In the Anthropocene era, human activity has very often caused large-scale degradation of entire ecosystems including the soil, with attempts to restore the degraded areas to their ecological functions. Human intervention consisting of afforestation with various tree species initiates and accelerates the long-term process of primary succession in post-mining sites and secondary succession on sites following large-scale disturbances caused by fires.

The advances of soil formation process were investigated in reclaimed areas. Variants afforested with different tree species located in post-mining and post-fire area were investigated. The research plots have been replanted with various tree species, Pinus sylvestris L., Larix decidua Mill., Betula pendula Roth, and Quercus robur L. First research area was opencast sand mine where primary succession supported by afforestation occurs (SM). Second place was reclaimed areas after a large scale fire with secondary succession supported by afforestation. In post-fire place were investigated two variants with (PF_C) and without (PF) pyrogenic (charcoal) carbon present in soil. Each combination of tree and place were investigated in one soil profile and three additional soil cores collected from 0-90 cm, what gave four repetitions of each variant. Soils were characterised on the basis of the World Reference Base (WRB) and their basic properties such as pH, organic carbon and total nitrogen content, sorption properties and grain size distribution were determined.

Studies in transformed areas such as post-mining or post-fire are focusing mainly on the topsoil, in presented research the main goal was to determine what are the differences in pedogenesis in mentioned above scenarios. 

There were slight differences in the thickness of humus horizons (H) in soils under investigated variants. The thickness of H horizons was higher in plots in post-fire in PF_C variant compared to PF and SM. In SM were noted that the highest thickness of H horizon occurs under Larch. In post-mining areas under each tree species occurs Arenosols in post-fire areas occurs Podzols. 

This research was funded by The National Science Centre, Poland, grant No. 2021/42/E/ST10/00248. 

How to cite: Józefowska, A., Ogar, W., Thị Hồng, V. T., Wanic, T., Woś, B., and Pietrzykowski, M.: Soil forming processes visible 30 years after the primary and secondary forest succession in post-mining and post-fire area, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13700, https://doi.org/10.5194/egusphere-egu23-13700, 2023.

The role of plantations for restoring humid forest ecosystems is subject to intense debate. Some studies suggest that plantations are inferior to secondary forests in most ecosystem services. In contrast, other studies emphasise the role of planted trees that could catalyse an accelerated development towards late-successional forests. Our study analyses a unique dataset of old (>40 years) unmanaged timber plantations. Planted species were Aucoumea klaineana, Cedrela odorata, Tarrietia utilis, and Terminalia ivorensis. We compare these to secondary forests, and pristine primary stands. Our results indicate that in the unmanaged plantations, species-rich stands with high biomass evolved. The carbon stocks of the unmanaged plantations exceeded the secondary forest and had similar levels to the primary stands. The biomass of the naturally regenerated trees in the plantations was similar to secondary forests. Not surprisingly, timber value of the plantations surpassed both primary forests and secondary forests. Results were more mixed for biodiversity attributes. Plantations of Aucoumea klaineana had lower diversity values than the primary and secondary forests. However, other species, especially plantations of Cedrela odorata, had similar diversity to primary and secondary forests. Species with high conservation value were present in all three ecosystem types. Above-ground carbon stocks in plantations were highest, and there were no statistical differences in below-ground carbon stocks. Our results indicate that plantations could play a role in rapidly accruing carbon in tropical landscapes. 

How to cite: Berninger, F., Brown, H., and Appiah, M.: The potential of plantations to restore ecosystem services, a case study from Ghana, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7858, https://doi.org/10.5194/egusphere-egu23-7858, 2023.

Available data indicates 2.8 million potentially contaminated sites, just across the EU-28. While 650,000 sites have been registered, only 1 in 10 have so far been remediated[1]. The management cost of European contaminated sites is estimated at €6 billion annually[2]. The main types of contaminants are potentially toxic elements (including heavy metals). Similarly, a 2014 Government study in China found 16.1% of all soil and 19.4% of arable land showed contamination, with Cd, Ni and As being the main pollutants[3]. Meanwhile, the global challenge of feeding growing populations while still reducing greenhouse gas emissions leaves less agricultural for dedicated bioenergy crops[4]. Therefore, there is a pressing need to successfully combine nature-based decontamination through phytoremediation with bioenergy production.

Given the wide variety of non-agricultural marginal lands[5], species selection must combine significant biomass production with acceptable levels of contamination for subsequent use or energy conversion.  Whereas specialist hyperaccumulator plants may achieve higher levels of contaminants and greater bioconcentration and translocation factors, their inherently lower productivity means that biomass, energy yield and mass of contaminants removed per unit area will be relatively small.  In contrast, high yielding, low contaminant uptake characteristics, such as for conventional energy crop species, could result in greater energy production, economic viability and biomass utilisation potential.

Here we report on field scale trials to implement this strategy, part of the CERESiS (ContaminatEd land Remediation through Energy crops for Soil improvement to liquid biofuels Strategies) H2020 Project (GA 101006717). We have evaluated the performance of Phalaris, Miscanthus, Saccharum and Pennisetum species for combined phyto-remediation and phyto-management of contaminated land during energy crop production in Brazil and Europe.  Reed canarygrass (Phalaris arundinacea) is a native perennial rhizomatous C3 species suitable for non-agricultural or marginal lands and climatic zones such as Scotland (where Miscanthus x giganteous cannot grow).  Our phytoremediation trials using Phalaris in Italy and Ukraine are the first we are aware of.  In the UK the CERESiS project has utilised field trials originally established during the BioReGen (Biomass, Remediation, re-Generation: Reusing Brownfield Sites for renewable energy crops) EU Life demonstration Project (LIFE05 ENV/UK/000128) in 2007.  These allowed direct comparison of the actual contaminant removal rates of three crop species:  Although the biomass of Miscanthus and short-rotation coppice Salix contained higher concentrations of certain elements, Phalaris far out-performed these in terms of biomass, ease and economy of production[6].  Surprisingly, despite lower contaminant concentrations in Phalaris, such was the increased biomass that the total mass removed was still greater than for Miscanthus or Salix.  This suggests that low-uptake phyto-excluding plants which can tolerate contaminated soils and grow productively may still represent the best and most economically viable option for clean-up of contaminated sites. Meanwhile this nature-based solution can simultaneously deliver a variety of wider societal and environmental benefits, such as greening-up derelict land or the enhanced storage of carbon in soils[7].

How to cite: Lord, R., Nunn, B., Wright, B., Colantoni, A., Bianchini, L., Alemanno, R., Tryboi, O., Severino, M., and Leandro, W.: Growing perennial grasses on contaminated soils for phytoremediation and renewable energy: a nature-based solution to maximise energy and eco-system service provision?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3221, https://doi.org/10.5194/egusphere-egu23-3221, 2023.

Soil salinization has a detrimental effect on plant growth and contributes to agricultural land degradation. The ionic composition of the soil is a significant indicator of soil health. The soluble and exchangeable cation affects the physio-chemical properties of the soil, which in turn determine the suitability of the soil for agricultural use. Currently, soil salinization is one of the major threats to the agricultural productivity of arable lands in many regions of the world. The soils in arid and semi-arid regions having low precipitation and high evaporation rates, like the Negev Desert in Israel, are especially prone to high salinization. Due to the scarcity of fresh water, marginal irrigation water sources such as brackish water in conjunction with surface or subsurface drip irrigation are used extensively in these regions. In the long term, such practices are unsustainable, as precipitation and irrigation are too low to leach the accumulated salts from the active root zone. Salinity and sodicity already existing in many soils of semi-arid and arid regions are further exacerbated by such practices and the continued use might render the land uncultivable. Hence developing a sustainable and economical reclamation regime for saline-sodic soil is essential, while considering the available irrigation water quality in these regions. The main objective of this study was to develop a viable reclamation strategy by using locally available water resources, like brackish water, treated wastewater, desalinated water, and distilled water as rain simulation, with/without soluble or solid gypsum as an amendment. We used flow-through soil column experiments to study the cation transport and exchange in saline-sodic soil from Kibbutz Revivim, Israel (drip irrigated with brackish water for three decades) with four different water qualities and soluble gypsum. The results showed the effect of different water qualities and soluble/solid gypsum on the saturated hydraulic conductivity (K_s) and dynamics of cation exchange and transport in the soil. The transport of the major cations Na⁺, Ca²⁺, Mg²⁺, K⁺, and the K_s of the soil will be presented and discussed.

Keywords: saline-sodic soil, soil reclamation, cation exchange, irrigation water quality, gypsum.

How to cite: Solomon, R. and Arye, G.: Reclamation of Saline and Sodic Soil: Effect of Irrigation Water Quality and Gypsum application form, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12454, https://doi.org/10.5194/egusphere-egu23-12454, 2023.

Irrigation with secondary treated waste water (TWW) may harm soils, especially clayey ones, through increasing soil salinity and sodicity that subsequently impair its physical and hydraulic properties. We compared the effects of TWW-irrigated  compost and tuff trenches placed in an almond orchard of Kibutz Lavee, Israel, on  properties of a clayey soil to those of TWW or fresh water (FW) irrigation.  Both types of trenches did not reduce soil sodicity (expressed in terms of sodium adsorption ratio, SAR). Compost trenches had no effect on soil salinity while the Tuff ones reduced salinity.  Compost trenches increased soil water content and oxygen concentration, whereas Tuff increased aeration but not soil water content. All treatments irrigated with TWW did not improve aggregate stability relative to irrigation with FW. We conclude that compost and tuff trenches could be considered as solutions for enhancing aeration in the root zone and thus potentially improve crop performance.

How to cite: Levy, G., Zireeni, Y., and Bar-Tal, A.: Effects of Trenches Filled with Compost or Tuff on some Properties of a Clayey Soil Irrigated  with Secondary Treated Waste Water., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4888, https://doi.org/10.5194/egusphere-egu23-4888, 2023.

Calcareous grasslands are some of Europe’s most species-rich plant communities and important biodiversity sites. These habitats are, however, threatened; many in the UK were lost to changing land use during the 20^th century and pressure continues on the remaining (often scarce and fragmented) sites. Habitat restoration and rewilding are increasingly important both in the public consciousness and in governmental policy, and the ecological value and threatened nature of calcareous grasslands make them a prime target for restoration efforts. A growing number of projects are therefore working to restore or re-create chalk grassland ecosystems. An under-explored aspect of this, however, is how by-products from land development projects might be re-purposed to create the specialised soil environment needed to support calcareous grassland communities. This has the potential to combine sustainable re-use of construction materials with novel ways to create or restore calcareous grassland habitats and thus ensure infrastructure projects contribute to net biodiversity gain.

In this study we investigate how to optimise the design of soil profiles to support calcareous grassland ecosystems. The study site is located in within the Central 1 section of the HS2 (High Speed 2) Phase One rail development in the Colne Valley (England) being delivered by the Align joint venture. The aim is to create a large area of calcareous grassland as part of a broader (127 hectare) mosaic habitat creation including calcareous grassland, wood pasture and wetland in land that is currently used for construction but was previously arable land. The ‘Colne Valley Western Slopes’ will, when complete, be the largest single area of habitat creation along the HS2 route and will significantly contribute to the project’s commitment to deliver ‘No Net Loss’ in biodiversity.

The properties of underlying soils are critical for the establishment, development and health of this internationally important chalk grassland ecosystem. Physical, chemical and biological properties such as soil structure, drainage and restricted nutrient availability are essential for supporting the diverse plant assemblages found in calcareous grasslands. In this project, we are testing through a combination of controlled environment studies and field trials four constructed soil profiles using different configurations of site-derived materials/construction by-products, using both controlled environment studies and field trials. The site-won materials include: 2.6 M m³ of excavated chalk from 16 km of tunnel construction, crushed limestone and concrete from decommissioned compounds/haul roads, and subsoils (stripped during site clearance) that contain highly variable percentages of CaCO₃. Here we present results from a large-scale mesocosm trial alongside initial field trial data to assess how these constructed soil profiles affect key factors for habitat creation, including soil hydrology, soil microbial dynamics, nutrient cycling, and vegetation establishment and diversity. The findings for this project will inform and effectively complete the earthworks design for the creation of 88 hectares of calcareous grassland in the Colne Valley, as well as providing insights for other chalk grassland restoration projects elsewhere.

How to cite: McCloskey, C., Rickson, R. J., Otten, W., Butler, R., Cantle, C., Hobbs, M., and Spears, C.: Optimising soil profiles to support calcareous grassland habitat creation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8507, https://doi.org/10.5194/egusphere-egu23-8507, 2023.

Post-tin mining soil in Bangka Island shows poor fertility and hence limited suitability for agricultural production. Previously, we found that organic amendments like compost, charcoal, and their combination improve the yield of intercropping cassava (Manihot esculenta Crantz) and legume species (Centrosema pubescens). We hypothesize that N-fixation by centrosema in combination with the application of organic amendments has a highly beneficial effect on crop production via improved the nitrogen content from both, the soil amendment and plant's atmospheric nitrogen fixation.

To evaluate the amount of nitrogen fixed by centrosema in post-tin mining soil; soil and crop samples were taken from different soil amendments treatments: (1) dolomite (10 t ha^-1); (2) compost (10 t ha^-1); (3) charcoal (10 t ha^-1); combined treatment of (4) charcoal+compost (10 t ha^-1 for each); and (5) charcoal+sawdust (10 t ha^-1 for each); and a control for intercropping system of local crops (Cassava and Centrosema) in July 2018. The centrosema was harvested twice during the first and second season (December 2018 and July 2019). The ¹⁵N natural abundance method was used to estimate nitrogen fixation (N₂-fixation) in centrosema at harvest time.

Comparing season and treatment, the proportion of nitrogen derived from N₂-fixation (%Ndfa) was comparable. However, the amount of N₂-fixation was significantly different due to biomass accumulation. Soil amended with compost increased N₂-fixation in centrosema by 6-fold compared to control (50 kg ha^-1), while combined treatment of charcoal and compost increased this value by 8-fold (73 kg ha^-1). When comparing the seasons, the average N₂-fixation in the first season was roughly ten times greater than in the second season (30 and 3.17 kg ha^-1, respectively). In terms of total nitrogen uptake by centrosema across seasons, soil amended with compost or charcoal+compost significantly improved total N uptake in centrosema (61 and 111 kg ha^-1, respectively). Accordingly, organic amendments, in particular in charcoal + compost treatment, significantly increased ammonium in the soil at harvest time (6.71±0.29 µg g^-1).

Our findings suggest that organic amendments, particularly combined application of charcoal and compost in post-tin mining soils can increase N₂-fixation of intercrop centrosema as well as nitrogen availability in the soil, which is of crucial importance in infertile post-mining soils.

Keywords: legume, mining, soil amendment, intercropping, nitrogen fixation

How to cite: Maftukhah, R., Keiblinger, K. M., Mentler, A., Ngadisih, N., Murtiningrum, M., Gartner, M., Kral, R. M., and Hood-Nowotny, R.: Post-tin-mining agricultural soil regeneration using local organic amendments improve nitrogen fixation in legume-cassava cropping system on Bangka Island, Indonesia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14817, https://doi.org/10.5194/egusphere-egu23-14817, 2023.

The total area of agricultural land in Europe and Slovenia is constantly decreasing, causing the loss of a potential for food production and self-sufficiency capacity. In addition to limiting soil sealing, one of the main objectives of the EU Soil Strategy for 2030 involves recultivating degraded sites, which requires appropriate materials, in particular for fertile, top layers.

Due to the complexity of the restoration process of agricultural land, the ability of the restored areas to provide full or any scope of ecosystem services as expected depends on several factors. What the opencast mines have in common is the removal of the top, fertile part of the soil in the exercising of mining rights. The availability of fertile soils with suitable properties is often one of the main limitations for appropriate recultivation. Whilst less fertile soil or even inert construction or industry residuals may be used to recultivate the lower layers, the top layers require using engineered soils with appropriate physical, biological and chemical properties. These properties depend on the purpose of the final use of sites. Apart from making sure that the engineered soils have appropriate physical, chemical and biological properties, it is also necessary that they do not contain excessive concentrations of potentially hazardous substances when it comes to agricultural use.

The primary aim and objective is to develop technologies for producing fertile soils from inorganic and organic waste resulting from construction work or opencast mines and other industrial processes. The main categories of waste where the Slovenian recycling rate is lower than the EU rate are sewage sludge and non-hazardous construction and demolition waste. In this contribution, we are studying how to improve non-fertile soils with various additives of secondary origin to prepare fertile soil mixtures that enable a safe space greening or even food production.

Acknowledgements: Project LIFE20 IPE/SI/000021 je co-financed by European Union.

Keywords: agricultural landscape, land rehabilitation, recultivation, top soil

How to cite: Gantar, A., Zupanc, V., Grčman, H., and Zupan, M.: Engineered soils for recultivation of degraded sites, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4373, https://doi.org/10.5194/egusphere-egu23-4373, 2023.

Recent estimates from satellite imageries indicated that extensive cropland abandonment took place across China due to rural outmigration, agricultural policy and environment changes[1-3]. Cropland abandonment provides an opportunity for C sequestration, and therefore climate change mitigation, soil retention and food security. However, this depends on the duration of cropland abandonment, which lacks comprehensive research. In this study, we map cropland abandonment and recultivation across the Yangtze River Basin in central China using a series of annual land cover maps of the period 2000 - 2020. The InVEST model is used to study the spatial distribution of carbon storage. We found that cropland abandonment is widespread, but last on average only 5.5 years. In addition, over 50% of the abandoned croplands will be recultivated (i.e. back into cropland) or convert into impervious surfaces (i.e. urban) within 20 years, limiting its ability to provide ecosystem services, such as climate regulation, soil retention and food security, due to a relatively small capacity of C sequestration. More precisely, the combined effect of recultivation and conversion into impervious surfaces resulted in an accumulated loss of 75% of abandoned croplands and 41% of carbon as compared to a situation without recultivation or conversion into impervious surfaces. In conclusion, this study highlights the need for land policymakers to make careful reflections as regards the conversion of abandoned croplands in order to mitigate climate change and combat soil degradation. Hence, it could be interesting to set up incentives for ecological restoration in order to valorize opportunities that cropland abandonment may provide us with when aiming to achieve the UN Sustainable Development Goals (SDGs).

References:

1. Liang, X.; Jin, X.; Yang, X.; Xu, W.; Lin, J.; Zhou, Y. Exploring cultivated land evolution in mountainous areas of Southwest China, an empirical study of developments since the 1980s. Land Degradation & Development 2021, 32, 546-558.

2. Long, Y.; Wu, W.; Wellens, J.; Colinet, G.; Meersmans, J. An In-Depth Assessment of the Drivers Changing China’s Crop Production Using an LMDI Decomposition Approach. Remote Sensing 2022, 14, 6399.

3. Yan, J.; Yang, Z.; Li, Z.; Li, X.; Xin, L.; Sun, L. Drivers of cropland abandonment in mountainous areas: A household decision model on farming scale in Southwest China. Land Use Policy 2016, 57, 459-469.

How to cite: Long, Y., Sun, J., Wellens, J., Colinet, G., Wu, W., and Meersmans, J.: Cropland abandonment across the Yangtze River Basin does provide only limited benefits for C sequestration, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13923, https://doi.org/10.5194/egusphere-egu23-13923, 2023.

Identifying an efficient microbial inoculant to promote plant growth is a key pillar in microbial ecology. A wide variety of microbial inoculants have been developed worldwide mostly driven by agricultural demand to define the best inocula. However, the efficacy and comparisons of different microbial inoculants used in dryland ecosystems have rarely been tested. Here, we provide the first quantitative comparison of the effects of commercial versus native inoculants and single versus multiple strain inoculants as well as bacteria versus fungi inoculants on plant growth under field conditions in dryland ecosystems. We used a global meta-analysis of 62 dryland studies to compare the performance of different inocula type on plant growth. We found that microbial inoculation increased plant growth by 43% (CI = 29.69% - 58%) on average in dryland ecosystems, however the magnitude of effect was statistically similar between native (53%, CI = 31% - 80%) and commercial inoculants (40%, CI = 9% - 78%), or between single (39%, CI = 24% - 55%) and multiple strain inoculants (49% , CI = 32% - 68%) or between fungi (39% , CI = 28% - 61%) or bacteria inoculants 43% (CI = 23% - 58%). Our results confirm an assumption that, microorganisms do not usually follow macro-ecological theories and that the choice of an inoculant should be tailored to the purpose and design of the project. In drylands. The result is not only beneficial for agricultural practices in dryland ecosystems, but it is very crucial in dryland restoration projects, especially when the soil system is severely degraded and microbial inoculation is integrated as a plant growth promoter.

How to cite: Dadzie, F., Muñoz-Rojas, M., Slavich, E., Pottier, P., Zeng, K., and Moles, A. T.: Paired comparisons of native and commercial inoculants, bacteria and fungi, and single and multi-strain microorganisms show equal effects on plant growth in dryland ecosystems., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17010, https://doi.org/10.5194/egusphere-egu23-17010, 2023.

The multidimensional dynamics of biodiversity and ecosystem function during the rewilding of Mediterranean forests remain poorly understood, limiting our capacity to predict how future restoration efforts may help mitigating climate change. Here, we investigated the changes in multiple dimensions of biodiversity and ecosystem services in a 120-year forest succession after harvest to identify potential trade-offs in multiple dimensions of ecosystem function, and further assess the link between above and belowground biodiversity and function. We found a positive influence of successional age on multiple dimensions of biodiversity and function, but also some important trade-offs. Two ecosystem axes of function explained nearly 75.4% functional variation during ecosystem rewilding. However, while the first axis increased with successional age promoting plant productivity and element stocks, the second axis followed a hump-shaped relationship with age supporting important reductions in nutrient availability and pathogen control in old forests. Our study further revealed that a significant positive relationship between plant and soil biodiversity with multiple elements of multifunctionality as forests develop. Moreover, the influence of plant and soil biodiversity were especially important to support a high number of function working at high levels of functioning. Our work provides new insights on the patterns and functional trade-offs in the multidimensional rewilding of forests, and further highlight the importance of biodiversity for long-term Mediterranean rewilding.

How to cite: Zhou, G., Lucas-Borja, M. E., Liu, S., and Delgado-Baquerizo, M.: Plant and soil biodiversity is essential for supporting highly multifunctional forests during Mediterranean rewilding, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13674, https://doi.org/10.5194/egusphere-egu23-13674, 2023.

Microorganisms called endophytes are passed from parent plants to their offspring and play significant roles in plant growth and development. In recent years, endophytes have gained attention for their ability to help plants withstand stress and have been used in revegetation efforts. However, there is still a lack of understanding about seed endophytes in ecosystems prone to fire, where the dormancy and germination of seeds are affected by various factors that can impact the persistence of plant populations. This gap in knowledge hinders the ability to predict how plant populations will respond to selective pressures and stress caused by climate change. To address this, the present study focused on characterizing seed-borne endophytes in order to understand their potential to enhance germination and growth under stress. Mixed and pure cultures of endophytes were isolated from the fire-prone species Anigozanthos manglesii, Haemodorum planifolium and Haemodorum spicatum, all of which are native to Banksia woodlands in Western Australia and belong to the Haemodoraceae family. The bacterial community composition and diversity of each species were also analyzed using next-generation sequencing targeting the 16S rRNA. This study is unique in examining seed endophytes in fire-prone species and provides a foundation for future research on the relationship between seed microbiome composition, germination success, and seedling vigour.

How to cite: Machado de Lima, N. M., Tangney, R., Muñoz Rojas, M., and Ooi, M.: Seed microbial community characterisation and isolation from three species common to fire-prone Australia., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10170, https://doi.org/10.5194/egusphere-egu23-10170, 2023.