SSS9.11 | The management of agricultural and forest soils in meeting global change mitigation goals
EDI
The management of agricultural and forest soils in meeting global change mitigation goals
Co-organized by BG8
Convener: Tuula Larmola | Co-conveners: Michael Kuhwald, Eduardo Martínez-García, Katja Augustin, Bertrand Guenet, Marco Lorenz, Marjo Palviainen
Orals
| Fri, 19 Apr, 08:30–12:25 (CEST)
 
Room -2.21
Posters on site
| Attendance Fri, 19 Apr, 16:15–18:00 (CEST) | Display Fri, 19 Apr, 14:00–18:00
 
Hall X3
Posters virtual
| Attendance Fri, 19 Apr, 14:00–15:45 (CEST) | Display Fri, 19 Apr, 08:30–18:00
 
vHall X3
Orals |
Fri, 08:30
Fri, 16:15
Fri, 14:00
A comprehensive understanding of how forest and agricultural management practices affect soil processes is urgently needed. Soils play a pivotal role in the global carbon cycle by storing about two to three times more carbon than the atmosphere. Additionally, emissions of CO2, CH4, and N2O from soils significantly impact the balance of greenhouse gases in the atmosphere. Therefore, it is essential to gain a better understanding of how soil management and degradation affect global change, considering both carbon sequestration and greenhouse gas emissions as well as soil physical properties.

Soil degradation poses a significant threat to soil functions and ecosystem services, including soil carbon stocks. Despite its importance, soil compaction is often overlooked in comparison to other soil degradation processes. In this context, the severity and extent of compaction and its impact on soil processes and functioning, and consequently, carbon sequestration, are not well understood.

Despite progress in this field, significant knowledge gaps still exist regarding the impact of soil management on soil carbon balances, greenhouse gas exchanges and physical properties. In addition, the effects of soil management on soil have not yet comprehensively integrated into decision-making modelling tools. This could potentially lead to neglecting these effects when formulating policies to achieve carbon neutrality and soil health objectives.

The session aims to offer solutions and develop strategies for effective global change mitigation. Therefore, contributions are invited from arable lands, grasslands, and forests around the world, exploring the current understanding of the effects of soil management and degradation on soil carbon sequestration and other processes. Contributions may be based on different methodological aspects, such as field work, laboratory analysis, sensor development, statistical analysis, and modelling), as well as spatial scales (from local to continental scale) and temporal scales (past, present, and future).

Orals: Fri, 19 Apr | Room -2.21

Chairpersons: Tuula Larmola, Eduardo Martínez-García, Bertrand Guenet
08:30–08:35
08:35–08:55
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EGU24-6553
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solicited
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On-site presentation
Aleksi Lehtonen, Kyle Eyvindson, Kari Härkönen, Kersti Leppä, Aura Salmivaara, Mikko Peltoniemi, Olli Salminen, Sakari Sarkkola, Samuli Launiainen, Paavo Ojanen, Minna Räty, and Raisa Mäkipää

Land-based mitigation measures are needed to achieve climate targets. One option is mitigation of currently high greenhouse gas (GHG) emissions of nutrient-rich drained peatland forest soils. Continuous cover forestry (CCF) has been proposed as a measure to manage this GHG emission source; however, its emission reduction potential and impact on timber production at regional and national scale have not been analysed.

To quantify the potential emission reduction, we simulated four management scenarios for Finnish forests: (i) clearcutting of nutrient-rich drained peatlands replaced by selection harvesting (CCF) and (ii) the current prevailing forest management regime (BAU), and both at two harvest levels, namely (i) the mean annual harvesting (2016–2018) and (ii) the maximum sustainable yield. The simulations were conducted with a forest simulator (MELA) coupled with hydrological model (SpaFHy), soil C model (Yasso07) and empirical GHG exchange models.

Simulations showed that the management scenario (CCF) that avoided clear-cutting on nutrient-rich drained peatlands produced approximately 1 Tg CO2 eq. higher carbon sinks annually compared to the BAU at equal harvest level for Finland. This emission reduction can be attributed to the maintenance of higher biomass sink and to the mitigation of soil emissions from nutrient-rich drained peatland sites.

How to cite: Lehtonen, A., Eyvindson, K., Härkönen, K., Leppä, K., Salmivaara, A., Peltoniemi, M., Salminen, O., Sarkkola, S., Launiainen, S., Ojanen, P., Räty, M., and Mäkipää, R.: Could continuous cover forestry on drained peatlands increase the carbon sink of Finnish forests? , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6553, https://doi.org/10.5194/egusphere-egu24-6553, 2024.

08:55–09:05
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EGU24-8649
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ECS,ECS
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On-site presentation
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Eva-Maria Roth, Kristiina Karhu, Matti Koivula, Heljä-Sisko Helmisaari, and Eeva-Stiina Tuittila

Boreal forests hold about 32% of the global forest carbon (C) stock and the majority of this C is stored in the soil. Forest management affects species composition, microclimate, plant growth, and litter production, and thus affects the soil organic carbon (SOC) storage. Hence, it is important to understand the effects of forest management practices on SOC storage and to adopt management strategies that protect SOC storage.

We aimed to assess how two major forest management approaches differ in their impact on SOC quality and degradability to evaluate their effects on long-term SOC storage. Rotation forest management (RFM) based on clear-cut harvesting is the most common forest management practice worldwide. Continuous-cover forestry (CCF) as an integrated forest management approach has been suggested to enhance SOC storage. It uses repeated partial harvesting and retains a continuous tree cover.

We present our recently published results from a field study in Ruunaa, Lieksa, eastern Finland. We compared the effects of logging methods applied in CCF and RFM on SOC storage and quality in boreal Scots pine (Pinus sylvestris) dominated forests ten years after the logging operations. We sampled gap-cuts as logging method applied in CCF, retention-cuts (20% of tree volume retained), and uncut mature forests and clear-cuts as two opposing stages of RFM. We tested the hypotheses: (1) colder microclimate and continuous litter input lead to higher SOC stocks in CCF plots than in clear-cuts and (2) more labile litter of grass- and herb-rich vegetation typical for clear-cut sites enhances SOC decomposition rates. We analyzed the SOC concentration and stock and modelled annual above- and belowground litter inputs based on stand characteristics (diameter at breast height, basal area, dominant tree height, understory species coverage). We used sequential chemical fractionation of organic layer samples and laboratory incubation to analyze the quality of SOC and its degradability under standardized conditions. To estimate the decomposition rate as impacted by the environment we incubated cellulose bags in situ. We assessed the impact of varying microclimate with field measurements of soil temperature and soil moisture. We analyzed the microbial biomass C pool with chloroform fumigation extraction.

The SOC content and stock did not differ significantly between the treatments, despite the warmer microclimate and lower litter input recorded in clear-cut plots than in CCF plots. However, we detected differences in quality and degradability of SOC. Soils in clear-cut sites held lower proportions of labile SOC compounds than the other treatments. As hypothesized, decomposition rate was elevated in clear-cuts, but was equally high within the canopy gaps of gap-cuts. Accumulation of labile SOC due to cooler microclimate, combined with decreased decomposition rate – both found in uncut forests and retention-cuts – indicate a higher potential for future SOC accumulation in these treatments than in clear-cuts. Our study highlights that forest management affects the quality, degradability, long-term accumulation and storage of SOC. Thus, the chosen logging method can be an important tool in climate change mitigation and the forest management regime needs to be adapted accordingly.

 

Publication in Forest Ecology and Management [2023]: https://doi.org/10.1016/j.foreco.2023.121144

How to cite: Roth, E.-M., Karhu, K., Koivula, M., Helmisaari, H.-S., and Tuittila, E.-S.: Unearthing the effects of harvesting methods applied in continuous-cover forestry and rotation forest management on soil carbon storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8649, https://doi.org/10.5194/egusphere-egu24-8649, 2024.

09:05–09:15
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EGU24-3103
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On-site presentation
Annamari Laurén and Marjo Palviainen

Different climate scenarios predict a clear rise in temperatures and a modest increase in precipitation to high latitudes. In forested peatlands, the consequent lowering of the water table and increasing peat temperature will enhance organic matter decomposition leading to higher nutrient release and CO2 emissions from the peat. These biogechemical changes will fundamentally alter the management schemes of peatland forests. Hydrological and biogeochemical processes in forested peatlands are complicated, interlinked and characterized by different feedback mechanisms. In addition, all these are dependent on weather conditions, peat characteristics, drainage dimensions, and stand structure.  High-resolution geospatial data combined with process-based ecosystem models provides a solution in searching for new forest management schemes that balance between different ecosystem services. We have developed this kind of ecosystem model, peatland simulator SUSI, and applied it to study how manipulation of drain network, ash fertilization and forest management affect tree growth, greenhouse gas balance and nutrient export to water courses under different temperature and rainfall scenarios. We found that without a change in the water management, the stand growth, the soil C emissions and nitrogen export to water courses will increase substantially. However, less intensive drainage together with ash fertilization helped to mitigate the harmful effects of changing climate whilst keeping the stand growth in adequate level. 

How to cite: Laurén, A. and Palviainen, M.: Decreasing carbon emissions in boreal peatland forests using fertilization and less intensive drainage in current and changing climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3103, https://doi.org/10.5194/egusphere-egu24-3103, 2024.

09:15–09:25
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EGU24-17138
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On-site presentation
Boris Ťupek, Aleksi Lehtonen, Stefano Manzoni, Petr Baldrian, Bartosz Adamczyk, and Raisa Mäkipää

Projections of soil carbon (C) models are known to underestimate soil C stocks in boreal soils with higher nutrient status which is likely because they do not account for effects of soil nutrient status on the kinetics of microbial respiration and their sensitivities to environmental conditions. Here we evaluated the effects of long-term N addition (once per decade since 1960 until 2020) on soil heterotrophic respiration (Rh) and its dependence on soil temperature and moisture in an originally N limited boreal Scots pine (Pinus sylvestris) forest.

We measured Rh, soil temperature and soil moisture biweekly during the vegetative seasons of 2021-2023 in both fertilized and control forests. We fitted Rh rates to soil temperature and moisture separately for the control and N fertilization treatment using parametric non-linear regression models and non-parametric machine learning (boosted regression tree) models.

The functional dependencies of Rh were similar between fertilized and control forests for soil temperature but differed for soil moisture. In the N fertilized forest soil, Rh increased rapidly from dry conditions towards a soil moisture optimum followed by a clear reduction in wet conditions. In contrast, in the N limited forest soil, Rh mainly increased with soil moisture.

The models based solely on temperature (assuming identical and non-limiting effect of moisture) predicted higher annual Rh than the models accounting for soil moisture effects. Thus, to avoid overestimation of soil CO2 emissions and underestimation of soil C stocks accumulation in fertile boreal soils, it is crucial to link the soil moisture dependencies in soil C models to nutrient status. The different Rh response to moisture between N limited and N fertilized soils could be related to different levels of enzyme activities and contrasting microbial traits found by other studies.

How to cite: Ťupek, B., Lehtonen, A., Manzoni, S., Baldrian, P., Adamczyk, B., and Mäkipää, R.: Increased sensitivity of microbial respiration to soil water content in a fertilized boreal forest, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17138, https://doi.org/10.5194/egusphere-egu24-17138, 2024.

09:25–09:35
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EGU24-19380
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On-site presentation
Forest management in temperate forests strongly affects carbon stocks in the organic layer but not in the mineral soil
(withdrawn)
Ingo Schöning and Marion Schrumpf
09:35–09:45
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EGU24-998
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ECS
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On-site presentation
Péter Végh, Pál Balázs, András Bidló, and Adrienn Horváth

Site factors determine the occurrence and growth of forest stands. The climate is one of the most important. In Hungary, several forest stands located near to the Xeric limit, where climate change is more sensitive. Therefore carbon-rich forests and their soils are being prioritized to achieve carbon neutrality as soon as possible. Our research aims to assess and compare the organic carbon stored in oak and beech forest ecosystems of different climate classes.

In the last period, we sampled 2 Beech, 11 Sessile oak and 13 Turkey oak forest stands to determine the amount of soil organic carbon stored in the soil.

The soils were collected by soil boring to 0-110 cm. Besides the soil sampling, the existing forest stand composition assessed on each stand near to sampling points.

Based on the analyses carried out in the 26 selected forest stands, the soils of the sites can be classified as Cambisols and Luvisols (WRB 2023). The soil pH showed slightly acidic to neutral (mean H2O = 6.7), and the texture can be determined as loam. The relative organic matter content (SOM) was 0.67% on average between 0-110 cm. It corresponds to ~8.2 t of carbon per hectare.

With the accelerated rate of climate change (drought), there is an increasing urgency to assess the status of ideal organic matter-rich soils and to develop adaptation strategies to increase the carbon stock.

This article was made in the frame of the project TKP2021-NKTA-43 which has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary (successor: Ministry of Culture and Innovation of Hungary) from the National Research, Development and Innovation Fund, financed under the TKP2021-NKTA funding scheme. This publication was supported by the project GINOP-2.3.3-15-2016-00039.

How to cite: Végh, P., Balázs, P., Bidló, A., and Horváth, A.: Investigation of SOM sequestration and storage in the Southern Transdanubian region of Hungary, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-998, https://doi.org/10.5194/egusphere-egu24-998, 2024.

09:45–09:55
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EGU24-12286
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On-site presentation
Different management strategies of disturbed forest areas in Central Germany: Effects on soil nutrient distribution, forest soil structure and microclimate
(withdrawn)
Philipp Koal, Simon George, Simon Grieger, Marie Brock, Ingolf Profft, and Birgitta Putzenlechner
09:55–10:05
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EGU24-16030
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ECS
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On-site presentation
Clément Bonnefoy-Claudet, Mathieu Thevenot, Jean Lévêque, Elodie Cognard, Anne-Lise Santoni, Jean Cacot, and Olivier Mathieu

Soils play a key role in regulating atmospheric concentrations of greenhouse gases notably by their action on organic carbon dynamics (storage vs. release). Forests occupy 31% of the continental surface and store around 40% of the continental organic carbon, half of it in soils. Ongoing climate change could alter the balance of this stock, and the effect of temperature on soil carbon fluxes remains an important question. In this study, we use the Q10 parameter (i.e. increase in CO2 emission for a 10°C rise in temperature) to estimate the temperature sensitivity of soil organic matter in four forest tree species (beech, spruce, douglas fir and silver fir). In addition, soil organic carbon stocks were estimated and compared with Q10 values and forestry data (volume, basal area, density and dead wood).

The mont Beuvray site (Morvan Regional Park, France), a mid-mountain area of around 1,000 ha with a quite homogeneous geology and pedology, was selected. On this site, Beech forests correspond to historical land use, while softwood forests have been gradually introduced over the past 70 years. Thus, 48 soil samples (0-20 cm) were collected (12 per tree species) and the main physicochemical characteristics were determined (bulk density, stone content, pH, organic carbon and total nitrogen contents, water-extractable organic carbon). The Q10 was calculated for a temperature range of 5 to 25°C in the laboratory using a Respicond X (Nordgren Innovations AB, Sweden).

Results show that soil organic carbon and water-extractable organic carbon contents are higher in silver fir and beech stand soils than in Douglas fir stand soils. For soil organic carbon stocks, the average values are slightly higher for beech and silver fir than for Douglas fir and spruce, but there is no statistical difference between the four tree species.  Q10 values range from 2.3 to 3.0, with a statistical higher value for beech (2.8 ± 0.1) than for the other softwood species (2.6 ± 0.1). This last result suggests that, for similar initial soil conditions, CO2 emissions from soil in beech stands would increase more strongly with temperature than in other species.

In conclusion, several decades after the introduction of softwood species, we did not measure in the top soil (0-20 cm) significant difference in carbon stocks. However, CO2 emissions and Q10 values are different and related to forest species. Hence, beech stand soils, corresponding to the historical land cover, could see their CO2 flux increase as they are the most sensitive to temperature. Conversely, silver fir stands, with their lower sensitivity to temperature, could be of interest in mitigating emissions. These results need to be confirmed by field data on soil respiration and compared with above-ground forest biomass and stand health.

How to cite: Bonnefoy-Claudet, C., Thevenot, M., Lévêque, J., Cognard, E., Santoni, A.-L., Cacot, J., and Mathieu, O.: Could tree species be a key factor on soil carbon balance in temperate forest?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16030, https://doi.org/10.5194/egusphere-egu24-16030, 2024.

10:05–10:15
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EGU24-9810
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ECS
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On-site presentation
Päivi Soronen, Sandra Jämtgård, Mari Myllymäki, and Aino Smolander

Norway spruce monocultures in the boreal region are vulnerable to the effects of climate change and unfavourable in terms of soil fertility. Introducing broadleaved tree species to these forests may increase not only the resilience of the forest ecosystem to climate change but also enhance soil productivity and carbon (C) stock. We studied how grey alder, having symbiosis with N2-fixing Frankia, and birch affect soil nitrogen (N) and carbon pools as an admixture in Norway spruce stands in Southern Finland.

Study sites were three 40–60-year-old Norway spruce (Picea abies (L.) Karst.) -dominated stands with both grey alder (Alnus incana) and birch (both Betula pendula and Betula pubescens) as an admixture and a 20-year-old spruce stand with an admixture of grey alder. The forest type was a relatively fertile Oxalis acetosella – Vaccinium myrtillus type (OMT) on the two older (60 yr) sites and a slightly less fertile Vaccinium myrtillus type (MT) on the two younger sites (20–40 yr), applying the Finnish forest type classification. We took the soil samples at a 50–100 cm distance from 3–8 stems of the different tree species for the determinations of soil C and N stocks from all sites and for additional characterisation of organic matter only from the 60-year OMT sites. Soil diffusive N fluxes were measured using in situ microdialysis sampling and the subsequent laboratory analyses of plant-available N compounds.

On average, forest floor N stock was larger under the canopy of alder versus birch or spruce. C-to-N ratios of forest floor and topmost 10 cm mineral soil layer were lower under alder versus spruce. Soil C stock was affected by tree species only at the 40-year MT site, where alder had a higher forest floor C stock than birch or spruce. Differences in diffusive N fluxes between tree species were non-significant, and we observed inconsistent trends at different sites. C mineralisation rate tended to be lower under alder versus spruce on the two 60-year OMT sites, and the amount of microbial biomass N was lower under alder versus birch. Microbial biomass C-to-N ratio and forest floor thickness were lower under birch than spruce on one of the 60-year OMT sites.

The results point towards complex interactions and dynamics between tree species in mixed forests. Although we observed tree-species-induced spatial variation in soil properties, the distribution of above- and belowground litter and root activities in mixed stands reduces the differences between tree species. We found tree species to affect N stocks and C-to-N ratios most strongly, alder altering soil properties of spruce stands more than birch.

How to cite: Soronen, P., Jämtgård, S., Myllymäki, M., and Smolander, A.: Grey alder and birch as an admixture in Norway spruce stands: Effects on soil nitrogen and carbon pools, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9810, https://doi.org/10.5194/egusphere-egu24-9810, 2024.

Coffee break
Chairpersons: Michael Kuhwald, Katja Augustin, Marco Lorenz
Soil degradation by soil compaction on arable land, grassland and in forests d, grassland and in forests
10:45–10:55
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EGU24-6522
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On-site presentation
Max Behringer, Christian Scheidl, Gerhard Markart, Gertraud Meißl, Marcus Froemel, Lisa Gasser, Julian Grünberg, Christoph Haas, Armin Hofbauer, Barbara Kitzler, Martin Kühmaier, Nikolaus Nemestothy, Boris Rewald, Alexandra Wieshaider, and Klaus Katzensteiner

Structural properties of undisturbed soils are critical for water retention and the reduction of peak flows after heavy rainfall events. Forest soils commonly show high infiltration rates that can be attributed to a high organic content and the formation of larger pores through biological activity. Though soil disturbances, especially soil compaction, due to timber logging can be considered a rare event, the impacts may be long lasting. The productive, often fine textured soils of the Alpine Flysch belt are particularly susceptible to compaction, posing a challenge for timber harvesting.

In a controlled experiment in the Flysch zone (Vienna Woods, Austria), we assessed the effects of different timber harvesting technologies – specifically harvester-forwarder (with or without bogie tracks) and chain saw-cable yarder – on soil functions. For the quantification of the surface runoff, we applied rainfall simulation experiments on seven plots of 50 m² each. All rainfall simulation experiments were conducted for one hour with a targeted intensity of 100 mm/h before and after harvesting. Within each irrigation plot, we sampled undisturbed soil cores at up to five depth levels (5, 15, 25, 40, 65 cm) for further analyses in the laboratory. We measured saturated hydraulic conductivity (KSAT device; METER Group, Munich, Germany), as well as soil water retention in the wet and medium soil moisture range using the HYPROP device (METER Group, Munich, Germany). In the dry soil moisture range (pF>4.2) we measured water retention with the dew point method using the WP4C device (METER Group, Pullman, USA). Additionally, soil texture and soil organic carbon were determined from the same soil samples.

Preliminary results suggest a strong impact of the harvester-forwarder system (w/wo bogie tracks) on all hydrologically effective soil properties, while the cable yarder system seems to have lower, yet still noticeable impacts. For the log10 of the saturated hydraulic conductivity (log10KS) the harvester-forwarder treatments cause significantly lower values, with reductions of up to >99% compared to values prior to harvesting. The decline of log10KS in cable yarding systems is only marginally significant (up to -49%). First order analyses of runoff coefficients show a strong effect of the harvester-forwarder system with observed values of up to 0.66. Undisturbed sites had no surface runoff and cable yarding only generated minimal surface runoff. 

How to cite: Behringer, M., Scheidl, C., Markart, G., Meißl, G., Froemel, M., Gasser, L., Grünberg, J., Haas, C., Hofbauer, A., Kitzler, B., Kühmaier, M., Nemestothy, N., Rewald, B., Wieshaider, A., and Katzensteiner, K.: On the impact of timber harvesting on soil water retention and surface runoff, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6522, https://doi.org/10.5194/egusphere-egu24-6522, 2024.

10:55–11:05
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EGU24-10630
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ECS
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On-site presentation
Armin Hofbauer, Maximilian Behringer, Marcus Froemel, Lisa Gasser, Julian Grünberg, Christoph Haas, Klaus Katzensteiner, Martin Kühmaier, Gerhard Markart, Gertraud Meissl, Nikolaus Nemestothy, Boris Rewald, Christian Scheidl, Matthias Schlögl, Alexandra Wieshaider, and Barbara Kitzler

Temperate forests are a substantial sink for the greenhouse gases (GHG) methane (CH4), carbon dioxide (CO2) and soil emissions of nitrous oxide (N2O) are low. However, most of these forests are managed with ground-based harvesting systems causing severe soil disturbance. Soil displacement and compaction has a long-term effect on the soil microbial community structure and alters soil respiration, CH4 uptake, and nitrogen turnover. This significantly reduces the soil ecosystem services on extraction tracks and landings. Soil disturbance is particularly severe and persistent in compaction-prone silty and loamy soils, emphasizing the urgent need for specific techniques for these sites.

In an empirical Before-After Control-Impact study we compare the effects of harvester-forwarder use with/without tracks (HF/HFt) and cable-yarding with motor-manual-felling (CMM), on the soil chemistry, microbial community, and the soil-GHG balance. Our study is carried out within the project HoBo: Securing the Sustainability of Forest Soil Functions via Optimized Harvesting Technologies (https://dafne.at/projekte/hobo). The study sites are located in the Flysch zone and in the Molasse basin (North Alpine foreland basin). Soil GHG flux rates of CO2, CH4, and N2O are measured with trace gas analyzers (Li-Cor 7810 and 7820), either manually at the recently thinned stands, or continuously with automatic chambers at plots that were thinned in 2016.  For deeper understanding of the effects on soil chemistry and the changes in the microbial community, we determine nitrogen availability, microbial biomass carbon and nitrogen as well as the phospholipid fatty acids (PLFA).

Preliminary results show a significant impact of all applied mechanized timber harvesting systems (HF/HFt/CMM) reducing CH4 uptake rates and increasing N2O emissions of both skid trails and cable yarding corridors, compared to the control plots outside the extraction tracks (thinned stand). Our findings underline that sustainable forest management practices should not only reduce soil compaction. It should also consider additional factors, particularly soil displacement induced by logging activities.

How to cite: Hofbauer, A., Behringer, M., Froemel, M., Gasser, L., Grünberg, J., Haas, C., Katzensteiner, K., Kühmaier, M., Markart, G., Meissl, G., Nemestothy, N., Rewald, B., Scheidl, C., Schlögl, M., Wieshaider, A., and Kitzler, B.: Effects of timber harvesting techniques on soil biodiversity and greenhouse gas fluxes of temperate forest soils susceptible to compaction, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10630, https://doi.org/10.5194/egusphere-egu24-10630, 2024.

11:05–11:15
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EGU24-17507
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ECS
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On-site presentation
Lisa Gasser, Maximilian Behringer, Marcus Froemel, Douglas Godbold, Julian Grünberg, Christoph Haas, Armin Hofbauer, Klaus Katzensteiner, Barbara Kitzler, Martin Kühmaier, Gerhard Markart, Gertraud Meissl, Nikolaus Nemestothy, Hans Sandén, Christian Scheidl, Alexandra Wieshaider, and Boris Rewald

Soil compaction in forests, often a result of logging activities, poses a significant threat to soil functioning and ecosystem services. Root systems and their symbiotic relationships with mycorrhizae are particularly affected. Given the vital role that sustainably managed forest ecosystems play for climate change resilience and mitigation, understanding the effects of soil compaction on belowground functioning is critical. To address knowledge gaps on the interactions between soil compaction, root growth, and mycorrhizal associations under real-world conditions, it is essential to conduct comparative studies on different harvesting methods. Detailed analyses are required to better understand the spatiotemporal effects of logging on soil as a rooting space. 

To investigate the complex relationships, we implemented different harvesting methods (harvester-forwarder with or without bogie tracks, cable-yarding with motor-manual-felling) and a control treatment between skidding trails in a beech-dominated forest in Lower Austria during the winter of 2022/23. In addition, we sampled ~20-year-old skidding trails (harvester-forwarder) to assess soil recovery.

Using a replicated transect approach across the skidding trails, we studied spatially explicit effects on standing fine root biomass to a depth of ~45 cm in a before-after control-impact design. To allow for upscaling, each transect included areas directly impacted by logging (i.e. skidding trails, cable-yarding corridors) and areas potentially indirectly affected (i.e. between the ruts, bulge area etc.). We conducted comprehensive assessments of fine root biomass depth distribution, and key traits such as anatomy, morphology and fine root nutrient content, as well as mycorrhization rates. 

The data indicate a significant negative influence of both recent and historical timber harvesting on standing root biomass, revealing altered patterns of root distribution with notable differences between and within transects. Our results suggest that different harvesting methods result in very different levels of soil compaction, leading to contrasting effects on fine root traits such as a reduction of absorptive surface area relative to biomass in compacted soil. 

The persistence of negative effects on the old skidding trails highlights the long-lasting impact on root systems and their mycorrhizal symbionts, and thus key ecosystem functions. This emphasizes the importance of conserving forest soils and the need to identify and implement management strategies to minimize soil compaction and promote recovery. These efforts are vital for ensuring the sustainable provision of ecosystem services by the 'hidden half' of forests.

How to cite: Gasser, L., Behringer, M., Froemel, M., Godbold, D., Grünberg, J., Haas, C., Hofbauer, A., Katzensteiner, K., Kitzler, B., Kühmaier, M., Markart, G., Meissl, G., Nemestothy, N., Sandén, H., Scheidl, C., Wieshaider, A., and Rewald, B.: Effects of Logging-Induced Soil Compaction on the Abundance and Characteristics of Fine Roots and Mycorrhizal Associations in Forest Soils and their Recovery, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17507, https://doi.org/10.5194/egusphere-egu24-17507, 2024.

11:15–11:25
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EGU24-9353
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ECS
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On-site presentation
Elron Wiedermann, Laura Reinelt, Lennart Rolfes, and Axel Don

Soil compaction has adverse impacts on key soil functions and can result in restricted root distribution. However, deep roots provide access to water and nutrient reservoirs and might enhance carbon (C) storage in subsoils. Deep rooting is thus a central element for climate-adapted plant productivity and has potential for climate mitigation. Clarity is missing, to what extent different soil traffic intensities impact root depth distribution and root-derived C inputs at field scale.

The present study was conducted to assess the impact of differing soil traffic intensities (i) on soil physical parameters related to compaction, and (ii) to what extent this affects root length density and depth distribution, as well as (iii) above ground biomass and (iV) SOC-stocks. Negative effects of increasing traffic intensities on soil physical parameters are expected to result in reduced root depth distribution and therefore reduced biomass productivity and root-induced carbon allocation.

Soil and plant biomass were sampled along increasing soil traffic intensities at three field sites in central Germany characterized as Luvisols. Penetration resistance was measured in the field, and undisturbed soil rings of top and sub soils were analyzed for bulk density and air capacity. Undisturbed soil cores were taken up to one meter depth during peak root biomass. Root biomass, depth distribution and root length density were evaluated with the core-break method using an automated root spectroscopy imaging system. Based on the results, root-derived C inputs were estimated and C/N-measurement of soil core samples was conducted.

Preliminary findings indicate higher penetration resistance and bulk density, coupled with reduced air capacity in top and subsoils on the headland, where greater traffic intensity takes place. The complete data set will be presented and discussed at the conference.

The conclusions of this study will provide a better understanding of the interactions between soil compaction, root growth and carbon storage. These findings are relevant to assess how soil management affects soil compaction and thus may hinder climate-adapted agriculture.

How to cite: Wiedermann, E., Reinelt, L., Rolfes, L., and Don, A.: Restricted root growth caused by traffic induced soil compaction – a field study in wheat and maize, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9353, https://doi.org/10.5194/egusphere-egu24-9353, 2024.

11:25–11:35
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EGU24-9895
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ECS
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On-site presentation
Shijie Qin, Lingling Liu, W. Richard Whalley, Hu Zhou, Tusheng Ren, and Weida Gao

Analysis of the effects of soil penetrometer resistance (PR) on root elongation and relative classic prediction models mostly ignore the role of macropores, which are important for root to penetrate compacted soils. In this study, undisturbed soil samples were collected from an 11-years tillage experiment (no-tillage and conventional tillage) in Northeast China, and their bulk density (BD), PR, air-filled porosity (AFV), and pore-size distribution were determined. Root elongation of maize seedlings was determined on each soil cores following equilibration at -20 kPa. Our results showed root elongation is significant negatively correlated with BD, PR, and the volume of Pores < 6 µm, while positively correlated with the AFV and macropores (Pores > 60 µm) (P < 0.001). Root elongation rate exhibited a 50% reduction when PR was over 1.3 MPa or AFV was below 10%. A new model has been developed to estimate the rate of root elongation that taken into account the interaction between PR and macropores. The new model had a better performance than previous ones and the root mean square error (RMSE) was 0.13.

How to cite: Qin, S., Liu, L., Whalley, W. R., Zhou, H., Ren, T., and Gao, W.: Revisiting the relationships between maize root elongation and penetrometer resistance, air-filled porosity and macro- porosity on a clay loam Mollisol, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9895, https://doi.org/10.5194/egusphere-egu24-9895, 2024.

11:35–11:45
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EGU24-10487
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On-site presentation
Weida Gao, Lingling Liu, and shijie Qin

Compaction is one of the main types of soil degradation worldwide. The macropores left by ex-plant roots were expected to provide channels to root to penetrate hard soil layers. However, there are few studies to quantitate the relationship between the elongation of maize roots and the root pores, due to complex morphological characteristics of the real root pore systems. In this study, we tried to build an artificial pore with sheath to simulate the effects of root pores on maize root growth in the compacted soil by X-ray CT. Our results indicated that the method for simulating root pores worked well. The sheath width of artificial root-pore was about 2.69 mm. Moreover, sheath of pores had higher organic carbon content and abundance of actinobacteria compared with bulk soil. Compared with artificial macropores, the presence of artificial root-pores diminished the border effects of the pot wall and increased the growth angle of node1 roots and the maximum growth depth of maize roots. However, there were no significant differences in terms of roots spatial distribution (in soil matrix, macropore sheath, macropore), and the ways (crossing or colonizing) of utilization by maize roots to macropores between the treatments with artificial macropores and artificial root-pores. This study provides a new insight into the interactions between root pore, root-pore sheath and maize roots.

How to cite: Gao, W., Liu, L., and Qin, S.: Effects of artificial root-pores on maize roots growth in compacted soil using X-ray computed tomography, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10487, https://doi.org/10.5194/egusphere-egu24-10487, 2024.

11:45–11:55
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EGU24-8055
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ECS
|
On-site presentation
Alberto Carrera, Luca Peruzzo, Giorgio Cassiani, and Francesco Morari

Monitoring soil structure is of paramount importance due to its key role in the critical zone as the foundation of terrestrial life. Variations in the arrangement of soil components significantly influence its hydro-mechanical properties, and therefore its impact on the surrounding ecosystem. Soil compaction, resulting from inappropriate agricultural practices, not only affects soil ecological functions by reducing soil porosity and water infiltration, but also decreases the yields spoiling the socio-economic aspect.

In this study, we compared the ability of electrical and electromagnetic geophysical methods, i.e. Electrical Resistivity Tomography and Frequency-domain Electromagnetic Method, to monitor the effects of compaction on agricultural soil. The objective is to highlight the electro-magnetic response caused by plastic deformation of the soil generated by both a super-heavy vehicle and the usual interrows surface compaction generated by tractor traffic for common practices. The survey was conducted both on a small scale, covering an area of 1.5 hectares, and in detail on individual targeted transects. This allowed to capture the 2-D and 3-D spatial heterogeneity that is often difficult to obtain with punctual and invasive traditional methods.

This work aims to contribute to the methodological optimization of agro-geophysical acquisitions and data processing, so as to obtain accurate soil models through non-invasive approach. Results, validated with traditional soil characterization techniques (i.e. penetration resistance, bulk density and volumetric water content on collected samples), show pros & cons of both techniques and how differences in their spatial resolution heavily influence the ability to characterize compacted areas with good confidence.

How to cite: Carrera, A., Peruzzo, L., Cassiani, G., and Morari, F.: Soil compaction signatures on electromagnetic and DC-current geophysics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8055, https://doi.org/10.5194/egusphere-egu24-8055, 2024.

11:55–12:05
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EGU24-17045
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ECS
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On-site presentation
Utibe Utin, Jo Smith, Josie Geris, and Paul Hallett

Organic amendment of soils with composts or slurries affects compaction resistance and resilience, but the longevity of these impacts has not been explored, and few data are available from controlled field studies.  Here we carried out a rapid soil compaction resilience test, where coarsely sieved soil to simulate a freshly prepared seedbed are exposed to controlled compaction and cycles of wetting and drying in the laboratory. Agricultural soils with long history of compost and slurry amendments were sampled from the Lower Pilmore field of the James Hutton Institute, Dundee, UK.  Replicated plots received three levels of compost (35, 100 and 200 Mg ha-1), three levels of slurry (10, 20 and 40 Mg ha-1) and control (no amendment) from 2005 to 2009. Subsequently, normal rates of 35t ha-1 and 10 t ha-1 were applied until 2014. Loose soils sampled in 2023 were sieved to 4mm and then compressed cyclically under uniaxial stresses of (i) 50kPa to simulate a roller, (ii) 200kPa to simulate a tractor, and (iii) again at 200kPa. Between each of these stress cycles the soils were saturated (wetting) for 24 hours and drained (drying) to field capacity (5kPa) for 12 hours on a sandbox. Changes in void ratio during the loading and unloading phases were obtained directly from sample displacement, while the void ratio after wetting and drying was calculated from soil mass-volume relationship. Void ratio increased with increase in organic carbon in both compost and slurry soils. Soil wetting-drying following the first and second 200kPa compression cycles caused significant recovery of void ratio for both compost and slurry. Final void ratio (measured after the wet-dry cycle that followed the second 200kPa compression) was 0.40 m3 m-3 in the control, versus 0.45 m3 m-3 in 35 Mg ha-1 compost and 0.49 m3 m-3 in both 100 and 200 Mg ha-1 compost. For slurry soils, final void ratio was 0.40, 0.41 and 0.45 m3 m-3 for 10, 20 and 40 Mg ha-1, respectively. Organic carbon accounted for a significant percentage (R2 = 0.48; p = 0.00) of variability in the final void ratio for compost soils whilst there was no significant relationship between void ratio and organic C in slurry soils. Compression and recompression indices increased more with increase in compost than with increase in slurry, but overall, they displayed no significant (p≤0.05) relationships with organic carbon. Soils treated with compost are therefore, better able to absorb compressive stresses than their slurry counterparts and could significantly recover their form and capacity to perform their ecological functions following stress withdrawal. Moreover, legacy applications of compost than slurry can affect compaction resilience for several years.

How to cite: Utin, U., Smith, J., Geris, J., and Hallett, P.: The legacy of compost and slurry amendments to soil on physical resilience to compaction, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17045, https://doi.org/10.5194/egusphere-egu24-17045, 2024.

12:05–12:15
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EGU24-12523
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On-site presentation
Svenja Roosch, Jocelyn Ormeno, Daniel Uteau, Heiner Fleige, Anneka Mordhorst, Jens Rostek, Conrad Wiermann, Gerrit Müller, and Stephan Peth

Soil structure influences important soil functions like hydraulic conductivity and air permeability, which in turn influence plant growth. The physical structure of soils is thus, besides chemical and biological parameters, one major component of soil fertility. Unfortunately, this physical fertility is often impaired by agricultural practices.

To study the structural status and the relationships between structural and functional parameters, 45 representative arable sites in Schleswig-Holstein, Germany, were sampled at three depths in top- and subsoil. Soil structure was described quantitatively using X-ray computed tomography of soil cores (continuity and size distribution of macropores). Measured soil functions included saturated hydraulic conductivity, air permeability, air capacity, and pore size distribution (via water retention curves).

The results not only help elucidate relations between structural and functional soil parameters. They also give a detailed and comprehensive insight into the structural state and their relation to soil physical functions of typical arable sites across Schleswig-Holstein that has not existed before.

How to cite: Roosch, S., Ormeno, J., Uteau, D., Fleige, H., Mordhorst, A., Rostek, J., Wiermann, C., Müller, G., and Peth, S.: Correlating tomography structure parameters with physical soil functions in representative sites in Schleswig-Holstein, Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12523, https://doi.org/10.5194/egusphere-egu24-12523, 2024.

12:15–12:25
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EGU24-5503
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On-site presentation
Laura Sofie Harbo and Florian Schneider

Aim: Anthropogenic compaction is typically assumed to be major threat to soil health in agriculture. Compaction of the subsoil is considered irreversible and therefore more severe than topsoil compaction. To-date, quantitative estimates about the extent and severity of soil compaction are hardly available. This study aims to quantify anthropogenic subsoil compaction in German croplands by reanalyzing data from the German Agricultural Soil Inventory (BZE-LW). Grassland sites, which are assumed to exhibit negligible traffic-induced compaction below 30 cm depth, serve as a reference for the prediction of bulk density in cropland sites before anthropogenic compaction.


Methods: A data-driven reciprocal modelling approach is employed to estimate human-induced increases in bulk density at 1477 cropland sites scattered in a regular 8 x 8 km grid across Germany. The model is trained on data from ~400 grassland sites using information about soil texture, organic C content, soil pH, climate, and geological parent material. The model is then applied to the cropland sites to predict the bulk density of the upper subsoil in 30-50 cm depth prior to anthropogenic compaction. The disparity between modelled and observed bulk density represents the trafficking induced changes in soil compactness. To explain the drivers of this change, another data-driven model, incorporating soil and climate information as well as cropland management data, is trained and interpreted.


Results: Traffic-induced compaction has significantly increased the median bulk density of subsoils under cropland by 0.055 g cm⁻³, corresponding to a 4% increase. The modelled effects ranges from -0.07 g cm-3 to 0.180 g cm⁻³ (10th and 90th quantile), with the largest increases in subsoil compaction observed in eastern Germany. For the 20% most severely affected sites in Germany, the median increase in bulk density was 0.180 g cm⁻³ (0.142 g cm⁻³ – 0.267 g cm⁻³, 10th and 90th quantile), which corresponds to a 12% increase in subsoil bulk density. The anthropogenic increase in soil bulk density was most pronounced in loamy soils with relatively low soil organic carbon content.


Conclusion: This study represents a significant advancement in our ability to quantitatively assess the extent and severity of anthropogenic subsoil compaction at a national scale. The data-driven reciprocal modelling approach employed is promising for broad application in relation to soil health monitoring initiatives across Europe. 

How to cite: Harbo, L. S. and Schneider, F.: Estimating anthropogenic subsoil compaction in Germany using data-driven reciprocal modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5503, https://doi.org/10.5194/egusphere-egu24-5503, 2024.

Posters on site: Fri, 19 Apr, 16:15–18:00 | Hall X3

Display time: Fri, 19 Apr 14:00–Fri, 19 Apr 18:00
Chairperson: Tuula Larmola
X3.11
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EGU24-3172
Katja Augustin, Marco Lorenz, Rainer Duttmann, and Michael Kuhwald

Sugar beet is one of the crops grown in Germany with the highest intensity of traffic on the field. Not only are there very high numbers of passes by the machines during the season, but the sugar beet harvesting vehicles are also among the largest and heaviest machines in use in Germany. The heavy harvesters are also used elsewhere in the world. In order to avoid multiple passes with the heavy wheel loads, the machines can often offset their rear axles parallel to the direction of travel - the so-called crab steering (CS). This distributes the load over a larger area, but also means that more area is covered in the field.

This study examines whether the distribution of wheel loads over a larger area using CS shows a significant difference in soil settlement and deformation compared to traffic without the use of crab steering (wCS). Different moisture contents of the soil are taken into account.

The model named FiTraM was used to model the traffic. The calculation of the soil deformation is based on empirical formulas, which are specially adapted to this field and the harvester.

The subsoil in particular is considered, as soil deformation should be avoided there, since it is difficult and cost-intensive to repair.

The results show that there are no significant differences in the distribution of soil deformation between CS and wCS.  In general, the moisture content of the soil determines the extent of deformation. In moist to very wet conditions (approx. 35 - 37 Vol-%), the first pass already achieves such a high degree of soil deformation that it should be avoided in practice. When the soil is dry (approx. 25-30% by volume), no soil deformation occurs in the subsoil in any of the variants - only slight deformation occurs in the topsoil. There are likewise no significant differences between the two traffic variants between 31 and 34 Vol.-% soil moisture.

In summary, it can be assumed that a wheel or axle of the beet harvester is already so heavy that it makes little difference whether the machine is running in CS or not. The limiting factors are the total weight and the soil moisture content during traffic.

How to cite: Augustin, K., Lorenz, M., Duttmann, R., and Kuhwald, M.: Is it more conservative to use the crab steering during sugar beet harvesting? A case study from Lower Saxony, Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3172, https://doi.org/10.5194/egusphere-egu24-3172, 2024.

X3.12
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EGU24-21890
Bastian Steinhoff-Knopp, Michael Kuhwald, Katharina Bäumler, Philipp Saggau, and Marco Lorenz

Soil compaction and soil erosion by water are among the top 5 threats to agricultural soils in Europe. Soil compaction has a direct impact on soil erosion, for instance by reducing infiltration rates. Therefore, measures directly addressing soil compaction (e.g. optimized field traffic and reduced wheel load) have an impact on soil erosion by water. In addition, measures such as crop rotation management, including cover crop management, allow combined effects on soil erosion and soil compaction. Currently, no evidence at regional scale is available that indicates which measures can generate this co-benefit and which regions having a high risk of soil erosion and compaction can benefit from those measures. Modelling exercises provide the option for generating this information and are tested here in a regional scale case study.

As a first step, we identified cropland with a combined risk of soil compaction and soil erosion by water in Lower Saxony (northern Germany). To this end, we derived typical crop rotations for 2017 to 2021 based on high-resolution crop type maps for three soil regions in the study area. Depending on the crop rotations and farm size, typical machinery equipment was defined and field work dates were derived according to phenological data. This data was combined with three weather scenarios using real observational data (dry: 2020, wet: 2017, intermediate: 2004). We employed the USLE (Universal Soil Loss Equation) and the SaSCiA-model (Spatially explicit Soil Compaction risk Assessment) to model soil erosion and soil compaction risk for the different weather scenarios and the three typical crop rotations in the soil regions. The results help to identify regions with combined risk for soil erosion and soil compaction. The next step will be the analysis of measures addressing both degradation processes.

How to cite: Steinhoff-Knopp, B., Kuhwald, M., Bäumler, K., Saggau, P., and Lorenz, M.: Identifying areas of multiple soil degradation processes at regional scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21890, https://doi.org/10.5194/egusphere-egu24-21890, 2024.

X3.13
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EGU24-12361
Michael Kuhwald, Katja Kuhwald, and Rainer Duttmann

Soil compaction caused by intensive field traffic is one of the main threats to agricultural soils. Soil compaction occurs when the applied soil stress is higher than the soil strength. Both, soil strength and stress, are highly variable in space and time. While soil strength mainly depends on environmental conditions (e.g. weather, soil type, crop type), soil stress results from the used machinery. One key parameter for the applied soil stress is the wheel load which results from the machinery setup. The wheel load carrying capacity (WLCC) approach takes this into account and specifies the maximum wheel load until soil stress does not exceed the soil strength.

The objective of this study is to model and analyse the dynamic variation of WLCC at regional scale for a 5-year period (2016-2020). We selected a study area (~2000 km²) with highly mechanized agriculture in Northern Germany where the main crops are cereals, maize and sugar beets. Sentinel-2 images were used to derive the crops for the 5-year period. We calculated the WLCC using an advanced version of the SaSCiA-model (Spatially explicit Soil Compaction risk Assessment) for each day of the 5 years.

The results show a high temporal dynamic characteristic of the WLCC during the crop rotation at regional scale. The relatively dry years 2016 and 2018 increased the maximum allowable wheel load, especially during harvesting of maize and sugar beets in autumn. In all 5 years, spring was the time with the lowest WLCC. At this time, however, high soil stresses occur due to the application of slurry and digestates, which is associated with high soil compaction risk. The spatial variation of WLCC depends on the one hand on soil properties such as soil texture. On the other hand, the used crop has a high effect on the WLCC due to different soil water utilization.

Based on the spatio-temporal analysis of WLCC at regional scale, an assessment can be performed to reduce the soil compaction risk either by increasing the soil strength or by decreasing the soil stress. We show exemplarily how the adjustment of tire inflation pressure affects the WLCC. Finally, this study may contribute to understand WLCC dynamics in crop rotations at regional scale and may help to mitigate further soil compaction.

How to cite: Kuhwald, M., Kuhwald, K., and Duttmann, R.: Spatio-temporal modelling of wheel load carrying capacity (WLCC) to mitigate soil degradation at regional scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12361, https://doi.org/10.5194/egusphere-egu24-12361, 2024.

X3.14
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EGU24-2983
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ECS
Sampling origins and directions affect the minimum sampling area in forest plots
(withdrawn)
Chenqi He
X3.15
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EGU24-3244
Liisa Ukonmaanaho, Tuula Larmola, Tuula Aalto, Erik Andersson, Kaido Soosaar, Alexandra Barthelmes, Marina Abramchuk, Juraj Balkovic, Emmi Haltia, Iryna Shchoka, Maud Raman, Kris Decleer, Andis Lazdins, Josep Penuelas, Adria Descals, Jose Miguel Sanchez-Perez, Odette Gonzalez, Julien Tournbize, and Francesc de Paula Sabater Comas

The global goal to mitigate climate change (CC) is to achieve net zero greenhouse gas emissions (GHGE) by 2050; the European Union (EU) aim is to cut GHGE at least by 55% already by 2030. These ambition targets require new GHGE mitigation measures across all land use sectors (LULUCF), where wetlands, as carbon (C) rich ecosystem, can effectively contribute to climate targets, biodiversity, and water-related ecosystem services. Natural peatlands accumulate C effectively due to water-logged conditions. However, they can turn into high GHG sources if they are drained, therefore there is still need to enhance knowledge regarding how and/or how much C is sequestered or released by peatlands after their restoration, as well as the socioeconomic effects.

“ALFAwetlands - Restoration for the future” (www.alfawetlands.eu) is a Horizon Europe funded project (2022-2026), which is coordinated by Luke and carried out at local to EU levels with 15 partners across Europe. It’s main goal, in short, is to mitigate CC while supporting biodiversity and ecosystem services (BES) and being socially just and rewarding. This includes, e.g., increasing the knowledge about C storage and release in peatlands, specifically after restoration. While, in terms of C fluxes, focussing on peatlands, the project scope is larger and includes additionally floodplains, coastal wetlands and few artificial wetlands. ALFAwetlands will develop and indicate management alternatives for wetlands including such that have been or will be restored during this project. Measures under this project are not restricted to ecological restoration but include rehabilitation and re-vegetation action to improve ecosystem conditions (e.g., peatland forest: continuous-cover-forestry, cultivated peatlands: paludiculture). Studies are conducted in 9 Living Labs (LL’s) including 30 sites, which are located in wetlands in different parts of Europe (north-south gradient). At the local level, LL’s support and integrate interdisciplinary and multi-actor research on ecological, environmental, economic, and social issues. Experimental data from local sites are scaled-up and will be utilized e.g., by models to gain and understanding the potential impacts of upscaled wetland restoration measures. To achieve ALFAwetlands goals, 5 research workpackages are being implemented, namely: 1)improve geospatial knowledge base of wetlands, 2)co-create socially fair and rewarding pathways for wetland restoration, 3)estimate effects of restoration on GHGE and BES, with the data achieved from field experiments, 4)develop policy relevant scenarios for CC and BES, and 5)study societal impacts of wetland restoration. The project will also encourage stakeholders to utilise outputs and support their active participation in wetland management.

How to cite: Ukonmaanaho, L., Larmola, T., Aalto, T., Andersson, E., Soosaar, K., Barthelmes, A., Abramchuk, M., Balkovic, J., Haltia, E., Shchoka, I., Raman, M., Decleer, K., Lazdins, A., Penuelas, J., Descals, A., Sanchez-Perez, J. M., Gonzalez, O., Tournbize, J., and Sabater Comas, F. D. P.: Wetland restoration for the future - ALFAwetlands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3244, https://doi.org/10.5194/egusphere-egu24-3244, 2024.

X3.16
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EGU24-3804
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Chun-Yu Lee, Guan-Ying Lin, Yu-Hsuan Liu, Hsiang-Wua Wang, Chien-Fan Chen, and Li-Wan Chang

The coastal areas are renowned for their exposure to strong winds, salt sprays, and blowing aeolian sands, collectively posing threats to farming and the health of residents. Well-established coastal forests offer protection to alleviate these adverse effects and provide various ecosystem functions, such as carbon sequestration and soil conservation. Soils account for approximately 74% of the carbon stock in terrestrial ecosystems. Consequently, even a subtle increase in soil carbon can lead to significant carbon sequestration. Reforestation is considered a suitable practice to enhance both above- and belowground carbon sequestration. However, the benefits of reforestation in coastal areas are hindered by land subsidence and seawater intrusion due to over-exploitation of groundwater for fish farming or manufacturing. To overcome these obstacles, a reforestation practice known as the "ditch-and-embankment technique (D-E technique)" is adopted. This technique involves reforesting coastal lands suffering from land subsidence by constructing inter-parallel ditches and hills. By applying the D-E technique, soil properties can be improved through salt leaching, and soil organic carbon (SOC) stock can be enriched by organic matter inputs from reforested trees. However, the effectiveness of this technique in terms of soil carbon and soil amelioration lacks sufficient evidence. In this study, we investigated the soil carbon stock and soil salinity of a 15-year-old coastal plantation, consisting of four dominant species (Casuarina equisetifolia, Millettia pinnata, Melaleuca leucadendra, Cerbera manghas) established by the D-E technique on the western coast of Taiwan. Soil samples from hills (O horizon and mineral soil) and ditches were collected using soil cores and a piston sampler. A proximate submerged forest was used as a reference baseline. Soil carbon was determined as organic, inorganic, and elemental carbon with a TOC analyzer. Soil salinity was measured in terms of soil pH and electrical conductance (EC1:5). Our results showed that the D-E technique could increase the total SOC stock (O horizon + 0-50 cm mineral SOC) to an average of 48.38 Mg C ha-1, compared to the submerged forest (12.22 Mg C ha-1). The total SOC stocks of hills ranged from 38.02-60.33 Mg C ha-1, significantly higher than the submerged forest, irrespective of species, although there were no significant differences in total SOC stocks between species. Consistent with total SOC stocks, mineral SOC stocks of hills (13.91 -24.49 Mg C ha-1) were generally higher than the submerged forest, with only those from Cerbera manghas and Millettia pinnata being significantly or marginally higher. The similar amount of total inorganic carbon stock between hills and the submerged forest further supported the contribution of reforestation. Soil pH at the 0-5 cm layer of hills was lower than in the deeper soil layer and soils from the ditch. Additionally, EC generally were lower at soil at 0-5 cm or 5-10 cm layers, suggesting the occurrence of salt leaching. In conclusion, our preliminary study suggests that the D-E technique could be an appropriate reforestation approach to establish coastal plantations in areas subject to land subsidence, meeting multiple objectives, including protecting residents' well-being, soil carbon sequestration, and soil salinity amelioration.

How to cite: Lee, C.-Y., Lin, G.-Y., Liu, Y.-H., Wang, H.-W., Chen, C.-F., and Chang, L.-W.: Reforestation based on the ditch-and-embankment technique increased soil carbon stock and alleviated soil salinity in a coastal area subject to land subsidence- a preliminary study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3804, https://doi.org/10.5194/egusphere-egu24-3804, 2024.

X3.17
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EGU24-3514
Salla Tenhovirta, Marjo Palviainen, Elina Peltomaa, and Annamari Laurén

Peatlands are a significant global storage of carbon (C), but also major sources of nutrients and dissolved organic carbon (DOC) to surface waters. Export of DOC from peatlands to watercourses cause emissions of  carbon dioxide (CO2) due to degradation of DOC, as well as enhances the brownification of surface waters, altering the ecological networks of the aquatic ecosystems. Managed peatland forests are hotspots for DOC export into downstream water bodies due to forestry practices such as harvesting and drainage. Water table, soil oxygen availability and vegetation control the release and transport of DOC.

Drainage of peatlands also alters the physical characteristics of peat (Word et al., 2022). However, the role of these peat characteristics in the processes and release of DOC, as well as their influence on the lateral fluxes of carbon from forested peatlands, remains unknown.

In this contribution, we present results from a laboratory experiment where the physical properties of peat and their relationship to peat decomposition are studied in a minerotrophic, nutrient-rich peatland forest that has been drained for ~80 years. The peat for the study was collected from the field site, located in southern Finland, into 50 cm columns along three transects. The transects  extend from 1 to 30 meter distance from the  ditch. In laboratory, the bulk density and water retention characteristics of the peat will first be determined in relation to distance to the ditch. The CO2 emission potential is then defined as the function of these peat properties. This is done by measuring the CO2 fluxes of the peat with a chamber enclosure method, using a Li-7810 online CH4-CO2-H2O analyser.

The results of this experiment will increase the process-level understanding of the mechanisms that drive the export of DOC from peatlands. The produced data will be further utilized in an ecosystem model, to be used in assessing and evaluating environmental impacts of forest management practises.

 

References

Word CS, McLaughlin DL, Strahm BD, Stewart RD, Varner JM, Wurster FC, Amestoy TJ, Link NT. 2022. Peatland drainage alters soil structure and water retention properties: Implications for ecosystem function and management. Hydrological Processes 36: e14533.

How to cite: Tenhovirta, S., Palviainen, M., Peltomaa, E., and Laurén, A.: Physical characteristics of peat and their influence on peat CO2 emission potential in a drained boreal peatland forest, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3514, https://doi.org/10.5194/egusphere-egu24-3514, 2024.

X3.18
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EGU24-20393
Michal Bosela, Boris Tupek, Peter Marcis, Dominik Poltak, Jergus Rybar, Jaroslav Vido, Paulína Nalevanková, Aleksi Lehtonen, and Raisa Makipaa

Spruce monocultures have been intensively planted across a wide area of Europe to increase timber production and meet the demand from society. However, evidence suggests that species monocultures may not be as resilient to drought spells and heat waves compared to mixtures of two or more species. The advantage of mixed forests over monocultures is particularly evident when the mixed species occupy different niches, reducing inter-specific competition and enabling better growth and increased carbon sequestration. However, it remains unclear how drought events and heat waves affect carbon sequestration in the soil and how this differs between mixed forests and species monocultures. In this study, we conducted two years of intensive monitoring of soil CO2 and CH4 fluxes, measured soil microbial diversity, and assessed long-term (tree ring) and seasonal tree growth to quantify carbon sequestration in a mixed forest and a spruce monoculture. Results showed that severe drought in 2022 significantly reduced the growth of Norway spruce stand and its' forest floor and soil CO2 fluxes but at lesser intensity impacted C fluxes of European beech and silver fir stand. The bark beetle outbreak in 2023 caused rapid tree infestation and die-back only in the spruce stand (followed by salvage clear-cut harvesting) which subsequently increased soil CO2 emissions via a sudden increase in litter input from dead trees, soil temperature and water content from reduction of shade and evapotranspiration.

How to cite: Bosela, M., Tupek, B., Marcis, P., Poltak, D., Rybar, J., Vido, J., Nalevanková, P., Lehtonen, A., and Makipaa, R.: Effects of drought and disturbance on the CO2 and CH4 fluxes in a mixed forest and spruce monoculture, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20393, https://doi.org/10.5194/egusphere-egu24-20393, 2024.

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EGU24-18128
Carolin Körbs, Michael Kuhwald, Marco Lorenz, and Rainer Duttmann

A new measure to mitigate soil compaction: Stabilisation effects of greening headlands

Authors: C. Körbs1, M. Kuhwald1, M. Lorenz2, R. Duttmann1,

1Working group of Landscape Ecology and Geoinformation, Institut of Geography, Kiel University, Christian-Albrechts-Platz 4, 24118 Kiel, Germany

2Johann Heinrich von Thünen-Institut (TI), Thünen Institute of Agricultural Technology, Bundesallee 47, 38116 Braunschweig, Germany

 

Submitted 10. January 2024 to the EGU24

Session: SSS9.1- Soil degradation by soil compaction on arable land, grassland and in forests

 

The greening of fields is a common measure in agriculture to prevent soil erosion and often serves as an intercrop. Grass buffer stripes can stabilise the topsoil and thus reduce runoff and promote sediment retention and water infiltration. The existing literature lacks emphasis on examining the stabilising effects specifically related to the greening of headlands. Moreover, there is a need to explore how the implementation of greening practices can mitigate the adverse effects of field traffic and to what extent it can contribute to reducing soil compaction.

As part of the SOILAssist project investigations were carried out on a selected field at the experimental farm in Adenstedt (Lower Saxony, Germany) to study soil structure and functionality. One part of the headland was used to establish a greening with a width of 18m.

To analyse the effects of the greened headland, soil samples were taken in the core field, the greened headland, and the non-greened headland directly after the greening in 2019 and after 4 years in 2023. Disturbed and undisturbed soil samples were taken at 20, 35 and 50cm depth. Afterwards, the soil samples were analysed in the laboratory to provide information on physical soil properties e.g. dry bulk density, air conductivity, air capacity and aggregate stability. In addition, the yield was measured every year in each of the variants.

The results show that the dry bulk density in 2023 was predominantly lower in the core field in 2023 compared to 2019. In contrast, the dry bulk density in the greened headland was generally constant and in the non-greened headland it was slightly lower in 2023 than in 2019 at the depth of 20cm. The lower dry bulk density in the non-greened headland can be explained by the used primary tillage, which lowered the dry bulk density in the topsoil. Since there was no tillage on the greened headland, the effects despite the similar intensity of field traffic remained constant at this part of the field. However, the dry bulk density did not increase in the greened headland which indicates a stabilisation by the vegetation and thus lower the negative impacts of field traffic. At the depth of 35 and 50cm no significant changes were measured, neither for greened nor for non-greened headland.

Whether these effects become more apparent considering the correlation between various soil properties and to which extent a change in soil type plays a role in the stabilisation of headlands through greening will be investigated in the following studies.

How to cite: Körbs, C., Kuhwald, M., Lorenz, M., and Duttmann, R.: A new measure to mitigate soil compaction: Stabilisation effects of greening headlands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18128, https://doi.org/10.5194/egusphere-egu24-18128, 2024.

Posters virtual: Fri, 19 Apr, 14:00–15:45 | vHall X3

Display time: Fri, 19 Apr 08:30–Fri, 19 Apr 18:00
Chairperson: Michael Kuhwald
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EGU24-15630
Noemí Lana-Renault, Manel Llena, José Arnáez, Elena Gómez-Eguílaz, Estela Nadal-Romero, and Erik Cammeraat

Agricultural terraces are very conspicuous features of many mountain landscapes in the world. In the Mediterranean region, rural depopulation and farmland abandonment has led to a process of vegetation expansion on former cultivated terraces, either by natural revegetation or afforestation programs. The main objectives of this study were i) to determine land use changes in a representative Mediterranean mountain area dominated by agricultural terraces in the past, and ii) investigate the effect of different land use and land cover (LULC) on soil properties, SOC and N stocks. For this purpose, five different LULCs (cultivated land, dense and sparse shrublands, old Q. ilex forest and P. sylvestris afforestation) were selected in terraced slopes in the Iberian range, in N. Spain. For each LULC, soil samples were collected every 10 cm down to 50 cm. The results showed that in the last 70 years, shrub cover has doubled (from 280 ha in 1957 to 430 ha in 2020) and forest cover has increased from 46 ha to 171 ha. SOC and N contents strongly decreased with depth, except for the cultivated plots, where the values remain similar through the soil profile. In the top layer, SOC contents were higher in Q. ilex, followed by afforested P. sylvestris, dense and sparse shrubland and cultivated plots. N contents presented a similar pattern except for afforested P. sylvestris, which presented the lowest values. SOC and N stocks were higher in Q. ilex, cultivated land, dense and sparse shrubs, and afforested P. sylvestris. Understanding the effects of LULCC on soil properties and nutrients is essential to assess land management practices after farmland abandonment on agricultural terraces.

Acknowledgements: This research was supported by the MANMOUNT project (PID2019-105983RB-100/AEI/10.13039/501100011033), funded by the MICINN-FEDER.

How to cite: Lana-Renault, N., Llena, M., Arnáez, J., Gómez-Eguílaz, E., Nadal-Romero, E., and Cammeraat, E.: How do land use and land cover changes affect soil properties and nutrients in abandoned agricultural terraces?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15630, https://doi.org/10.5194/egusphere-egu24-15630, 2024.