreased