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Agricultural equipment is working in very high-stress conditions. However, it has a significant influence on the wear losses of soil processing parts. Chisel is operating at 30 cm working depth at a maximum of 12 km·h−1 working speed. Due to unpredictable soil conditions, chisel tines suffer high wear losses. It leads to time consumption and cost expenses during the soil preparation period. Wear resistance, and agronomical requirements (working depth, loosening of soil) are the main criteria of agricultural equipment producers. The discrete element method is a solution that simulates soil as sphere shape particles with soil properties. Wear results reveal the change of parts shape, acting forces, and stresses during the simulation in the virtual soil bin. The used Rocky DEM software uses a parameter C (volume/shear work ratio) to describe wear intensity, which varies for different geometry. Chisel tine geometry should be divided into sections with varied parameter C according to stress acting on the surface. The test conditions can be used for future wear analysis of varied tool geometry and protection (sintered tungsten carbide plates, hard-faced surface, etc.) agricultural tools to compare its durability in different soil conditions.

Crops with branching characteristics, such as rapeseed, are difficult to harvest owing to their specific plant geometry. To solve this problem, an harvesting reel with improved tine trajectory, considering the reel working process and a function suitable for oilseed rape, is proposed in this study. The improved tine, of which angle can be continuously adjusted to adapt to the plant structure and meet the operating requirements of the reel in the stages of pushing the reel into the crops, feeding plants into the auger, and releasing the reel. The kinematics of the tine trajectory between the new and standard reels were calculated and a simulation comparative analysis was performed, which proved that the new reel satisfies the theoretical requirements. Single-factor field experiments were conducted for the two types of reels. The test results demonstrated that the proposed reel has a lower header loss rate and is significantly affected by the reel speed than the reel height or machine forward speed. According to the multivariate orthogonal results, the combination of optimal parameters with minimum loss rate yielded a reel rotational speed of 1.88 rad s−1, machine speed of 0.6 m s−1, and reel vertical height of 1100 mm. The actual loss rate was found to authentically decrease to 1.04% in the supplementary field test under this condition, which verified that the parameters are reasonable. This study combines experiments and trajectory analysis to explain the advantages of the improved reel and provide a new study direction of reducing rapeseed harvesting losses.

HighlightsA mathematical model of soil reaction forces on a rotary tine tool was developed.Soil bin experiments using artificial soil enabled observation of soil failure due to soil-tine interaction.The model-predicted forces were similar to experimentally measured forces.Abstract. Understanding soil-tool interaction can enable better control of weeding tools to achieve higher weeding efficacy. The interaction between a vertical tine (mounted on a rotating disc) and soil was investigated using a mathematical model that estimated soil horizontal forces on the tine operating at different linear and rotational velocities. The kinematics associated with the linear and rotational velocities of the rotary tine tool were modeled, and the shearing and inertial forces were estimated. To evaluate model performance with different experimental factors, two sets of soil bin experiments were conducted using an artificial soil: with one tine to estimate model parameters and with two tines 180° apart. Experimental factors were longitudinal velocity (travel speed) at three levels (0.09, 0.29, and 0.5 m s-1) and speed ratio, i.e., the ratio of longitudinal velocity to peripheral velocity of the tines, at three levels (1, 1.5, and 2). Soil horizontal force and torque on the rotary tine tool were measured. A nonlinear least squares method was used to estimate model parameters from the experimental data, resulting in shearing force coefficients ranging from 2.9 to 37 N and inertial force coefficients ranging from 16 to 528 N s2 m-2. The variations in the shearing and inertial forces on the tine were due to differences in soil failure patterns among the treatments. The predicted longitudinal and tangential forces for two tines using the model showed trends that were similar to the forces measured in the experiment. However, the model overestimated the predicted forces because it did not account for the reduced force on a tine due to soil disturbance created by the other tine. Keywords: Soil-tine interaction, Weed control.

The spring-tine harrow is gaining popularity for mechanical weeding. However, its weeding performance and mechanism have not been well understood. A spring-tine harrow was first tested in a controlled indoor soil bin at four different travel speeds (4, 6, 8, and 10 km h−1) with three different spring-loading settings (low, medium, and high). Then the harrow was tested in a wheat (Triticum aestivum L.) field at the same spring-loading settings at three different weeding timings (early, middle, and late) in 2019 and 2020. Soil cutting forces (draft and vertical), soil displacements (forward and lateral), soil working depth, weed control efficacy, weed density, and crop damage were measured. The results showed that the spring-loading setting had a more dominant effect on working depth and soil cutting forces than the speed. The soil displacements were more dependent on the speed compared with the spring-loading setting. Treatment effects on weeding performance indicators in the field were similar across years. Adjusting the spring-loading setting from low to high improved the weeding efficacy from 44.9% to 73.9% in 2019 and from 51.6% to 78.1% in 2020. Consequently, the final weed density was minimized at the high loading setting, with the reduction in 2020 being significant. The middle weeding timing caused the least crop damage, while reducing the final weed density by approximately one-third compared with the control (without mechanical weeding), which was the most desired outcome among the three timings tested.

The discrete element method (DEM) is one of the main modelling techniques in the agricultural sector to investigate soil tillage. There is a model-like description for material abrasion, which is often based on the determination of a virtual material removal, but the geometrical changes of the geometry, as well as the continuous load change upon the tool, are often not considered in the DEM simulations. Research on wear of tillage tools have been focused mostly on experimental studies with the result that abrasion is mainly caused by micro cutting on the contact surface. The single asperity scratch test is considered to be most suitable for evaluating materials due to its abrasive wear resistance. This paper presents an innovative approach that investigates the influence on the continuous wear process. The presented method describes the geometrical changes of the geometry based on the material loss. DEM simulations have replicated the single asperity test for different normal forces. Taking into account the geometric changes, these achieve the same wear volume and are therefore suitable for investigations of wear processes during soil tillage.

With the increased use of agricultural machinery in field operations, soil compaction has become increasingly severe, and the plough pan has become deeper. Subsoiling is an excellent way to address this problem. However, it is limited by high energy consumption, which is closely related to tillage force. To investigate the effect of the geometric shape of shanks and tines on tillage force and soil disturbance in loam, a layered soil model in accordance with the actual conditions was established and five different subsoilers were simulated via discrete element modeling. The results indicated that the shank impacted soil disturbance and tine impacted tillage force. The draft force of curved shank and chisel tine was 8% less than that of the straight shank and sweep tine. The straight shank and sweep tine produced a larger furrow profile and a higher furrow width. The subsoiler with curved shank and chisel tine (C-C) exhibited the lowest specific resistance (12.87, 17.52, 19.46 and 21.18 kN/m2 in the 30, 35, 40 and 45 cm tillage depth, respectively) considering the draft force and soil disturbance characteristics. Hence, these results will facilitate in the selection of a suitable subsoiler and design of new subsoilers with lower energy consumption requirements for loam areas worldwide.

Commercially available agricultural machines are not matching with standards which affect the performances. Many times, commercially available rigid cultivator tines used in tractor drawn cultivator do not match in dimensions as given in respective BIS code. A study conducted in Udaipur, Rajasthan revealed that out of four such tines only one tine T 1 fulfilled the requirement of BIS code 7565:1975 whereas maximum deviation was observed for tine T 2 .

CITATION: Swanepoela, P. A. & Labuschagne, J. 2020. Canola is injured by in‐row nitrogen placement associated with disc openers, but not by tine openers. Crop Science, 60(1):466-474, doi:10.1002/csc2.20084.

The aim of the research presented in the paper is to reduce the mass of the structural elements of the subsoiler using the response surface optimization method. Two structural elements are optimized tine and structural support. The CAD model of the subsoiler was created in SolidWorks, a CAD system for parametric modeling using features. For the purpose of optimizing structural elements, soil load calculations were made using the Matlab software package. The geometric parameters of the structural elements, which represent the input parameters, were optimized. Output parameters (responses) consist of mass, maximum equivalent stress according to von-Mises and deformations. After the optimization, the control calculation of the optimized structural elements was made again with regard to s tresses and deformations. Through the control calculation, the stresses and deformations of the optimized structural elements meet the permissible values.

Wear and friction cause huge economic losses in the agriculture and mining industries. Wear simulations of working elements, materials, and surfaces that can reduce downtime and economic losses. This work proposes the use a cone penetration resistance measurement result as option to determine movement resistance of soil ripper tine by the discrete element method. It allows avoiding mechanical properties investigation of soil. Simulation made in sand and sandy clay helps to compare wear track of tine wear plates with actual wear. The actual wear was evaluated by 3D scanning of a soil ripper tine wear plates made from tungsten carbide and cobalt alloy and compared with simulated tines. Wear loss expressed as loss of area at the cross-section of tine wear plate. The maximum wear loss of scanned ripper wear plate at 0–150 mm working depth is 1.8% and simulated-in-sand and simulated-in-sandy-clay 1.2 and 1.7%. The maximum actual wear loss caused 57.9% wear loss of cross-section area at 150–204 mm working depth. Simulation in sand and simulation in sandy clay soil 6.9 and 9% caused by lower soil resistance than in field experiments. Simulations in sandy clay soil increased the draft force by 3.9 and 2.8 times that in the sand, at 0–200 mm depth, for tine parts to account for the stiffness fraction of sandy clay soil. As an alternative, tine wear evaluation is also suggested from shear energy values.

In 1990, I began experimenting with the manufacture of Folsom-style fluted projectile points using freehand direct percussion on obsidian preforms. This technique occasionally yielded finished points resembling Folsom points shown in the literature, but the chances of successfully removing two channel flakes from opposite sides of any given preform, while retaining enough length to allow the completion of even a modest point, were very low. Moreover, the few points that were finished seemed too thick in comparison to published metric data for Folsom points. Abandoning freehand percussion, I next tried indirect percussion using methods similar to those employed by Flenniken (1978). Obsidian preforms were either held between the heels as the worker sat or secured against the side of a small mud-plastered backfilled pit excavated in the ground; the blow was delivered to the channel flake platform using the tip of a severed antler tine as a punch, and a heavier piece of antler as a mallet. A critical problem encountered with this form of indirect percussion was that the tip of the antler punch chipped under the force of the mallet blow more often than the blow resulted in the removal of a channel flake. When the blow did initiate a fracture in the preform, preform splitting and disastrously off-centered channel flakes were the prevalent outcomes. With persistence, several points were finished, but because over 50 obsidian preforms and 20 antler tines had been consumed, indirect percussion using the tip of an antler tine as punch seemed no more plausible as an explanation for typical Folsom technology than was direct percussion.

Setting the right intensity is crucial for the success of post-emergence weed harrowing in cereals. The percentage of crop soil cover (CSC) correlates with the selectivity of weed harrowing. Therefore, real-time camera-based measurements of CSC offer a novel approach to automatically adjust the intensity of harrowing. The intensity of harrowing is varied by hydraulic steering of the tine angle. Five field experiments in cereals were conducted at three locations in southwestern Germany in 2019 and 2020 to measure the effect of camera-based harrowing (2020) and conventional harrowing on weed control efficacy (WCE), crop density, and grain yield. For this purpose, pair-wise comparisons of three fixed harrowing intensities (10°, 40°, and 70° tine angle) and three predefined CSC thresholds (CSC of 10%, 20%, and 60%) were realized in randomized complete block designs. Camera-based intensity adjustment resulted in more homogeneous CSC across the whole plot (6–16% less standard deviation variation) compared to conventional fixed settings of the tine angle. Crop density, WCE, crop biomass, and grain yield were significantly higher for camera-based harrowing than for conventional harrowing. WCE and yields of all automatic adjusted harrowing treatments were equal to the herbicide control plots. Camera-based harrowing provides a robust technology for effective weed management with a lower risk of crop damage than conventional harrowing.

This article presents the kinematic analysis of the tine motion of a rotary harrow. In particular, it analyses the trajectories that the tines describe when they are pulled by the motion of the tractor and rotated by the rotors. This analysis, has led to the identification of the parameters that influence the motion of the tines and how these parameters intervene in the secondary tillage. The interaction between the tines and the soil is evaluated considering a plastic soil, i.e. without any cleavage and its propagation. With this hypothesis, the dimensions of the soil clods created by the passage of the tines in the soil have been analysed. The trajectories described by the tines of the machine, and therefore the dimensions of the portions of worked or unworked soil, are influenced by the operating parameters of the soil tillage process, such as the tractor speed and the angular speed of the tines themselves. Furthermore, a contribution is also given by the geometric parameters of the machine, such as the rotor radius and the geometric configuration of the rotary harrow in terms of rotor arrangement. This study is based on the creation of a mathematical model of the trajectories of the tines of a rotary harrow during soil tillage. The model is parametric and makes it possible to simulate and optimise the tillage process. The approach adopted also makes it possible to visualise the trajectories in graphic form for an easy visual interpretation of the results.

One of the main challenges in tribology of agricultural tools is establishing a relationship between lab-scale testing and real applications. Nevertheless, the wear micro-mechanism stands as an effective mediator amid different test scales. In this research, different scale of testing (1) in-field testing of agricultural tines (real scale), (2) intermediate test using ASTM G132 tester (macro scale/multi-asperity test) and (3) single asperity testing using scratch tester (micro-scale) were performed. A relationship was established between different scales based on the qualitative output (wear micro-mechanism) and validated using the quantitative data (degree of penetration (Dp) using 3D profiles and wear). Test variables such as particle geometry/nose radius (22 µm − 200 µm), attack angle (90°–120°) and normal force (4.5–24.2 N) were adapted to achieve various micro-mechanisms. From real scale tests, co-existing micro-mechanisms were observed, amongst which micro-cutting was the dominant mechanism responsible for material removal. Dp value 0.4 representing micro-cutting at the cutting edge contributes significantly to the reduction in service life of the tines. Dp corresponding to micro-cutting was prevalent in the intermediate test, and in the single asperity test micro-cutting was experienced with samples tested at 25 µm nose radius. The cross-sectional analysis revealed the tribo-layer formation in the test material for both real scale and multi-asperity testing. The in-situ vision observations on single asperity testing elucidate the transition in micro-mechanism. Considering the three scales of testing, it is evident that the degree of penetration, wear micro-mechanism and wear rate are in-line with each other. This novel approach in linking different scales can be extended to other abrasion prone applications such as mining, drilling, etc for material selection.

Theoretical bases of soil movement were developed whereby a drill furrow was formed by an anchor plowshare with an acute angle of soil penetration with spaced structural elements. When the seeding working tool penetrates the soil at the depth of 0.06-0.08 m and the radius of its tine 0.2 m, the speed of movement of soil particles by the tine increases almost linearly on average by 11%, with the coefficient of soil friction against steel being from 0.3 up to 0.6 and the speed of the sowing unit movement - from 1 to 3 m/s. At the same time the speed of soil movement by the tine point and the tine of the seeding working tool exceeds the speed of the sowing unit by 1.6-1.8 times depending on the values of the coefficient of soil friction against steel. The height of the real soil tillage by the tine of the seeding working tool given the same speed range of the sowing unit increases by almost 4 times. The dependency was revealed between the value of the soil layer shift by the seeding working tool from the sowing zone into the inter-row space and the sowing unit speed. When the speed increases from 1 to 3 m/s, the shift increases by 15-32%. The maximum soil movement is observed with the angle of inclination of the side edge of the seeding working tool by 75°. Absolute values of soil movement were within the range of 0.35-0.45 m, which is sufficient to move the required amount of soil into the inter- row space when doing furrow sowing.

Research from the 1980s reported sweep cultivation being a cost-effective component in an integrated system to manage weeds in peanut. Previous weed management research conducted on organic peanut indicated that repeated cultivation with a tine weeder was an effective component in that production system. Studies were conducted in Tifton, GA, from 2014 through 2017 to determine whether tine weeding can be integrated with herbicides in conventional peanut production to supplement herbicides. Experiments evaluated a factorial arrangement of eight herbicide combinations and two levels of cultivation using a tine weeder. Herbicides were labeled rates of ethalfluralin PRE, S-metolachlor PRE, imazapic POST, ethalfluralin PRE + S-metolachlor PRE, ethalfluralin PRE + imazapic POST, S-metolachlor PRE + imazapic POST, ethalfluralin PRE + S-metolachlor PRE + imazapic POST, and a nontreated control. The herbicides chosen were based on knowledge of the weed species composition at the research sites and their common use in peanut. Cultivation regimes were cultivation with a tine weeder (six times at weekly intervals) and a noncultivated control. Benefits of tine weeding supplementing control from herbicides varied according to herbicide and weed species. For example, annual grasses were effectively controlled (88% to 97%) by ethalfluralin or S-metolachlor and did not need cultivation to supplement control provided by the herbicides. However, imazapic alone did not effectively control (54% to 75%) annual grasses and needed supplemental control from cultivation with the tine weeder. Similarly, imazapic effectively controlled (84% to 93%) smallflower morningglory and did not require cultivation to supplement control from the herbicide. However, cultivation with the tine weeder improved smallflower morningglory control (76% to 95%) when supplementing ethalfluralin or S-metolachlor. Peanut yields did not respond to any of the herbicide combinations integrated with cultivation using the tine weeder. During the time period when peanut was cultivated, there was greater total rainfall and more days of rainfall events in 2014 and 2017 compared with the other years. Rainfall and wet soils reduced the performance and weed control benefits of the tine weeder. This highlights the risk of depending on cultivation for weed control.

Mechanical weeding augmented with automation technology should result in highly effective weeding systems. However, the interaction between weeding mechanisms and soil is not well understood. Moreover, soil is highly variable, which makes studying this interaction challenging. The main objective of this research was to develop a method to investigate the effects of mechanical tool-soil interaction on weeding performance for different operating conditions in a controlled environment. Experiments were conducted in an indoor soil bin with loam soil, and the weeding performance was studied using small wooden cylinders as simulated weed plants. The investigations featured a single cylindrical tine and a rotating tine mechanism, vertically oriented and inserted into the soil. The total width of soil disturbance and potential weeding rate were evaluated for the single cylindrical tine at different levels of three operating parameters: tine diameter (6.35, 7.94, and 9.53 mm), working soil depth (25.4, 50.8, and 76.2 mm), and tine speed (0.23 and 0.45 m s-1). Potential weeding rate was examined for the rotating tine mechanism with two operating parameters: working soil depth (25.4 and 76.2 mm) and rotational speed (25, 50, and 100 rpm). Statistical analysis was performed using ANOVA at p < 0.05. A simulation of the rotating tine mechanism was developed that estimated the disturbed area. For the single tine, soil disturbance width was independent of tine speed; however, tine diameter and depth had significant effects, as the width increased with increased levels of these two parameters. All three parameters had significant effects on the potential weeding rate of the single tine, and the rates were observed to increase with higher levels of the parameters. For the rotating tine mechanism, both depth and rotational speed were significant. The potential weeding rate for the rotating tine mechanism was found to increase with higher levels of these parameters. The results showed that although the width of soil disturbance due to a cylindrical tine was affected by the tine diameter and working soil depth, operating parameters such as increased longitudinal and rotational speeds also affected plant disturbance. The percentage of disturbed soil area in the simulation followed similar patterns as the percentage of disturbed plants observed in the experiments. Keywords: Inter-row weeding, Intra-row weeding, Mechanical weeding, Rotating tine mechanism, Soil disturbance, Tine.

Pile-soil interaction is considered to be one of the most important problems in the study of the mechanical behaviour of pile foundation. In this paper, the lateral friction resistance and pile-soil relative displacement of bridge piles in deep soft soils are monitored for an extended period by using concrete strain gauges that are embedded in the test pile. Field test results show that both the pile lateral frictional resistance and pile-soil relative displacement increase along with time, while the pile-soil interaction demonstrates a time effect. Therefore, an elastic-viscoplastic constitutive model must be established to better simulate the time-dependent mechanical behaviour of the pile-soil contact. Based on the Goodman model, we developed an elastic-viscoplastic interface constitutive model of the pile-soil interface into the FRIC subroutine through ABAQUS software, which is one of the most commonly used finite element analysis softwares in the world, to simulate a well-recorded pile test in deep soft soils. The calculated pile lateral frictional resistance and pile-soil relative displacement are close to the measured values, and the ability of the interface model to describe the changes in the shear stress-strain of the pile-soil interface along with time is validated., Međudjelovanje odlagališta (jalovine) i tla jedan je od najvažnijih problema kod izučavanja mehaničkih svojstava takvih odlagališta. Praćeno je bočno smicanje te otpor na dodiru mekoga tla i odloženoga materijala unutar njega tijekom vremena. Unutar testnoga odlagališta također su postavljeni betonski blokovi za mjerenje naprezanja. Rezultati su pokazali kako su bočna smicanja između odloženoga materijala i tla ovisna o vremenu. Ta zavisnost modelirana je elastično-viskozno-plastičnim modelom, čime je opisana ovisnost mehaničkih pojava o vremenu. Prikazani model deriviran je iz Goodmanova, te je rutinom (FRIC) opisan u programskome paketu (ABAQUS), koji je ujedno i najčešći program za analizu konačnih elemenata s ovakvom namjenom. Izračunani otpor na bočno smicanje te relativni pomaci u odlagalištu vrlo su slični onima izmjerenim na mjestu eksperimentalnoga testiranja. Također je potvrđena mogućnost predviđanja modelom promjena nastalih zbog naprezanja tijekom vremena.

Forklifts are one of the most common types of material handling equipment used in warehouses and distribution centers. Vibration generated by forklifts may have an effect on the performance of unit loads and product damage rates. Historical research projects have focused predominantly on the measurement of vibration for over-the-road transportation. Thus, there is still a lack of understanding of the level of vibration caused by forklifts. The goal of this study was to understand how the vibration that is experienced by unit loads while being transported by forklifts is affected by factors such as speed, road condition, unit load weight, type of forklift, and sensor location. For this study, power spectral density (PSD) measurements were collected using a Lansmont Saver 9X30 data logger. Vibration levels were measured for three different industrial forklifts on two different surface types. The forklifts were driven at two different speeds while carrying two different unit load weights. For all of these conditions, the vibration levels were measured at the forklift carriage, at the back of the fork tine heel, and at the fork tine tips. The results obtained show that the highest vibrational intensity occurred at 3–4 Hz, while the highest overall Grms value observed was 0.145 G2/Hz (between 1–200 Hz). An increase in the forklift speed caused an increase in vibration intensity. In contrast, an increase in the unit load weight carried by the forklift caused a decrease in vibration intensity. Among the three forklifts studied, the gas-powered forklift had the highest vibration intensity, and all forklifts, when driven on asphalt, experienced more vibration. Published version

Fertilizing and spraying techniques are repeatedly driven in tramlines for crop care with products whose demand increases for higher yields. The soil in tramlines is so compacted by heavy crop care machinery what leads breakdown to lifelessness. Such damaged state of the soil continues all season and leads to dejected soil productivity. The aim of this study is to find an optimal process of soil renovation in tramlines on loam and clay loam soil and to determine the required fuel consumption. The soil renovation was investigated by specially made Tiller on the dependence of tine shape types (narrow and winged) and working speed 1.6, 2.2 and 3.6 m∙s−1 in loam and clay loam soil. The beneficial relationships of soil aggregate fraction ratio, which varied from 0.54 to 4.08 and fuel consumption, which varied from 1.04 to 1.82 L·km−1 independence on tine shape and soil type was established. Based on research results, the sufficient soil loosening to suitable proportion of soil aggregates fraction ratio on loam soil was accomplished at working speed 3.6 m∙s−1 with winged tine type and fuel consumption was 1.04 L·km−1. The suitable soil aggregate fraction ratio on clay loam was achieved at working speed 3.6 m∙s−1 with narrow tine shape type and fuel consumption was 1.31 L·km−1. The volume of loosed soil in tramlines was particularly influenced by variation of tines shapes but was not influenced by the working speed majorly. The aligning of soil surface was influenced by the working speed majorly and particularly by variation of tines shapes.

Subsoiling consumes huge amount of energy in tillage operation. with the purpose of mitigat-ing this problem, it was found sandfish (Scincus scincus) has excellent ability of moving effec-tively below soil. The special geometrical feature of sandfish head provided an excellent bionic prototype for the design of novel subsoiler tine and reduce soil breaking force of subsoiling. Thereby save energy and improve operating efficiency. In this study, three innovative bionic subsoiler tines B-T-1, B-T-2, and B-T-3 were designed by learning from the special feature curves of sandfish head. The commercialized and extensively used traditional tine T-T was used as a control. Tines were assembled into four with arc-shaped shank subsoilers T-S, B-S-1, B-S-2, and B-S-3. To investigate the effect of the bionic subsoiler tines on tillage force and the reveal the in-teraction mechanism between subsoiler tine and soil, the discrete element model (DEM) was used to simulate the subsoiler tines in a virtual layered soil bin. The results showed that bionic subsoiler tines had lower draft and vertical force. At the operation speed of 0.8 m/s, under the condition of tillage depth of 300 mm, compared to T-S, the draft force of B-S-1, B-S-2, and B-S-3 decreased by 6.42%, 9.31% and 7.96%, respectively, and the vertical force decreased by 13.13%, 19.31% and 16.99%, respectively. This study provides theoretical and design reference for drag reduction of agricultural tillage components. Through the actual vertical penetration test and using the DEM simulation, the Pearson correlations between the test and simulation results of T-T, B-T-1, B-T-2 and B-T-3 were 0.9942, 0.9931, 0.9899, and 0.9886, respectively, which proved that DEM had a good predictive effect on the actual test. This study provided a novel bionic design approach that by learning from special feature curves of sandfish head to reduce the energy consumption of soil-engaging component of agricultural machinery.

One of our most valuable natural resources is soil. Sustainable agricultural production is achieved with proper soil management. Tillage is considered to be one of the largest operations, as the most energy need in agricultural production occurs in tillage. The main purpose of this study is to investigate the effects of chisel tine on draft force and disturbed soil area and estimate them using artificial neural networks (ANN) and multiple linear regression equations (MLR). The experiments were carried out in a closed soil bin filled with clay loam soil at an average moisture content of 13.2% (on dry basis). The draft force and disturbed soil area were evaluated as affected by the share width at two levels (60 and 120 mm), forward speed at four levels (0,7, 1, 1.25 and 1.5 ms-1) and working depth at four levels (160, 200, 240 and 280 mm) at three replications. The draft force varied from 0,5 to 1.42 kN, depending on the controlled variables, while the disturbed soil area varied from 260 to 865 cm2. Test results show that share width, forward speed and working depth were significant on the draft force and disturbed soil area. Input variables of the ANN models were considered share width, forward speed and working depth. In prediction of required draft force and disturbed soil area respectively, on account of statistical performance criteria, the best ANN model with coefficient of determination of 0.999 and 0.998, root mean square error of 0.010 and 0.016 and mean relative percentage error of 0.960 and 1.673 was better performed than the MLR model.

Bentleg furrow openers can significantly reduce soil disturbance and reaction forces relative to conventional narrow point openers used in no-tillage farming. The effect of bentleg opener geometry on soil disturbance and reaction forces in a cohesive soil was assessed in a virtual soil bin using the discrete element method. Soil disturbance and reaction forces at an operating depth and a speed of 100 mm and 8 km h−1, were shown to be minimised by using (1) a shank lateral offset of 70 mm, (2) a side leg bend angle that ensures the elbow, which is the transition between the side leg and vertical shank, is not located below the soil surface, (3) an arched instead of angled elbow, (4) a cutting edge chamfer angle as low as practical, and (5) tine thickness as small as practical. Furrow size was found to be more dependent on shank lateral offset and side leg bend angle than side leg forward angle. Though side leg forward angles >90° reduce particle displacement and will work better in fields with stones and roots, they also considerably increase draught and penetration resistance. A low rake angled foot minimises soil reaction forces and drives soil loosening. Reducing foot height and interaction of the vertical shank with soil particles minimises surface soil displacement. These results have expanded the understanding of bentleg opener mechanics and are in close agreement with those reported for sandy soils. Therefore, similar criteria can be followed to optimise bentleg opener design for different soil types. Refereed/Peer-reviewed

Part II brings together four articles dealing with aspects of the secularity of the modern state. It opens with one of Böckenförde’s most widely cited articles—translated into seven languages—‘The Rise of the State as a Process of Secularization’ published in 1967, in which he lays out the emergence of the modern state as a process of emancipation from the influence of religious authority that occurred in three distinct stages. Although less well-known internationally, the second article included here is no less important in Böckenförde’s intellectual development. It deals with ‘The Fundamental Right of Freedom of Conscience’ (1970), which Böckenförde regards as the cornerstone of the religiously neutral modern state and as the cardinal individual liberty, from which all others spring. In the third article, ‘Remarks on the Relationship between State and Religion in Hegel’, written in 1982, Böckenförde reviews Hegel’s major writings on questions of religion and the state to guide him in his own quest for the ‘inner regulatory forces’ and the binding ethos that keep democratic societies together. The interest in this binding ethos and the Hegelian notion of freedom places the article in a direct line with Böckenförde’s 1967 secularization essay as well as his 1978 article on ‘The State as an Ethical State’ (included in volume I). In the fourth article in this part, ‘The Secularized State: Its Character, Justification, and Problems in the Twenty-first Century’ of 2007, Böckenförde returns to the core ideas of the 1967 secularization essay fifty years later, asking what is the secular state, and how can it deal with a plurality of worldviews? Böckenförde lays out the cornerstones of his views on the desirable relationship between religion and state in contemporary democracy by juxtaposing his concept of ‘open encompassing neutrality’ vis-à-vis that of ‘distancing neutrality’, of which he regards the French laïcist model as paradigmatic. The latter ‘tends towards consigning and confining religion to the private and private-social sphere’ and prioritizes the freedom ...