SSS9.7 | Soil degradation by soil compaction on arable land, grassland and in forests
Soil degradation by soil compaction on arable land, grassland and in forests
Convener: Michael KuhwaldECSECS | Co-conveners: Marco Lorenz, Katja AugustinECSECS
Orals
| Tue, 25 Apr, 08:30–10:15 (CEST)
 
Room K2
Posters on site
| Attendance Tue, 25 Apr, 10:45–12:30 (CEST)
 
Hall X3
Posters virtual
| Attendance Tue, 25 Apr, 10:45–12:30 (CEST)
 
vHall SSS
Orals |
Tue, 08:30
Tue, 10:45
Tue, 10:45
Anthropogenic soil compaction is one of the main soil degradation processes in agriculture and forestry worldwide. Steadily increasing masses of machinery and their intensive use in agriculture and forestry increase the risk of harmful soil compaction, especially under unfavourable soil conditions.
Once a soil is compacted, reduced water infiltration, impaired plant and root growth and lower biological activity occur, whereas surface runoff, soil erosion and nutrient leaching increase. Among others, this influences the yield potential and yield security as well as the resilience to extreme weather events due to climate change.

Despite its importance, soil compaction receives relatively low awareness compared to other soil degradation processes such as soil erosion, which might be attributed to a reduced visibility of soil compaction. Deep ruts of the tyres may be recognisable at the soil surface, but surface smoothening by tillage and seedbed preparation will remove them. The effects of soil compaction in deeper soil layers are mostly invisible at all.

Within this session, we will focus on all aspects of soil compaction in agriculture and forests. This includes all methodological aspect (field work, laboratory analysis, sensor development, statistical analysis, and modelling), all spatial scales (from pedon to regional to continental scale) and all temporal scales (past, present, and future). Furthermore, applications and solutions for reducing soil compaction in agriculture and forestry are very welcome.

All researchers involved in soil compaction are warmly invited to attend this session.

Orals: Tue, 25 Apr | Room K2

Chairpersons: Michael Kuhwald, Marco Lorenz, Katja Augustin
08:30–08:35
08:35–08:45
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EGU23-3137
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ECS
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On-site presentation
Emanuela Lepore, Olaf Schmidt, Owen Fenton, Saoirse Tracy, Giulia Bondi, and David Wall

Soil compaction is one of the primary threats to soil degradation in Europe; however, data to guide grassland farmers on how to avoid traffic induced soil compaction is limited. In grassland systems, soil moisture regimes are measured by daily soil moisture deficit (SMD) values and, when coupled with soil physical indicators could help safeguard the soil physical quality (SPQ). The objective of this study is to investigate how soil physical quality changes across different induced traffic compaction events at targeted SMD. A field study at Johnstown Castle Beef Farm (Wexford, Ireland) investigated the severity of soil physical changes caused by machine trafficking across different targeted soil moisture regimes. A tractor and a fully loaded slurry tanker trafficked moderately drained soil plots at SMD targets of 10 (dry (D)), 0 (moist (M)) and – 10 (wet (W)) mm. Compaction events simulated four passes across one year of grassland management: at the time of the first silage cut, in April; after the first cut silage harvest, in June; before the slurry spreading opening season, in October; and at the beginning of the slurry spreading period, in January. Soil bulk density (BD) samples were taken in the middle of the tyre marks at different depths (0-10, 10-20 and 20-30 cm). To examine indirect soil physical quality of various treatments, soil physical data was used to calculate the S value (Si) using the SawCal model. Initial results showed that the progressive increase in the number of trafficking events occurring above SMD 0 mm  led to major compaction, which significantly increased (P<0.05) compared to trafficking at SMD 10 mm. The cumulative effect of the four passes showed a significant difference from M to D and W, with M’s BD increasing by 22.2% compared to the control. D and W BDs remained similar ranging between 1.10 and 1.11 Mg m-3. Accordingly, Si values were indicative of very poor (i.e. degraded; S < .035) SPQ in M only. These early results indicate that the most severe degradation occurred in the 0 – 10 cm depth. Forecasting soil moisture is a valuable tool for the protection of SPQ and to enable farmers to minimise any soil degradation due to trafficking.

Keywords: soil compaction, grasslands, soil moisture, field traffic, soil physical quality indicators

How to cite: Lepore, E., Schmidt, O., Fenton, O., Tracy, S., Bondi, G., and Wall, D.: Moisture limits for grassland soil to avoid structural damage due to machine trafficking, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3137, https://doi.org/10.5194/egusphere-egu23-3137, 2023.

08:45–08:55
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EGU23-5466
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On-site presentation
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Karin Pepers, Gijs Staats, Fenny Van Egmond, Ronald Koomans, Kees Teuling, and Gera Van Os

Soil compaction and soil bulk density are gaining in importance as soil parameters. The standard measurement with rings is labour intensive and therefore expensive. Medusa Explorations developed a sensor for in situ density measurements, the RhoC. This sensor measures in situ a full soil profile of bulk density every 5 cm up to 1 m depth in 15 minutes, without the need to extract a soil core. The measurement uses gamma ray attenuation combined with a soil moisture sensor. A validation study was performed in two locations, on sandy clay loam and sand soil, both with large within field variation in subsoil compaction. The first results show a good correspondence between both methods. Statistical analysis shows a slightly lower precision for the RhoC measurements than for the rings measurements. The results of this validation study will be discussed.

How to cite: Pepers, K., Staats, G., Van Egmond, F., Koomans, R., Teuling, K., and Van Os, G.: New in situ soil bulk density sensor using gamma radiation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5466, https://doi.org/10.5194/egusphere-egu23-5466, 2023.

08:55–09:05
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EGU23-5907
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ECS
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On-site presentation
Leonardo Bianchini, Riccardo Alemanno, Richard Lord, Ben Nunn, and Andrea Colantoni

Harvesting operations of perennial forage crops can lead to soil compaction problems, which in turn lead to poorer soil structure, increased erosion, and reduced organic matter. The present study focuses on the evaluation of soil compaction caused by harvesting operations of Phalaris arundinacea (Reed Canary Grass) by measuring soil penetration resistance in two different areas of the farm of the University of Tuscia. The measurements were carried out in two consecutive years following the biomass harvesting operations. These field trials are part of the H2020 project CERESiS (ContaminatEd land Remediation through Energy crops for Soil improvement to liquid biofuels Strategies) (GA 101006717), which started in November 2020 and will continue until the end of the project in 2024. P. arundinacea is a species that lends itself to biomass production and phytoremediation of contaminated soils. The areas with different textures were treated with a minimum tillage system, notably, only a secondary tillage of the field with a disc harrow was carried out in late winter 2021 and sown in spring 2021. Part of each area was allocated for control and was fenced off after sowing, to avoid any trampling. The remaining areas were divided into 3 plots in which the operations were repeated. Measurements were taken in 2021 and 2022 following harvesting operations using a John Deere 5100 GF tractor with disc mower. Penetration resistance and soil moisture measurements followed, to verify the impact of the operations and the effect of soil type on compaction. For penetration resistance, 15 measurements per plot were taken up to a depth of 80 cm using an electronic penetrometer model Penetrologger (Royal Eijkelkamp Soil &Water; Giesbeek, The Netherlands). The results of the soil analysis indicate different chemical and physical characteristics between the two areas, in particular, one area has a clay texture and the other a sandy loam texture. The data collected from the measurement of penetration resistance pointed out significant differences between the plots subjected to tractor passage for harvesting operations and the control areas. Differences were also observed between the two areas, which was an expected result given the different texture and humidity recorded; thus, confirming the effect that this parameter can have on compaction and giving an indication of when to avoid entering the field.  It was interesting to note that an effect on the soil can already be seen after two years, despite the minimal intervention. Inspection at different depths showed a general tendency for resistance to penetration to increase with increasing depth, a greater difference between treatments (with tractor and control) up to 40 cm and a tendency to overlap beyond this depth. It will now be interesting to see how this will evolve over the next few years and to assess how the increase in penetration resistance can be further reduced. Compaction affects many other soil parameters, in a context of climate change, it is crucial to implement strategies to reduce it in agricultural operations.

How to cite: Bianchini, L., Alemanno, R., Lord, R., Nunn, B., and Colantoni, A.: Assessing penetration resistance in Phalaris arundinacea harvest operations under minimum tillage conditions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5907, https://doi.org/10.5194/egusphere-egu23-5907, 2023.

09:05–09:15
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EGU23-6402
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ECS
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On-site presentation
Muhammad Mohsin Nawaz, Emmanuel Arthur, Joséphine Peigné, Meisam Nazari, Maliheh Fouladidorhani, and Mathieu Lamandé

Conservation tillage practices, such as reduced tillage, are often considered beneficial regarding soil fertility and sustainability. However, a risk of developing a shallow compact hardpan is associated with these practices that can hinder optimal water and gas transport within the root zone and thus impact soil health and productivity. To explore this risk, we compared conventional mouldboard ploughing (to 30 cm depth; MP) and reduced tillage (5-7 cm; RT) in a long-term experiment (approximately 15 years) on sandy loam soil. The field was uniformly tilled to a depth of 15-20 cm depth after the termination of the experiment. We evaluated the soil water and gas flow variables (saturated hydraulic conductivity, gas diffusion, and effective air-filled porosity), and biological soil properties for the 20-30 cm layer for the MP and RT treatments.

Soil was more compact in the reduced tillage treatment compared to conventional tillage, especially in the 20-30 cm soil layer. Soil bulk densities in the 20-30 cm soil layer were 1.62 and 1.80 g cm-3 in MP and RT treatments, respectively. There was no difference between the conventional and reduced tillage for effective air-filled porosity or gas diffusivity measured at -100 hPa water potential. Similarly, saturated hydraulic conductivity measured in the field was not different under the two tillage practices. The conventional tillage had 61% more earthworm abundance than the reduced tillage. The results indicated that despite the formation of a compact hardpan at 20-30 cm soil layer, as characterized by a higher bulk density, there were little to no effects of tillage on the soil functions related to water and gas transport. Moreover, the linkages between the soil physical quality indicators and microbial indicators (enzyme activity, microbial biomass carbon and nitrogen) were also explored.

How to cite: Nawaz, M. M., Arthur, E., Peigné, J., Nazari, M., Fouladidorhani, M., and Lamandé, M.: Impact of long-term reduced tillage on water and gas transport in a sandy-loam soil and linkages to biological indicators, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6402, https://doi.org/10.5194/egusphere-egu23-6402, 2023.

09:15–09:25
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EGU23-8891
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ECS
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Highlight
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On-site presentation
Thomas Weninger, Matthias Konzett, Tommy D´Hose, Kees Teuling, and Elmar Schmaltz

Soil compaction is a major threat to global agriculture as it can affect crop production and negatively impact the environment. This can result in increased production costs, additional labor requirements and reduced time windows for field access. Nevertheless, the actual effects of soil compaction on the growth of different crops in different pedo-climatic regions are insufficiently investigated. In this study, possibilities for such assessments by remote sensing are evaluated in three pedo-climatic zones of Europe using a harmonized experimental design. Oceanic climate is subject in Belgium and The Netherlands, while in Austria a location with continental, drier climate and another location in an intermediate continental-hemiboreal climate are included.

By means of unmanned aerial vehicles (UAV) equipped with optical and multispectral cameras, plant-physiological indicators are surveyed frequently throughout the vegetation period. Examples for such indicators are crop height, vegetation cover and density, NDVI, and a set of further indices derived from the reflectance signature of the plants. Fields are monitored that partly underwent a defined and delimited compaction (headlands or wheel tracks from management using heavy machinery) and soil physical standard methods are applied to characterize the compaction state of the soils (e.g. bulk/packing density, soil penetration resistance). Differences in the listed indicators are analyzed between plants in compacted parts and the non-compacted areas closely nearby under the same growing conditions.

Results from the first year of observations revealed distinct differences between plant growth in compacted and non-compacted areas. Several indicators showed interesting patterns throughout the vegetation period, which will be subject of further in-depth analyses. In the continental climate and affected by an exceptionally dry winter, early stage development of winter wheat was even more vital in compacted areas. Further statistical analyses of the gathered datasets from the UAV- and in-field-observations will provide insights on whether information about the state of soil compaction and its effects on plant physiology are supposed to be derived from these surficial indicators.

How to cite: Weninger, T., Konzett, M., D´Hose, T., Teuling, K., and Schmaltz, E.: Remote sensing of vegetation dynamics as an indirect assessment of soil compaction, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8891, https://doi.org/10.5194/egusphere-egu23-8891, 2023.

09:25–09:35
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EGU23-11751
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ECS
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Highlight
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On-site presentation
Frauke Lindenstruth, Michael Kuhwald, Katja Augstin, and Rainer Duttmann

Soil compaction due to field traffic can reduce yields and increase a fields susceptibility to surface runoff and soil erosion. However, detecting and monitoring compacted soils is time and labor intensive. Additionally, most detection methods focus on few points within a field and usually do not provide information on the spatial distribution of soil compaction and its effects on a field scale. 
In this study, we aim to present a method for detecting potentially compacted areas on field scale using an unpiloted aerial vehicle (UAV). Using an UAV enable the non-inversive collection of field vegetation patterns want, which can be linked to differences in soil properties and soil structure.
In two study regions, we monitored six fields for four years. For each field, at least four UAV-flights were carried out per season. The UAV was equipped with a RGB and a multispectral sensor. Spatial corrections and spectral calibrations were performed with ground control points and calibration targets. To analyze the data for patterns in the vegetation, models of plant height and various vegetation indices (NDVI, SAVI, WDRVI, EVI) were calculated and combined with three different clustering algorithms (k-means, fuzzy k-means, CLARA). To validate the identified vegetation patterns, several field campaigns were conducted to analyze soil texture, saturated hydraulic conductivity, air permeability, bulk density, and yield. 
Our study shows that patterns in the vegetation can be distinguished by their geometry and orientation. Linear patterns running parallel to the tramlines and planar patterns in the headland indicate potential compaction, whereas rounded patterns are indicators for topography changes. Soil samples within the detected linear patterns overall showed an increase in bulk density, and a decrease in saturated hydraulic conductivity and air permeability. Yield samples were also reduced in those patterns for all studied crops. Thus, we can conclude that UAV analysis is suitable method for soil compaction detection. However, detected patterns can be overlaid by other causes.

How to cite: Lindenstruth, F., Kuhwald, M., Augstin, K., and Duttmann, R.: Detection of soil compaction by the spatial analysis of vegetation characteristics via UAV and clustering algorithms, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11751, https://doi.org/10.5194/egusphere-egu23-11751, 2023.

09:35–09:45
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EGU23-9118
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On-site presentation
Maliheh Fouladidorhani, Mathieu Lamandé, Gerhard Moitzi, Muhammad Mohsin Nawaz, Meisam Nazari, Helmut Wagentristl, and Emmanuel Arthur

Soil compaction caused by modern mechanized agriculture has severe impacts on soil functioning and negative consequences on crop production. In the subsoil, these effects are persistent and difficult to ameliorate. To further clarify the compaction effect on the subsoil, we imposed compaction on 21st April 2022 on a moist Calcaric Chernozem (silty clay loam) by pulling a full 2-axle slurry tanker (10 m3, pendulum tandem axle, max. wheel load 3 Mg) with a tractor (19.5 Mg total load) through the field. Six months after the compaction event (in autumn (18th October 2022)), we evaluated the effects on field-measured soil structural quality indicators (SubVESS, bulk density, penetration resistance) and saturated hydraulic conductivity, then compared them to laboratory-measured gas flow-related parameters on intact 100 cm3 soil cores at -100 hPa (air-filled porosity, gas diffusion, and air permeability) at one depth in the subsoil (30-40 cm) and quantified pore geometry and tortuosity and geometry.

Simulation of traffic using TerranimoÒ indicated a risk of compaction down to 30 cm depth. The compacted treatment did not noticeably affect the soil bulk density. However, based on visual evaluation by SubVESS, compaction decreased porosity and aggregate friability. The overall soil structural quality (Ssq) scores were 2.1 and 1.4 for the compacted and control subsoil layers, respectively. Further, compared to the control treatment, a higher penetration resistance for the compacted treatment was observed from 5 cm to 35 cm. Field-measured saturated hydraulic conductivity decreased by 42% after compaction. Soil gas transport by convection (air permeability) and diffusion (gas diffusivity) decreased by 67% and 48%, respectively, after compaction. Furthermore, compaction decreased air-filled porosity and pore organization by 28 and 60%, respectively, and increased pore tortuosity. It can be concluded that although compaction did not increase bulk density in the subsoil, the negative effects of traffic was detectable by SubVESS, and the quantitative parameters related to air and water flow.

How to cite: Fouladidorhani, M., Lamandé, M., Moitzi, G., Nawaz, M. M., Nazari, M., Wagentristl, H., and Arthur, E.: Subsoil compaction impacts soil quality indicators in a Calcaric Chernozem, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9118, https://doi.org/10.5194/egusphere-egu23-9118, 2023.

09:45–09:55
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EGU23-9332
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On-site presentation
Emmanuel Arthur, Maliheh Fouladidorhani, Fulai Yan, Meisam Nazari, Muhammad Mohsin Nawaz, Lars Munkholm, and Mathieu Lamandé

Mechanization operations in agriculture have, for the last two decades, involved consistently higher wheel loads with an increased risk of soil compaction, particularly in the subsoil. Subsoil compaction is more persistent compared to the topsoil due to limited mitigation options. There is, however, a potential for the natural recovery of compacted subsoils through processes such as freeze-thaw and wet-dry cycles, and biological activity. The objectives of the present study were to (i) quantify the persistent effects of subsoil compaction on subsoil pore characteristics and water flow, based on visual and quantitative methods, and (b) investigate the potential for natural recovery nine years after the compaction event.

Soil compaction was achieved by tractor-trailer combinations for slurry application with a maximum wheel load of 8 Mg on a loamy Luvisol. The compacted plots were trafficked annually for four years (2010-2013). Nine years later (2022), field measurements (saturated hydraulic conductivity, visual evaluation of subsoil structure [SubVESS], and penetration resistance) were conducted at a depth of 0.3-0.4 m. Additionally, undisturbed samples of 100 cm3 were taken for measurements of gas flow (air permeability [ka] gas diffusivity [Dp/Do], and air-filled porosity[ε]) after equilibration at a matric potential of −100 hPa. The negative impact of compaction on the measured variables was compared to previous measurements conducted four years after (2017) the compaction event.

Nine years after compaction, there was still a marked negative effect of compaction on the soil structure assessed by the SubVESS method, with the largest impact observed on soil strength, root growth restriction, and aggregate friability. Saturated hydraulic conductivity was 63% lower in the compacted treatments compared to the control, while penetration resistance increased from 1.91 to 2.65 MPa after compaction. We also observed a strong negative effect of compaction on soil air permeability (−54%), gas diffusion (−30%) and the effective air-filled porosity (−24%). These changes were reflected in decreased pore organization [PO] and tortuosity in the compacted plots. Compared to five years earlier, there was a potential for natural recovery of the gas transport and pore structure variables (ka, Dp/Do, ε, PO). In 2017, there was an average compaction-induced reduction of 55% in the mentioned variables, and this changed to 38% in 2022, suggesting an increased recovery with time. Thus, although the effect of compaction on the subsoil was persistent after several years, there is a possibility that natural processes may play a significant role in recovering critical soil functions after compaction in the upper subsoil.

How to cite: Arthur, E., Fouladidorhani, M., Yan, F., Nazari, M., Nawaz, M. M., Munkholm, L., and Lamandé, M.: Persistence of subsoil compaction and potential for natural recovery in a sandy loam soil, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9332, https://doi.org/10.5194/egusphere-egu23-9332, 2023.

09:55–10:05
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EGU23-17436
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On-site presentation
Rainer Duttmann, Philipp Saggau, and Michael Kuhwald

Soil erosion by water is one of the main causes of degradation of arable soils worldwide. Through the degradation of soil functionality and the long-distance effect of polluted soil particles, water erosion can severely limit soil fertility and the condition of aquatic ecosystems. Nowadays, a variety of different soil erosion models are used on different spatial and temporal scales to assess soil erosion risk, identify risk areas and support decision makers in adapting soil protection measures. Field studies show that highly compacted field areas such as wheel tracks, can have a major influence on the extent of soil erosion and runoff, but so far, they are not considered in any model-based soil erosion assessment.

The aim of this study is therefore to present an approach for integrating compaction effects of tramlines into process-based soil erosion models. Furthermore, the effects of tramlines on soil erosion and runoff processes within a watershed are to be identified. For this purpose, the soil erosion model EROSION 3D (E3D) was parameterized by accounting for soil conditions of compacted wheel tracks for a watershed in Norther Germany. In a further step, the modelling was conducted for a real heavy rainfall event and calibrated and tested with mapped runoff and soil erosion data. Additionally, a sensitivity analysis of the input parameters was conducted in order to assess soil properties which have a major impact on the model results.

The study shows that small-scale features such as tramlines can be integrated into soil erosion models and that this can significantly improves the spatial prediction of runoff and soil erosion. The model results also show that tramline tracks can have a significant contribution (up to 75 %) to total erosion as well as to sediment input into the water network, while bulk density of the wheel tracks is a major factor influencing modelled runoff and soil loss. The model results indicate that tramlines can play a key role in runoff and erosion processes and that the consideration of highly compacted areas in soil erosion assessments in agricultural landscapes is crucial. The results also indicate, that soil conservation measures may need to foster on tramlines and other compacted field areas such as headlands.

 

How to cite: Duttmann, R., Saggau, P., and Kuhwald, M.: Compacted wheel tracks as underestimated structures in water erosion events in agricultural landscapes: Results of a first process-based model application at catchment level., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17436, https://doi.org/10.5194/egusphere-egu23-17436, 2023.

10:05–10:15

Posters on site: Tue, 25 Apr, 10:45–12:30 | Hall X3

Chairpersons: Michael Kuhwald, Marco Lorenz, Katja Augustin
X3.131
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EGU23-8893
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ECS
Michael Kuhwald, Katja Augustin, and Rainer Duttmann

Soil compaction due to intensive field traffic is one of the main threats to 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 work processes.

For this purpose, we modelled and analysed the soil compaction risk for each work process during a 4-year crop rotation (winter wheat, maize, winter wheat, sugar beets) for one field in Lower Saxony, Germany. Based on RTK-GPS tracks recorded by the farm machineries, FiTraM (field traffic model) was used to model the spatial representation and the wheel load for each tire of each work process. Subsequently, these data were used for the soil compaction risk assessment by the SaSCiA-model (Spatially explicit Soil Compaction risk Assessment). In total, 63 work processes were modelled with a spatial resolution of 20 cm.

The model results revealed that the soil compaction risk at field scale is highly variable in space and time. The spatial variations in soil compaction risk are mainly determined by the spatial distribution of soil properties like soil texture, carbon content and soil moisture. In combination with changing wheel loads, e.g. during harvest processes, the soil compaction risk ranges from low to extremely high during one work process. The temporal variation is mainly caused by the weather conditions. A prolonged period with low precipitation resulted in no subsoil compaction risk during maize harvest, although maize harvest is often a major cause of soil compaction.

This study shows that the soil compaction risk varies in a wide range within a certain field. Efforts to mitigate soil compaction should consider spatio-temporal dynamics at high resolution to achieve a sustainable soil management.

How to cite: Kuhwald, M., Augustin, K., and Duttmann, R.: A spatially and temporally high-resolution 4-year soil compaction risk analysis at field scale, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8893, https://doi.org/10.5194/egusphere-egu23-8893, 2023.

X3.132
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EGU23-17480
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ECS
Lennart Rolfes, Kai Germer, and Andre Peters

In highly mechanized modern timber harvest, forest soils are wheeled by heavy vehicles on skid trails. This leads to structural changes in the soil. The aim of this work was to quantify the soil physical properties of skid trail lanes of different depths (0-10, 10-20, 20-30 cm). Between 2017 and 2021, 18 existing skid trails in a spruce stand in the low mountain range Solling (southern Lower-Saxony, Germany) were examined from a soil physical point of view after repeated use with a harvester (25 Mg total mass) and a forwarder (35 Mg). Undisturbed soil samples were taken at six soil depths in the lane, in the adjacent edge area and in the nearby undisturbed forest soil. In addition, disturbed samples were collected as well for analysis like soil texture. The dry bulk density increases with lane depth and, on average, reaches maximum values in the middle of the lane. This decreases in the edge areas. Significant differences between the treatments can be determined up to a sampling depth of 35 cm. The saturated hydraulic conductivity is lowest in the deepest lanes. With the exception of the sampling depth of 50 cm, this also applies to the porosity, which can primarily be explained by a decrease in the coarse pores. A trend can be derived from the results: The deeper the shape of the lane, the more it deviates from the unwheeled comparison area in terms of its physical soil properties.

How to cite: Rolfes, L., Germer, K., and Peters, A.: The deeper the lane, the stronger the changes: Soil physical properties of forest skid trails and their spatial distribution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17480, https://doi.org/10.5194/egusphere-egu23-17480, 2023.

X3.133
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EGU23-2712
Katja Augustin, Santiago Focke-Martinez, Rainer Duttmann, Joachim Hertzberg, and Michael Kuhwald

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.

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.

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.

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).

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.

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.

How to cite: Augustin, K., Focke-Martinez, S., Duttmann, R., Hertzberg, J., and Kuhwald, M.: The Relationship of Field Geometry, Harvester Size, and Traffic Intensity during Wheat Harvesting, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2712, https://doi.org/10.5194/egusphere-egu23-2712, 2023.

X3.134
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EGU23-7276
Christabel Ansah, Robert Rettig, Marcel Storch, and Thomas Jarmer

In recent decades, due to the increasing weight of agricultural machineries, undesirable soil compaction has become a severe factor for soil degradation. It does not only have negative ecological, but also economic effects. Successfully detecting, monitoring and predicting depths of ruts that were used by heavy vehicles can potentially reduce soil compaction. A crucial task is to generate real-world data at site-specific locations. UAV-based approaches have the advantage of providing sufficient spatial coverage and resolution to assess vital information, which can be used to directly evaluate the compaction resulting from the utilization of these heavy machineries. This information could be used for agricultural predictions, optimized routing and best time for treatments, soil regeneration purposes and many more. Therefore, the aim of this research was to spatially detect the depth of ruts, caused by heavy farm machineries on agricultural fields with consumer-grade Unmanned Aerial Vehicles (UAVs).

We therefore created a semi-automatic processing pipeline for UAV based data. The georeferenced RGB orthomosaic was used to spatially predict lanes, in the early stages of the crop cycle, by employing a Machine Learning approach. This prediction was subsequently used to extract the height information of the rut and the surrounding area from the SfM (Structure from Motion) Digital Elevation Model. As a reference method for the absolute height information, we compared this DEM (DJI Phantom 4) to the UAV - LiDAR derived DEM (RIEGL miniVUX-1UAV). For both systems, no substantial difference in the quality of the evaluated compaction depth was observed. This allows the use of low-cost UAV RGB systems to contribute to the ongoing research on soil compaction.

How to cite: Ansah, C., Rettig, R., Storch, M., and Jarmer, T.: A UAV-based rut depth detection - A potential for evaluating soil compaction on farmlands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7276, https://doi.org/10.5194/egusphere-egu23-7276, 2023.

X3.135
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EGU23-7426
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Martin Lanzendörfer, Jakub Roháč, Martin Slavík, Tomáš Weiss, and Jan Najser

While there are many methods available for the characterization of pore space of soils, most of them are not suitable for observing the gradual changes of the pore sizes of a given sample during the process of its compaction. Non-Newtonian fluids have been utilized recently for approximating the pore size distribution, providing not only a cheaper and more accessible alternative to the classical porosimetry techniques but also a method that allows to keep the sample undisturbed and to be used repeatedly. In particular, the so-called ANA method [1] computes the effective pore size distribution based on a set of saturated flow experiments with different shear-thinning fluids, such as the aqueous xanthan gum solutions of different concentrations.

We will discuss a methodology to measure the progressive changes in the pore size distribution of the sand sample placed in the standard triaxial test chamber where it is subject to a drained compression. After every compression step (i.e. after increasing the pressure level maintained in the chamber, thus further compacting the sample), a sequence of permeability measurements with fluids of different rheology is performed and the effective pore size distribution is approximated. The ANA approach is used in our case since the similar yield-stress method [2] requires using larger hydraulic gradients, which would disturb the effective stress imposed on the compressed sample.

[1] Hauswirth, S.C., Abou Najm, M.R., Miller, C.T., 2019. Characterization of the Pore Structure of Porous Media Using non-Newtonian Fluids. Water Resources Research 55, 7182–7195. https://doi.org/10.1029/2019WR025044

[2] Rodríguez de Castro, A., Agnaou, M., Ahmadi-Sénichault, A., Omari, A., 2020. Numerical porosimetry: Evaluation and comparison of yield stress fluids method, mercury intrusion porosimetry and pore network modelling approaches. Computers and Chemical Engineering 133. https://doi.org/10.1016/j.compchemeng.2019.106662

 

How to cite: Lanzendörfer, M., Roháč, J., Slavík, M., Weiss, T., and Najser, J.: Measuring the pore size distribution of a soil sample during the saturated triaxial compression using non-Newtonian fluids, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7426, https://doi.org/10.5194/egusphere-egu23-7426, 2023.

X3.136
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EGU23-8501
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ECS
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Soheil Safari Anarkouli and Martin Lanzendörfer

Since there is no doubt that soil compaction can induce substantial changes in the soil properties, affecting all kinds of physical, chemical, and biological processes in soils, it is worth some effort to attempt to characterize these changes quantitatively [1]. Soil properties, such as its permeability and hydraulic conductivity or the pressure-saturation relations, to name a few, are closely related to the pore space geometry, in particular to the pore size distribution (PSD). Future progress in incorporating the soil hydraulic properties in the modeling studies related to soil compaction will require, among others, an enhanced understanding of how PSD evolves during the compaction process. In addition to much-needed experimental observations, we believe that a significant part of this endeavor should be devoted to making use of the available pore-scale numerical techniques.

We will focus on the approach based on obtaining the pore structure in between the grains (of idealized grain geometries) for given porosity and particle size distribution. In this study, we use the discrete element method (DEM) [2] to obtain the evolution of pore structure by simulating the movement of grains during the compaction process, for a variety of sphere packings (mono-sized particles and binary mixtures, to start with). For this purpose, we use the open-source platform Yade-DEM [3]. The hydraulic properties of the fluid-saturated granular materials are simulated with the pore-scale finite volume (PFV) model [4]. Also, we use a combination of regular Delaunay facets and regular Voronoi vertices to extract the geometry of the pore structure. The effects of compaction on the pore structure and the hydraulic properties of different spherical packings will be discussed.

 

References:

[1] Mahmoodlu, M. G., Raoof, A., Sweijen, T., & Van Genuchten, M. T. (2016). Effects of sand compaction and mixing on pore structure and the unsaturated soil hydraulic properties. Vadose Zone Journal, 15(8).

[2] Cundall, P.A., and Strack, O.D.L. (1979) A Discrete Numerical Model for Granular Assemblies. Geotechnique, 29, 47-65.

[3] V. Šmilauer et al. (2021), Yade Documentation 3rd ed. The Yade Project. (http://yade-dem.org/doc/)

[4] Chareyre, B., Cortis, A., Catalano, E. et al. (2012). Pore-Scale Modeling of Viscous Flow and Induced Forces in Dense Sphere Packings. Transp Porous Med 92, 473–493.

How to cite: Safari Anarkouli, S. and Lanzendörfer, M.: Numerical investigation of compaction effects on pore structure and hydraulic properties of fluid-saturated granular materials, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8501, https://doi.org/10.5194/egusphere-egu23-8501, 2023.

X3.137
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EGU23-11647
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Glenda Garcia Santos, Marianna Puff, Martin Orel, and Andreas Bohner

The study of the causes and possible remediation strategies at regional level complies with the current European Green deal to monitor soil compaction. We have investigated the influence of different management strategies (use of cattle and machinery) on the storage density and the penetration resistance of permanent grasslands in the south of Austria (Carinthia) based on the recent evidences of soil compaction in two grasslands as studied by Klinger et al. in (2019). Based on this, we have extended the study by selecting more than ten grasslands within two catchments with different management strategies.

The studied indicators were bulk density, soil texture, plant indicators, infiltration capacity, water repellence, water content and electric conductivity at the surface level. Soil profiles of approximately 30 cm were also studied to detect the possible compaction layer and vertical bulk density variations. First results may explain spatial topographical differences i.e. slope and hydrological soil properties and interestingly in some cases, possible correlation between the use of cattle and number of entries in the field and compaction level. We checked if these results contributed or matched farmers awareness.

How to cite: Garcia Santos, G., Puff, M., Orel, M., and Bohner, A.: Preliminary study about soil compaction and awareness in grasslands in Carinthia (south Austria), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11647, https://doi.org/10.5194/egusphere-egu23-11647, 2023.

X3.138
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EGU23-11665
Kai Germer, Maike Weise, and Marco Lorenz

Agricultural sites are often influenced by soil deformation and compaction through vehicular traffic. Both can lead to changes in pore-size distribution and consequently in changes at the water retention properties. Compaction usually has the disadvantage that crop yields are reduced and, conversely, avoiding soil compaction has the potential to increase yields and is also more sustainable for the soil. By compaction mainly the macro pores are affected and the lost in pore volume comes from a transformation of macro pores and coarse pores to middle and fine pores.

In this study presented here agricultural sites in Lower Saxony (Germany) were soil sampled before and after vehicle wheelings with different machines. The samples were lab investigated to become soil moisture to pore pressure pairs and based on these pairs samples retention curves were yield by fittings with the traditional constrained van Genuchten model using the HYPROP-Fit software. The goal of the study is mainly to compare the van Genuchten parameters θs (saturated water content) and α (van Genuchten shape parameter) between unwheeled and wheeled situations and this in relation to the used vehicles, depth and position in the field.

The results show that soil compaction mainly occurs as a result of vehicular traffic, which is reflected in predominantly decreasing θs values. In most cases, the van Genuchten parameter α is significantly reduced after traffic loading, indicating that the mean and dominant pore size range is shifting towards finer pores. Based on these results, it may be possible in the future to identify vehicles and types of traffic where the slightest possible negative soil changes are to be expected.

How to cite: Germer, K., Weise, M., and Lorenz, M.: Loads and soil deformations from agricultural vehicles and their influence on soil water retention properties, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11665, https://doi.org/10.5194/egusphere-egu23-11665, 2023.

Posters virtual: Tue, 25 Apr, 10:45–12:30 | vHall SSS

Chairpersons: Michael Kuhwald, Marco Lorenz, Katja Augustin
vSSS.6
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EGU23-14940
Marco Lorenz, Maike Weise, Kai Germer, and Joachim Brunotte

Under moist soil conditions, high wheel loads and repeated wheel passes due to intensive field traffic, e.g. at sugar beet harvest, significantly increase the risk of soil compaction and harmful soil structure damages. The tires of the machines induce loads into the soil via the tire soil interface. The pressure is transmitted into the soil and may induce soil deformations. Plastic soil deformation lead to soil compaction with multiple effects on soil parameter (e.g. dry bulk density, air capacity), soil structure and soil pore system.

A measurement device is presented to measure soil pressure and soil deformation simultaniously in different soil depth. It was applied for different field traffic situations and techniques at silage maize and sugar beet harvest, as well as for the application of digestates on a stagnic Luvisol in northern Germany. Under moist soil conditions, almost every wheel pass leads to plastic soil deformation in the topsoil. Depending on soil loads and conditions, the subsoil can also be deformed. In all measurements, the first wheel pass induces the highest deformation, but every further wheel leads to further soil deformation. Therefore, in addition to the wheel load, the number of wheel passes also plays an essential role in evaluating field traffic and soil compaction processes.

Undisturbed soil cores were collected before and after field traffic in different soil depth (20, 35, 50 cm) and analyzed in the soil physical laboratory. With increasing plastic deformation the total pore volume decreases, wider soil pores were reduced and finer soil pores generally increase. Hence, mainly parameters like dry bulk density, air capacity and saturated hydraulic conductivity react negatively to increasing soil deformation.

How to cite: Lorenz, M., Weise, M., Germer, K., and Brunotte, J.: Soil deformation during field traffic, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14940, https://doi.org/10.5194/egusphere-egu23-14940, 2023.

vSSS.7
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EGU23-17310
Marie Eden, Joachim Brunotte, and Marco Lorenz

Compaction is considered as one of the major threats to soil quality and health. The use of heavy farm machinery may compact the soil, reducing the pore volume and simultaneously increasing soil bulk density. In this context, a multitude of internal (soil-related) and external factors are at play and influence soil physical properties like bulk density, which is a widely used indicator of compaction.

Undisturbed soil samples were collected on a North German farm from six individual fields, all located within the same area of ~1.2 km². All fields display loess-derived soils, similar in soil type, texture and management (same farmer).  Since 1995, samples were extracted from ~20 and ~40 cm (~35 cm as of 2016) representing top- and subsoil.

For one of the fields, there are approximately 15 observations within a timeframe of roughly 20 years. For the topsoil, a trend of decreasing bulk density was observed, whereas the subsoil showed a trend for the opposite behaviour, with bulk density increasing over time. Soil compaction and thus increased bulk densities are expectable on agricultural fields managed with heavy machinery. However, for the topsoil, regular tillage accompanied by soil loosening might have caused the decrease in bulk density over time. From a soil structural and stability point of view, this might nonetheless not be beneficial.

How to cite: Eden, M., Brunotte, J., and Lorenz, M.: Evolution of soil structure at field-scale on a silt loam in Northern Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17310, https://doi.org/10.5194/egusphere-egu23-17310, 2023.