The Influence of Changes in the Vertical Acceleration of Tractor Unit on Soil Compaction during Field Operations

A study of volumetric behaviour of compacted clayey soils in the void ratio, moisture ratio and net stress space

Introduction: Soil compaction has become a widespread problem in the world and it is considered as one of the main factors affecting land degradation in arid and semi-arid agricultural land. Compaction in arable soils is a gradual phenomenon that appearing over time and most important factors that influence it include: soil properties, high clay content, low organic matter, and frequency of wet-dry in the soil, impervious layer of soil, load heavy agricultural implements and soil and water mismanagement. Compaction induced soil degradation affects about 68 million hectares of land globally. The vast majority of compaction in modern agriculture is caused by vehicular traffic. Carbon sequestration by long-term management operation of the plant and soil, not only increase the soil carbon storage but also lead to reduce the carbon exchange and greenhouse gases emissions like CO2 from the soil profile. The aim of this study was evaluating the effect of soil compaction on carbon and nitrogen sequestration of wheat and soil and some soil physical properties such as: aggregate stability, saturated soil moisture content, bulk density and soil porosity. Materials and Methods: This experiment was accomplished in which is located near Aq Qala in a randomized completely block design (with 4 treatments and 3 replications). Soil compaction was artificially created by using a 5/7 ton heavy tractor. The treatments arrangements were: 1) T1: control, 2) T2: twice passing of tractor, 3) T3: four time of passing tractor, and 4) T4: six time of passing heavy tractor. Utilize of all agricultural inputs (fertilizers, herbicides, etc.) has been identical for all treatments. Since rain-fed farming is the common method to cultivation of cereals in the study area, so no complementary irrigation was carried out in this period. In this study, after the measurement of the parameters, the data were analyzed by using SPSS 16.0 Software. LSD test was used for comparison of means. Results and Discussion: The results showed that the different levels of soil compaction significantly increased soil bulk density. All the soil compaction treatments have caused a significant reduction on carbon and nitrogen sequestration in soil and wheat, soil aggregates stability and saturated soil moisture values. In the other hand the amount of soil pH and EC has increased significantly by increasing soil compaction levels that Indicates the negative effect of compaction on salinization of arable land. Conclusion: The results of this study showed that the negative effects of soil compaction on soil physiochemical attributes are dependent on escalation of compaction. In total, even low levels of soil compaction (the treatment of two passes of a heavy tractor) is able to remarkably alter soil physiochemical attributes and thus carbon and nitrogen sequestration in soil and wheat. Induced changes in nitrogen and carbon sequestration levels are important for who concerned of global warming and climate change. Regarding the inability of deactivating soil compaction adverse effects in the deep soil layers of agricultural fields is the best way of handling and preventing soil compaction. Using these sluggish renewable resources should be consistence with land capability and its physical nature. This type of land use will result in sustainable development. From the remarks given here, it might be concluded that revising agricultural regimes and production methods is inevitable. On this ground, revisiting current agricultural systems should be considered and an urgent demand for state-of-the-art methods consistent with environmental objectives is being felt. To prevent soil compaction as much as possible, tractors and machinery traffic must be avoided to an acceptable level and this is of high priority during the time which soil is wet. It is more preferable to perform the operations with lighter machineries. As much as possible in a sophisticated agricultural plan these recommendations must be considered: Increasing soil organic matter, leaving crop residue from the previous crop at the soil surface, using crops with deep-and-vertical-penetrating roots during crop rotation, tillage depth variation in different years, using super absorbent for better ventilation and reduces soil compaction, implementing no-tillage system to reduce traffic of farming machineries, maintaining plant residues at the soil surface, applying lacking nutrients to the soil, and subsoil operations to reduce the detrimental effects. As a field-based study, the results could be transferred to the local farmers. Authorities have to remove the obstacles to deliver the message to the farmers in order to enhance production and reach nation self-sufficiency.

The demand to sail at high forward speeds in both calm water and in a seaway remains high. For various patrol, search and rescue or military operations attaining high forward speeds is essential. In head and bow quartering seas, the main factor for voluntary speed reduction is the occurrence of large vertical peak accelerations. The occurrence of large vertical peak accelerations imposes limits to the operability of planing monohulls sailing in head seas. A challenge for designers of fast monohulls is to explore different possibilities to increase the operability of planing monohulls sailing in head seas. To achieve this a reduction of the vertical accelerations is required. The operability can be considered improved if the level of accelerations can be reduced compared to a trip at an equal but constant forward speed. This implies that it is possible to sail at a higher speed without increasing the discomfort on board. A solution for increasing the operability of planing monohulls sailing in head seas has been found in proactive control. Vertical peak accelerations have a very short duration. Unacceptably large vertical peak accelerations have a low frequency of occurrence. These two aspects are the incentive for a proactive control system. What makes proactive control unique is the fact that the control is based on predicted vertical peak accelerations. The response of the ship for the next few seconds needs to be simulated real-time while sailing. These predictions should be carried much faster than real-time, since there is little to effectuate control because of the high relative velocity between ship and incoming waves. In this dissertation proactive control of the forward speed, also termed automated proactive thrust control, has been presented. The purpose of this study is to show the level of reduction of the vertical accelerations possible with automated proactive thrust control.

Seismic bearing capacity for a shallow strip footing embedded in a sloping ground is derived along with seismic uplift capacity of horizontal strip anchors. c-ϕ soil medium is used with limit equilibrium method of analysis. A planar failure mechanism has been adopted. The seismic bearing capacity is determined in the form of a single pseudo-static bearing capacity coefficient (N γe ) in association with unit weight, surcharge and cohesion, which becomes more practical to simulate the actual field problem. The seismic forces are considered to act both on the footing and on the soil below the footing. The effects of soil friction angle, soil cohesion, wall friction angle, horizontal and vertical seismic accelerations are taken into account to evaluate the seismic bearing capacity of the foundation. Also seismic uplift capacity factors for horizontal strip anchors is found. The factor is determined as a function of embedment ratio, angle of internal friction of soil, angle of wall friction, cohesion of soil and seismic acceleration coefficients. The uplift capacity factors have been determined for the simultaneous resistance of cohesion and unit weight of soil. Effect of the vertical seismic acceleration coefficient has been found to always reduce the uplift capacity factor whereas the effect of horizontal seismic acceleration coefficient has also been found to reduce the uplift capacity factor in maximum cases. The results obtained from both the cases has been compared with existing literature and the effect of parametric variations discussed.

The increasing degree of mechanization in agriculture has resulted in the use of more powerful and heavier tractors and machines. Consequently, mechanical burden to soils has increased, too, which can lead to persistent subsoil compaction at depths below 30cm. In soils damaged by compaction soil functions like transportation of water and air decrease. Because of that, conditions for plant growth are getting worse and the soils' natural regulation functions could be impaired. In order to take counteractive measures, it is necessary to get information about the status of soil compaction. Up to now, the status of soil compaction can only be determined at single points in laboratory measurements or with less accuracy in field measurements. Therefore, the demand for an efficient planar-mapping system arises. The applicability of different geophysical prospecting methods with regard to this problem has been examined. For this purpose, geophysical and soil measurements were performed in a field with conventional agricultural land use in Schleswig-Holstein (Germany) on a young moraine site. We applied GPR (Ground Penetrating Radar) with main frequencies 500 MHz and 900 MHz, supplemented by inductive electromagnetic technique (EM) using the Ground Conductivity Meter EM38 and high-resolution refraction seismic using compressional and shear waves. Differences in soil type were found by all these geophysical methods and confirmed by soil measurements, therefore, locations with higher risk for compaction (loamy soils) could be distinguished from locations with lower risk (sandy soils). Under humid conditions, radar data showed strong reflections at a depth of approx. 30cm. During summer, under dry conditions, these reflections did not occur. This temporal variation of radar reflections can be explained by variable water layers inside the soil, which can be regarded as an indicator for compacted soil. The seismic investigation was performed along short (12 m) profiles with dense (20cm) sensor spacing. Excellent data quality showed that this sort of measurement, known from engineering geophysics, is also feasible for soil investigations. We performed both compressional- (P-) and shear- (SH-) wave refraction studies. Differences in soil type of subsoil affected especially seismic velocities of P-waves. Whether or not areas of compacted soil can be detected is still unknown, because deeper soil horizons of our test area showed only uniformly strong compaction with little contrasts.

Introduction. To improve the vibrating rollers in order to increase sealing capacity, reliability and vibration safety, the interaction of vibrating roller parts between each other and with compacted soil is simulated mathematically. The developed models are validated, i.e. compared with the results of experimental studies. However, the known results of experimental studies were obtained based on a relatively small list of vibrating roller models and soil types, as well as in a steady vibration mode. The paper presents the results of experimental studies, which used a vibratory drum of a roller to study its vertical vibration accelerations both in the steady vibration, as well as transient mode at turning the vibration generator on (speedup) and off (halt). This expands the range of opportunities to validate the existing and newly developed mathematical models.Materials and methods. Experimental studies of vertical vibration accelerations of a drum were conducted using the DM-617 vibrating roller when compacting natural sand-gravel aggregate. The accelerometer readings show high-frequency harmonics, which makes it significantly more difficult to determine amplitude values of vibration accelerations, therefore a low-frequency filter with a boundary frequency of 200 Hz was used for digital processing.Results. It was determined that when the DM-617 vibrating roller is compacting soil with maximum driving force within the range of variation of dynamic modulus of soil deformation Evd=14…25 MPа, amplitude values of vertical vibration accelerations of the vibratory drum are from 65... 77 to -61... -69 m/s2 . At the start-up (speedup) of vibration generator, acceleration amplitudes are 1.1 times higher than vertical accelerations of steady operation mode of the vibrating drum and practically do not depend on the dynamic modulus of soil deformation Evd. At turning off (stop) of the vibration generator, amplitude of vertical accelerations do not exceed the vertical accelerations of the steady operation mode of the vibratory drum.Discussion and conclusion. The vertical acceleration amplitudes of vibratory drums of DM-617 do not depend on the dynamic soil deformation modulus Evd, and this is consistent with the results of experimental studies of the vibratory drum mounted on DM-614. The obtained vertical vibration accelerations of the drum mounted on DM-617 in the steady vibration mode, as well as at switching the vibration generator on (speedup) and off (halt) make it possible to verify the existing and developed mathematical models of interaction of vibrating rollers with compacted soil.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Article history: Received: February 2014 Received in the revised form: March 2014 Accepted: April 2014 Te objective of the research was determination of the impact of loading capacity of fertilization sets on soil compaction. Degree of soil compaction was determined based on four indexes. Three fertilization sets were selected for research: set A – tractor Renault 95.14 plus a waste removal vehicle of cubic capacity of 6 m, set B – tractor John Deere 6420 plus a waste removal vehicle 12 m, and set C Valtra N121 plus a waste removal vehicle 8 m. Four indexes were determined: field area compaction, loading a field with sets crossings, degree of compaction in the trace of wheels and cubic capacity of ruts. It was determined that the biggest surface of the compacted field was for the set A (27%) and the smallest for the set B (16%). Loading of a field with the sets crossings was the highest also for the set A (212 kN∙km∙ha) and the lowest for the set B (167 kN∙km∙ha). Degree of compaction in the trace of wheels was the highest for the set B (105 kN∙m) and the lowest for the set A (77 kN∙m). The highest cubic capacity of ruts was determined on the field fertilized with the set A (99 m) and the lowest for the set B (61 m). From among the technical parameters of fertilization machines the following affect the soil compaction degree: tractor mass and a waste removal vehicle mass and its cubic capacity and the working width, which depends on the application unit which was used. The set B may be recognized as the the best selected fertilization set (a tractor and a waste removal vehicle) on account of soil compaction and the least favourable – the set A.

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.

We compared the spatial organization patterns of linear and angular vestibuloocular reflexes in frogs by recording the multiunit spike activity from cranial nerve branches innervating the lateral rectus, the inferior rectus, or the inferior obliquus eye muscles. Responses were evoked by linear horizontal and/or vertical accelerations on a sled or by angular accelerations about an earth-vertical axis on a turntable. Before each sinusoidal oscillation test in darkness, the static head position was systematically altered to determine those directions of horizontal linear acceleration and those planes of angular head oscillation that were associated with minimal response amplitudes. Inhibitory response components during angular accelerations were clearly present, whereas inhibitory response components during linear accelerations were absent. Likewise was no contribution from the vertical otolith organs (i.e., lagena and saccule) observed during vertical linear acceleration. Horizontal linear acceleration evoked responses that originated from eye muscle-specific sectors on the contralateral utricular macula. The sectors of the inferior obliquus and lateral rectus muscles on the utricle had an opening angle of 45 and 60 degrees, respectively and overlapped to a large extent in the laterorostral part of the utricle. Both sectors were coplanar with the horizontal semicircular canals. The sector of the inferior rectus muscle was narrow (opening 5 degrees), laterocaudally oriented, and slightly pitched up by 6 degrees. Angular acceleration evoked maximal responses in the inferior obliquus muscle nerve that originated from the ipsilateral horizontal and the contralateral anterior vertical canals in a ratio of 50:50. Lateral rectus excitation originated from the contralateral horizontal and anterior vertical semicircular canals in a ratio of 80:20. The excitatory responses of the inferior rectus muscle nerve originated exclusively from the contralateral posterior vertical canal. Measured data and known semicircular canal plane vectors were used to calculate the spatial orientation of maximum sensitivity vectors for the investigated eye muscle nerves in semicircular canal coordinates. Comparison of the directions of maximal sensitivity vectors of responses evoked by linear or angular accelerations in a given eye muscle nerve showed that the two vector directions were oriented about orthogonally with respect to each other. With this arrangement the linear and the angular vestibuloocular reflex can support each other dynamically whenever they are co-activated without a change in the spatial response characteristics. The mutual adaptation of angular and linear vestibuloocular reflexes as well as the differences in their organization described here for frogs may represent a basic feature common for vertebrates in general.

ABSTRACTA simplified approach is presented for estimating permanent displacements in slopes as a result of both vertical and horizontal seismic accelerations. A study of 52 earthquake records showed that the time difference between maximum horizontal and vertical accelerations varied between 0 and 10.3 s. The approach is illustrated for an earth dam embankment by analysing the effects of five of the above earthquake records. The approach combines a pseudo-static slope stability analysis for estimation of the critical (or yield) horizontal-vertical acceleration combinations, and a Newmark type displacement analysis. Guidelines are presented for conservative choice of soil strength parameters of saturated clays for use in the stability analysis. While permanent displacements of up to 40 cm were predicted without considering the vertical acceleration component, no additional displacement above 3.5 cm resulted when this component was included. The predicted additional displacement was consistently less than 10%, and in 50% of the analyses, vertical acceleration led to smaller predicted displacements. The simple approach may be applied in analysis for any slope using real earthquake records. Using existing, empirical expressions for permanent displacement, based only on horizontal accelerations, the effect of the vertical accelerations may be conservatively estimated by increasing the displacement by 10%.

Introduction Improving the efficiency of all agricultural operations has always been important for farmers and engineers. It is well known that the force required for cutting a soil using narrow blades is a function of soil and environmental physical properties, tool shape geometry and the tool’s surface characteristics like soil-tool adhesion and friction. Soil tool adhesion can reduce ploughing efficiency and quality. It may also halt the movement of tillage machines in more severe conditions. Adhesion can also disable some machine abilities, which can result in a significant reduction of machine performance. Adhesion of the soil to seed-bed preparation tools like furrowers can significantly affect the germination rate. Reducing soil tool adhesion of furrowers can reduce draft force and improve ploughing efficiency. Many researchers have worked on methods of reducing draft force by modifying the surface material and/or surface texture of the plough tools. A good prediction on draft force of a tool before producing it has always been important for farmers and engineers. There are some models for predicting the draft force of narrow blades in soil. McKyes-Ali’s model is widely used because of its accuracy and simplicity. Ultra-high molecular weight polythene (UHMW-PE) is a polymer with ultra-high weight and long molecular chains and is well known for its outstanding physical and chemical properties and self-cleaning abilities, which reduce soil-tool adhesion. The aim of this study was to investigate usability of UHMW-PE coated furrower tines for draft force. Analytical and experimental investigations were carried out during the research. A comparison was conducted between the analytical and the experimental method. The results of this comparison can be used to determine reliability of the analytical model for predicting the draft force improvement caused by the surface modification on tines using different surface coatings. Materials and Methods Eight tines have been built. Four of them had a thick coating layer of UHMW-PE, and the other four were made of pure mild steel. Each set of the tines have been installed on a four shanked chisel plough chassis and then attached to a tractor. The draft force required for pulling the furrowers attached to the tractor has been measured by a simple load meter mechanism connecting two tractors. Draft force has been measured in two different speeds. Slip ratio of the tractor has been recorded. Each test has been repeated three times.McKyes-Ali’s proposed model for evaluating the draft force of narrow blades has been chosen to predict draft force of the traditional steel furrower tines and the surface coated ones. To drive the model, a computer program has been coded in the script environment of Matlab software. The model required some of the mechanical properties of the soil and the tool to operate. Specific gravity, cohesion and internal friction angle of the soil have been measured by routine laboratory methods. Soil-tool adhesion and friction of the mild steel and the UHMW-PE plates have been measured using the direct shear apparatus. Results and Discussions MkKyes-Ali’s model has predicted draft forces with an accuracy of 90%. According to the results of the driven model, applying a UHMW-PE coating layer to the surface of the tines can improve draft force by 13%. The change of tractor speed from 3.5 km h-1 to 5.5 km h-1 have no significant effect on the predicted draft forces. The model also predicted different angles of the soil failure zone for coated and uncoated tines. On the other hand, the improvement of the draft force for the UHMW-PE coated tine in the field test was about 27%. According to The results obtained from the field test, the draft force of the furrower tines had significant correlation with the speed. Conclusions The UHMW-PE coated tines required significantly less draft force to work in compare with the steel tines. McKyes-Ali’s model predicted a significant improvement (13%) in draft force for the UHMW-PE coated tines. According to the experimental results, the improvement of the draft force was about 27%, which was almost twice as predicted. Although the McKyes-Ali’s model could predict an improvement for draft force of the UHMW-PE coated tine, but the actual improvement was about twice of the prediction. According to analytical and experimental results, applying a layer of UHMW-PE plastic on furrower tines can improve the draft force significantly.

Soil compaction occurs when external pressures (from heavy machinery or grazing animals) exerted on the soil surface increase soil bulk density, reducing porosity and aggregation. Nutrient, air and water holding capacities of the soil are reduced, and plant roots encounter increased mechanical resistance as they grow. Soil compaction also stunts shoot growth, with hydraulic and chemical signalling systems between below- and above-ground parts allowing the plant to adapt to this multi-stress environment. However, relatively few studies have characterised root-to-shoot signalling systems of plants with mechanically-impeded roots. Tomato plants (Solanum lycopersicum cv. Ailsa Craig) were grown under low and high soil bulk densities, and allowed to dry the soil to investigate plant physiological responses. Compact soil stunted plant growth, decreased stomatal conductance of well-watered plants and decreased plant water status at higher soil water contents. Multi-hormone analyses of root xylem sap and foliar tissues revealed that high bulk density soils attenuated the soil drying-induced increase in xylem [ABA]. Moreover, high bulk density soil increased xylem jasmonic acid concentrations and decreased foliar bioactive gibberellins, which were correlated with reduced shoot growth. Root drenches of bioactive gibberellic acid (GA3) were then applied to determine its ability to improve tomato shoot growth in compact soil. GA3 was transported from root to shoot tissues and significantly increased leaf expansion, but at the expense of plant water status. Further multi-hormone analyses indicated that GA3 application increased foliar cytokinin (trans-Zeatin) levels and decreased xylem jasmonic acid concentrations. Finally, to isolate soil strength from possible confounding effects of nutrient and water availability, tomato plants were grown in a sand culture system. A light foam block or 17 kg weight was placed upon the surface of the sand to increase substrate strength, while tanks were supplied with ample nutrients and water by capillary action. While GA3 again rescued shoot growth, shoot and leaf water potentials were reduced. Furthermore, xylem jasmonic acid concentration consistently decreased in both sand- and soil-grown plants as soil strength increased, which was not attributed to any decrease in leaf water status. Taken together, this thesis is the first to employ multi-hormone analyses on tissues and sap from plants growing in compact or strong soils. Novel roles for gibberellins and jasmonic acid in regulating plant growth when roots are mechanically impeded were discovered. GA3 appears to promote shoot growth against water potential gradients. Further study of the physiological significance of xylem-transported jasmonic acid and its cross-talk with gibberellins seem necessary to help determine how plants respond to soil mechanical stresses.

La humanidad actual camina sobreun puente que une dos épocas: la linealy la exponencial. Los avancestecnológicos que hemos visto sonsolo la punta del iceberg. Se hace tanurgente como respirar, comprenderlas implicaciones que todo esto tienesobre nuestra vida.Para empezar, hay tres grandestransformaciones que afectan todaslas actividades humanas. Esas tresdisrupciones globales han estado actualizandonuestra forma de actuar onuestro “sistema operativo”. Ahoranavegamos el mundo de otra forma.

The inclination angle of such components with respect to the principal orthogonal axes cannot be neglected in the direct seismic analysis of soil-foundation-superstructure systems, specifically in a piled liquefiable soil bed. This study validated numerical simulations and numerically modeled a concrete moment frame on a pile foundation within a liquefiable soil bed. The direct seismic analysis of the superstructure-foundation-soil system was carried out in a single step (through nonlinear dynamic time-history analysis) under longitudinal and vertical near-field seismic acceleration component records. The effects of the inclination of longitudinal and vertical acceleration components on the seismic responses of the soil-foundation-superstructure system in the liquefiable soil bed were explored, evaluating the critical inclination based on the near-field earthquake magnitude. It was observed that the simultaneous application of longitudinal and vertical near-field seismic acceleration components substantially changed the liquefiable soil bed drift of the pile foundation-superstructure system, significantly altering [Formula: see text] in depth, particularly in the middle of the pile depth. The change in [Formula: see text] and its effects on the seismic responses of the superstructure and piles (interstory drift and pile shear force and bending moment) were different upon a 30° change (rotation) in the acceleration records from 0 to 90° with respect to the orthogonal principal axes.

The investigation deals with the specific behavior of tire and new half-track based tractor chassis concepts under pull-condition, where horizontal and vertical forces occur between tractor and implement. These forces lead to a change of the front- and rearaxle loads, compared to non-pull condition. The pulling forces lead to a pitch effects of the tractor and can also result in a pitch effect of the track system, depending on the design of the track system. This effect can lead to an uneven contact pressure in the belt-soil contact. To evaluate the pitch effect and the risk of soil compaction, measurements of the ground pressure with “Bolling Sensors” have been carried out to indicate the effect of the pulling forces to the tractor chassis and the soil pressure. The investigation of the ground pressures have been done in a comparison of a standard tractor Axion 960, two half-track tractors Axion 960 TerraTrac and CASE-IH Magnum 380 Rowtrac under pulling conditions with specific ballasting configurations. The investigation of the pulling behavior of the tractors have been executed as a compari-son of two Axion 960 tractors, one in standard tire version and the other as half-track ver-sion. Both tractors have the same configuration of engine-power and transmission config-uration with CVT transmission. The results are, that the CLAAS Terratrac track system features a significant reduced soil pressure in no-pull and also in pull-condition in comparison to standard tires. Also in com-parison to a triangle track system with positive drive principle the soil pressure of the CLAAS Terratrac system with the suspension is much lower. The comparison of pulling performance shows an improved pulling potential at speeds < 10kph of the Terratrac sys-tem. At higher speeds, the tire-soil contact is not the limiting factor and so wheeled and track-typed tractor show a similar pulling performance.