The traffic-induced soil compaction in the field has gradually become an important constraint to sustainable agricultural development. A field experiment was conducted to acquire the stress transmitted caused by multiple passes with different types of tractors and to investigate the impact of these stresses on soil bulk density and crop growth. The experiment applied two tractors with different masses: LOVOL M904 (HC) and John Deer 280 (LC), and six different treatments of 0 (C0), 1 (C1), 3 (C3), 5 (C5), 7 (C7), and 9 (C9) tractor passes for each tractor. The results showed that at each number of passes, tractors with small axle-loads at 0–20 cm depth generated higher soil additional stress, while tractors with large axle-loads at 20–80 cm depth generated higher soil additional stress. In the 0–20 cm soil layer, when the number of continuous passes is less than 7 times, the passes of a small axle-load tractor lead to larger soil bulk density, and when the number of continuous passes is more than 7, the compaction of large axle-load tractor leads to larger soil bulk density. At depths of 20–80 cm, compaction by large axle-load tractors results in larger soil bulk density. In this study, different levels of tractor compaction inhibited key growth indicators of maize, resulting in yield reductions. The effect of different tractor load compaction on maize yield increased significantly with the number of compaction passes, with 1–5 tractor passes having no significant effect on yield and 7–9 passes producing greater yield reductions for HC. This study will provide a theoretical basis and technical support for the selection of agricultural machinery and reasonable tillage technology.

Aiming to solve the problems of easy generation of clods, poor soil fluidity and poor soil-covering effect in the no-tillage seeding operation mode, this study has designed a soil-covering device with a soil-closing function for the chisel-type furrow opener of a corn no-tillage planter. Theoretical analysis and design of the soil dividing plate and the soil-covering disc were carried out, and the key parameters were determined. Then, the soil-covering device with soil-closing function and the soil movement model was constructed in Altair EDEM, and the spatial soil particle mobility was analyzed. The numerical simulation method was combined with the center plane composite response test scheme to carry out the simulation test, and the optimal working parameter combination was obtained. The operating speed was 6.35 km·h⁻¹, the inclination angle of the soil-covering disc was 60°, the opening angle of the soil-covering disc was 70°, and the inclination angle of the soil dividing plate was 40°. A comparative test of the soil-covering effect and performance was carried out, and the results showed that the designed device was better than the traditional soil-covering device in terms of the consistency of soil-covering thickness and the stability of seed position deviation. The relative errors of the soil bin experiment results and the simulation optimization results for the cover soil thickness and seed position deviation were 5.7% and 11.1%, respectively. The operation effect of the designed soil-covering device with soil-closing function meets the requirements of soil covering under no-tillage conditions and provides a basis for the research and development of soil-covering suppression technology and devices under no-tillage seeding mode.

Wheat sowing has the characteristics of wide and short sowing periods, and there are situations in which the suitable sowing period is missed. In order to meet the needs of high-speed sowing, a centrifugal wheat strip seeding device was designed, the principle of which is that rotating parts were mainly composed of centrifugal concave plate and guide strip rotating in the shell to provide the mechanical force and drive the airflow and then realize high-speed seeding. The influence of the rotational speed of the seed discharging plate, the seed feed rate, and the dip angle of the guide strip on the distribution of the flow field and trajectory of seeds in the device was analyzed. The aerodynamic characteristics of seeds and the distribution of the gas-phase flow field inside the seed displacer under airflow were analyzed by CFD–DEM coupled simulation. The effects of three operating parameters on the coefficient of variation of sowing uniformity (CVSU) and the row-to-row seeding amount coefficient of variation (RSCV) were clarified, and the simulation results were verified by bench experiments after secondary optimization. When the centrifugal concave plate rotational speed, seed feed rate, and guide strip angle were 408 rpm, 4938 grains/s, and 69°, the results showed that CVSU and RSCV were 1.12% and 2.39%, respectively, which was in line with the standards for grain strip seeders stipulated. The designed seed discharge device can sow 3.4 ha per hour. This study provides a reference for research of centrifugal airflow-assisted high-speed seeding devices for wheat.

The strip rotary tillage method effectively reduces the occurrence of straw clogging and creates a favorable seed bed environment. However, the mixture of crushed straw and soil in the seeding area results in inadequate seed-soil contact following compaction by the press wheels. A chisel-type opener furrow side pick-up blade was proposed to improve seed-soil contact by picking up wet soil from the furrow's side. The discrete element method was used to investigate the impact of earth blade surface parameters on soil dynamics. The key factors of the blade, including forward velocity, endpoint tangent angle, and angle of soil entry, were determined through theoretical analysis. Soil cover thickness and straw ratio in the seed furrow were evaluated using orthogonal rotation regression tests. The results show that the endpoint tangent angle and angle of soil entry have the greatest influence on soil cover thickness, while the angle of soil entry has the greatest influence on the straw ratio. The optimal values for the forward velocity, endpoint tangent angle, and angle of soil entry are 4.86 km/h, 107.17°, and 5.46°, respectively, resulting in a soil cover thickness of 40 mm and a straw ratio of 21.46%. Confirmatory soil bin tests showed similar results, with a soil cover thickness of 40.4 mm and a straw ratio of 18.03%. These results provide a viable solution for improving seed-soil contact after strip rotary tillage planter seeding.

In this study, a device was designed for tillage of compacted soil in wheel ruts formed by the repeated passage of agricultural machines.[Ed1] Soil parameters were measured, and then the wheel rut tillage device was divided into two parts, the soil lifting unit and the soil breaking unit, for separate simulation tests to study the tillage process. EDEM[Ed2] simulations were applied to the soil lifting device to compare and analyze the microscopic movement of the simulated soil particles and the operational resistance of the device. Analysis of variance (ANOVA) was performed using Design-Expert10 [Ed3] software to obtain the optimum combination of parameters of 125 mm device offset distance, 43.6° entry angle and 28° lifting angle. A full-factor test was conducted on the soil crushing device using EDEM coupled with RecuDyn multi-body system dynamics simulation software. The number of bond breaks and the traction resistance of the soil crushing device were used as the test indicators, and the optimum parameters were obtained for a soil crushing knife blade thickness of 6 mm and a cutting edge angle of 30° for the largest number of bond breaks and least traction resistance. The results of this study will provide technical support for the reduction of compaction zones in wheel ruts after tire travel on agricultural machinery in real time.

Vehicle-induced soil compaction occurs when agricultural machinery is working in the fields. The accumulated soil compaction could destroy soil structure and inhibit crop growth. The low degree of visualization of soil compaction has always been an important reason for restricting the development of compaction alleviation technology. Therefore, the main objective of this study was to predict soil compaction based on soil and agricultural implement parameters. The component of soil compaction prediction includes traffic-induced stress transmission evaluation and the quantitative relationship between soil stress and bulk density. The modified FRIDA model was used to elucidate the soil stress propagation, which has been validated by previous studies. The Bailey formula was used to establish the intrinsic relationship between soil stress and bulk density. The soil uniaxial compression test was applied to obtain the parameters of the Bailey formula, and soil samples were prepared with three different levels of water content. After fitting with the Bailey formula, under the condition that the soil moisture contents were 16%, 20%, and 24%, the fitting coefficients of soil bulk density were respectively 0.980, 0.959, and 0.975, which were close to 1. The results indicated that the Bailey formula could be used to calculate soil bulk density based on the stress conditions of the soil. To verify the practicality of the soil compaction prediction model, a field experiment was carried out in Zhuozhou City, Hebei Province, China. The treatment was set for 1, 3, 5, 7, and 9 times compaction with two different loads of compaction equipment. The results showed that the fit coefficient between the predicted and measured values of soil bulk density was greater than 0.641. The slope of the equation was greater than 0.782, proving that the soil bulk density prediction model based on agricultural implements and soil parameters has a good predictive effect on soil bulk density. The soil compaction evaluation model can provide a theoretical basis to further understand the soil compaction mechanism, allowing rational measures of soil compaction alleviation to be made. Keywords: soil traffic-induced compaction, agricultural implement, soil bulk density, no-tillage, soil structure, quantification DOI: 10.25165/j.ijabe.20201305.5480 Citation: Wang X L, Zhang X C, Lin X N, Sha L M, Yang H Y, Guo Z Y, et al. Quantification of traffic-induced compaction based on soil and agricultural implement parameters. Int J Agric & Biol Eng, 2020; 13(5): 134–140.