Session SSS11.5

SSS11.5 | Check dams and Agricultural Terraces: Heritage, Sustainability and Resilience

Check dams and Agricultural Terraces: Heritage, Sustainability and Resilience

Convener: Sara CucchiaroECSECS | Co-conveners: Demetrio Antonio Zema, Daniel FalluECSECS, Fei Wang, Rosa Maria Albert, Xiangzhou Xu, Manuel Esteban Lucas-Borja

Orals

| Tue, 25 Apr, 10:45–12:30 (CEST)

Room K2

Posters on site

| Attendance Tue, 25 Apr, 08:30–10:15 (CEST)

Hall X3

Posters virtual

| Attendance Tue, 25 Apr, 08:30–10:15 (CEST)

vHall SSS

Both check dams and agricultural terraces are effective measures and they have long histories of use in retaining soil and developing agriculture around the world. Agricultural terraces, resilient systems on the slope, are associated with both environmental and social benefits, including the control of soil erosion and high rural population densities. However, the history of these systems is poorly known, including their original and, therefore, potential land uses. On the other hand, check dams have been used worldwide in the gullies since the first century to control flows of water and sediment on the catchment scale. Research experiences have demonstrated their effectiveness in many environments, but the literature also documents examples of poor structure functioning or even failure, due to inadequate design criteria, improper construction methods, and undesired secondary effects. This session provides an avenue for soil scientists, hydrologists, and policy makers to discuss pressing issues on the construction and management of check dams and agricultural terraces. Topics to be discussed here include: (1) Past and recent land-us, environmental benefits, soil erosion, and even policy arenas. (2) Roles of check dams and agricultural terraces on the ecological and hydrogeological security, and food supply. (3) Theories and criteria for the construction of check dams and agricultural terraces. (4) Experiences and methods for the management of check dams and agricultural terraces. (5) Comparison and emulation of check dams among different regions. (6) Other topics related to check dams and agricultural terraces.

Orals: Tue, 25 Apr | Room K2

Chairpersons: Sara Cucchiaro, Demetrio Antonio Zema, Manuel Esteban Lucas-Borja

10:45–10:47

Session introduction

10:47–11:07

EGU23-4040

solicited

Virtual presentation

Sediment connection modes of check dams and its effects for sediment interception efficiency in the loess hill and gully region

Juying Jiao, Leichao Bai, Nan Wang, and Yulan Chen

The Loess Plateau is the area with the most serious soil erosion in China, and its control of soil erosion has always been a focus of attention and research. As an important engineering measure of soil and water conservation, the check dam plays an irreplaceable role. However, the effect of connection mode between check dam and downstream channel is not considered in the evaluation of sediment interception efficiency of check dam, which may lead to the high calculation result. In this study, in order to evaluate the sediment interception efficiency of check dam more accurately, the control areas of Caoping hydrological station in Wudinghe River Basin and Ganguyi hydrological station in Yanhe River Basin were taken as study areas, and 24 typical dam-controlled watersheds with different land use types, 4 typical small watersheds with different combinations of check dam were selected, the check dam types and their connection modes between check dam and downstream channel were investigated and analyzed, and the sediment interception efficiency of check dam was estimated. According to the difference of connectivity between check dams and downstream channels, there are 11 types of connection modes between check dam and downstream channel: disconnected, connected with spillway, connected with shaft or horizontal pipe, connected with spillway and shaft or spillway and horizontal pipe, connected with shaft, horizontal pipe and spillway, connected with dam body damaged gap, connected with discharge canal, connected with discharge canal and shaft, connected with discharge canal–spillway, connected with discharge canal–shaft and spillway, connected with discharge canal–dam body damaged gap. Based on the actual control area percentage of dam land, the structure connectivity of sediment between check dam and downstream channel was evaluated. The results show that the structure connectivity of sediment is mainly affected by the discharge canal and its length. The sediment interception efficiency of dam system is greater than the sum of single dams. If there is no drainage channel at the bottom of the key check dam, the sediment interception efficiency of the whole dam system will be greatly increased. The results show that the sediment interception efficiency would be 9.74–18.78% higher if the connection mode is not considered. And extreme rainfall increased the sediment connectivity between check dams and downstream channels, thus greatly reduced the sediment interception efficiency of check dams.

How to cite: Jiao, J., Bai, L., Wang, N., and Chen, Y.: Sediment connection modes of check dams and its effects for sediment interception efficiency in the loess hill and gully region, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4040, https://doi.org/10.5194/egusphere-egu23-4040, 2023.

11:07–11:17

EGU23-4867

On-site presentation

A probabilistic approach for planning the ordinary maintenance of existing torrent control structures: from first-level inspections to maintenance strategy

Alessio Cislaghi, Paola Morando, Emanuele Morlotti, and Gian Battista Bischetti

Check dams, submerged and ground sills, ground ramps, and bendway weirs are in-channel countermeasures built for mitigating flood and debris flow hazards. These torrent control structures have an own durability depending on structure type, material, design, construction, and maintenance, as well as on the physical pressures exerted on them. During the last half-century, while the natural degradation of the structures endangers their functionality, investments in ordinary maintenance have been significantly decreasing, worldwide. Thus, monitoring and planning an ordinary maintenance of existing structures should be a primary purpose for maintaining (or even improving) an adequate level of protection against natural hazards.

The present study proposes a framework for planning and promoting decision-making on the structure maintenance activities. The methodology consists in a procedure of first-level inspection based on three indicators (i.e., damage index, residual functionality, and active process index), followed by the application of a homogeneous Markov chain model on the collected field observations. The study has been conducted on three rivers in North Italy (Oglio, Pioverna, and Staffora) characterised by different hydrological-sediment transport regime, and level of artificiality.

The results of the first-level inspections, merged with a wide spectrum of other information (width, length, height, age of construction, materials, etc.), clearly show the actual status of the structures, whereas the Markov chain model provides different scenarios of physical structure degradation and decline of functionality, in function of time and levels of maintenance.

This framework is an interesting decision support tool for planning a long-term ordinary maintenance on torrent control structures, through a probabilistic assessment of structure failure, and a cost-effectiveness analysis of different maintenance activities. Moreover, this study represents a practical example of watershed management, starting from planning the first-level inspections of the existing torrent control structures until the assessment of the present and future vulnerability of the areas developed along the river channel network.

How to cite: Cislaghi, A., Morando, P., Morlotti, E., and Bischetti, G. B.: A probabilistic approach for planning the ordinary maintenance of existing torrent control structures: from first-level inspections to maintenance strategy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4867, https://doi.org/10.5194/egusphere-egu23-4867, 2023.

11:17–11:27

EGU23-12149

ECS

Virtual presentation

A new English term of 'Yudiba dam' and its differences from check dam

Zhongbao Xin

The ‘Yudiba’ is the Chinese Pinyin of an erosion control engineering measure, which has been widely implemented in the Chinese Loess Plateau and plays an important role in reducing sediment discharge and increasing cultivated land area. Although ‘check dam’ has been widely used as the English term to represent the engineering practice for erosion control and become the general English translation of ‘Yudiba’, the ‘check dam’ could not authentically highlight the soil and water conservation engineering of ‘Yudiba’ in the Loess Plateau.

Here the differences between the ‘Yudiba dam’ and the‘check dam’ were specifically discussed in aspects of purposes, sizes and main functions. Moreover, the English translations for the ‘Yudiba ’ were analyzed by comparing the connotations of the concepts, the different functions of the erosion control engineering in agricultural development and ecological improvement, as well as the simplicity when used in scientific studies.

The ‘Yudiba’ is special soil and water conservation engineering measures, initiated from the Loess Plateau of China, referring to the dam structures built in various levels of gullies for the purpose of blocking sediment into cultivated land. The ‘check dam’ is a small temporary barrier, grade control structure or dam constructed across a swale, drainage ditch, or area of concentrated flow. The 'check dam’ differed with the Yudiba dam’ in purposes, sizes and main functions. Currently, various English translations were used in the literature, which were hardly accepted widely as either without representativeness or without simplicity.

We recommend the ‘Yudiba dam’ based on Chinese Pinyin as the formal English term in order to distinguish between the ‘Yudiba dam’ in the Loess Plateau and check dam’ in other places. Thus, the ‘Yudiba dam’ is suggested to refer to the erosion control measure, which has been widely built in the Loess Plateau of China with the main functions including trapping sediment, reducing gully erosion and increasing the area of farmland in the sediment rich area.

How to cite: Xin, Z.: A new English term of 'Yudiba dam' and its differences from check dam, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12149, https://doi.org/10.5194/egusphere-egu23-12149, 2023.

11:27–11:37

EGU23-3879

ECS

Virtual presentation

Large-scale extraction of check dams and silted fields on the Chinese Loess Plateau using ensemble learning methods

Jianlin Zhao

Check dams are an effective soil and water conservation measure which is widely constructed in the world. A large number of check dams have been installed on the Chinese Loess Plateau during the last 70 years, which have played an important role in sediment control and soil conservation. However, high-resolution and large-scale mapping of the location of the check dam and silted field is absent, thus hampering the efficient management of the check dams and quantitative evaluation of their eco-environmental benefits. In this study, we present a methodological framework to extract silted fields and estimate the location of the check dam at a pixel level by using three ensemble learning methods combined with a novel resampling procedure to lessen the influence of class imbalance. Our results indicate that the distribution of check dams and silted fields is a typical imbalanced binary classification problem that the amount of silted field samples only accounted for 4% of the total randomly collected samples, which has a significant impact on the accuracy of both model training and validation. By using the random under-sampling method, the optimal imbalance ratio was determined for each model, combined with the optimal modeling parameters and 23 features, to train and validate the model. The validation results on the testing set show that the F1-score of Random Forest, Extreme Gradient Boosting, and EasyEnsemble model for the silted field is 0.7501, 0.7664, and 0.7754, respectively. The feature importance analysis shows that three macro-terrain features and multi-temporal spectral indices contributed mostly to the accurate extraction of silted fields, among which the multi-temporal vegetation cover change index has the highest feature importance for all models. Applying the tuned model to the whole Wuding River catchment, we produced a 10m-resolution silted fields and check dams map showing that there are ca. 10,500 check dams correspondingly forming ca.283.3 km² area of silted fields. This study provides an important and efficient methodological framework for quick mapping of check dams and silted fields at a high-resolution and a large scale with addressing the imbalanced classification problems.

How to cite: Zhao, J.: Large-scale extraction of check dams and silted fields on the Chinese Loess Plateau using ensemble learning methods, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3879, https://doi.org/10.5194/egusphere-egu23-3879, 2023.

11:37–11:47

EGU23-6709

ECS

Virtual presentation

Experimental Study on the Control Effect of Different Types of Warping Dams on Sediment

(withdrawn)

shaobo xue

11:47–11:48

Block Introduction

11:48–11:58

EGU23-2374

Highlight

On-site presentation

Agricultural Terraces As DNA Archives and Implications for Terrace Archaeology

Antony G. Brown, Andreas Lang, Daniel J. Fallu, Kevin Walsh, Francesco Ficetola, and Inger Alsos

Although agricultural terraces have a long history of use in the steepland areas of Europe very little is known about their use-history and its variability over space or time. This is partly because, being composed of generally inorganic well drained soil horizons, they often have poor preservation of pollen, spores and even phytoliths. The TerrACE project (ERC funded) set out to test the application of sedaDNA from terrace soils sampled from Greece to northern Norway using metabarcoding. The findings have been surprising - as the expectation was that only soils from the most northerly sites (Norway, UK) with mean annual temperatures below 10^oC would provide positive results. This has proven not to be the case, with most sites providing usable data except the very warmest and driest (Crete). This also relates to the timing of agriculture with usable data from the Bronze Age throughout all periods to Late Medieval times. This reveals soil DNA of both a variety of crops, including but not exclusively cereals, and domesticated stock. However, there are, as expected, indications of both leaching and bioturbation effecting these records. These taphonomic aspects will be discussed alongside the potential of sedaDNA for tracing agricultural histories from cumulative soils.

How to cite: Brown, A. G., Lang, A., Fallu, D. J., Walsh, K., Ficetola, F., and Alsos, I.: Agricultural Terraces As DNA Archives and Implications for Terrace Archaeology, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2374, https://doi.org/10.5194/egusphere-egu23-2374, 2023.

11:58–12:08

EGU23-7783

ECS

On-site presentation

Remote sensing-based analysis for resilient agriculture in steep slope cultural landscapes

Eugenio Straffelini and Paolo Tarolli

The morphology of cultivated steep slopes is often the result of the layering of traditional agricultural practices. Their complexity and uniqueness result in high cultural-historical value, sometimes leading to the inclusion of landscapes on special protection lists (such as FAO-GIAHS or UNESCO). Agricultural terraces, adopted in different parts of the world for centuries, successfully combine cultivation needs with various valuable ecosystem services. However, cultivating in steep-slope areas is complex and requires a great effort in terms of human and economic resources (primary reasons for agricultural land abandonment). Moreover, their inherent complexity can become a problem during external disturbances. Heavy rainfall, increasingly frequent due to climate change, can generate surface runoff, soil erosion, terrace wall collapse, and landslides. Therefore, it is crucial to establish appropriate management plans to ensure the functionality of these cultural landscapes, guaranteeing agricultural production and territorial security. The advancement of new technologies in remote sensing, high-resolution mapping, and spatial analysis is opening new frontiers to support the management of such landscapes. A virtuous example is the SOiLUTION SYSTEM project (www.soilutionsystem.com; Rural Development Program for Veneto 2014-2020), carried out in the GIAHS site "Soave Traditional Vineyards" (Italy). It aims to develop innovative soil erosion risk mitigation solutions and improve vineyard management in hilly and mountainous landscapes. It involved high-resolution mapping of terraced landscapes based on low-cost methodologies (such as UAV-SfM photogrammetry) and identifying erosion-prone areas through specific algorithms. In addition, optimal soil management was researched to mitigate surface runoff and sediment production, including adopting biodiversity enhancement strategies. A modelling approach (validated by field measurements) was adopted for the analyses to maximize the reproducibility of the methodology in other contexts. An overview of the opportunities that remote sensing-based analysis can offer to steep-slope agricultural landscapes is proposed here. High-resolution mapping of hydroerosive processes is useful for preventing soil degradation, which, combined with sustainable management, helps to increase the resilience of such cultural and agricultural landscapes.

How to cite: Straffelini, E. and Tarolli, P.: Remote sensing-based analysis for resilient agriculture in steep slope cultural landscapes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7783, https://doi.org/10.5194/egusphere-egu23-7783, 2023.

12:08–12:18

EGU23-5591

ECS

Virtual presentation

Intensification of terrace agriculture on the Northern Apennines during the Medieval Climate Anomaly

Filippo Brandolini, Tim C. Kinnaird, Aayush Srivastava, and Sam Turner

Recent environmental studies and policies have recommended maintaining archaeological landscape features such as intercropping, agroforestry and cross-slope barriers (e.g. hedgerows, stone walls, earth banks) for their potential benefits to ecosystems. This study focuses on a portion of the Tuscan-Emilian Apennines coinciding with the municipality of Vetto d'Enza (commonly referred as Vetto), located on the right bank of the Enza River in the Man and the Biosphere UNESCO reserve (Emilia-Romagna region, Northern Italy). The main characteristics of this historic rural landscape trace their origin back to the Middle Ages at the period of the Great Countess Matilda of Canossa (10-11th century CE) and the area’s land management system appears to have remained largely unaltered until the end of the 19th-century CE. Among the most distinctive characteristics of this historic landscape are relicts of agroforestry practices (known as ‘alberata emiliana’) and well-preserved stone walls and earth banks that have been used extensively between steeply-sloping fields to delimit tenurial boundaries and to face agricultural terraces. Optically stimulated luminescence profiling and dating (OSL-PD) has been applied to date the sediments associated with earth banks, stone walls and agricultural terraces. The results provide secure construction dates during the Medieval Climate Anomaly - (MCA). This period (ca. 900–1350 CE) is arguably one of the most crucial moments of recent climate change that impacted societies, particularly in Europe. Above average temperatures allowed high-elevation settlements to persist throughout the MCA, though social trends played a large role in the conversion of uplands into an agro-pastoral landscape. These processes are particularly evident on the Apennine mountains, where mediaeval deforestation coincided with intensification of agriculture associated with development of monastic estates that exploited increasingly larger land holdings as well as new settlement patterns in higher-elevation defensible locations.

How to cite: Brandolini, F., Kinnaird, T. C., Srivastava, A., and Turner, S.: Intensification of terrace agriculture on the Northern Apennines during the Medieval Climate Anomaly, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5591, https://doi.org/10.5194/egusphere-egu23-5591, 2023.

12:18–12:28

EGU23-6090

On-site presentation

Spatial distribution patterns and soil properties of lynchet systems in Northeastern Bavaria, Germany

Anna Schneider, Thomas Raab, Alexandra Raab, Simran Sekhri, and Alexander Bonhage

Former field systems (FFS) in recent forest areas of Central and Northern Europe are often discernible by their characteristic morphology with slightly flattened slope areas and intermediary ridges formed by tillage and water erosion. Soils of such lynchet systems feature distinctly modified stratigraphy and properties and thereby constitute a memory of past land use. At the same time, the legacies of past agriculture affect recent forest ecosystems. High-resolution digital elevation models (DEMs) allow to identify lynchets over large areas and open up new opportunities to study the spatial distribution patterns and soils of FFS. Within our research on different land use legacy features in forest areas, we study FFS in Northeastern Bavaria (Germany) in a geopedological approach, combining large-scale mapping and spatial analysis with the description and analysis of soil properties for specific sites.

Lynchet areas (and other remnants of pre-industrial FFS) in recent forests were mapped from LIDAR DEMs for an area of 2045 km² (972 km² forest area). The mapping results show more than 100 km² of abandoned field systems within the study area, mostly appearing as lynchet systems. Their spatial distribution patterns differ within the study area, mainly depending on parent material and landform. In the limestone region of the Franconian Jura, FFS occur spatially dispersed, often as considerably small, irregularly shaped parcels, presumably reflecting proceeding abandonment of less productive and accessible fields with intensification of agriculture. In contrast, FFS in the Bohemian Massif in the eastern part of our study area were often found in compounds of many regularly shaped parcels, frequently associated with deserted settlement areas.

Soil stratigraphy and properties were studied for FFS and reference positions (forest areas with no indications of former agricultural use) in six study sites, combining detailed characterization of principal soil profiles and an assessment of spatial variations of soil properties in a near-surface sampling approach. First results show that FFS soils are characterized by truncated profiles over most parts of the treads and accumulation of colluvium confined to relatively small areas upslope of lynchet risers. The depth of soil profile truncation and height of lynchet risers differ, mainly related to slope and erodibility of the initial soils. Stratigraphy of the lynchet soils indicates a gradually proceeding formation. Carbon and nitrogen contents were found to differ between FFS and reference soils and to be more homogeneous within the FFS. Carbon contents were mainly lower in the FFS, while both lower and higher nitrogen contents were observed for FFS soils, presumably related to different duration and intensity of agricultural use.

Overall, the results show that the legacy effects of past agriculture affect large fractions of recent forest areas, and can be of different quality depending on lithology of the soils’ parent material and land use history.

How to cite: Schneider, A., Raab, T., Raab, A., Sekhri, S., and Bonhage, A.: Spatial distribution patterns and soil properties of lynchet systems in Northeastern Bavaria, Germany, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6090, https://doi.org/10.5194/egusphere-egu23-6090, 2023.

12:28–12:30

Closing Session

Posters on site: Tue, 25 Apr, 08:30–10:15 | Hall X3

Chairpersons: Daniel Fallu, Demetrio Antonio Zema, Sara Cucchiaro

X3.148

EGU23-4210

Optical Dating of Agricultural Terrace Deposits

Andreas Lang, Chiara Bahl, Lisa Snape, Barbara Mauz, and Anthony Brown

Agricultural terraces are common features of cultivated hillsides across the world and have recently attracted increasing attention as archives of land-use practices and as soil carbon depositories. Such terraces originate from various soil translocation processes and throughout usage are subject of frequent reworking. Establishing chronologies for agricultural terraces usage is, thus, notoriously difficult. Here, we report results from optically-stimulated luminescence dating of terrace sediments that (i) originate from a wide range of locations across Europe stretching from the Polar circle to the Mediterranean; (ii) are derived from various host lithologies including igneous rocks, Triassic sedimentary rocks, Neogene marine deposits, and Pleistocene glacial and periglacial sediments; (iii) represent a range of cultivation styles including labour intensive manual techniques as well as mechanised tillage; and, (iv) cover a wide span of time periods from the Early Bronze Age through to modern times. Reliable chronologies of optical ages, consistent internally and in agreement with independent age information, were established on silt-sized quartz extracts from loess derived terrace deposits and on sand-sized quartz grains derived mostly from sedimentary host rocks. OSL signals of quartz extracted from deposits with igneous and turbiditic host rocks are often not of sufficient quality for optical dating purposes.

How to cite: Lang, A., Bahl, C., Snape, L., Mauz, B., and Brown, A.: Optical Dating of Agricultural Terrace Deposits, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4210, https://doi.org/10.5194/egusphere-egu23-4210, 2023.

X3.149

EGU23-8240

Modeling water flow rate and soil erosion in Mediterranean headwaters (with or without check dams) under land use and climate change scenarios using SWAT

Demetrio Antonio Zema, Bruno Gianmarco Carrà, Manuel Esteban Lucas Borja, Pasquale Giuseppe Fabio Filianoti, Pedro Perez Cutillas, and Carmelo Conesa Garcia

The use of check dams is a common strategy to contrast soil erosion in the Mediterranean headwaters. However, the effects of these control works on water flow rates and sediment yields have been scarcely investigated under possible scenarios of climate and land use changes. On this regard, the use of hydrological models, such as SWAT, provide reliable hydrological predictions under variable environmental conditions. To fill this gap, this study has evaluated the effectiveness of check dams on the hydrological response of a forest headwater in Calabria (Southern Italy) in comparison to an unregulated sub-catchment with very similar environmental conditions. On this regard, the effects of different combined scenarios of climate change (through three GCMs and two RCP applied to the next 80 years) and land use (forest, pasture, and cropland) on water flow rates and sediment yields in the two headwaters were analysed using the SWAT model. SWAT was first calibrated in a third headwater with very similar climatic, soil and land use conditions, and this verification showed a satisfactory prediction capacity of water flow rate. The water flow rate prediction capacity of the model was satisfactory (coefficients of determination and efficiency of Nash and Sutcliffe equal to 0.71 and 0.67, respectively, and percent bias of 14.9%). No significant differences were detected for the water flow rates and sediment yields between the two sub-catchments (with or without check dams) among the different land uses and climate change scenarios. This was linked to the low hydrological response of both headwaters to the forcing actions, which influenced the low effectiveness of the control works. SWAT estimated higher values of both mean and maximum values of water flow rates and sediment yields under RCP2.6 compared to RCP8.5. Both water flow rates and sediment yields will be very low under all climate and land use scenarios. The regulated headwater with check dams will always produce more runoff and erosion compared to the sub-catchment without check dams. The increases will be up to 60% for the maximum flow rate and 30-35% for the sediment yield in forest land use and under RCP2.6. Although the limitation of this study linked to the lack of validation of the erosion data (due to unavailable records of sediment yield), this study has demonstrated how the use of check dams in headwater catchments may be not effective several decades after their installation for soil conservation purposes in Mediterranean semi-arid areas, where the water flow and erosion rate are limited.

How to cite: Zema, D. A., Carrà, B. G., Lucas Borja, M. E., Filianoti, P. G. F., Perez Cutillas, P., and Conesa Garcia, C.: Modeling water flow rate and soil erosion in Mediterranean headwaters (with or without check dams) under land use and climate change scenarios using SWAT, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8240, https://doi.org/10.5194/egusphere-egu23-8240, 2023.

X3.150

EGU23-16433

Microbial communities investigation and biocontrol activity in saffron cultures

Maddalena del Gallo, Beatrice Farda, Rihab Djebaili, Enrico Sabbi, Claudia Ercole, Loretta Pace, and Marika Pellegrini

Crocus sativus L., commonly known as saffron, is recognized as one of the most valuable spices in the world for the flavouring, nutritional and bioactive properties of its dried stigmas. As underground organs, saffron corms are exposed to infections caused by fungi, bacteria, viruses and nematodes. Among the latter, the genus Fusarium includes fungal pathogens that destroy these cultures, affecting also the composition of the microbial communities associated with the plant. The corms are typically chemically disinfested before sowing to control diseases. However, most fungal pathogens, such as Fusarium spp., are resistant to this treatment. The aim of this work was to i) investigate the microbial communities associated with the rhizosphere of saffron in presence of fusariosis; ii) isolate and characterize the Fusarium pathogen strains; iii) evaluate the biocontrol potential of selected beneficial bacterial strains against the isolated phytopathogens. Soil and plant samples of the saffron cultures were sampled in L’Aquila territory (Italy) and analysed with microbiological approaches, including culture–independent and – dependent methods. The 16S rRNA metabarcoding ITS barcoding was performed to investigate microbial communities composition and identify fungal pathogen isolated strains respectively. Four beneficial bacteria were tested against phytopathogen strains by dual culture method and microscope observations. The metabarcoding analysis revealed the presence of taxa related to the Proteobacteria phylum. The three isolated fungal strains were identified as Fusarium oxysporum ff. spp. and two of the four selected beneficial strains (Bacillus pumilus and WG6) showed an inhibition percentage greater than 50% with disgregation and vacuolization of the hyphae. These preliminary findings serve as the basis for future studies about the possibility of asses more sustainable agricultural practices and eco-friendly strategies to avoid or mitigate Fusarium disease in saffron cultivation and protect a such valuable and precious plant.

Keywords: Fusarium, pathogens, biocontrol

How to cite: del Gallo, M., Farda, B., Djebaili, R., Sabbi, E., Ercole, C., Pace, L., and Pellegrini, M.: Microbial communities investigation and biocontrol activity in saffron cultures, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16433, https://doi.org/10.5194/egusphere-egu23-16433, 2023.

X3.151

EGU23-15944

ECS

Agricultural terraces in the UK, new insights from biogenic microremains.

Mónica Alonso Eguiluz and Rosa María Albert

Agricultural terraces are anthropological features that shape the landscape. In Europe, their construction and use dates back to the late Neolithic and today they can be documented across the continent corresponding to different chronological periods. In addition to the impact on the landscape and the environment, the possibility of expanding the production area, through the construction of terraces, makes it possible to improve the quality and diversity of the crops produced, thus contributing to increasing demographic and social complexity. To better understand the role of agricultural terraces in the environment and society, the TerrACE project has developed a high-resolution research protocol to be applied to different agricultural terrace systems in Europe without chronological distinction. This multi-proxy research includes, among others, the analysis of biogenic microremains to identify past cultivars.

We focus here on the use of biogenic microremains (phytoliths, diatoms, ash pseudomorphs, and faecal spherulites) and FTIR analysis applied to four agricultural terraces from the United Kingdom, with different chronologies: on the one hand, the prehistoric terraces of Plantation Camp and the medieval terraces of Gueswick both in northern England, 72 km apart; and on the other hand, the prehistoric terraces of Charlton Forest and Blick Mead both in southern England, 78 km apart. In addition to evaluating exploited cultivars, we also seek to identify differences and similarities between these sites. While ash pseudomorphs and fecal spherulites were not documented at any of the sites, phytoliths were well preserved at Plantation Camp, Gueswick, and Charlton Forest. In general, it can be observed that the amount of phytoliths decreases with depth. Along with the phytoliths, diatoms have been identified, although to a lesser extent. The most abundant phytoliths were those produced by grasses, especially those of the C₃ Pooideae subfamily. Even though evidence of crops is scarce, analyzing the short silica short cells phytoliths we were able to identify barley in Plantation camp, which agrees with its location and chronology. These same analytics, along with complementary methods (i.e., DNA), are being conducted in the other sites to obtain more information regarding the plants cultivated in the terraces.

How to cite: Alonso Eguiluz, M. and Albert, R. M.: Agricultural terraces in the UK, new insights from biogenic microremains., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15944, https://doi.org/10.5194/egusphere-egu23-15944, 2023.

X3.152

EGU23-17109

Highlight

Check dam uses for soil conservation and erosion control: a worldwide review

Manuel Esteban Lucas-Borja and Demetrio Antonio-Zema

Abstract

The construction of check dams is one of the most common watershed management tools in degraded catchments. For example, check dams have been used throughout the world for torrent control, water supply enhancement, agricultural land development, and watershed restoration among others. Historically, managers have spent important resources for both maintenance of existing and the construction of new check dams. This contribution presents a comprehensive review related to check dams objectives, functions, effectiveness and undesired effects worldwide. Authors aim to synthesize check dams use and efficacy across the wide range of locations and contexts in which the check dams have been installed. The role of complex interactions between ecological impacts, geomorphic processes and engineering activities is also highlighted. Overall, check dams construction is a widely used tool in degraded catchments, although their efficacy in achieving proposed objectives is often not thoroughly assessed. The authors have identified check dams characteristics and the process feedback loops that these tools initiate across a range of spatial scales and geographic locations.

Keywords: Soil erosion, land use change; flooding; watershed management.

How to cite: Lucas-Borja, M. E. and Antonio-Zema, D.: Check dam uses for soil conservation and erosion control: a worldwide review, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17109, https://doi.org/10.5194/egusphere-egu23-17109, 2023.

X3.153

EGU23-6273

Multi-Scalar analysis of Terrace use and Abandonment in Soave, northern Italy.

Daniel Fallu, Sara Cucchiaro, Andreas Lang, and Rosa Maria Albert

Agricultural terraces preserve evidence of human action and subsistence strategies from the smallest scales of soil chemistry to the scale of their geographic extent, often hectares. These soils are subject to processes of reworking, both through their construction, use and maintenance by humans and by natural slope processes and pedogenesis. Changes in use, either through abandonment or re-purposing, affect the pedogical and sedimentological processes on the slope, often resulting in partial or toal collapse of the terrase walls. Recent research into soil organic carbon storage makes the understanding of terrace anthrosols an important aspect of modern environmental monitoring and Anthropocene landscape transformations.

Here, we attempt to demonstrate the integration of chemical, micromorphological, stratigraphic, and topographic data for construction, use and abandonment of terraces into three study areas (Soave Castle, Fornace Michelon and Belloca )in Veneto, northern Italy (45.420198°N, 11.255179°E). Soil geochemical data, microbotanical evidence (including phytoliths and soil DNA), luminescence data (both pOSL and OSL dating, radiocarbon, and topographical information are integrated to produce a socio-environmental synthesis which is compared to the known archaeological, historical and environmental records for the region during the past 3000 years. In particular, erosion risk and soil volumes calculated from surface models and test pits aid in understanding how the slope has been modified over time, and how intensity of human activity has impacted soil development and loss. This integrated data provides us a robust platform for assessing the understanding actions taken by farmers to alter the slope and make it more suitable for cultivation, as well as the effects of abandonment and reuse.

How to cite: Fallu, D., Cucchiaro, S., Lang, A., and Albert, R. M.: Multi-Scalar analysis of Terrace use and Abandonment in Soave, northern Italy., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6273, https://doi.org/10.5194/egusphere-egu23-6273, 2023.

Posters virtual: Tue, 25 Apr, 08:30–10:15 | vHall SSS

Chairpersons: Fei Wang, Rosa Maria Albert, Xiangzhou Xu

vSSS.10

EGU23-3717

A new technology for green urban construction：using sand-based concrete permeable brick to conserve rainwater in the urban area

Xiangzhou Xu and Hang Gao

Abstract

Rainwater management is an important solution to climate change and flood risk reduction in the urban area. This study presents a nature-based solution to conserve rainwater in the urban area: a kind of permeable brick made of desert sand, of which compressive strength is intensive, water permeability is high, and fabrication cost is low. The desert-sand bricks presented here will be more in line with both the environmental and economic aims of developing countries. The compressive strength is one of the most important factors that impact the service life of permeable bricks, while the fabrication cost is one of the key reasons influencing the market share of permeable bricks. In this study, the minimum compressive strength of the desert-sand brick is 34.9 Mpa, which has exceeded the requirements of the standard JC/T 945-2005. Moreover, the mean and maximum compressive strengths of the desert-sand bricks are 69.6 and 102.8 Mpa, which are 2.3 and 3.4 times of the strength required by the standard JC/T 945-2005, respectively. The fabrication cost of the water-permeable brick designed by the authors is only 12 US dollars/m², which is much lower than that of the sand-based permeable bricks that already exist in the market. Additionally, more ecological benefits could be gotten because the main aggregate in the sand-based permeable bricks is the desert sand rather than river sand. The results show that the kind of permeable brick can render substantial economic benefits and ecological improvements.

Keywords: Urban area; Water conservation; Permeable brick; Desert sand

How to cite: Xu, X. and Gao, H.: A new technology for green urban construction：using sand-based concrete permeable brick to conserve rainwater in the urban area, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3717, https://doi.org/10.5194/egusphere-egu23-3717, 2023.

vSSS.11

EGU23-6010

Check dam and its functions on the Loess Plateau of North Shaanxi Province, China

Fei Wang, Wenyan Ge, and Hao Chen

The Loess Plateau is one of the most severe soil erosion area worldwide, and the north Shaanxi Loess Plateau is the main sediment source of the Yellow River. The functions of check dam are analyzed based on the data of land use and land cover change, hydrological process and filed survey on soil property and yield. The average annual soil erosion rate in this region varied from 8000-10000 ton per square kilometer before 1980s and reduce to 2000-4000 ton per square kilometer in recent years. The check dam is one of the most important practices of soil and water conservation in this region. It has a long-term history inspired by the natural dam caused by great landslide in 1969 of Ming Dynasty and developed very fast since 1960s. The functions of check dam cover the whole soil erosion process, sediment and flow of the branches and the Yellow River, agricultural production, soil carbon consequence, and local climate regulation. There were about 33.9 thousand check dams in this region, and the sedimentation in the check dams is around 5.9 billion tons that the average annual reduction of sediment load of the river accounted for 3000-5000 ton per square kilometer in their formation period of 20 to 30 years. The current check-dam land was about 57.3 thousand hectors with very good fertility condition and soil moisture because of the deposition induced by soil erosion of the topsoil and seasonal flashflood in the catchment. The average yield on the check-dam land could be 6000-15000 kg per hector in the semiarid cropland, about 3-10 time of that on the slope, that could reduce the cultivation on the slopes for more food demands and the relating soil erosion generation. The soil moisture retained in the check dam were estimated to about 2 billion ton annually and the SOM in the whole profile of check-dam land could be 3 times high than that in the top-soil layer (less than 1g/kg). The reduction of sediment load in the Yellow River could save a great amount of capacity of reservoirs, decrease the rising of the riverbed and flood risks of the lower stream of the Yellow River, and it also could save 1-3 billion cubic meters of runoff to flush the sediment away into the Bohai Sea. The functions of check dam could be sustainable if well-maintained.

How to cite: Wang, F., Ge, W., and Chen, H.: Check dam and its functions on the Loess Plateau of North Shaanxi Province, China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6010, https://doi.org/10.5194/egusphere-egu23-6010, 2023.

vSSS.12

EGU23-16426

Telecoupled impacts of Yudiba Dam on reforestation in the Loess Hill Ravine Region of northern Shaanxi

Runqi Wu and Xiangzhou Xu

Abstract: As a large-scale check dam, Yudiba Dam on the Loess Plateau of China, is a kind of check dam with the height more than 5 m which is used to retain soil and water, produce grain and control flood. The Yudiba dam plays an important role for vegetation restoration in the process of returning cropland to forest in the Loess Hill Ravine Region of northern Shaanxi. This study explores the telecoupling relationship between the check dam in Yulin, and the vegetation reforestation in the local and adjacent areas based on the statistical yearbook data and remote sensing data of the northern Shaanxi from 2000 to 2020. The results show that: (1) The normalized vegetation index (NDVI) of Yulin, Shaanxi Province, shows an increasing trend during 2001-2015. The NDVI is higher in the east of northern Shaanxi, Yulin, where the check dams are more concentrated, and shows a decreasing pattern in the west of northern Shaanxi where the check dams are more dispersed. The NDVIs of Mizhi, Suide and Qingjian counties in the east are 0.510, 0.511 and 0.520, respectively. The NDVI of Dingbian County in the west is only 0.354, while the NDVIs of Zizhou and Hengshan counties which are closer to the east, are 0.414 and 0.390, respectively. This indicates that the construction of Yudiba dam in Yulin significantly contributed to the growth of vegetation cover in local and other surrounding regions of Yulin. (2) Driven by the policy of returning cropland to forest in Shaanxi Province, the construction of Yudiba dam in the west of northern Shaanxi, e.g. Dingbian county, may be also strengthened because of the need of vegetation restoration. The construction of Yudiba dam will promote the infertile slope farmlands to be replaced with high-productivity check-dam farmlands in the west of northern Shaanxi. Hence the construction of Yudiba dam in Yulin may be helpful in realizing sustainable development of resource and environment in northern Shaanxi Province.

Keywords: Telecoupling, Yudiba dam, sloping farmland, vegetation restoration, returning cropland to forest

How to cite: Wu, R. and Xu, X.: Telecoupled impacts of Yudiba Dam on reforestation in the Loess Hill Ravine Region of northern Shaanxi, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16426, https://doi.org/10.5194/egusphere-egu23-16426, 2023.

vSSS.13

EGU23-16334

ECS

Evolution of farm terraces in the upper Sacos River catchment (Alacant) and the effects on soil conservation

Francesc Cuello-Llobell, Carolina Boix-Fayos, Adolfo Calvo-Cases, and Joan Estrany

Abandoning farm terraces can lead to the collapse of its walls, triggering high soil losses, with the consequent deterioration of the ecosystem services that these terraces generate in Mediterranean mid-mountainous areas. For the management of these areas, a very useful tool is the quantification and detection of processes promoting the degradation of these structures.

In this work, the terraces of the upper area of the Sacos River, (0.44 km²; Tàrbena, Alacant, Spain) were characterized and the material volume lost in the breaks is quantified. For this purpose, SfM-MVS (Structure from Motion, Multiview Stereo) photogrammetry was used to create a high-resolution DEM (0.01 m) of each break. For each one, around 45-50 photographs were taken with the phone camera to create the DEM that matched the surface and height of the collapse, obtaining a 3D model with the Metashape Pro v1.7 software allowing to adjust the surface to calculate the losses. This procedure was applied in 9 of the 82 breaks, representing 10% of them at the whole study area. With this DEM and the ArcGIS software, an interpolation of the terrace heights was carried out without considering the collapse to subsequently obtain the volume lost, from the difference of both rasters. The characterisation of the walls was done by a semi-automatic process that allowed the estimation of the walls’ height and the total length (in metres) within the study area, obtaining densities and relating this to the breaks. To explain the position of the collapses within the catchment, ergo the convergence pattern of surface runoff, a Connectivity Index (CI) was applied on a 1 m resolution DEM obtained from LiDAR data (https://pnoa.ign.es/web/portal/pnoa-lidar/presentacion).

The results showed an estimated volume of runoff loss, ranging from 0.02 m³ to 0.34 m³ depending on the walls’ height. A loss of 7.28 t ha^-1 yr^-1 was estimated for all the studied sub-catchments, higher than an erosion rate of 1 t ha^-1 yr^-1, considered to be the "sustainable" limit that can occur in a system in the form of sediment loss, indicating the severity of the losses due to falling walls. In addition, the normalised CI allowed the establishment of a threshold at ca. 40% of the same CI, above which, the 96% of the breaks were located. The type of terraces is another determining factor for the location of the breaks, since 68% of them were check-dam terraces, although this type only occupies 32% of the total surface.

The estimated volume per wall collapse in the study area is 15.78 m³, estimated from the regression line of the breaks analysed in detail, obtained from the height of each wall and the material mobilised in each collapse. This is extrapolated to all the breaks detected, considering their height for this extrapolation. This amount of eroded material indicates the need for establishing urgent conservation strategies of these soils, due to their collapse is promoting a sediment cascade process in which concentrated erosion initiate the generation of new watercourses at these hillslopes, no longer functioning as terraces.

How to cite: Cuello-Llobell, F., Boix-Fayos, C., Calvo-Cases, A., and Estrany, J.: Evolution of farm terraces in the upper Sacos River catchment (Alacant) and the effects on soil conservation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16334, https://doi.org/10.5194/egusphere-egu23-16334, 2023.

vSSS.14

EGU23-7175

Application of AHP in flood combination calculation of check dam system

Lili Gui and Zhijian Wang

Check dam is an important water and soil conservation measure for comprehensive treatment of small watershed in the Loess Plateau. The reinforcement of sick and dangerous check dam is an important measure to ensure the safe operation of check dam and promote the high-quality development of the Yellow River basin. How to scientifically and reasonably determine the flood control standard of each dam and do a good job in flood combination and hydrological calculation is a key technical problem to be solved in the reinforcement design of check dam system engineering. Taking the dam system project of Wan'angou small watershed in Shanxi Linxian County as an example, the overall layout of the dam system project is shown in Fig.1. Based on the relevant theory of "AHP", starting from the upstream of the main and branch ditches in the basin, comprehensively analyze the distribution location of each dam and its impact on the downstream, construct the hierarchical structure model of large and medium-sized silting dams in the dam system, as shown in Fig. 2, from which the distribution characteristics of the dam system in the basin and the correlation between the upstream and downstream dams can be intuitively and quickly analyzed, and on this basis, determine the flood control standard, flood combination and hydrological calculation of each dam. It can be seen intuitively in Fig. 2 that during the design of danger removal and reinforcement, the check dam and the reasons for the improvement of flood control standards need to be improved. For example, two large (1) check dams G_Z4* and G_Z5*inlevel 1, first because there are residential areas in the downstream influence area, the flood control standards are increased to large (2) check dams D_Z4* and D_Z5* according to the specification requirements; Secondly, since its downstream is the large (1)check dam G1 inlevel 2, considering the flood combination, it is raised to the large (1) check dam G_Z4*and G_Z5*. At the same time, from Fig.2, it can be determined that the flood combination is analyzed and the hydrological calculation is carried out according to the three conditions of single dam, series dam and parallel dam, for example, the large (1) check dam G_D6inlevel 5 is calculated according to three parallel check dams.

How to cite: Gui, L. and Wang, Z.: Application of AHP in flood combination calculation of check dam system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7175, https://doi.org/10.5194/egusphere-egu23-7175, 2023.

vSSS.15

EGU23-3904

Control technology of gully sediment yield in Yellow River basin

zhenzhou shen

The ecological protection and the high quality of national strategic in the Yellow River is pointed out that the Yellow River basin management to adhere to the concept of Lvshui Qingshan is the Jinshan Yinshan, strive to strengthen management of ecological protection, promote the implementation of a batch of major ecological restoration and construction projects, including Pisha stone areas in the middle reaches of the Yellow River is to focus on one of the areas to carry out the comprehensive control of ecological. Based on the analysis of the previous treatment theory and practice in the Pisha stone area, the research and development of the ecology-economy comprehensive treatment technology in the Pisha stone area is carried out. Including slope runoff efficient reservoir and utilization technology, the top economic fruit industry mode, block polymer grouting treatment technology of gravity erosion, slope erosion resistance and comprehensive treatment technology, flexible dam-Pisha stone channel modification material check dam and warping DAMS erosion prevention and control technology research and development and integration, finally enhance sieved Pisha stone areas are summarized ecological comprehensive control mode. The comprehensive ecological management model of Pisha stone can provide strong technical support for ecological protection and high-quality development of the Yellow River Basin.

How to cite: shen, Z.: Control technology of gully sediment yield in Yellow River basin, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3904, https://doi.org/10.5194/egusphere-egu23-3904, 2023.