SSS7.6

This contribution explore role of natural processes in restoration of post mining sites, particularly as concern forest sites restoration.  Extensive metaanalysis of succession chronosequences, reveal that rate of woody vegetation cover recovery in post mining sites is quite fast in fact faster that that recovery of woody vegetation in abandoned filed.    However results from Czechia and Eastern USA show that site compaction associated with levelling and other site improvements substantially reduce spontaneous establishment of woody vegetation.  When ungraded rough and loose substrate is available, the biomass of sites reclaimed by planting is usually but not always higher 5-10 years after planting.  In older plots this difference decrease and succession sites may even show high biomass and faster woody production than reclaimed ones. Caron storage is lover that the most successful reclamation but is comparable to reclaimed sites planted by trees with similar CN ratio of the foliage. Spontaneous site may represent very suitable nursing sites for late succession woody species. Also recovery of otter ecosystem function such as water retention is similar. Several wind dispersal species dominate in site colonization, which vary in their colonization strategy which generate variation in site development depending of distance form source of diaspores. These research indicate that natural processes of passive restoration may be useful strategy to restore forest in post mining sites.

How to cite: Bartuška, M. and Frouz, J.: Natural processes useful tool in post mining site restoration., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11137, https://doi.org/10.5194/egusphere-egu22-11137, 2022.

The establishment of monospecific eucalypt plantations has increased considerably over the last half-century. At present, eucalypts are the tree species that are planted most widely across the world, and the common practice of soil mobilization prior to their planting has been associated with negative effects on soil functions such as nutrient and water cycling, carbon sequestration, soil erosion control and soil biodiversity conservation. In Central Portugal, the construction of bench terraces for eucalypt plantations areas has become increasingly common on steep terrain. Bench terrace construction implies the mobilization of large quantities of topsoil and, hence, elevated installation costs that are justified by the advantages in planting, fertilizer application, mechanical and agrichemical weed control and, ultimately, salvage logging and extraction of wood and logging residues. Although terraces are a traditional soil and water conservation technique, the hydrological impacts of bench terracing for forest plantations have been poorly studied. The use of heavy machinery in forests has been reported to increase soil compaction and bulk density and, thereby, decrease soil infiltration capacity and increase runoff generation. At the same time, the flat sections of bench terraces will increase not only infiltration of rainfall but also re-infiltration of run-on, for example from the adjacent risers or diverted forest tracks. In the case of eucalypt plantations, (re-)infiltration patterns may be strongly affected by soil water repellency (SWR), as eucalypts have been widely associated with strong to extreme SWR, especially during dry periods. This study aimed to quantify the short- to long-term impacts of bench terrace construction on SWR in eucalypt plantations along a chrono-sequence. To this end, SWR was measured in-situ, using the Methanol droplet (MED) test, for four different periods of time-since-terracing, i.e. 0, 5, 10 and 17 years after terracing. For each of these periods, three pairs of nearby terraced and non-terraced eucalypt plantations were studied, giving a total of 24 study sites. The MED measurements were done during the dry summer of 2020 (in plain covid-19 crisis conditions). The results showed clear differences in SWR between terraced and non-terraced eucalypt plantations. The median SWR was extreme in all non-terraced sites (MED classes 7 to 8) as opposed to highly variable at the terraced sites, ranging from wettable to strong (MED classes 0 to 6). In the case of the terraced sites, the time elapsed since terrace construction had a major impact. The median SWR was very wettable immediately as well as 5 years after terracing, while it was moderate and strong water repellent 10 and 17 years after terracing.

How to cite: Martins, M. A. S., González-Pelayo, O., Machado, A. I., Simões, L. B., Ben-Hur, M., and Keizer, J. J.: The short-to medium-to long-term effects of bench terrace construction for planting eucalypt trees on soil water repellency, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-513, https://doi.org/10.5194/egusphere-egu22-513, 2022.

Conventional cropping practices in soils that are under imminent threat of desertification, as those on Crete, often lead to soil erosion. An experiment under the framework of the SoilCare H2020 EU project was set up in three field sites in Western Crete, Greece, to evaluate the impacts of diverse cultivation techniques on soil loss. The targeted crops were olive orchards, vineyards and fruit orchards, in which a control versus treatment (soil-improving cropping system, SICS) experimental design was applied. Different tillage practices were compared in olive orchards (normally tilled to no-tilled), vetch cover crop to no vetch application was tested in a vineyard, whereas the conversion of an orange grove to an avocado farm was implemented. Soil loss (erosion/deposition) rate and soil properties as well were monitored between 2018 and 2021 in the field studies, comparing the results from control areas and SICS areas. The soil loss rate monitoring occurred with measurements through cross sections on the olive orchards and vineyards, or soil pins on the fruit orchards. The biophysical measurements concerned soil texture, saturated hydraulic conductivity, water stable aggregates, bulk density, mineral nitrogen, available phosphorous, exchangeable potassium, sodium and magnesium, soil organic carbon, soil pH, soil electrical conductivity, and earthworm count. The results [1] indicate that for the olive orchards, no-tillage practice reduced average erosion/deposition by 14%. The application of vetch treatment reduced mean soil loss by 13% and for the fruit orchards, the rotation of orange trees to avocado trees reduced mean soil erosion/deposition by over 34%. The biological health and condition of the SICS plots of the olive orchards and vineyards were improved compared to the control ones. Water and solute movement as well as soil aeration were appropriate for no-tillage and avocado trees treatments, and slightly improved in the case of vetch cover application. The experimental results demonstrate the critical footprint of improved cropping techniques to soil loss mitigation and sustainable land management.

[1] Tsanis, I.K., Seiradakis, K.D., Sarchani, S., Panagea, I.S., Alexakis, D.D., Koutroulis, A.G.: The Impact of Soil-Improving Cropping Practices on Erosion Rates: A Stakeholder-Oriented Field Experiment Assessment, Land 2021, 10(9): 964. https://doi.org/10.3390/land10090964 

How to cite: Tsanis, I., Sarchani, S., Panagea, I., and Koutroulis, A.: Biophysical Measurements and Soil Loss Rate Assessment in Field Studies with Improved Cropping Techniques, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2961, https://doi.org/10.5194/egusphere-egu22-2961, 2022.

Vineyards cultivated in steep terrains are widespread all over the world, constituting the main economic activity and landscape element in many territories. However, these vineyards can be affected by several problems, mainly due to water stress in dry periods and shallow slope instabilities during very intense thunderstorms or prolonged rainy periods. Both these problems provoke significant damages to the grapevines and the implants, together with a general loss of fertility and biodiversity in the soil horizons. Sustainable managements of the inter-rows, which limit or exclude tillage operations in soils, can represent a useful solutions to reduce the phenomena of water stress and of the triggering of shallow slope failures. Since they could modify the soil hydrological behaviors, a continuous-in-time soil hydrological monitoring is required to highlight differences on soil moisture along different dry and wet periods between vineyards managed in different ways. The aim of this work is, then, to present the results of a field hydrological monitoring carried on vineyards managed in different ways to highlight differences on soil water content trends in different seasons. The results of this monitoring can infer to different responses in terms of possible water stress phenomena and susceptibility towards shallow slope failures. Some test-sites were selected in northern Italian Appenines, in two important wine districts very prone to water stress and slope instabilities. The field monitoring is carried out with a set of soil water content sensors, installed at different depths in the soil profile and in inter-rows characterized by different soil managements, both with traditional tillages and sustainable practices (permanent grass cover, alternation between grass cover). Soil water content trends collected at the same depth in different test-sites allow to highlight the impact of the different practices in soil hydrological behaviors and on the probability of low soil moisture (predisposing factor to water stress) or saturated conditions (predisposing factor to slope instaibilities). This work is realized in the frame of VIRECLI (funded by Regione Lombardia) and LIFE-DRIVE projects.

How to cite: Bordoni, M., Vivaldi, V., Panza, G., and Meisina, C.: Field hydrological monitoring in vineyards for the analysis of shallow slope failures susceptibility and water stress phenomena, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4553, https://doi.org/10.5194/egusphere-egu22-4553, 2022.

Severe subsoil compaction can occur during construction due to heavy construction machinery or storage of excavation material. This has consequences on many soil functions such as water storage and purification capacity, water and nutrient uptake by plants, etc. The consequences of subsoil compaction are known but the means and time for recovery are not well documented. Subsoil recovery is sometimes even considered unreachable at human scale.

The aim of the ROCSUB project (Restoration Of Compacted SUBsoil) is to monitor the effects of subsoil compaction on the long term and evaluate the potential of two different restoration methods (mechanical and biological) and the time needed for recovery.

The experiment started in 2020 and takes place on a field in western Switzerland with loamy texture. The subsoil was severely compacted by a heavy pile of excavation material. Compaction occurred directly on the subsoil, after topsoil removal. Visible signs of compaction were detected up to 70 cm depth.

The experiment is designed along three mechanical axes (compacted, mechanically loosened, control) and three vegetal axes (permanent grass, crop, willow trees) with four replication of each combination, resulting in 36 plots. The mechanical loosening was performed with an excavator and willow trees were selected as the most promising bioengineering method for restoring the subsoil structure.

Following properties are monitored or sampled on a yearly basis: soil moisture via TDR probe, yield, plant biomass and physiology, soil structure properties including bulk density, air capacity, water holding capacity, air permeability. The soil structure evolution is also assessed via X-ray computed tomography.

Preliminary results show an improvement in plant biomass (grass and willow) after mechanical loosening treatment. We expect plants of the compacted plots to suffer most during extreme weather conditions (dry or wet). The mechanically loosened treatment is expected to recover drainage function rapidly while water holding capacity should take more time. The combination of mechanical loosening and willow tree is expected to recover most subsoil functions fastest.

How to cite: Johannes, A., Fontana, M., Köstel, J., Keller, T., Weisskopf, P., and Bragazza, L.: Recovery of compacted subsoil : introducing the ROCSUB project, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5230, https://doi.org/10.5194/egusphere-egu22-5230, 2022.

Grazing by mammalian herbivores can serve as a climate mitigation strategy as it influences the size and stability of a large soil-C pool (more than 200 Pg C in the world’s grasslands, steppes, and savannas). With the continuing decline in large mammalian herbivores, the resultant loss in grazer functions can be consequential for this soil-C pool, and ultimately for the global carbon cycle. While herbivore effects on the size of the soil-C pool and conditions under which they lead to gains/loss in soil-C are well known, their effects on the equally important aspect of stability of soil-C remain unknown. Also unknown is whether herbivore effects on soil-C and soil-N are related to each other. We use a replicated long-term grazer-exclusion experiment in the Trans-Himalayan ecosystem of northern India to evaluate the consequences of herbivore-loss on the stability of soil-C by quantifying interannual fluctuations (2006-2021). We test how grazers influence the stability of soil-C due to their impacts on both soil-C and soil-N. We find that experimental herbivore-exclusion raises inter-annual fluctuations in both soil-C and soil-N. Importantly, structural equations modelling show that herbivore-exclusion increases the soil-C and soil-N coupling, and weakens the stabilizing effect of soil-N on soil-C. Herbivore-loss, and consequent decline in grazer functions in soil, can therefore undermine the stability of soil-C. Conserving and restoring the functional role of large mammalian herbivores is critical for this valuable ecological service and towards climate mitigation.

How to cite: Naidu, D. and Bagchi, S.: Large mammalian herbivores increase the stability of soil carbon in grazing ecosystems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5471, https://doi.org/10.5194/egusphere-egu22-5471, 2022.

Forest management is a common practice to reduce wildfire risk, furthermore in ecosystems prone to fire and where wildfires are recurrent as is the Mediterranean ecosystem. However, few studies were carried out about the effects of pre-fire management in wildfire affected areas and the effectivity of these managements decreasing soil nutrients depletion. The aim of this study is to examine the effectivity of this treatment (clear-cutting operation whereby part of the vegetation was cut and left covering soil surface) carried out before a wildfire that broke out in 2015 and evaluate if the management had influence on wildfire severity of three sites: two exposed to management practices in 2005 (site M05B) and in 2015 (site M15B)–and one that did not undergo any management (NMB) and to compare their properties with those recorded in a Control area unaffected by 2015 wildfire. The fourth areas were sampled and compared 2, 10 and 18 months after wildfire. The study area is located in Ódena (NE Spain). The wildfire occurred at July 27th of 2015 and burned 1237 ha. In each area and in each sampling moment we collected 9 topsoil samples (0-5 cm depth) and analyzed: aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K). Two-way ANOVA statistical analysis was carried out to check the differences between managements and time. Results show significant differences (p value < 0.05) between managements 2 months after wildfire in AS, TN, SOM, pH, EC, Ca and Mg; 10 months after wildfire in AS, SOM, pH, EC, Ca, Mg and Na; and 18 months after wildfire in AS, SOM, pH, EC, Ca and Mg. Differences between sampling time were registered in M05B, M15B and NMB for each soil analyzed property. Control did not vary significantly (p value > 0.05) over time due to the absence of fire or manage perturbation. The vegetation removal in M05B decreased the wildfire impact on soil, perhaps due to the fuel load reduction and consequent low fire severity. In this case if forest management is carried out few months before the fire, the impact is strongly reduced as occurs in M15B. High fuel density that we found in NMB site should be managed to avoid high wildfire severity. Overall, the time of forest management previous to fire is a crucial aspect that influence on fire severity and the consequent impact on soil properties. Therefore, this type of studies and knowledge should be taken into account and incorporated when carrying out forest management plans to periodically manage certain areas.

How to cite: Francos, M., Úbeda, X., and Pereira, P.: Wildfire and forest management necessities to avoid soil degradation. A case study in a Mediterranean forest, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6043, https://doi.org/10.5194/egusphere-egu22-6043, 2022.

A proper monitoring and management of semi-arid landscapes affected by wildfire is needed to reduce its effects on the soil hydrological response in the wet season. Despite ample literature on the post-fire hydrology in forest soils, it is not well documented how the hydrologic processes respond to changes in vegetation cover and soil properties of semi-arid lands (such as the rangeland and areas with sparse forests) after wildfire. To fill this gap, this study evaluates soil hydrology in a semi-arid soil of Central Eastern Spain dominated by Macrochloa tenacissima (a widely-spread species in Northern Africa and Iberian Peninsula) after a wildfire. Rainfall simulations were  carried out under three soil conditions (bare soil, burned and soils with unburned vegetation) and low-to-high slopes, and infiltration, surface runoff and erosion were measured. Infiltration rates did not noticeably vary among the three soil conditions (maximum variability equal to 20%). Compared to the bare soil, the burned area (previously vegetated with M. tenacissima) produced a runoff volume lowered by 27%. In contrast, in the area covered by the same species but unburned, runoff was lowered by 58%. The burned areas with M. tenacissima produced soil losses that were similar as those measured in bare soils, and, in steeper slopes, even higher. Erosion was instead much lower (-83%) in the sites with unburned vegetation. Overall, the control of erosion in these semi-arid lands is beneficial to reduce the possible hydrological effects downstream of these fire-prone areas. In this direction, the establishment of vegetation strips of M. tenacissima in large and steep drylands of bare soil left by fire may be suggested to land managers.

How to cite: Zema, D. A., Plaza-Àlvarez, P. A., Mijan Uddin, S. M., Parhizkar, M., and Lucas-Borja, M. E.: Short-term hydrological response of soil after wildfire in a semi-arid landscape covered by Macrochloa tenacissima (L.) Kunth, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5518, https://doi.org/10.5194/egusphere-egu22-5518, 2022.

The application of carbonaceous materials for the restoration of degraded soil has been a field of active research for the last decades. Several studies show their ability to immobilize heavy metals and polycyclic aromatic compounds (PACs) in contaminated soils. However, there is still a lack of guidance to translate what has been demonstrated in the lab into practice. The possibility of immobilising a contaminant depends on the type of material used and its specific chemical and physical properties, as well as the quantity applied. The suitable sorbent selection from the variety of carbon-based materials available, including biochar and activated carbon, is one of the major difficulties for practitioners. Nevertheless, a generic assement of sorbent quantities needed for a specific immobilization at a given site is not possible, due to specific material properties, as well as differences in contamination scenario and soil properties. To overcome this bottleneck, we propose a workflow to evaluate the applicability of carbon-based materials for heavy metal- and PACs contaminated soil remediation, for scientists and practitioners alike.

We initially carried out a literature review collecting knowledge on the influence of feedstock, production temperature and possible modification steps on a material’s physical and chemical characteristics. We further conducted expert interviews with practitioners and regulators in Austria. Thereafter, we performed laboratory scale experiments to complement the knowledge collected. For our experimental work, eleven carbon-based materials were used. A total of ten anonymized contaminated soil samples from existing remediation sites containing varying amounts of arsenic, antimony, cadmium, zinc, lead and PACs were used for batch and column experimentation to determine suitability and amendment rate of biochar for soil remediation. These experiments included the investigation of amendment scenarios at different scales (laboratory batch- to percolation column scale) to assess the suitability of small-scale batch experiments in our workflow. Batch tests with 5g of <2 mm sieved soil were performed according to OECD 106 (2000). Batch tests with 100 g of non-sieved soil were performed to maintain the heterogeneity of the sample at a solid/liquid ratio of 1:2 (EN 19529:2015-12) and 1:10 (EN 12457-4:2002). After 24 h shaking we centrifuged the samples and filtered the supernatant at < 45 µm for subsequent sample preparation and analysis via ICP-MS, GC-MS and LC-MS. At last, column percolation tests were performed according to EN 14405:2017, using columns with 6 cm diameter, 38 cm height and containing 1.5 kg of soil.

Our work will be summarized by a contaminant and site specific decision tree for suitability of biochar application. The decision tree will guide the practitioner through a series of questions that will assess whether the site is suitable for biochar-based soil remediation, which contaminants can be treated, what characteristics a suitable sorbent should have, what range in sorption affinity could be expected for a suitable sorbent, and what are potential application rates in the field.

This study was partially funded by the Austrian Federal Ministry of Sustainability and Tourism (BMNT), management by Kommunalkredit Public Consulting GmbH (grant number B820017).

How to cite: Carlini, C., Chaudhuri, S., Greggio, N., Marazza, D., Mann, O., Huffer, T., Hofmann, T., and Sigmund, G.: Practical guideline for applying carbon-based materials for restoration of degraded soil, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6279, https://doi.org/10.5194/egusphere-egu22-6279, 2022.

Crop rotation and manure application are agricultural practices that are regularly used to improve soil quality and crop yields, and long term experiments (LTEs) provide an excellent platform to assess their impact. There is a large volume of literature on the benefits of these practices on soil structure, organic matter contents, soil nutrient levels, and other soil chemical properties. There is, however, little to no information on the impact of manure application and crop rotation on water retention at low matric potentials (pF > 5.0; <−10 MPa) as occurs under dry conditions. The study utilizes LTEs (20 to 127 years) from Denmark, Sweden, Germany, Spain and the UK that includes manure application and various crop rotation sequences. The sites vary in soil texture, organic matter content, and manuring rates. We measured water vapour adsorption and desorption isotherms covering the range from −10 MPa to −465 MPa (pF 5.0 to 6.8) on soil samples from the LTEs. The presentation will discuss the interactive effect of soil texture, manure and crop rotation on the magnitude of water sorption, its hysteresis, and the specific surface area.

How to cite: Arthur, E., Fu, Y., Paradelo, M., and de Jonge, L. W.: Manure and crop rotation affect water retention under dry conditions in long term experiments, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9787, https://doi.org/10.5194/egusphere-egu22-9787, 2022.

Many intensively cultivated areas suffer from soil losses, due to accelerated soil erosion processes, which eventually deposit in the stream channel. To prevent flood risks, the deposited sediments are routinely dredged from the streambed, and due to the lack of a cost-effective solution, piled upon the stream bank. Dredged sediments (DS) piles may disturb the ecological balance in the riparian habitat, serve as a reservoir for weed seeds and may enable the further establishment of invasive species. Studies have shown that DS tend to be richer in organic matter and plant nutrients compared to the adjacent local soil, thus DS might be used as amendments to agricultural fields. However, the seedbank in DS may contain harmful weed species that threaten farmers from applying this valuable soil. The main objective of the current study is to assess the quality of DS as an agronomic substrate and its potential risk for weed invasion and establishment in the agricultural environment in case of applying DS in agricultural fields. DS that were piled (0.6-1.2 m height) on the eastern bank of Nahalal stream (Jezre'el Valley, northern Israel) were sampled along the bank, from a section of 1 km in 10 transects at three depths (top, middle, bottom). The upper (0-20 cm) soil layer at the adjacent agricultural field (AF) was sampled in parallel to the DS transects and along the hillslope Catena. Soil properties analyses was conducted in order to assess the soil quality of DS compared with AF. The soil seedbank was recorded for DS and AF samples using a germination assay. Preliminary results shows that the quality of DS can fit agronomic requirements. However, a trend of increased species richness and seed density was observed in the DS compared with the AF samples. Future analysis will include the calculation of a soil quality index and a Weed Risk Factor in order to assess the potential risk of reusing DS in agricultural fields.  

How to cite: Tanner, S., Laor, Y., Matzrafi, M., and Egozi, R.: Reuse of dredged streambed sediments in agricultural fields: soil quality and weed risk assessment, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11151, https://doi.org/10.5194/egusphere-egu22-11151, 2022.

Fruit and crop cultivation represents the main food source and produce important incomes in many countries worldwide but, in many cases, they can cause soil erosion and lead to extreme land degradation. Understanding and quantifying the impact of land use on soil erosion is essential to achieve sustainable land management. In Umbria region in Central Italy, olive and tobacco are two of the most profitable crops, spread on the slopes of mountains and hills or in the Tiber river valley, respectively. In particular, tobacco production, spread in the last decades along the plains and foothills of the northern part of the region, posed serious threats to the ecosystem, causing soil erosion and representing an alarming source of chemical pollution.

In this study, the environmental advantages of replacing tobacco crop with perennial olive groves were evaluated. For this purpose, a method is proposed, initially, to evaluate land suitability for olive cultivation based on machine learning methods and on a set of geomorphological and climatic variables, and then to evaluate the impact of land use conversion from arable crops to olive groves on soil erosion, using LANDPLANER model and considering different rainfall scenarios. LANDPLANER is able to estimate the effects of rainfall on the triggering of landslides and erosion processes and their competition on the slopes. Results show that such conversion is sustainable for more than 40% of the current tobacco production area and it may reduce soil erosion up to 50%. This study provides a framework that starting from a statistical model for land evaluation for new agricultural purposes, assesses the impact of land use change on soil erosion. It provides a method useful to promote a sustainable use of soil, taking into account also effects of agricultural changes effect on soil erosion and degradation.

How to cite: Fiorucci, F., Mariotti, R., Pandolfi, S., Moussavi, S., Baldoni, L., and Rossi, M.: Land evaluation for olive growing after tobacco and its implication on soil erosion, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9817, https://doi.org/10.5194/egusphere-egu22-9817, 2022.

Shallow landslides induced by rainfall are very common movements that occur in hilly and mountainous areas causing losses of human life, ecological and environmental impacts and considerable economical costs. The predisposing factors for shallow landslides are represented by morphology, lithology, soil type, land cover, and land use, and their changes. Land use is constantly evolving because it is linked to human activities; the increase of population pressure and economic development forced more people to use all areas available. 
A lot of scientific contributions analyzed the positive effects of vegetation cover on slope stability, focusing on the mechanical effects of vegetation (both vegetation cover and roots) in terms of providing additional mechanical root reinforcement. Conversely, the effects of agricultural practices on slope stability conditions are poorly investigated. Indeed, while agriculture contributes positively to the landscape, biodiversity, climate and fires, on the other hand, improper agricultural practices and soil uses can modify the mechanical properties of the involved soils leading to a possible increase of instability phenomena. 
To evaluate the effect of agricultural practices on the slope stability conditions, we present an application of a probabilistic, physically-based model for the triggering of rainfall-induced landslides (PG_TRIGRS – a probabilistic, geostatistic-based extension of the TRIGRS model) to the Collazzone area, a cultivated area located in Umbria, central Italy, characterized by a high susceptibility to landslides, which is studied and periodically monitored through systematic image analysis and on-site surveys.
The method applied in this research included the comparison between landslides observed in situ and the spatial distribution of the probability of failure derived from the application of PG_TRIGRS model, which models the study area in a GIS grid and treats each cell as an infinite slope. More in detail, a heuristic approach was adopted: after a first run of the model with unbiased parameters, the slope stability analysis has been carried out assuming several percentages of reduction of the effective soil cohesion (c’) to mimic an increasing impact of agricultural practices on the strength conditions.
A back-analysis methodology, with the support of sensitivity indices, was adopted to provide a preliminary quantitative evaluation of the effect induced by agricultural practices on the mechanical properties of the soil. To test the reliability of the method, standard contingency matrix and skill scores were adopted and the best compromise between correct and incorrect model outcomes was obtained considering a reduction of c’ between 20% and 30%. 
In conclusion, we could estimate that in the analyzed area the agricultural practices can cause a 20 to 30% reduction in soil.

How to cite: Volpe, E., Gariano, S. L., Ardizzone, F., Fiorucci, F., and Salciarini, D.: A first attempt to evaluate the impact of agricultural practices on slope stability, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7424, https://doi.org/10.5194/egusphere-egu22-7424, 2022.

Land use change drives shifts in the taxonomic and functional diversity of soil organisms. Soil biota response will depend on both local scale agricultural management, and regional scale environmental conditions, with the diverse pool of soil taxa unlikely to respond in a uniform manner. To monitor the effect of land management and potential restoration efforts, we require techniques which can be deployed at various spatial scales, and which account for the high diversity of these communities. In this presentation, we describe the role of eDNA metabarcoding targeting a broad range of taxa to detect and parameterise these responses. We present the results of studies of habitat conversion of humid and dry forests in French Guiana and Colombia respectively, before detailing how the method will be used to monitor agricultural pasture in the UK undergoing conversion to “regenerative” management. In these studies, we combine measures of alpha and beta diversity to account for shifts in species abundance dependent on habitat management, and assignment of functional groups to infer shifts in soil biota functioning.  Overall, we find that results track expected shifts in biota, for example a replacement of a broad diversity of plant eDNA to a community signal largely dominated by grasses. Agricultural soils are characterised by a greater proportion of bacteria and protists associated with the cycling of labile nitrogen. We conclude by pointing to the weaknesses of the method, and highlighting the importance of complimentary methods in spite of fruitful deployment across varied habitats.

How to cite: Donald, J., Wills, J., Early, R., Chave, J., Iribar, A., Murienne, J., Zinger, L., and Gonzales, M.: Multi-taxa eDNA metabarcoding to monitor the degradation and restoration of belowground biota in agricultural soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-786, https://doi.org/10.5194/egusphere-egu22-786, 2022.

Soils are connected to key ecosystems services such as biomass production, nutrients supplying and biodiversity conservation. Critical to human life and nature preservation, soil health, sustainable management, and restoration are central topics to achieve the Sustainable Development Goals proposed by the United Nations in 2015. Despite the active roles of the scientific community, land planners, and stakeholders for advancing science and developing applications to achieve global restoration goals, there is a lack of public perception in relation to the importance of soils and their roles in ecosystem conservation and restoration. For this reason, communicating these concepts to younger generations can be critical to promote actions for soil conservation and restoration in society. In this context, we used the concepts of soil biology and ecosystem functions, with a particular focus on soil biocrust communities, as the central topics for our laboratory’s contribution to The L’Oréal Girls in Science Forum (LGSF) 2018 and 2019. Biological crusts communities (also known as biocrusts) are not commonly known by the public but are extremely important for soil establishment, succession, nutrition, and control of abiotic stress.  The LGSF program encompasses a collaboration between L’Oréal Australia and the University of New South Wales, aiming to raise the profile of science as an attractive career option for them in the future. With a large number of young students attending this event, we took advantage of this opportunity to teach them about soil sustainability and highlight biocrusts’ structure and composition, as well as sensitiveness to anthropogenic disturbances, and their potential for land restoration. The presentation was divided into stations or stands, starting with a showcase of degraded lands in Australia due to mining activities, and subsequently introducing real biocrusts portions while underlining important functions, components, and structure. Lastly, we showed them ‘alive’ cyanobacterial communities, which are the primary colonizers of biocrusts, and can be applied combined with seed enhancement technologies to improve restoration. Seeds of endemic plants from Australia and bio primed with cyanobacteria were presented together with the contrast treatment (control), proving, and emphasizing the ability of cyanobacteria for producing plant growth hormones and contributing to revegetation. Finally, cyanobacteria-made pellets were exposed in Petri dishes together with pictures of regions successfully colonized after their introduction. The whole pedagogical experience was enriched with matching games, where the girls were able to recognize Australian endemic trees and main cyanobacteria related to soil structure and nutrition. This activity pointed to the importance of preserving soil biological communities in the context of land restoration, to ensure the provision of key ecosystems services provided by soils.

How to cite: Machado de Lima, N. and Munoz Rojas, M.: Teaching and enriching younger generations perception of soil ecosystems and dryland restoration through soil biocrusts, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8943, https://doi.org/10.5194/egusphere-egu22-8943, 2022.

Soil salinity can result in osmotic and ionic stresses that critically impede seedling emergence, especially in drylands. Novel microbial-based technologies are emerging in the context of ecosystem restoration as a promising strategy to improve seedling establishment in saline environments. However, with recent concerns and the potential adverse impact of the use of exogenous microorganisms as bio-inoculants, much work is needed to develop groups of native microorganisms that can overcome soil salinity stress during restoration. In this study, we tested the effect of bio-inoculants individually composed of halophilic bacteria, biocrust cyanobacteria, and a consortium combination of both, on improving seedling emergence in soils with three salinity levels (low, moderate, and high salinity). Seedling emergence was assessed in four Australian native plants, Triodia epactia, Triodia pungens, Acacia ampliceps and Canavalia rosea, all inoculated with each of the inoculants and a control treatment without microbial inoculation. Our results showed that the highest seedling emergence was recorded in soils with low salinity, followed by moderate salinity soil and high salinity soil. Both Triodia spp. were severely impacted by salinity with very low emergence in all soil types. Acacia sp. emergence was higher when inoculated with halophilic bacteria in low and moderate salinity soils while Canavalia sp. emergence was higher under cyanobacteria inoculation in moderate salinity soils. Overall, our study shows that individual inoculation of halophilic bacteria and cyanobacteria improves the emergence of Acacia sp. and Canavalia sp. seedlings in low and moderate saline soils, while seedling emergence in high salinity soils can only be enhanced when using the combined consortia composed of halophiles and cyanobacteria. The analyses of the soil bacterial community composition by 16S rRNA gene amplicon sequencing showed that the inoculants did not negatively affect the resident bacterial soil communities. In conclusion, poor seedling emergence from salinity stress during the restoration of some plant species can be ameliorated with the inoculation of native halophilic bacteria and cyanobacteria. Grass species such as Triodia might need additional treatments to overcome salinity stress.

How to cite: Dadzie, F., Machado de Lima, N., and Muñoz- Rojas, M.: Native soil bacteria and biocrust cyanobacteria inoculation improve seedling emergence of native plants on saline dryland soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9005, https://doi.org/10.5194/egusphere-egu22-9005, 2022.