Avoiding soil compaction is one of the objectives to ensure sustainable agriculture. Subsoil compaction in particular can be irreversible. Frequent passages by (increasingly heavy) agricultural machinery are one trigger for compaction. The aim of this work is to map and analyze the extent of traffic intensity over four years. The analysis is made for complete seasons and individual operations. The traffic intensity is distinguished into areas with more than five wheel passes, more than 5 Mg and 3 Mg wheel load. From 2014 to 2018, 63 work processes on a field were recorded and the wheel load and wheel passes were modeled spatially with FiTraM. Between 82% (winter wheat) and 100% (sugar beet) of the total infield area is trafficked during a season. The sugar beet season has the highest intensities. High intensities of more than five wheel passes and more than 5 Mg wheel load occur mainly during harvests in the headland. At wheel load ≥3 Mg, soil tillage also stresses the headland. In summary, no work process stays below one of the upper thresholds set. Based on the results, the importance of a soil-conserving management becomes obvious in order to secure the soil for agriculture in a sustainable way.

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“The Anthropocene” currently serves as a framework to acknowledge global human influences on the earth systems. Different prominent authors call for geographers and especially physical geographers to intensify their involvement in the discussions on the theme. A bibliometric analysis shows that geographers are already one of the leading contributors to the keyword Anthropocene in journal articles. While we generally support the standpoint of increased engagement with the topic, we want to emphasize that we need to do more than only attaching the “Anthropocene” label to our daily research practice. A critical engagement with and reflection of the research questions and contexts is needed to play a vital role as discussant in the debate. We should take advantage of the diverse themes, topics and viewpoints of our subject by actively following a more critical approach to our research practices in order to find those geographic ties that join us and our discipline and that enable us to contribute more substantially to the Anthropocene debate.

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<p>Investigations of soil compaction in agricultural land often deal with the deployment of heavy, high-performance machinery and their impact on soil structure and functions. The traffic intensity on the field considers the spatial distribution of the number of wheel passes and the wheel load of the machinery. The intensity can vary due to changing machine and field characteristics. However, these dependencies are not analyzed in detail yet.</p> <p>To what extent the machine’s working size and field geometry influence the traffic intensities during wheat harvesting shall be presented in this contribution. A route planning system planned the routes of three different combine harvesters on 59 fields with varying field geometries. With these routes the spatial traffic intensities of the work process were modeled for all variants.</p> <p>To represent the structure of the field geometry, eight shape-indices were calculated. The traffic intensities were divided into classes indicating the percentage area for different threshold values of wheel load and wheel passes.</p> <p>The analysis of the three harvesters showed that the size of the machine has a significant influence on the total trafficked field area and the wheel load distribution. The larger the machine and working width, the more area is affected by high wheel loads, but less total area of the field is passed. Those relations are independent from the field zone (headland, infield or complete field area).</p> <p>The analysis of the field geometry shows that there is a strong correlation between the passed area with more than 5 and 10 wheel passes in the headland and three shape indices. These shape indices are the interior edge ratio (IER), the interior area ratio (IAR), and the mean fractal dimension (MFD). Both the IER and IAR are dependent on the size of the field. It shows that the larger the field area relative to the perimeter and headland area, the bigger the proportion of area in the headland that has been passed more than 5 and 10 times. Analogously, the more complex the field structure, the greater the proportion of area with more than 5 and 10 passes. This increased traffic intensity is probably because a larger field requires more yield transportations from the infield across the headland.</p> <p>The study shows that in wheat harvesting, the geometry of the field and the choice of the machine should be considered if high traffic intensities should be avoided to preserve the soil structure.</p>

<p>Soil compaction by field traffic is one of the main threats to all agricultural soils. Besides lower biomass productivity, compacted soils have a reduced regulation function which affects the air, water and nutrient cycles. To evaluate and mitigate soil degradation by field traffic, it is important to know where, when and to what extent soil compaction may occur during certain traffic events.</p><p>This study presents an approach to assess soil compaction risk at the field scale, considering the spatio-temporal changes of soil strengths and the machinery-induced changes in load and stress. Two newly developed models, the field traffic model “FiTraM” and the spatially explicit soil compaction risk assessment model “SaSCiA”, were used to evaluate the individual soil compaction risk for each field traffic activity during the maize cropping season. RTK-GPS data recorded by all farm vehicles served for the spatial calculation of traffic intensity and changing wheel loads at high spatial resolution (< 30 cm). These data were subsequently used for soil compaction risk assessment based on readily available soil and weather data.</p><p>Our model results indicated that nearly 95% of a field was trafficked throughout the maize-season; harvest traffic at high wheel load contributed to more than the half of the total trafficked area. Furthermore, the analyses showed that soil compaction risk varies greatly within individual fields. Soil moisture and soil texture variation inside the field results in varying soil strength and, therefore, in varying effects of field traffic on soil functions. Thus, one part of a field can be negatively affected by field traffic through an increase in dry bulk density and a decrease in hydraulic conductivity, while the other part is not affected.</p><p>In addition to the spatio-temporal assessment of field traffic intensity and soil compaction risk, the presented approach enables the calculation of maximum allowable wheel load until no harmful soil degradation occurs. Thus, the approach may support farmers in their decision-making for a more sustainable soil management.  </p>

The increasing mechanical intensification of cultivation (Keller et al., 2019;Schjønning et al., 2015) represents one of the major challenges to the preservation of healthy soils in arable land (FAO, 2015).Soil compaction and especially subsoil compaction is often accompanied by mechanical intensification