Orals: Mon, 28 Apr | Room -2.20
Subsoil compaction is a major environmental threat adversely affecting soil functions with potentially negative effects on topsoil too. In the present study, that is part of a long-term experiment called ROCSUB (restoration of compacted subsoil), we aim at better understanding how subsoil compaction and loosening can affect topsoil quality and plant development. The study takes place in a loamy field in western Switzerland and was setup in 2020 after a severe compaction event. Only the subsoil was severely compacted by a heavy pile of excavation material, while the topsoil was removed and stored gently aside during the construction process. Visible signs of compaction were detected up to 70 cm depth. The study includes 2 mechanical treatments (subsoil compaction Vs mechanical loosening) and 2 culture treatments (Salix Vs crop rotation) with 4 plots per treatment, totaling 16 plots. The Salix trees were planted in 2021 as a potential biological soil loosening technique. The crop rotation treatment included temporary grassland in 2021 and 2022, winter wheat in 2023 and maize in 2024.
Soil sampling took place in 2023 in the Salix plots and in 2024 in the cropped plots (during maize). We sampled at 5-10 cm depth and at 30-35 cm depth for bulk density, water content and air content at -60 hPa. Soil structure quality was visually evaluated with the CoreVESS method. Plant productivity was measured for the Salix trees, wheat and maize. Root biomass allocation in the root system was recorded for Salix and maize plants. Earthworm activity was recorded in the Salix treatment.
Our study found that in compacted subsoil, the topsoil structure quality was superior to that in loosened subsoil. This conclusion was drawn by the results from the Salix treatment. In the Salix treatment, subsoil compaction negatively affected aboveground biomass productivity only during the first year after planting but not in the following years. This was attributed to the ability of the Salix roots to adapt to physical constraints through changes in biomass allocation. We hypothesized that this phenomenon occurred because biological activity was concentrated in the topsoil, intensifying its effects and compensating for the inaccessibility of the compacted subsoil. This surprising finding highlights the resilience of soil systems when operating in a "natural" state. In contrast, in agricultural settings such as maize cultivation, the topsoil structure quality did not compensate for the compacted subsoil and root biomass, aboveground biomass, and grain yield were negatively impacted. Taken together, these findings suggest that the impact of subsoil compaction on topsoil structure quality is highly dependent on soil management practices: natural systems demonstrate resilience and compensatory mechanisms, while high-disturbance systems do not.
How to cite: Johannes, A., Liardet, B., Delévaux, P., Fontana, M., and Bragazza, L.: How does subsoil compaction affect topsoil structure? Insights from the ROCSUB project, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17314, https://doi.org/10.5194/egusphere-egu25-17314, 2025.
Given the contribution from the livestock sector to greenhouse gas emissions (GHGe) and soil degradation via compaction and defecations it is imperative that best grazing management approaches are identified. Compacted soil from animal treading can lead to conditions that activate denitrifying bacteria and result in heightened nitrous oxide (N2O) emissions. In addition, nitrogen input from cattle urination events amplify these emissions, however more data is required in this area. In this study we aimed to quantify soil N2O emissions in parallel with soil compaction following a simulated grazing event using three stocking densities (control, low (LSD) and high (HSD) with 0, 10 and 100 cows/ha/day respectively) on a temperate Southwest UK pasture. In addition, data was collected to assess how cattle urinations affect soil GHGe under the different stocking densities. Following the grazing event measurements were taken for 12 weeks, soil GHGe were sampled via the use of static chambers and compaction was assessed via penetration resistance. Immediately after the simulated grazing the penetration resistance was 1379 kPa (SD ±368) for the control, 1544 kPa (SD ±429) for the LSD, and 1767 kPa (SD ±490) for the HSD. Differences in penetration resistance were found between the HSD and LSD (p=0.03), and HSD and control (p=0.0001), with a tendency between the control and LSD (p=0.07). Cumulative N2O emissions were 493 g N2O - N/ha for the control +urine, 804 g N2O - N/ha for the LSD +urine and 1237 g N2O - N/ha for the HSD +urine, with differences found between the control +urine and HSD +urine (p=0.0342). The N2O emissions from the stocking densities without urine were however similar. This suggests that denitrification in soils is enhanced under high stocking densities from animal treading when there is a source of nitrogen present, such as cattle urine. The developing results are informative for improving pasture management under cattle grazing and provide data for models simulating soil mechanisms in these systems.
How to cite: Dauksta, K., Cardenas, L., Romero-Ruiz, A., Sgouridis, F., Memmott, J., and Enriquez-Hidalgo, D.: The effect of different stocking densities and cattle urine on soil nitrous oxide emissions and compaction on a temperate pasture, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20221, https://doi.org/10.5194/egusphere-egu25-20221, 2025.
Soil compaction induced by mechanical stress of heavy machinery and intensive field traffic can reduce crop yields and is one of the main threats to soil functions. Even though soil compaction is one of the most serious types of soil degradation worldwide, its detection on a large scale remains challenging. Current methods of soil compaction detection are limited to selective samplings and laboratory analyses, which are both labor-intensive.
This study examines whether field traffic effects and soil compaction can be detected non-invasively on field scale using multispectral UAV (unmanned aerial vehicle) images. The objective of the study is to establish a link between soil properties, crop yields and multispectral images in order to determine the spatial extent of soil compaction. Two fields in Northern Germany cultivated with winter wheat and winter barley served as study area during the years 2020-2022. To analyse the effects of soil compaction on soil functions and crop yields, the slurry application in spring was used as a reference event for anthropogenically induced soil compaction.
Multispectral images of the two study sites were recorded up to four times with UAV during the vegetation period. The images were used to calculate vegetation indices (e.g. GRVI, MGRVI) and the plant height. In addition, soil sampling and manual harvests were carried out in the ruts of the slurry tanker and in the non-trafficked areas. In the laboratory soil physical (e.g. dry bulk density, air capacity) and chemical (e.g. carbon content) properties were measured as well as the grain yield.
The results of the UAV analysis show linear patterns of low plant height and vegetation index values, that can be recognized over the entire extent of the study fields, particularly in spring. The linear patterns are attributed to the slurry application. As an example, the NDVI in March 2021 shows a mean value of 0.55 in the ruts of the slurry tanker, whereas the mean value in the non-trafficked field is 0.63. These findings are consistent with the laboratory analyses. The results demonstrate that the mechanical stress by the slurry tanker leads to increased dry bulk density and reduced air capacity, air conductivity and saturated hydraulic conductivity in the trafficked areas compared to the non-trafficked inner field. In addition, the grain yield in the ruts of the slurry tanker is on average about 13 % lower than in the non-trafficked field.
However, sampling time and weather conditions have a strong effect on the analysis. In 2022, for instance, weather extremes occurred with low precipitation, which lower the correlation between UAV data and soil properties and made the analysis more complex. Nevertheless, this study shows that UAV imagery is a reliable tool to detect soil compaction at a continuous spatial scale for individual fields.
How to cite: Steckel, S., Lindenstruth, F., Duttmann, R., and Kuhwald, M.: Detecting soil compaction through multispectral UAV images – A spatial analysis of traffic effects and compaction patterns in arable land, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11093, https://doi.org/10.5194/egusphere-egu25-11093, 2025.
The physical structure of peat, particularly porosity, regulates both biochemical and physical processes in drained peatlands. Porosity influences key subsidence mechanisms such as consolidation, creep, and organic matter decomposition. This study investigated how compaction alters porosity and how these structural changes affect decomposition rates in peat with two levels of degradation over the short term.
Intact peat samples were collected from a drained peat meadow in the Netherlands, representing less decomposed fibric peat (FP) from saturated depths and more degraded peat (DP) from unsaturated layers. The samples were subjected to controlled compaction under different stress levels (10 kPa and 40 kPa) in the laboratory to assess changes in porosity and decomposition through CO2 emissions and ß-D-Glucosidase potential activities (PA).
The results showed that compaction reduced porosity in both peat types with this reduction leading to a decline in CO2 emissions and ß-D-Glucosidase PA, which was more significant in fibric peat. The average CO2 emissions decreased by 33.1% and 48.1% for FP, and by 11.2% and 14.4% for DP, when subjected to compaction of 10 kPa and 40 kPa, respectively. The reduction in ß-D-Glucosidase PA with compaction averaged approximately 30%.
These findings highlight the complex interplay between mechanical and biochemical processes in drained peatlands, where changes in the physical structure of peat can directly influence subsidence dynamics. By demonstrating how mechanical stresses alter porosity and, consequently, biochemical activity, this research underscores the critical role of soil structure in driving organic matter dynamics and overall peatland function.
How to cite: Tolunay, D., van Elderen, P., Hefting, M. M., Kowalchuk, G. A., Stouthamer, E., and Erkens, G.: The Impact of Compaction on Porosity and Decomposition in Peat, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17049, https://doi.org/10.5194/egusphere-egu25-17049, 2025.
The use of heavy machinery lead to severe soil compaction, especially in the headland. In sustainable headland management, in contrast, it is necessary to manage compacted soils and promote soil health. Therefore, a new measure of “greening headlands” was studied to analyse stabilisation effects. The aim was to detect changes in soil functionality during intensive field traffic in the headlands.
The study was carried out on two study fields in Lower Saxony, Germany, to analyse changes after a four-year period of greening. On field A, part of the headland was newly planted with clover grass over a width of 18 m. At Field B, a 6 m grass-buffer from original water protection strip was used as headland. The former headland had a width of 27 m. All turning manoeuvres during the four years occurred in the (greened) headlands. Sampling was carried out in the core field, (former) headland and greened headland at the depth of 20, 35 and 50 cm. Mainly soil physical properties (e.g. dry bulk density, air capacity) and soil nutrients (e.g. phosphorus) were analysed.
After four years, the air capacity in 50 cm depth in the greened headland of field A increased compared to the core field. Despite intensive field traffic, the dry bulk density on the greened headland did not decrease significantly compared to the headland. Furthermore, the greening had a positive effect on the yield at the former headland due to edge effects of the greening.
In field B, positive effects can be observed in the former headland, with slightly decreasing dry bulk densities and significantly increasing air capacities at all depths. The greened headland is clearly influenced by field traffic, as the bulk density increased from 1.53 g/cm³ to 1.58 g/cm³ at 20 cm depth and 1.41 to 1.58 g/cm³ at 50 cm depth after four years. The air capacity decreased from 7.78 % to 6.47 % at 20 cm depth and slightly decreased in 50 cm depth. At 35 cm, the parameters show similar tendencies compared to 50 cm depth.
Overall, a stabilising effect of a dominant root network in the vegetation cover can be identified as soil functions in field A improved in the greened headland despite the intensity of field traffic. Field B was less compacted at the beginning of the study. As a result, the negative effects of field traffic are more apparent. Nevertheless, the greening mitigates the negative effects of field traffic, as the effects are relatively small compared to field A.
The yield on compacted headlands is lower compared to the other locations. The greening of headlands can be used to reduce negative soil compaction effects in the headlands and promote soil health. However, the greening reduces the area available for arable farming. Nevertheless, the new method can additionally reduce runoff and promote sediment retention and thus prevents soil erosion.
How to cite: Körbs, C., Kuhwald, M., Brunotte, J., Duttmann, R., and Lorenz, M.: Greening Headlands: A new method to reduce soil compaction and enhance soil health, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11085, https://doi.org/10.5194/egusphere-egu25-11085, 2025.
The behavior of soils under seismic loading is a critical aspect of geotechnical engineering, particularly in regions prone to strong earthquakes. Soils are subjected to complex cyclic loading conditions combining both vertical and horizontal stresses under strong seismic excitations. However, previous experimental studies seldom considered the effect of horizontal cyclic stresses on soils, especially for cohesive gravelly soils. To address this limitation, this study aims to conduct a series of large-scale cyclic triaxial tests on gravelly clay sample with various gravel contents subjected to dynamic confining pressures (represented as DCP stress path η), more closely replicating the actual conditions soils encounter during seismic events. The features of cyclic stress-strain responses, effective stress paths (p-q) and excess pore water built-ups are firstly analyzed. The test results showed the axial strains at failure are increased with the increasing of DCP stress path η. The effect of the gravel content on the dynamic characteristics of gravelly clay is furtherly discussed in detail. Moreover, a unified formula incorporating axial strains, excess pore pressure, and gravel contents was established that can provide a good reference for predicting dynamic behaviors in cyclic triaxial tests with different DCP stress paths η. The test results will help to identify potential failure mechanisms, evaluate the soil’s resilience, and inform the development of improved seismic design practices for soil-infrastructure in earthquake-prone areas.
How to cite: Chen, Q. and Du, W.: Mechanical characteristics of cohesive gravelly soils under bidirectional cyclic loading, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9729, https://doi.org/10.5194/egusphere-egu25-9729, 2025.
Soil structure plays an important role in many soil processes such as roots penetration, water retention and the development of microbial habitats. For this reason, studying soil structure is a fundamental step to better understand how these processes work.
Recently, AI-based models development has paved the way for their implementation in analysing and classifying soil features. Convolutional neural networks (CNNs) like U-Net and Mask R-CNN have shown great potential and are often used for segmenting soil pores or plant roots but, despite this, the potential of deep learning in segmenting different types of soil structures remains relatively unexplored. Currently, soil structure evaluation methods often rely on subjective interpretations and therefore subject to human error.
This study explores the potential of an AI-based method as a reliable decision support tool for soil microstructure assessment. The goal of the training was the correct segmentation of different types of soil structures (e.g. Crumb, Granular, Angular, Sub-angular, Massive).
Since some structures were underrepresented in the original dataset, data augmentation was applied to balance the dataset. Subsequently, the dataset was split into training (70%), validation (20%), and test (10%) sets. The training and validation sets were used for model training and validation. The test set, which was excluded from the training phase, was used to evaluate model performance through four accuracy metrics: Precision, Recall, Dice coefficient, and Intersection over Union (IoU).
According to the test set predictions, with a mean Dice coefficient of 0.81 and mean IoU of 0.73 across all soil structure classes, the model demonstrated strong performance in segmenting soil structures. As expected, the model achieved the best results for those structures that were better represented in the training dataset.
Our findings suggest that, although the quality and heterogeneity of the training dataset play a crucial role, AI has the potential to transform soil structure evaluation, providing more objective analyses while reducing the incidence of human bias.
How to cite: Perreca, C., Langella, G., and Terribile, F.: AI-based approaches can improve soil structure evaluation in micromorphological analyses, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13718, https://doi.org/10.5194/egusphere-egu25-13718, 2025.
Soil structure is fundamental in determining soil functionality, including water retention, nutrient availability, microbial growth processes, and gas exchange. Analysing soil structure through 3D grayscale imaging provides an innovative approach to understand its properties without resorting to binarization, a process that can oversimplify complex soil features. By systematically altering the global threshold applied to grayscale images, detailed geometrical and network-based parameters can be extracted, preserving the nuanced heterogeneity of natural (real) soils.
This study compared natural soil images with randomly generated models to calculate critical parameters. Geometrical metrics such as porosity, pore size distribution, tortuosity, formation factor, and fractal dimension were determined to characterise the structural complexity of the soil matrix. Additionally, connectivity and other network-based parameters, reflecting the porous network's topology, were analysed to reveal insights into the soil's functionality and capacity to support biological and physical processes.
Our approach highlights the importance of maintaining grayscale image fidelity to capture subtle but essential soil features, offering a more nuanced analysis than traditional binarization techniques. The findings emphasise the interplay between geometrical and network properties in defining soil structure and its ecological roles. This method holds promise for advancing soil science and sustainable land management practices.
Keywords: soil structure, 3D grayscale imaging, porosity, tortuosity, fractal dimension, porous network, connectivity.
References
- Samec, M., Santiago, A., Cárdenas, J. P., Benito, R. M., Tarquis, A. M., Mooney, S. J., & Korošak, D. (2013). "Quantifying soil complexity using network models of soil porous structure." Nonlinear Processes in Geophysics, 20(1), 41-45.
- Tarquis, A. M., Heck, R. J., & Antón, J. M. (2009). "3D Soil Images Structure Quantification using Relative Entropy." Ecological Complexity, 6(3), 230-239.
- Tarquis, A. M., Heck, R. J., Andina, D., Álvarez, A., & Antón, J. M. (2009). "Pore network complexity and thresholding of 3D soil images." Ecological Complexity, 6(3), 230-239.
- Torre, I. G., Losada, J. C., Heck, R. J., & Tarquis, A. M. (2018). "Multifractal analysis of 3D images of tillage soil." Geoderma, 311, 167-174.
- Torre, I. G., Martín-Sotoca, J. J., Losada, J. C., López, P., & Tarquis, A. M. (2020). "Scaling properties of binary and greyscale images in the context of X-ray soil tomography." Geoderma, 365, 114205.
How to cite: Paternain, M. Á., Martin Sotoca, J. J., and Tarquis, A. M.: Analysing Soil Structure Through 3D Grayscale Imaging: Geometrical and Network-Based Insights Without Binarization, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13288, https://doi.org/10.5194/egusphere-egu25-13288, 2025.
Soil structure is essential to most soil functions. An intact network of soil structural pores allows fast drainage and aeration under wet conditions and ensures water retention in small pores within aggregates under dry conditions. The measurement of shrinkage curves (the relationship between the reduction of soil volume and the loss of water) has the advantage to quantify soil structural features at all scales, ranging from macropores to the interstitial voids of clay minerals. In this study, we measured the shrinkage curves of 24 agricultural soil samples of contrasting texture (ranging from 16% to 43% clay content) and soil organic content (SOC) (ranging from 1.16% to 7.3% SOC), and compared the results with visual evaluation of soil structures (CoreVESS) and X-ray imaging. In addition to the typical ‘S-shaped’ shrinkage curves reported in literature as described in the model of Braudeau et al. (1999) (including the S-shape with an additional linear drop of soil volume in the wet range), several samples showed a ‘double S-shape’ with a well-defined bimodal function or a ‘J-shaped’ curve. Samples with a ‘double-S-shape’ had better soil structural quality as quantified by CoreVESS and were found in samples with high SOC content. These samples also had a large macropore volume according to the X-ray images. The curve in the wet range of the commonly reported ‘S-shape’ reveals the stability of the structures and aggregate arrangements that do not shrink with the onset of water loss and capillary suction and is said to characterize hydrostructural stability. However, the curve in the wet range which is typical for S-shaped curves is lost in samples with poor structure quality (high CoreVESS scores). These poorly structured samples are usually characterized by a linear domain in the wet range, followed by a gradual stabilization of the soil volume at the dry end, thus displaying what we called a ‘J-shaped’ curve. These curves denote a loss of hydrostructural stability. Based on the dataset we want to define conditions for the presence of these new forms of shrinkage curves. The different shapes (‘double-S-shape’, ’S-shape’ and ‘J-shape’) could then be used as indicators for soil functions and soil health.
How to cite: Messmer, L., Lehmann, P., Schmücker, N., and Johannes, A.: Shrinkage curve features to characterize soil structure quality of agricultural soils with contrasting texture and soil organic content, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21461, https://doi.org/10.5194/egusphere-egu25-21461, 2025.
In this presentation, the development, scope and concepts underlying a phenomenological model of soil structure dynamics embedded in a new soil-crop simulation model (USSF; Uppsala model of Soil Structure and Function) will be described. This model accounts for seasonal soil structure dynamics (e.g. tillage/consolidation, surface sealing, swell-shrink) as well as those occurring at much longer (i.e. decadal and centennial) time-scales arising from processes such as microbial-mediated soil aggregation, macro-faunal activity and root growth. The USSF model couples these descriptions of soil structure dynamics with modules for crop growth, soil hydrology and organic matter cycling at the scale of the soil profile. This means that the model can be used to evaluate the effects of soil structure dynamics driven by changes in climate or land management (e.g. soil degradation or regeneration) on the soil water balance, crop growth and stocks of soil organic matter. To finish, some initial applications of the USSF model will be presented, followed by a brief discussion of some important current limitations as well as future prospects.
How to cite: Jarvis, N.: An exploratory model of soil structure dynamics: concepts, scope and initial applications, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4708, https://doi.org/10.5194/egusphere-egu25-4708, 2025.
In agriculture, soil management practices directly affect soil structure and herewith soil hydraulic properties (SHP), namely the water retention curve (WRC) and the hydraulic conductivity curve (HCC). Although it has been hypothesized that management practices affect the wet range of both the WRC and HCC, limited experimental data exists on the topic. Currently, the full extent of these effects is not well understood and is often overlooked in soil-plant-atmosphere models. This study aims to characterize the WRC and HCC, from saturation to oven dryness, for one soil subjected to common agricultural practices for over 30 years.
During one growing season, 160 undisturbed soil cores were collected at three different times (mid- season, post-harvest, and after seedbed preparation) from the topsoil (5–10 cm depth) and subsoil (30–35 cm depth) in a long-term field experiment. This experiment included plots managed with conventional plowing, two types of mulching, and direct seeding, all with the same loamy soil texture and crop rotation. To quantify SHP, four laboratory methods were employed for the same soil core: the Falling Head method for saturated hydraulic conductivity (Ksat), the Multistep Flux method for estimating near-saturation conductivity to capture the structural effect on the HCC, the evaporation method for the wet and mid-range of WRC and HCC (pf < 3), and the dewpoint method for the dry part of the WRC.
The results show that 30 years soil management practices directly affect the SHPs of the topsoil and not of the subsoil, with the highest changes at the wet range (pF < 1) of the WRC. Conventional plowing resulted in 8% higher water content at pF<1 compared to direct seeding, while both mulching treatments were closer to the direct seeding. In the dry range of the WRC, no differences were observed between the management practices, supporting the assumption that this range is controlled by soil texture. For the HCC, we measured on average a 35% higher ksat for conventional plowing compared to cores taken under direct seeding. It is noted that ksat measurements of all treatments showed high variability. For the near saturation conductivity, we observed a highly bimodal behavior for all treatments. We conclude that the structural effect of agriculture managements operations controls the wet range of both the WRC and HCC and soil texture controls the dry range. Seasonal dynamics were observed in all topsoil treatments and current results indicate that the wet part of the SHP varies during a single season, with the most changes occurring between post-harvest and seedbed preparation. Overall, this study presents experimental evidence on the effect of soil structure on SHP and its potential effect on soil water dynamics.
How to cite: Nielsen, M., Leuther, F., Ebertseder, F., and Diamantopoulos, E.: Do agriculture management operations and their seasonal dynamics affect soil hydraulic properties? , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-479, https://doi.org/10.5194/egusphere-egu25-479, 2025.
In order to study the process of structural changes in remolded loess caused by water infiltration, the structural change characteristics and effects of the remolded loess before and after water infiltration are studied using mechanical, CT and simulation tests. The results show that: (1) The peak frequency of the equivalent diameter of the remolded loess particles after infiltration is between 10μm~30μm, and the sphericity value of remolded loess particles after infiltration becomes significantly smaller, which is concentrated in the interval greater than 0.8 before infiltration and extends to the interval range of 0.6-1. (2) After saturation and infiltration, the total porosity and pore connectivity of the remolded loess increased significantly, and the three-dimensional total porosity of the loess increased by 27.51% after infiltration, and the water infiltration only caused the obvious expansion of the macropores, and the rapid development of the macropores led to the increase of the pore area ratio to 17.9%. It shows that macropores are the main reason for the development of pore structure and the deterioration of soil structure. (3) After the infiltration test, the porosity of the remolded loess with a specific surface area of less than 0.15 increased to 71.23%, indicating that the sample developed from a compact state to a loose and softened state. The decrease of the pore-throat ratio and the increase of the coordination number of the remolded loess after infiltration indicate that the water forms a large-scale channel with good fluidity in the sample, and the scale of the complex pore structure in the soil decreases, thereby increasing the dominant seepage channel of the loess. (4) The migration of fine particles and structural damage caused by water entering the loess are the reasons for its collapsibility, and at the same time, the strength of the reshaped loess will be reduced after water infiltration. The results of this study provide a reference for revealing the damage mechanism and process of water.
How to cite: Zhu, Y.: The structural evolution of remolded loess due to water infiltration, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2640, https://doi.org/10.5194/egusphere-egu25-2640, 2025.
This study investigates sustainable soil management strategies for Fluvisol in northwestCroatia, a fertile but degradation-prone soil, by examining how different tillage practices and straw mulch management affect soil health and crop productivity. On the Šašinovec experimental farm (University of Zagreb Faculty of Agriculture), three tillage practices (conventional tillage, minimum tillage, and reduced tillage) with and without straw mulch are compared on the soil physical properties, soil organic matter and crop yields over three growing seasons. The experimental field was set up in a split-plot design with three replicates for each tillage system. Each block (100 m x 10 m) represents a different tillage system, with or without mulch (straw) as a sub-factor (50 m x 10 m). Conventional tillage (CT) is involves plowing (18-20 cm) in autumn and disc harrowing in spring, while minimum tillage (MT) with multitiller (10-15 cm) in spring and reduced tillage (RT) with subsoiling (35-40 cm) in autumn and multitiller in spring were selected for their potential to minimize soil disturbance, while preserving soil structure and fertility. The mulch used in this study was wheat straw (2.75 t/ha), which is known to better retain moisture, prevent erosion and increase organic matter content. Samples were collected immediately after sowing and after harvest at two depths in three replicates for each plot. The study found that RT with mulch consistently reduced bulk density, lowering soil compaction and improved conditions for root development. This treatment significantly improved water retention, an essential factor for plant health, especially under changing climatic conditions. While the MT and CT treatments had limited effect on reducing the soil bulk density, both MT and RT with mulch increased water holding capacity and soil moisture, which is critical for maintaining crops under drought or erratic rainfall patterns. Another focus was on soil structure, particularly the stability of aggregates, which help resist erosion and retain nutrients. MT with mulch (71.41 %) had a positive effect on aggregate stability, more so than the CT (65.61 %) and RT (61.61 %) treatments. In addition, RT and MT with mulch (4.64% and 4.91%, respectively) had supported higher organic matter content than CT (3.86%), indicating better soil fertility and resilience over time. In terms of yield, the MT and RT treatments with mulch achieved higher soybean (+21 %; +15 % and spring wheat (+55 %; +18 %) yields compared to bare plots with same tillage. This indicates that reduced tillage in combination with mulching can not only maintain but possibly even increase productivity in Fluvisols. Throughout the trial, mulching consistently improved soil moisture and organic matter, highlighting its role in supporting long-term soil health. These results suggest that reduced and minimum tillage in combination with straw mulch, is a sustainable alternative to conventional plowing. The continuous use of mulch and non-inverting tillage practices helps to reduce soil degradation and improve resilience, particularly in soils that are susceptible to degradation, such as Fluvisols. Furthermore, these practices are wellsuited to mitigate the challenges of fluctuating climatic conditions and ensure stable crop yields.
How to cite: Brezinščak, L. and Bogunovic, I.: Straw management and alternative tillage methods for minimizing soil degradation of Fluvisol, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-230, https://doi.org/10.5194/egusphere-egu25-230, 2025.
The soil hydraulic conductivity function describes the soil’s ability to transmit water and in land surface models (LSMs) this function is often estimated from soil texture and soil organic carbon (SOC) content. In addition, soil hydraulic conductivity in the wet range (Ksat and K@h=-2cm) is strongly influenced by soil structure, whereby structural information is currently not used to estimate the soil’s hydraulic conductivity. Neglect of soil structure can therefore lead to false estimations of soil hydrological fluxes and soil water storage. In order to quantify the impact of soil structure on the soil’s hydraulic conductivity, we conducted infiltration measurements and analysed aggregate size distribution as an indicator of soil structure in croplands along a climate and organic carbon gradient across Europe. We found that soil aggregation was controlled by a combination of the log transformed SOC and clay content, as well as by the log transformed soil moisture. When information on the mean weighted diameter (MWD) of the sand-free aggregates and the mass distribution between aggregate size fractions was included in linear models that predicted Ksat or K@h=-2cm, the predictions had a 13.3 % lower RMSE and could explain up to 67 % of variation in the Ksat data. When the information was not included, the models could only explain 56 % of the variation in the Ksat data, in general predictions were better for Ksat than K@h=-2cm. For K@h=-2cm, the mass distribution between sand-free aggregate size was more important than the MWD of the aggregates, which was not the case for Ksat. For Ksat, the most important predictors were the interaction of the MWD of the aggregates with the carbon and clay content, the interaction of the carbon and clay content and the soil moisture and soil temperature at the time of field measurement. The significant contribution of indicators of soil structure in these models confirm that soils with larger aggregate MWD, indicating a more developed soil structure, have higher Ksat. Therefore, soil aggregation should be taken into account, either by including the MWD of soil aggregates as a variable or developing proxies, in order to estimate water partitioning in soils to ultimately incorporate into LSMs.
How to cite: Burger, D., Amelung, W., Heidtmann, P., Geske, M., Schimmel, H., Weihermüller, L., Vereecken, H., and Bauke, S.: Connecting (near) saturated hydraulic conductivity to soil aggregation and carbon content on croplands across Europe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11018, https://doi.org/10.5194/egusphere-egu25-11018, 2025.
Soil pore structure influences hydraulic conductivity and saturation regimes. The influence of soil structure, and mechanisms of overland flow on the form of phosphorus (P) loss is not fully understood. Models of P transport assume either saturation excess (SE) or infiltration excess (IE) overland flow as the triggering mechanism. SE runoff may lead to higher dissolved P losses, due to a) lower applied energy hence less physical separation of particulates, and/or b) greater mobilization of P from sorbed reserves during antecedent saturation. Conversely, IE runoff may lead to greater particulate P loss due to increased physical separation. Structure, and contingent runoff mechanisms, is therefore likely to impact not only gross P losses, but also forms of P delivered to surface water. The influence of soil structure, and type of overland flow (SE or IE) on forms of P loss from grasslands is being examined through a runoff trial. Soil was collected, air dried, and sieved. Subsequently, soil was packed into boxes at two different bulk densities, to reflect good and poor soil structures. Perennial ryegrass was sown and rooting was allowed to establish over a 6 month period to encourage structural development. After the priming period, the runoff boxes will be saturated to two different levels. A simulated rainfall event will be imposed, and runoff water will be collected. The resulting dissolved and particulate P concentrations will be measured. Soil pore structure will be assessed at the conclusion of the trial in 2025. Intact soil cores will be extracted from each box and soil water retention curves will be measured.
How to cite: Roche, P., Cleary, J., Harty, M., Browett, S., and Vero, S.: How do runoff mechanisms influence the form of phosporus lost from grassland soils?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8833, https://doi.org/10.5194/egusphere-egu25-8833, 2025.
Soil structure determines crucial soil physical processes, such as water distribution, gas flow, and cycling of carbon and nutrients. This way, it builds and constrains biological habitats. The resulting environmental conditions at the micro- or mesoscale builds and constrains habitats for plants, soil fauna, and microorganisms. However, the direct impact of soil structure on these biological actors remains poorly understood. So far, research primarily focused on mechanisms at the aggregate or pore scale. Although process knowledge on this scale is still needed, it is also essential to understand the implications of such interactions for soil functions at the field scale.
Within this study, we tested different concepts of microbe-structure interactions using the systemic soil model BODIUM (König et al., 2023; bonares.de/bodium), and analysed the consequences for carbon dynamics at the field scale.
Our model integrates a dynamic soil structure with distinct pore size classes and explicit representation of microorganisms, recently extended to distinguish between bacteria and fungi. This framework allows us to explore microbe-structure interactions, by adjusting fungi and bacteria mobility, growth strategies as well as microbe and carbon distributions within the pore size classes. The evaluation of the soil structure is supported by the Soil Structure Library (Weller et al., 2022; https://structurelib.ufz.de/lit/), which provides a collection of analysed soil CT images with pore size distributions down to 10 µm. For some of the images additional information was obtained on the distribution of particulate organic matter and its correlation with the pore system. This allows further process analysis on aerobic and anaerobic matter turnover.
We performed simulations spanning temporal and spatial scales relevant to agriculture, and analysed the implications for soil total soil carbon and C to N ratio, the proportions of fungi and bacteria, as well as emission rates. Additionally, we simulated scenarios involving tillage and bioturbation, which alter soil structure, to account for soil structure dynamics and resulting spatial distribution of organic matter.
Our simulation results suggest that soil structure indeed exerts a significant influence on field-scale soil functions, but rather by shaping environmental conditions for microbes and not due to direct interactions. However, the extent of this influence critically depends on our assumptions for the mobility and growth behaviour of microorganisms. This dependency also suggests that in our scenarios soil structure is not a limiting factor, and we should extend our simulations to more extreme scenarios such as a high compaction.
Consequently, further modelling and experimental research is needed to unravel the underlying mechanisms and develop robust upscaling approaches.
König, S., Weller, U., Betancur-Corredor, B., Lang, B., Reitz, T., Wiesmeier, M., Wollschläger, U., Vogel, H.-J. (2023): BODIUM - a systemic approach to model the dynamics of soil functions. Eur. J. Soil Sci. 74 (5), e13411, 10.1111/ejss.13411
Weller, U., Albrecht, L., Schlüter, S., Vogel, H.-J. (2022): An open Soil Structure Library based on X-ray CT data. Soil 8 (2), 507 – 515, 10.5194/soil-8-507-2022
How to cite: König, S., Weller, U., Ansorge, J., Reitz, T., Schlüter, S., Wollschläger, U., and Vogel, H.-J.: Does structure really matter? Exploring implications of microbe-structure interactions to carbon dynamics at the field scale, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11398, https://doi.org/10.5194/egusphere-egu25-11398, 2025.
Compaction may affect soil functions for decades. To minimize soil compaction, ground-based timber harvesting in Central European hardwood forests was traditionally practiced in the dormant season on frozen soils. However, due to rising winter temperatures, timber is now often harvested on wet, non-frozen soil, increasing the susceptibility to compaction. In a controlled experiment on clayey soils (60 % clay, 38 % silt) in the Vienna woods, we assessed the effects of ground-based timber harvesting on soil functions and their recovery. We compared skid trails established and trafficked 1 versus 18 years ago at the same site. Earthworm data was collected in the tracks and at adjacent undisturbed plots (paired sampling design) using mustard extraction and hand-sorting. To evaluate soil structure with X-ray imaging, we sampled undisturbed soil cores at 5 and 15 cm depths in a similar design as the earthworms. We identified five earthworm species: Aporrectodea rosea, Dendrobaena platyura, Dendrodrilus rubidus, Lumbricus rubellus, and Octolasion lacteum. Earthworm abundance was highest on trails trafficked 18 years ago, indicating earthworm population recovery, particularly among endogeic and juvenile anecic individuals, while adult anecic earthworm abundance did not fully recover. X-ray data showed that image-resolved porosity was significantly reduced directly after trafficking (from 14.4 ± 5.0 % at untrafficked positions (U) to 3.5 ± 1.6 % at 5 cm depth in the tracks (T) and from 13.5 ± 4.9 % to 2.0 ± 1.1 % at 15 cm depth) and recovered at 5 cm within 18 years (12.0 ± 3.4 % (U) to 12.2 ± 4.3 % (T)), but only partially at 15 cm (14.2 ± 2.6 % (U) versus 7.1 ± 2.5 % (T)). Other imaging-based parameters, such as bio-pores, pore anisotropy, connectivity measures (Euler number and gamma), and percolating porosity, reflected similar patterns. Bulk density increased significantly directly after timber harvesting (from 1.0 ± 0.1 g/cm³ (U) to 1.3 ± 0.1 g/cm³ (T) at 5 cm and from 1.1 ± 0.1 g/cm³ (U) to 1.4 ± 0.1 g/cm³ (T) at 15 cm) and showed partial recovery after 18 years (1.0 ± 0.1 g/cm³ (U) versus 1.1 ± 0.2 g/cm³ (T) at 5 cm and from 1.0 ± 0.1 g/cm³ (U) to 1.3 ± 0.1 g/cm³ (T) at 15 cm). However, the anisotropy of stones did not recover. Pressure and shearing forces obviously arranged the platy stones in the trails horizontally, which might be irreversible. Our data demonstrate that earthworms can recolonize heavily compacted forest soils. The recovery of soil structure follows a depth gradient and is only partial at 15 cm depth 18 years after trafficking.
How to cite: Behringer, M., Koestel, J., Muys, B., and Katzensteiner, K.: A long road to recovery: Soil structure and earthworms show partial recovery in skid trails of a clayey temperate forest soil after 18 years., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4441, https://doi.org/10.5194/egusphere-egu25-4441, 2025.
Soil compaction caused by logging activities poses a significant challenge to root systems, their symbiotic interactions with mycorrhizal fungi, and their respective growth through altered biotic and abiotic soil factors. These impacts are closely tied to biogeochemical cycles and carbon sequestration, highlighting the importance of sustainable forestry strategies. Undisturbed forest ecosystems play a key role in enhancing climate resilience and supporting carbon storage, yet knowledge gaps remain in understanding the interplay between soil properties, root growth, and mycorrhizal associations under different harvesting conditions.
In this study, we investigated the effects of soil compaction on root and mycorrhizal dynamics and their implications for carbon cycling and ecosystem function. We implemented different harvesting methods (harvester-forwarder with/without tracks and cable-yarding with motor-manual felling) in a beech-dominated forest in Lower Austria during the winter of 2022/23. Using a transect approach, we assessed spatially explicit impacts on root and mycorrhizal dynamics by installing ingrowth cores and ingrowth bags. Transects were strategically placed across tracks, covering areas directly impacted by logging activities (tracks, cable-yarding corridors) and indirectly affected areas (between wheel tracks, marginal zones). Comprehensive assessments included root biomass, mycorrhizal hyphae distribution, anatomy, and morphology, alongside analyses of logging effects on mycorrhizal morphotypes and root-tip mycorrhization rates.
Preliminary data reveal significant influences of timber harvesting on root and mycorrhizal dynamics, with altered root growth patterns and notable differences between treatments and within transects. Harvesting methods resulted in widely varying degrees of soil compaction, leading to contrasting impacts on fine root characteristics, such as morphology and biomass. These changes, in turn, affect carbon sequestration potential and nutrient cycling processes, emphasizing the critical role of soil health in ecosystem resilience.
The persistent impacts of soil compaction on root and mycorrhizal development underscore the urgent need for sustainable forest management practices that mitigate adverse effects. By preserving soil integrity, such strategies enhance the long-term viability of root and mycorrhizal systems, supporting carbon storage and the broader biogeochemical functions essential for forest ecosystems to meet climate challenges.
How to cite: Gasser, L., Godbold, D., Katzensteiner, K., Sandén, H., and Rewald, B.: Harvesting methods shape root and mycorrhizal growth in forest ecosystems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17595, https://doi.org/10.5194/egusphere-egu25-17595, 2025.
Posters on site: Mon, 28 Apr, 10:45–12:30 | Hall X3
Climate change affects the agriculture in manifold ways. One important point is the change of the weather conditions, which results in variation of precipitation and temperature. Both, precipitation and temperature changes, will affect plant and root growth as well as the available water content in the soil. In addition to many other soil and plant processes, soil moisture has a major influence on soil strength. A change in soil moisture due to climate change will therefore have an impact on the trafficability of soils and the risk of soil compaction. However, it is currently not known to what extent and in what direction the trafficability and soil compaction risk may change as a result of climate change.
In this study, we used a modelling approach to analyse the behaviour of soil compaction risk in times of climate change. First, we collected soil, crop and weather data from 12 different pedo-climatic zones in Europe. Using a new version of the SaSCiA model (Spatially explicit Soil Compaction risk Assessment), we calculated the wheel load carrying capacity (WLCC) for the last two decades. To model the effects of climate change, we selected 10 different climatic models and 2 SSP-scenarios (SSP1-2.6 and SSP5-8.5). For each pedo-climatic zone, we calculated the WLCC for each climate model and each SSP-scenario from present to 2100 on a daily basis.
The results show that climate change will increase the WLCC and thus potentially reduce the soil compaction risk. In the short-term (2020-2050), a slight increase of maximum 5.1% of WLCC occurred on average across all study sites when comparing SSP5-8.5 (worst-case scenario) with SSP1-2.6 (best-case scenario). In the long-term (2051-2100), the WLCC increased by 17.8%. The largest increases in WLCC occurred from May to the end of October. From January to April, only minor changes were recorded. At this time, soils are often at field capacity which is likely to be reached in the future. The soil compactions risk therefore remains high during this period, which has an impact on slurry spreading, for instance.
In addition to the average long-term effects, the variation in the WLCC between years is significantly high. There is an irregular alternation of dry and wet years within certain periods. The effects of these dry or wet years exceed the long-term changes in WLCC caused by climate change. This is an important point, as the compaction of the subsoil lasts for a long time.
How to cite: Kuhwald, M. and Lamande, M.: Modelling soil compaction risk under climate change: an analysis of wheel load carrying capacity for different pedoclimatic zones in Europe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13134, https://doi.org/10.5194/egusphere-egu25-13134, 2025.
Soil compaction poses significant challenges to agricultural productivity worldwide, with Sweden being particularly vulnerable due to its heavy machinery usage and moist soil conditions. Negative effects of compaction may persist for decades, especially in case of subsoil compaction. This risk is anticipated to escalate as agricultural machinery continues to grow heavier. The temporal variability in soil compaction risk, influenced by seasonal changes in weather, crops, and machinery, is often overlooked but is crucial for optimizing crop rotations and machinery use to reduce the negative impacts of field traffic. This study aims to evaluate the seasonal variability of subsoil compaction risks in major cropping areas of Sweden. We integrated data from in situ soil moisture monitoring from selected representative fields with precompression stress data to examine the seasonal dynamics of soil strength throughout a growing season. By combining variations in soil strength and estimated soil stress for different machinery, we conducted a seasonal evaluation of subsoil compaction risk. We evaluated which field operation pose the highest risk of subsoil compaction and examined how this varies across different regions in Sweden. We examine compaction risks during tillage and show that conventional in-furrow ploughing is an overlooked risk of subsoil compaction. By using historical machinery data, we show how “windows of opportunity” (i.e., periods with low compaction risks) have become smaller and how the critical field operation causing subsoil compaction has shifted over time. The findings underscore the growing challenge of subsoil compaction and highlight the need for developing targeted management strategies to mitigate its impacts.
How to cite: Chagas Torres, L. and Keller, T.: Temporal dynamics of subsoil compaction risks in Sweden under a seasonal perspective, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9915, https://doi.org/10.5194/egusphere-egu25-9915, 2025.
The intensification of agriculture has increased production but has also had negative effects on the soil. One negative effect of intensified management is soil compaction caused by heavy agricultural machinery. The depth to which problematic compaction occurs depends on the load, the bearing capacity of the soil and the prevailing soil conditions. The most persistent problem is subsoil compaction, as natural or mechanical loosening in great soil depths is ineffective or difficult. A key strategy to prevent subsoil compaction is to increase the carrying capacity of the soil through appropriate management. We investigated whether two common conservation agriculture systems, reduced shallow tillage and no-tillage, can protect the subsoil from compaction compared to conventional tillage management with similar loads applied through agricultural machinery. We assessed the effects on soil structure in the soil profile down to 50 cm depth at two sites in Austria (temperate continental climate) in terms of compaction and structural, hydraulic and biological parameters. Both conservation management systems led to better structural stability at the soil cultivation horizon than in conventionally managed soils. Based on measurements taken at three depths down to 30 cm soil depth, we measured higher aggregate stability of 142 % (reduced shallow tillage) and 135 % (no-tillage) for conservation tillage than for conventional tillage. In undisturbed soil layers, the dependence of structural stability on humus content was observed. However, this stability decreased when the soil was mechanically disturbed, regardless of the remaining humus content. Under the soil cultivation horizon, differences in structural and biological parameters were negligible. For hydraulic parameters, there was a slight trend towards higher water storage capacity (+ 1-2 %) and hydraulic conductivity. This is attributed to the lower subsoil compaction achieved by both conservation systems. At a soil depth of 45-50 cm, we measured a 6% (reduced shallow tillage) or 9% (no-tillage) lower bulk density with conservation tillage than with conventional tillage. As the positive effects of no-tillage on soil structure are more limited to the soil surface, and the reduced shallow tillage has a more uniform effect on deeper soil layers, we recommend reduced shallow tillage in similar pedoclimatic regions where there is a risk of subsoil compaction.
How to cite: Liebhard, G., Toth, M., Stumpp, C., Strohmeier, S., and Strauss, P.: Protecting the subsoil from compaction through conservation management., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3103, https://doi.org/10.5194/egusphere-egu25-3103, 2025.
Subsoil compaction is a serious threat to the fertility of our agricultural lands. In severe cases it impedes aeration of and water infiltration into the subsoil, increasing risks of water-logging and overland run-off with erosion. It also may prevent roots from growing to larger depths, being unable to exploit subsoil water resources in the case of droughts. In this study we investigated soil structural properties in the aftermath of a heavy compaction event caused by storage of excavated soil in an approximately 10 m tall heap over several years. In addition, we evaluated a mechanical loosening method to ameliorate the soil physical properties. We contrasted soil physical properties of undisturbed soil samples (100 cm3 volume, sampled approximately 9 months after the subsoil loosening) as well as X-ray image-data of compacted, mechanically loosened and pristine subsoil down to approximately 80 cm below the soil surface. We found that the soil loosening improved penetration resistances, porosities and soil aeration properties, especially in the deepest investigated soil layer at 60 cm depth. At this depth, the loosened soil had similar or even better properties than the pristine soil. The compacted soil was almost completely devoid of X-ray imaged macropores. In contrast, the loosened soil featured similar imaged porosities as the pristine soil, but was lacking biopore networks, which resulted in a less well-connected imaged pore system and decreased soil aeration under wet conditions. Note that classical pore-network connectivity measures like the Gamma connectivity or the Euler number turned out to be unsuited as indicators of degraded pore networks. Instead, we encourage to use approaches from percolation theory to quantify loss of macropore connectivity in compacted soil, for example the critical pore diameter or the fraction of percolating soil samples per treatment. Our results quantify the beneficial effects of mechanical soil loosening of severely compacted subsoil to soil macropore-networks and associated soil functions. However, our results also confirm that natural and ameliorated soil structures are clearly dissimilar. Time is required until the loosened subsoil has consolidated and re-developed a biopore network, while the loosening is expected to shorten the time for subsoil recovery considerably. We are currently monitoring this process and will present the respective findings on the subsoil recovery rate in a future study.
How to cite: Widmer, A., Johannes, A., Fontana, M., Sommer, M., Elfouki, S., Bragazza, L., and Koestel, J.: Short-term impact of mechanical loosening on physical soil properties in a severely compacted subsoil, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15120, https://doi.org/10.5194/egusphere-egu25-15120, 2025.
Soil compaction is seen as a major challenge in modern agriculture. It could result in a decrease in soil qualities such as permeability of water and air, infiltration capacity, water storage, oxygen supply and rootability. Especially subsoil compaction is problematic because of its more permanent nature. Several techniques have been developed to recover compacted subsoils, with bio-subsoiling as one that is promising due to its alleviation potential and limited drawbacks. This study addresses the knowledge gap about the efficacy of different crops as bio-subsoilers and how these effects can be quantified. A literature-review has been performed on 57 different experiments performed in 20 studies. 19 different bio-subsoilers were investigated with the main focus on radish, alfalfa and chicory. Experiments ranged from a few months till several years and were mainly performed on sandy and silty loam either in controlled pot (soil column) experiments or in the field.
In general, compaction has several effects on roots such as decrease in root length and number, increase in root diameter, shallower root systems which are concentrated above compacted zones (increase in root growth outside of compaction) and decrease in root hair length. Plants can, however, adapt in several ways to increase the probability of penetrating dense zones.
In almost none of the studies the bio-subsoiler was able to significantly improve bulk density or total porosity in the subsoil even after many years of crop growth. There can be several reasons why these indicators do not significantly change with bio-subsoiling. The root systems of the crops that are grown and their created channels can be too small to change the bulk density of the soil. Or, the variability of these indicators can be so large that the effects of the small roots seem negligible. It can also be that after a short period of time the roots that would have improved the subsoil characteristics, are currently not decomposed and therefore the results do not show the improvements that are made.
Although differences in large scale indicators are not seen across the studies, several studies have shown that some of the potential bio-subsoilers are able to significantly affect other soil structural or functional indicators in the subsoil like macro- and microporosity. These indicators seem to be more sensitive to changes compared to bulk density and total porosity and therefore might be more useful to assess the effects of different bio-subsoilers.
How to cite: van Schaik, L., Bakema, G., and van Boxtel, Q.: Effects of bio-subsoiling species on the recovery of compacted subsoils: a literature review, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21631, https://doi.org/10.5194/egusphere-egu25-21631, 2025.
Water-induced loess geo-disasters are closely related to the loess microstructure evolution after water injection. To study the infiltration process and microstructural changes of intact loess, we conducted water injection seepage tests of the Malan loess in the Loess Plateau of China. We used magnetic resonance T2 spectra and magnetic resonance imaging to monitor the water absorption rate, pore size distribution, and the shape of wetting front of loess samples with different seepage rates. Water preferentially entered large and medium pores; subsequently, influenced by adsorption, water diffused and accumulated into micro- and small pores. Continuous seepage resulted in skeletal collapse of the loess, including an increase in minimum pore size, enhancement of pore connectivity, and closure of large pores. Particle size analysis and scanning electron microscope images of loess samples after seepage indicated that fine particles gradually migrated downwards along the direction of seepage, eventually accumulating between, and blocking, large pores. As the clay fraction increased by 4.29% and 7.85%, the shear strength decreased by 22.3% and 59.6% respectively. In addition， the pore water pressure increased by 66.7% and 300%, respectively. The softening of loess strength caused by accumulation of fine particles and the water-resisting effect caused by clogged pores reduced the stability of loess slopes.
How to cite: Leng, Y., Peng, J., Zhuang, J., and He, M.: Nuclear magnetic resonance analysis of loess microstructure evolution and internal erosion driven by water seepage, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4652, https://doi.org/10.5194/egusphere-egu25-4652, 2025.
Understanding the temporal evolution of soil hydraulic properties is critical for improving agricultural sustainability and adapting to climate change. These properties drive water and solute movement, but most studies and models overlook their temporal variability, leading to poor decision-making. Furthermore, many studies focus on specific practices or surface soil layers, neglecting deeper horizons. To address these gaps, a long-term database has been established as part of the Agriculture Is Life for Water Quality project to monitor soil water dynamics, soil structure, and agrochemical leaching under innovative agricultural systems designed for sustainable production.
This database is part of the EcoFoodSystem project, a 16-year initiative comparing four contrasting systems with long-term 8-year rotations. These systems align with EAT-Lancet recommendations and were implemented in November 2020 to assess their compatibility or competition in terms of food security, agronomic, and environmental objectives:
- A reference rotation integrating livestock through flows of by-products and manure, with two variants: herbicide-only and no pesticides.
- An integrated crop-livestock rotation with intercrops and temporary pastures for ruminants as functional tools for pest and weed control, managed without pesticides.
- A vegan rotation, simulating agriculture without livestock and manure, to reflect a "zero flow" scenario.
These systems are implemented on eight loamy plots in the first and fifth years of rotation at the Faculty of Gembloux Agro-Bio Tech (ULiège, Belgium). The set-up includes 24 Teros 12 soil moisture sensors and 24 Teros 21 soil potential sensors at 30, 60, and 90 cm depth, connected to ZL6 data loggers for real-time monitoring. Soil solution sampling plates at 120 cm collect data on agrochemicals leaching. Intact soil cores are taken every three months to track bulk density and porosity, enabling the quantification of alternative practices' impacts on soil structure and nitrate, pesticides and metabolites leaching.
After four years (2021-2024), results highlight significant variations in soil water retention influenced by crop diversity, weed control, residue management and contrasting climatic conditions, such as the 2021 floods or the 2022 drought. Different drying dynamics and resilience to climatic extremes were observed under some practices, demonstrating their potential to enhance water retention (Pirlot et al., 2024). Nitrate leaching showed seasonal patterns, with higher concentrations following fertilisation and residue incorporation, particularly in rapeseed plots. While parent pesticides were rarely detected at 1.2 m depth in the reference rotation, metabolites of previously applied pesticides persisted and gradually declined.
This database provides valuable insights into the temporal dynamics of soil hydraulic properties, soil structure and agrochemical leaching under contrasting systems. By monitoring them at multiple depths and over time, the database supports the development of sustainable practices to optimise soil water retention and manage nitrate pollution. These data can also refine models to improve their predictive accuracy. This resource is a critical tool for assessing the transition to sustainable agriculture, addressing challenges such as climate resilience, food security and environmental protection. The poster will present the database and how it can be accessed by the scientific community.
How to cite: Pirlot, C., De Clerck, C., and Degré, A.: A comprehensive database for evaluating the impact of contrasting agricultural systems on soil water dynamics and agrochemical leaching, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3518, https://doi.org/10.5194/egusphere-egu25-3518, 2025.
Soil conditioning aims at improving the physical, chemical and biological properties of soils and thereby serves as one measure to enhance crop productivity and to reduce water quality impacts of arable fields. In this study, we consider the effects of three soil amendments (gypsum, structure lime, and pulp and paper mill sludges) on soil structure development. The positive impacts of these amendments on erosion reduction have been observed in previous studies but detection of their effects on soil pore structure has turned out to be challenging. Here we studied the structural development of packed and sieved soil samples imitating topsoil after seedbed preparation using a ‘semifield’ approach. Arable topsoil (clay and OC contents were 38% and 2.4%, respectively) was mixed with the soil amendment, packed to perforated PVC cylinders (diameter 46 mm and height 70 mm) and buried in a field plot. The samples were removed from the field at certain times to quantify their structure with X-ray tomography and re-buried after the X-ray scanning. Our results show differences in the structure evolution during the first growing season for the considered treatments. The inorganic amendments (gypsum and structure lime) did not differ from the unamended control whereas fibre sludge had a clear impact on the structure evolution. Fibre amendment increased the porosity in the largest macropores (pore diameter > 1.2 mm) whereas the effects were opposite in smaller pore size classes (pore diameter < 0.6 mm). Our results indicate that soil amendments can influence the soil structure dynamics and thus soil functioning, but the effect depends on the amendment used.
How to cite: Hyväluoma, J., Miettinen, A., Soinne, H., Kinnunen, S., Harjupatana, T., and Keskinen, R.: Structure evolution in arable soil after gypsum, structure lime and fibre sludge amendment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15037, https://doi.org/10.5194/egusphere-egu25-15037, 2025.
Reducing tree defects after transplanting is essential for sustainable urban greening. As urban areas face increasing challenges from droughts and flooding, optimizing soil water conditions to support the successful establishment of newly planted trees has become increasingly important. While biochar is widely recognized as an effective strategy for enhancing soil water conditions, its long-term effects on soil pore structure, aggregate modification, and their fundamental impact on defect rate and mortality in transplanted trees remain poorly explored. To address this knowledge gap, we hypothesized that applying biochar to the subsoil with newly planted trees would decrease tree defect rate and mortality by improving the micro-aggregate formation and pore size distribution. To investigate how biochar decreases plant defect rate and mortality, we conducted a four-year field experiment by planting 30 six-year-old trees of representative urban roadside species each for the control and biochar treatment, respectively. For biochar treatment, the wood chip biochar of 4% by soil mass was applied at two subsoil depths (15–25 cm and 30–45 cm). Soil samples were collected by depth (0–15, 15–30, 30–60 cm) to analyze soil aggregates, pore distribution, and root biomass. Especially, additional soil samples for synchrotron-based X-ray computed microtomography (μCT) analysis were taken from a section (25–30 cm) between the two biochar layers. The volumetric soil water contents (SWC) by depth, tree defect rates, and mortality were continuously monitored.
Our results showed that biochar treatment halved both the tree defect rate in the first growing season and the final tree mortality after four years compared to the control. As plants require abundant water for initial establishment, the initial tree defect rate in the biochar treatment could be lower due to biochar maintaining SWC within an adequate range, particularly during the dry season (March to May). This is supported by a larger plant-available water (PAW) range in the biochar treatment, driven by an increased proportion of micro-aggregates (53–250 µm) and the corresponding rise in micro-pore volume (0.2–9.1 µm). We expect that μCT images will support our findings. The long-term tree mortality is likely influenced by the resilience and rehabilitation ability to extreme climate events. As our field site was affected by the monsoon climate zone, it experienced periodic extreme flooding during observation. The days when SWC exceeded field capacity were 5.6 times higher in the control than in the biochar treatment. This is reflected in the marginally higher dry biomass observed in both coarse roots (>2 mm) and fine roots (<2 mm) in the biochar treatment compared to the control. This indicates the biochar treatment could enhance root resilience, alleviating flood-induced water stress. Further analysis of nutrients, including inorganic nitrogen and phosphorus, will help determine whether nutrient dynamics also contributed to improved tree survival and root development. Our results provided the evidence that subsoil biochar application improves early tree establishment and resilience to extreme climate events, thereby enhancing the long-term survival rate for newly planted trees.
How to cite: Seo, I., Jeong, M., Park, Y. L., and Yoo, G.: Biochar application can decrease urban trees’ defect rate and mortality after transplanting by optimizing soil water condition, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19162, https://doi.org/10.5194/egusphere-egu25-19162, 2025.
Posters virtual: Tue, 29 Apr, 14:00–15:45 | vPoster spot 3
EGU25-20672 | ECS | Posters virtual | VPS14
Enhancing Sustainability in Concrete: Evaluating the Effects of Rubber Particle Replacement on Workability and Mechanical PropertiesTue, 29 Apr, 14:00–15:45 (CEST) | vP3.20
This research aims to study the experimental behavior of the addition of rubber particles obtained from waste tires to concrete, as a partial replacement of fine and coarse natural aggregates to various levels. Fine rubber particles (2.5–5 mm) were used as a replacement for fine aggregates, while coarse rubber particles (5–20 mm) were used for coarse aggregates, at levels of replacement of 10%, 20%, 30%, 40% and 50% by volume. This experimental program investigated the fresh properties of rubberized concrete, as well as the mechanical properties (compressive and flexural strengths) of the hardened material.
The results showed that workability increased significantly at replacement of fine rubber type at 30% to 50% and moderately with coarse rubber type replacement at 10% to 30%. Notably, compressive and flexural strengths were reduced at increased replacement levels, with more losses noted for coarse aggregate replacement than for fine aggregate replacement. The mechanical properties were preserved, with the compressive and flexural strengths not significantly affected by the low proportions (up to 10%) of replacement of fine aggregates with fine rubber particles, which is a promising indication that fine rubber could potentially replace fine aggregates.
These results indicate that rubberized concrete, especially at low volumes of fine rubber, seems to be a potential solution for sustainable construction by improving workability and recycling waste tires, as well as having suitable structural performance in some applications. The results of this study warrant the further investigation to optimize the mix designs and develop advanced treatments to improve the bond between rubber particles and the cement matrix.
How to cite: Bajbouji, M., Rkha chaham, K., and Bensallam, S.: Enhancing Sustainability in Concrete: Evaluating the Effects of Rubber Particle Replacement on Workability and Mechanical Properties, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20672, https://doi.org/10.5194/egusphere-egu25-20672, 2025.
