Tillage Resistance Research Articles

A 3D simulation model of corn stubble cutting using finite element method

The finite element method (FEM) has been widely used to model interaction of tillage tool and soil, because it is capable to provide an accurate prediction of tillage resistance. However, there is little research on modeling soil-root interaction in soil tillage practice. The object of this paper is to advance a well adaptable numerical assistance to simulate the root-soil interaction and predict the resistance force on a stubble cutting tool. A 3D dynamic simulation model using the FEM was established to predict the resistance acting on the stubble-cutting blade in the present work. Soil was modeled as elastic-plastic material, corn stubble was simplified as an assembly of lines with various diameters, and soil and stubble were tied together as a complex. Two stubble-cutting blades with different cutting edges and two forward velocities were examined using a FE computation model and verified experimentally by field tests. Comparison result of simulation and experiment showed that the prediction from the FE model agreed well with the measurements in a field test. It can be concluded from these results that the FE model designed in this work is capable of being used as a convenient and dependable prediction tool in analysis and development of the working capacity of tillage tool.

Application of an original soil tillage resistance sensor in spatial prediction of selected soil properties

Horizontal and vertical variability of soil properties, temporal dynamics, and the complexity of monitoring and prediction processes are the limiting factors for full implementation of all the postulates of site specific crop management. The aim of this research was to prove the possibilities for utilization of original soil tillage resistance measuring device in spatial assessment of some physical properties of soil.The tillage resistance measurement and soil evaluation were performed in 2012 on a field of 0.78ha, with calcic chernozem type of soil. The year before, the field was divided into three equal plots where three types of tillage were applied (moldboard plowing, disc harrowing and chisel plowing) in order to increase spatial soil differences and to ensure more reliable testing. Soil physical properties were observed at 30 points that were arranged on the nodes of a rectangular grid all over the field along with their geopositioning. Soil tillage resistance was measured in real time and space, during 30 passes that were made on the entire field by a standard tractor and plow.The tillage management applied in 2011 resulted in the differences of some soil parameters. Significant differences between the field plots arose with respect to cone index, moisture content and soil tillage resistance. However, no differences arose regarding the texture (sand, silt+clay content) and bulk density. The correlation analysis showed a high positive correlation between soil resistance and cone index (R=0.82) and a negative correlation between soil resistance and moisture content (R=−0.41). Fitting of variograms in the modeling of spatial correlation gave the highest prediction error for cone index (13.9%), then for tillage resistance (9.32%), sand content (3.95%), moisture content (3.34%), bulk density (2.4%), and finally clay+silt content (2.2%). The generated maps showed that the soil compaction, moisture and tillage resistance had certain orientations with respect to the field plots.

Simulation of Bionic Anti-Drag Subsoiler with Exponential Curve Feature Using Discrete Element Method

Subsoiling, as an important mode of conservation tillage, can break plowpan and increase permeability and water retention ability of soil which increase the crop yield. Subsoiler, as a key component of subsoiling, significantly effects on the tillage resistance. Reduction of working resistance of subsoiler can decrease output power of tractor and then further reduce the cost of subsoiling operation. The existing subsoilers have problem of overlarge subsoiling resistance. The conventional methods to resolve such problem include optimal design of the structural parameters of subsoiler and application of oscillation subsoiling device, but those methods not only make the structure of subsoiler more complex, but also increase the cost of agricultural production. Based on biomimetics principles, the upper surface outline of the claw of the house mouse (mus musculus), which has exponential function curve feature, was applied to the structural design of cutting soil edge of subsoiler shaft. Accordingly, the bionic subsoiler which has exponential function curve feature was designed and manufactured. The comparative experiments were conducted using the two types of subsoilers which have exponential function curve shape and parabola type in tillage depth at 300mm and 350mm with the forward velocitys of 0.5m/s and 1.0m/s in the indoor soil bin. The horizontal tillage resistances of the two types of subsoilers were measured using remote-measuring system of agricultural machinery dynamic parameters under different experimental conditions. The results showed that the horizontal tillage resistances increased with the increase of tillage depth and forward velocity. The horizontal tillage resistances of bionic anti-drag subsoiler (BAS) were obviously less than those of parabola type subsoiler (PTS) under same experimental conditions and the reduction was in the range of 8.5-38.2%. It indicated that the cutting soil edge of shaft with exponential function curve structure has remarkable anti-drag property. The simulations of tillage processes of the two types of subsoilers were conducted using discrete element method (DEM), the stress fields and velocity fields were obtained under different simulation conditions. The results showed that the directions of stress fields and velocity fields of the two types of subsoilers have forward and upward variation trend, but the directionality of contact stress of PTS was nonuniform compared with BAS, and such results lead to an increase in soil disturbance. The intensities of stress field and velocity field of BAS were obviously less than those of PTS under same experimental conditions, The results of simulation were consistent with the results of tillage experiments, indicating that the bionic subsoiler with exponential function curve feature has significant anti-drag property. The exponential function curve can be applied to the structural design of cutting soil edge of subsoiler aiming to reduce tillage resistance.

Development of the Measuring Device for Six-Components of Rotary Tillage Resistance and Analysis of Torque Waves

Development of the Measuring Device for Six-Components of Rotary Tillage Resistance and Analysis of Torque Waves

Tillage Resistance Characteristics of Japanese Rotary Blades

Tillage Resistance Characteristics of Japanese Rotary Blades

Experimental Investigation of the Effect of Vibration During Tillage Process of Multi Shank Plough Blade

The motion of plough during a quasi-static tillage process is opposed by a high tillage resistance that typically limits the cutting depth to 30 cm. This study experimentally investigates the effects of the blade geometry and operating conditions on the draft force during tillage. Scaled V-multi-shank ploughs with three different blade angles are examined at different soil types, tillage speeds and cutting depths. Tests are repeated with an added plough vibratory motion at various frequencies and amplitudes. Blade vibration during the tillage process is found to have a considerable effect in reducingthe tillage resistance. This effect may occasionally lead to overcoming the resistance at operating conditions where the driving mechanism without vibration could not match the tillage requirements. Results show that tillage depth, tillage velocity and blade angle all have direct and proportional effects on the tillage resistance force. Vibration frequency andamplitude on the other hand, reflect in desirable inverse and proportional effects.

Soil-blade dynamics in reverse-rotational rotary tillage

Soil cutting and the clod crack formation process during reverse-rotational rotary tillage in a heavy clay soil were investigated. Of particular interest was the relationship between clod crack formation and tillage resistance during sequential rotations of the tillage blade. Investigation of the crack formation process is helpful to develop and to design more effective and high performance tillage methods. This paper describes two new discoveries. The first is that the tillage resistance showed a higher cross-correlation between sequential rotations within a certain distance of tilling, while there was little or no cross-correlation between different tillage plots that were separated more than 0.4 m. The forward distance of untilled soil that was disturbed by the tillage blade was estimated to be 36.4 mm. This is the distance of two tillage pitches. The second discovery involved the blade frequencies during tilling. Fluctuation in tillage resistance frequencies of a single blade was nearly equal to the predicted occurrence of crack intervals on the tilled clod's surface. This frequency was 120 Hz. When these frequencies were translated into the distance along the trochoid trajectory of the blade cutting edge, they were the same as the length of the clods tilled by the reverse-rotational rotary tiller. These minute vibrations in the tillage resistance were considered the important indexes for recognizing the tilled soil conditions and the tilled clod failure on the reverse-rotational rotary tiller. The analytical results of this paper will be utilized for the active occurrence of the cracks regarding with natural frequency of the blade and the operation condition of the reverse-rotational rotary tiller.

PA—Precision AgricultureSoil Tillage Resistance as a Tool to map Soil Type Differences

Abstract Precision agriculture is based on spatial knowledge of soil and crop conditions in the management decisions. In this paper, a method to improve determination of soil physical properties is proposed. Current practice is to analyse soil samples, taken at several locations in a field, for physical properties. To obtain a sound coverage, many soil samples have to be analysed. When soil properties are correlated, it is possible to reduce the number of soil samples of one property and enhance its spatial resolution with the information of another, more densely sampled, property. In this study, information gathered automatically during the major soil tillage operation, ploughing, is used to improve the spatial resolution of sampled topsoil clay content. Plough draught was measured during two seasons on a 6 ha field. The specific plough draught varied between 30 and 50 kNm −2 . Clay content varied between 6 and 22% and topsoil moisture content range was 120–240 g kg −1 during the first year and 180–300 g kg −1 in the second year. The specific plough draught maps of both years showed a similar spatial pattern with a cross correlation coefficient at zero distance of 0·6. The use of specific plough draught as co-variable in the co-kriging technique made it possible to decrease the number of topsoil clay content samples from 60 to 18 ha −1 with only 20% increase in prediction error. On this field, the spatial variation in top soil clay content was correlated with the spatial variation of the crop yield.

PA—Precision Agriculture: Soil Tillage Resistance as a Tool to map Soil Type Differences

Precision agriculture is based on spatial knowledge of soil and crop conditions in the management decisions. In this paper, a method to improve determination of soil physical properties is proposed. Current practice is to analyse soil samples, taken at several locations in a field, for physical properties. To obtain a sound coverage, many soil samples have to be analysed. When soil properties are correlated, it is possible to reduce the number of soil samples of one property and enhance its spatial resolution with the information of another, more densely sampled, property. In this study, information gathered automatically during the major soil tillage operation, ploughing, is used to improve the spatial resolution of sampled topsoil clay content.Plough draught was measured during two seasons on a 6 ha field. The specific plough draught varied between 30 and 50 kNm−2. Clay content varied between 6 and 22% and topsoil moisture content range was 120–240 g kg−1during the first year and 180–300 g kg−1in the second year. The specific plough draught maps of both years showed a similar spatial pattern with a cross correlation coefficient at zero distance of 0·6.The use of specific plough draught as co-variable in the co-kriging technique made it possible to decrease the number of topsoil clay content samples from 60 to 18 ha−1with only 20% increase in prediction error. On this field, the spatial variation in top soil clay content was correlated with the spatial variation of the crop yield.

Optimum Design of Tractor-Rotary Tillage System by Parameter Identification

Abstract From the viewpoint of evaluation of torque curve generated by tillage resistance of rotary blade, reliable techniques of simulation and identification through torque curve separation by using the Gauss-Newton method (GNM) are discussed. A simple method for identifying the parameters is established, which are characterized by soil condition and are of importance for the design of the tractor-rotary tillage system in agricultural machinery . It is clarified that the order of the values of mean and standard deviation of measured torque curve can be estimated by the simulation using the torque curve quadrilateral model.

ロータリ耕うん刃の形状要素と耕うんトルク

The shape of the rotary blade which influences the rotary tillage resistance consists of the bending tip portion and the straight portion. As these portions have many dimensions and the complicated form, the multiformity of their factors greatly affects the performance of rotary tillage.In this paper, the form similarity of the rotary blade were analyzed by the cluster method. The relation between the rotary tillage resistance and the form factor of the rotary blade was analyzed by the multiple regression method. The estimation of rotary tillage resistance was carried out to find the minimum parameter of the form factor, precisely. The obtained results were indicated as follows.1) The number of measured form factors was 15 variables for 19 kinds of rotary blades. The form similarity of the rotary blade could be grouped 2 classes by the group average method and the medium method.2) With the 4 main components of the form factors such as B1, B2, R2, R3 76% of the 15 variables could be explained.3) The maximum torque of the rotary tillage was estimated using 7 variables, mainly form factors of R2, D2, D3 and the average torque was estimated only 3 variables of R3, R4, Q2.4) The estimation were showed better agreement with the maximum tillage torque than the average torque.5) For the development of the selecting method of rotary blades, further study on form factors and dimensions of the blade is expected regarding various soil conditions.