Soil compaction by agricultural machinery in general by and tractors in particular is an important problem in modern agricultural production. Such compaction destroys the soil structure, creates unfavorable physical parameters of the soil, and as a result, reduces crop yields. Therefore, it is important to clearly establish how the tractor wheels affect the soil. The experiments were conducted on the sandy loam soil by using CLAAS Xerion 5000 tractor with TRELLEBORG IF 900/60 R42 tires with internal pressures varying from 0.08 to 0.24 MPa in 0.04 MPa increments. To determine the stress propagation a developed simulation model was adapted to the parameters of the tractor in use. The iterative method was used for the numerical determination of the soil stress state. The impact of soil compaction starting from a 40 cm depth is not noticeable following the tractor's pass. In fact, from a depth of 40 cm, the normal stresses reach equilibration according to the developed mathematical model. From a depth of 20 cm, the soil compaction pattern is similar for all tire widths tested. Tires with a width up to 10 cm, 0.92 m wide tires compact the soil 25.4% less on average than tires with a width up 0.872 m wide tires. To the depth of 20 cm, tires with a width up the 0.92 m wide tires compact the soil 18.9% less on average than the tires with a width up 0.872 m, and to a depth of 30 cm - only 5.1% less. The tractor with a working tire width of 0.92 m and an axle load of 119.5 kN generate contact stresses on the field surface of up to 150 kPa, which is a permissible load for soil structure safety. Thus, the suggested simulation model of the soil stress state is suitable for use, and studies and modeling advance the idea that using wider tires results in a more equitable distribution of loads. The proposed model for analyzing stress propagation in soil enables to estimate the potential adverse impacts of wheeled or tracked agricultural machinery on soil structure by assessing stress levels that may disrupt or damage soil integrity, with the stresses varying according to the specific physical and chemical properties of each soil type.

Knowing tractor drawbar pull is crucial to ensure the tractor can handle the required workload efficiently and safely, preventing soil damage and optimising field productivity. The present study proposes a novel approach for tractor drawbar pull prediction by utilising the tractor's geometric parameters and forward speed to develop a cloud-infused, server-less, machine learning-based real-time generalised tractor drawbar pull prediction model for any tractor between the 6-58 kW power range. The drawbar pull prediction models from ANN and six ML algorithms were developed, and the data analysis with hyperparameter tuning concluded that the Extreme Gradient Boosting (XGB) ML model outperformed the other ML models. A reasonable accuracy with R2 = 0.93 and MAPE = 6.77% was achieved using the XGB ML model for a separate validation dataset, which was not used for training. Furthermore, a cloud-based serverless Android App integrated with the XGB ML-based drawbar pull prediction model was developed for real-time tractor drawbar pull prediction and monitoring during tillage operations. The field validation demonstrated the XGB ML model's generalisation ability and effectiveness, with R2 = 0.90 and maximum MAPE of 9.86%. It can be used to simulate and optimize tractor performance, guiding manufacturers in selecting geometric parameters for tractor design.

The advancement of agriculture and a shortage of labor have led to an increased use of agricultural machinery. However, the resulting environmental issues have prompted a shift from internal combustion engines to electric drivetrains. The electric drivetrain includes the installation of batteries, which can lead to decreased energy efficiency and significant loads on the vehicle due to their heavy weight. Consequently, the importance of ensuring the safety of agricultural machinery is being increasingly emphasized. The load on the frame of agricultural machinery is not consistent during off-road driving, and the accumulation of load cycles can lead to the destruction and failure of components. Therefore, it is necessary to ensure a level of safety and to predict the fatigue life. In this study, we estimate the safety factor and predict the fatigue life of weak points in an electrically driven, multi-purpose cultivation tractor based on working conditions (width, soil, and drive). Strain gauges were attached to these weak points to measure the strain, which was then converted to von Mises stress. Fatigue life was predicted using the rainflow counting method and the Palmgren-Miner rule. The results showed that the safety factor measured under various working conditions was greater than 1. The estimated minimum fatigue life was 124,176 years. Considering that the cultivator is used for 29.7 h annually and has a durability lifespan of 5 years, it is expected to be safely usable throughout its service life.

The disturbance that ground-based extraction operations can imply on the forests ecosystem is an issue which demands more attention. Skidding and forwarding are the two most common ground-based extraction systems. While skidding implies to partially or fully dragging the logs on the ground, in forwarding, timber is transported on a deck thus avoiding direct contact with the soil. Generally, skidding is considered to be more impactful than forwarding in relation to the amount of disturbance on forest soil and residual stand. However, the framework depicted in current literature is not so strict. While skidding actually implies a higher level of damage to residual stand, the situation concerning disturbance to forest soil is much more complex. The dissimilarities in the results from various studies on this topic have shown the level of complexity. The lack of research investigating the consequences of the two extraction systems on the overall forest ecosystem is evident. Only a few studies were focused for example on the implications on biodiversity. However, the beneficial effects of best management practices, such as the application of snatch blocks during winching or positioning brush mats on the skid trails/ strip roads to reduce soil compaction, have been clearly demonstrated.

Determination of the traction forces between the tractor and its implement is important due to optimal utilization of tractor power and its connected implement, estimation of soil properties or strength, and fatigue studies. The working width of agriculture implements is increasing, which demands higher traction forces. The article presents the design and test in-field measurement of a double-frame dynamometer for the three-point hitch of the tractors, which can measure forces up to 400 kN. The dynamometer is equipped with six force transducers positioned so that force measurement on all axes is possible. The connection of the dynamometer follows the standard ISO 730. The design of the dynamometer and force calculations are presented. The in-field measurement was performed using disc and chisel tillage implements at different tillage depths. The increasing magnitude of the resultant traction force with increasing tillage depth and the effect of the geometry of tillage machines were found.