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.

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.

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.

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.

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.

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.

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.

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.

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.