D2.2 Citizen Science Soil Health Toolbox

E C H O S O I L . E U Deliverable 2.2 “Citizen Science Soil Health Toolbox” 2 Project information Project number 101112869 Project acronym ECHO Project name Engaging Citizens in Soil Science: The Road to Healthier Soils Call HORIZON-MISS-2022-SOIL-01 Topic HORIZON-MISS-2022-SOIL-01-09 Type of Action HORIZON Research and Innovation Actions Responsible Service REA.B.2 Project starting date 01 June 2023 Project duration 48 months Document Details Deliverable D2.2 – Citizen Science Soil Health Toolbox Work Package WP2 – Citizen Science Platform Task T2.2 – Development of a Citizen Science Toolbox Deliverable Type Other Dissemination Level PU – Public Deliverable Lead UEX Date of publication 30 November 2024 Disclaimer Funded by the European Union under GA no. 101112869 – ECHO and co-funded by UK Research and Innovation (UKRI) under GA no. 10068004. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union, UKRI, or the European Research Executive Agency (REA). Neither the European Union, UKRI nor the REA can be held responsible for them. 3 Short description of the deliverable This document is a compilation of field guidelines and protocols that make up part of the Citizen Science Soil Health Toolbox. It consolidates and summarizes key information for regular users of the ECHO app regarding the eight soil health indicators outlined in the Mission Soil Implementation Plan: presence of pollutants, soil structure, soil organic carbon stock, soil biodiversity, soil pH, vegetation cover, landscape heterogeneity and forest cover. This document is a supplement to the handbook derived from D2.3, providing a deeper understanding of the theory behind each protocol for assessing the eight soil health indicators. Designed as a support resource, the Toolbox (Appendix: “Citizen Science Factsheets for soil health indicators”) can be assessed through a dedicated feature in the ECHO app, providing users with auxiliary information to help them understand and assess each soil health indicator. Versioning and contribution history Version Date Modified by Notes 1 11/02/2024 Manuel Pulido and Juana Labrador (UEX) Draft version 2 16/06/2024 Manuel Pulido and Juana Labrador (UEX) Draft version 3 31/07/2024 Manuel Pulido and Juana Labrador (UEX) Draft version 4 15/09/2024 Manuel Pulido and Juana Labrador (UEX) Draft version 5 29/10/2024 Manuel Pulido (UEX), Juana Labrador (UEX), Tanja Mimmo (UNIBZ), Claudia Cappello (UNIBZ), Celine Laurent (UNIBZ), Virpi Virjamo (UEF) and Alba Peiro (IBERCIVIS) Draft version 6 11/11/2024 Roy Neilson (Hutton) Draft version 7 19/11/2024 Tanja Mimmo (UNIBZ), Claudia Cappello (UNIBZ), Celine Laurent (UNIBZ), Manuel Pulido (UEX) Roy Neilson (HUTTON), Alba Peiro (IBERCIVIS) Draft version 8 23/11/2024 Tanja Mimmo (UNIBZ), Claudia Cappello (UNIBZ), Celine Laurent (UNIBZ) Draf version 9 25/11/2024 Tanja Mimmo (UNIBZ), Claudia Cappello (UNIBZ), Celine Laurent (UNIBZ), Manuel Pulido (UEX), Wiktoria Witek (AgroHorti Media) Final version 4 Foreword Soil is a vital, yet often disregarded, resource that supports life on Earth by providing the foundation for agriculture, forests, and various other natural ecosystems. However, soil degradation is a growing concern around the world, and it can have severe consequences for our planet including, such as reduced crop yields, increased greenhouse gas emissions, and decreased biodiversity. The ECHO project aims to prevent this by bringing together citizens and volunteer scientists from around Europe and Scotland to work towards a common goal of protecting and preserving our soils, thus contributing to the transition towards healthy soils as outlined by the European Union (EU) Mission: “A Soil Deal for Europe”. ECHO will generate new data on the health status of EU soils, complementing existing soil mapping and monitoring in EU Member States and Scotland, including the EU Soil Observatory (EUSO). The project will develop and deploy 28 tailor-made citizen science initiatives, taking into account different land-uses, soil types, and biogeographical regions, as well as stakeholder needs. With 16 participants from all over Europe, including 10 leading universities and research centres, four SMEs, and two Foundations, under the coordination of the Free University of Bolzano-Bozen, ECHO will assess 16,500 sites in different climate and biogeographic regions to achieve its ambitious goals. The project aims to engage citizens in protecting and restoring soils by building their capacities and enhancing their knowledge. Citizens will thereby not only actively contribute to project data collection but also promote soil stewardship and foster behavioural change across the EU and Scotland. ECHOREPO, a long-term open access repository with a direct link to the EUSO, will make the citizen science data available for exploitation not only by scientists but also by citizens, policy makers, farmers, landowners and other end-users, providing added value to existing data and other relevant soil monitoring initiatives. ECHOREPO will thus provide valuable information about the state of soil health in various regions, and help citizens make informed decisions about land use and conservation. We believe that the ECHO project will have a significant impact on soil health and citizen engagement across Europe and become an important step towards protecting and preserving our soil for future generations. By working together, we can ensure that our soil remains healthy and productive, and that we continue to enjoy the many benefits it provides. 5 Contents 1. Introduction ..................................................................................................................................... 7 2. Description of the ECHO soil health indicators .............................................................................. 10 2.1 Presence of pollutants ......................................................................................................... 10 2.2 Soil organic carbon stock ...................................................................................................... 11 2.3 Soil structure and texture..................................................................................................... 13 2.4 Soil pH .................................................................................................................................. 18 2.5 Soil biodiversity .................................................................................................................... 20 2.6 Vegetation cover, forest cover, landscape heterogeneity .................................................... 23 3. Field protocols ............................................................................................................................... 24 3.1 On-site activities ................................................................................................................... 24 3.1.1 Selecting the sampling site and time ............................................................................... 24 3.1.2 GPS coordinates ............................................................................................................... 25 3.1.3 Vegetation cover, forest cover, landscape heterogeneity ................................................ 25 3.1.4 Soil digging procedure ..................................................................................................... 26 3.1.5 Soil structure .................................................................................................................... 27 3.1.6 Soil biodiversity in terms of earthworms ......................................................................... 28 3.1.7 Presence of pollutants ..................................................................................................... 29 3.1.8 Soil texture ....................................................................................................................... 29 3.1.9 Soil organic matter ........................................................................................................... 30 3.1.10 Soil pH .......................................................................................................................... 31 3.2 Off-site activities ................................................................................................................... 32 3.2.1 Soil biodiversity in terms of bacteria and fungi ............................................................... 32 3.2.2 Heavy metals and soil nutrients....................................................................................... 33 4. Site cleanup and sample shipment ................................................................................................ 34 5. References ..................................................................................................................................... 35 6. Appendix: Citizen Science Factsheets for soil health indicators………………………………..………………….. 38 6 List of figures Figure 1: Spatial distribution of soil organic carbon stock in the European Union ............................... 12 Figure 2: Soil profile of a Leptosol developed on schists. The top 5 cm shows a higher percentage of soil organic carbon stock; however shallow depth results in soil organic carbon stock of approximately 25 Mg ha-1 ............................................................................................................................................ 13 Figure 3: Examples some different soil structure types. A: massive, B: prismatic, C: blocky, D: granular. ............................................................................................................................................................... 14 Figure 4: Mineral fractions of the soil’s fine earth (ø <2 mm) ............................................................... 15 Figure 5: Soil texture triangle. Author: USDA Soil Survey Division Staff ................................................ 16 Figure 6: Indicative values of pH within a logical context aimed at their proper interpretation .......... 18 Figure 7: Spatial distribution of soil pH in the European Union ............................................................ 20 Figure 8: Examples of photos to upload on the ECHO App .................................................................... 26 Figure 9: Soil digging ............................................................................................................................. 27 Figure 10: Reference grid to use for the visual evaluation of soil structure (adapted from Agriculture and Horticulture Development Board) .................................................................................................. 28 Figure 11: Decision-making flowchart to determine soil type according to the “texture-by-feel method” (modified after USDA soil quality guide) ................................................................................ 30 Figure 12: Soil colour chart to assess soil organic matter content ........................................................ 31 Figure 13: Step-by-step process for soil pH measurement .................................................................... 31 Figure 14: Procedure to collect a soil sample for off-site biodiversity assessment ............................... 32 Figure 15: Procedure to collect soil sample for off-site heavy metals and nutrients assessment ......... 33 Figure 16: Sample shipment process ..................................................................................................... 34 7 1. Introduction Soil is a vital, limited resource, considered non-renewable and irreplaceable on a human timescale, and essential for supporting the economy, environment and society. According to the European Soil Observatory (EUSO), 60-70% of European soils are in an unhealthy state (ESDAC, 2024a). Therefore, it is critical to manage and protect soils to ensure their preservation for future generations. To address this, various initiatives have been launched within the EU Soil Strategy for 2030, the EU Mission ‘A Soil Deal for Europe’ - Implementation Plan, and the new Soil Monitoring and Resilience Directive 1 , with the goal of protecting, restoring, and ensuring healthy soils by 2050. Raising awareness about the vital and societal importance of soil is crucial to achieving these objectives. The Soil Monitoring and Resilience Directive defines soil as “the top layer of the Earth’s crust situated between the bedrock and the land surface, which is composed of mineral particles, organic matter, water, air and living organisms.” This vital, dynamic, and heterogeneous component of ecosystems plays a crucial role in sustaining life on Earth. Its ability to support plant growth, regulate water, and enhance climate resilience makes understanding soil properties essential for sustainable land management. Soil is also fundamental to food production and contributes to sustainability by supporting essential societal and ecosystem services. The concept of soil health emerged in the early 2000s, highlighting the critical link between the health of soils, humans, animals, and the environment— a key idea in the 'One Health' framework. As the importance of soil health continues to gain recognition, its definition and practical application are still evolving, alongside related concepts like soil quality and soil fertility (Bossio et al., 2020). While distinct, these concepts collectively address various aspects of soil function in agriculture and broader ecosystem services, providing a comprehensive approach to effective soil management. a. Soil Health: Refers to the soil’s ongoing ability to function as a living, dynamic system that sustains plants, animals, and humans, while also supporting broader ecosystem services such as water purification, biodiversity, and climate regulation. b. Soil Quality: Focuses on the soil's ability to perform specific functions, particularly in agriculture and environmental services, such as water filtration and plant growth. c. Soil Fertility: Specifically relates to the soil’s ability to supply essential nutrients for plant growth, supporting agricultural productivity. Soil health in the EU and Scotland faces multiple threats from land degradation processes such as pollution (e.g., pesticides, heavy metals), nutrient imbalance, aridity, water and wind erosion, and soil compaction, among others (Prăvălie et al., 2024). The main drivers of these processes often include agricultural intensification, overgrazing, and changes in land use (Ferreira et al., 2024), the effects of which are further catalysed by climate change (David Raj et al., 2024). These factors disrupt crucial soil-based ecological processes (e.g., carbon sequestration, habitats for microorganisms), underscoring the importance of maintaining soil 1 https://data.consilium.europa.eu/doc/document/ST-11299-2024-INIT/en/pdf 8 health. Maintaining and restoring soil health is achievable through sustainable soil management, defined as “soil management practices that maintain or enhance the ecosystem services provided by the soil without impairing the functions enabling those services or causing harm to other environmental properties.” The concept of soil health is highly contextdependent, varying with land use (e.g., agricultural land, forests, urban and industrial areas, natural and semi-natural areas). For this reason, the ECHO project takes into account various land uses, including agricultural, forestry, urban areas and natural/seminatural areas, as well as mixed land uses such as agroforestry, reflecting the diversity of ecosystems and their specific soil health needs. To account for this variability, assessing and monitoring soil health requires the use of indicators—easily measurable and interpretable variables. These indicators, such as pollutant levels, soil organic matter, pH, soil structure, and earthworm abundance (a proxy measure of biodiversity), help land users understand the natural limits of each system. In addition, soil health may need to be assessed for several reasons including crop fertility, identification of land degradation processes, assessment of soil biodiversity, educational purposes, and selfassessment of farms. According to the 2018 Corine Land Cover data, agricultural soils cover over 33% of the EU’s land surface. These soils are a strategic resource for the EU, providing food for people and livestock, raw materials for industry, and exports to third countries. They are essential for ensuring food sovereignty, help deliver nutritional security and supporting rural communities predominantly in highly urbanised countries. However, conserving these soils is challenging due to environmental pressures such as soil compaction, erosion, organic carbon depletion, overfertilization, and pollution. Natural areas, including forests and grasslands, account for nearly 40% of the EU's land surface. Their sustainable use is critical for providing key ecosystem services, such as carbon sequestration, water retention and purification, and wildlife habitats, among others. Urban soils, while only making up 3.4% of the EU’s land surface, are often found in green urban spaces like parks. Despite their limited size, assessing the health of urban soils is crucial for raising public awareness about soil conservation and promoting nature-based solutions, such as gardens, orchards, and trees. Evaluating soil health across different land uses and increasing citizen awareness of soil conservation are key objectives of the ECHO project. Assessing soil health across different land uses presents several challenges, including: 1. Variability in Soil Properties: Soil health indicators can vary significantly between different land uses (e.g., agricultural, urban, natural). This variability complicates the establishment of universal assessment criteria. 2. Data Availability: There may be a lack of historical data or baseline information on soil health for certain land uses, particularly in urban and under-studied areas. This makes it difficult to track changes over time. 3. Complexity of Soil Ecosystems: Soil is a complex living system influenced by numerous factors (e.g., climate, topography, vegetation). This complexity makes it challenging to 9 isolate specific indicators of soil health. 4. Sampling Techniques: Different land uses may require tailored soil sampling techniques to accurately capture soil health indicators. For instance, urban soils may have unique contaminants that necessitate specific sampling protocols. 5. Temporal Variability: Soil health can fluctuate over time due to seasonal changes, land management practices, and environmental conditions. Capturing these temporal dynamics can be difficult and may require long-term monitoring. 6. Interdisciplinary Approaches: Assessing soil health often requires integrating knowledge from various disciplines, including soil science, ecology, and agriculture. This can be challenging due to differing methodologies and terminologies. 7. Public Awareness and Engagement: Engaging citizens and stakeholders in soil health assessments can be challenging, especially in urban areas where the connection to soil may be less apparent. Raising awareness and promoting participation is crucial for successful assessments. Addressing these challenges requires a collaborative and interdisciplinary approach to develop standardized protocols, improve data availability and interoperability, and enhance public engagement in soil health assessment efforts across different land uses. The ECHO project addresses the challenges in assessing soil health across different land uses through several key strategies: 1. Citizen Engagement: The project aims to increase public awareness and engagement in soil health issues. ECHO involves local communities, stakeholders, and citizen scientists in soil assessments, promoting a better understanding of soil conservation and its importance. 2. Standardized Protocols: ECHO will develop standardized methodologies and protocols for soil health assessment that can be applied across various land uses. This helps ensure consistency and comparability of data, making it easier to evaluate and interpret soil health indicators. However, ECHO recognizes also the unique characteristics of different land uses and tailors its assessment approaches accordingly. This ensures that the specific challenges and needs of each land use are addressed effectively. 3. Interdisciplinary Collaboration: ECHO promotes collaboration among experts from various fields, including soil science, ecology, agriculture, and social sciences. This interdisciplinary approach enhances the understanding of soil health and its relationship with different land uses. 4. Capacity Building: ECHO will provide training and resources to enhance the capacity to assess and manage soil health effectively. This includes workshops, educational materials. 5. Data Sharing and Accessibility: The project focuses on improving data availability, interoperability and accessibility by creating databases and platforms (ECHOREPO) for sharing soil health information. This facilitates collaboration and knowledge exchange 16 Soil texture plays a crucial role in determining soil characteristics and suitability for various land uses. Here’s how soil texture relates to different applications: 1. Agricultural Land • Clayey Soils: These soils retain moisture well and have good nutrient-holding capacity, making them suitable for crops that require consistent water availability. However, excessive clay can lead to compaction and poor drainage, which may hinder root development. • Sandy Soils: With larger particles, sandy soils drain quickly and warm up faster in spring, which is beneficial for early planting. However, they have low nutrient and water retention, often requiring more frequent irrigation and fertilization. • Loamy Soils: Often considered the ideal soil type for agriculture, loamy soils balance sand, silt, and clay, providing good drainage, nutrient-holding capacity, and moisture retention. 2. Urban Areas • Clayey Soils: In urban settings, clay soils can cause drainage problems, making stormwater management a challenge. However, when properly managed and stabilised, they provide a strong foundation for heavy structures and infrastructure. • Sandy Soils: These soils are often preferred for landscaping and green spaces due to their excellent drainage and reduced flooding risk. However, their low water and nutrient retention require careful management, such as incorporating organic matter or using irrigation systems, to maintain plant health. Figure 5: Soil texture triangle. Author: USDA Soil Survey Division Staff 17 • Loamy Soils: Loamy soils are highly versatile in urban areas, offering a balance of drainage and moisture retention. They are ideal for green spaces, urban gardens, and landscaping, as they support a wide variety of plants and require less modification compared to other soil types. • Mixed Textures: Urban developers frequently amend soils to create suitable conditions for planting and landscaping. Understanding the existing soil texture helps in selecting appropriate amendments, such as compost or sand, and in choosing plant species that can thrive in the modified conditions. Proper soil management enhances green infrastructure and improves urban resilience. 3. Forestry • Clayey and Silty Soils: These soils can support tree growth by retaining moisture and nutrients. However, compaction from logging activities can harm soil structure. • Loamy Soils: Loamy soils are ideal for forestry as they offer a balanced mixture of sand, silt, and clay, providing excellent drainage, aeration, and nutrient availability. This soil type supports robust root development and sustains a wide variety of tree species, making it highly suited for sustainable forest ecosystems. • Sandy Soils: While sandy soils can support certain tree species, they may require irrigation in dry periods due to their low water retention. 4. Parks and Recreational Areas • Loamy Soils: Ideal for parks and recreational spaces, loamy soils support diverse vegetation and provide good drainage while retaining moisture. • Clayey and Sandy Soils: These can be managed through soil amendments and proper landscape design to ensure they meet the needs of plants and recreational activities. 5. Wetlands and Natural Areas • Silty and Clay Soils: Wetland areas often have fine-textured soils that retain water and support diverse plant and animal life. These soils are crucial for maintaining wetland ecosystems. • Sandy Soils: In some wetland and natural areas, sandy soils play a vital role in facilitating water infiltration and maintaining hydrological balance. While they drain quickly, sandy soils often contribute to the formation of unique habitats, such as riparian zones and coastal wetlands, where specialised plant species thrive. These areas are essential for biodiversity and act as buffers against erosion and flooding. Understanding soil texture is essential for effective management across different land uses. It influences water retention, nutrient availability, plant growth, and susceptibility to soil erosion, all of which are critical for optimizing land use practices and ensuring sustainability. Proper management strategies tailored to soil texture can help mitigate erosion risks, preserve soil fertility, and maintain the long-term productivity and stability of ecosystems. Human activities are the main cause of alteration in soil structure and texture, reducing soil porosity due to compaction from heavy machinery or soil erosion from practices such as 18 tillage, ploughing, or subsoiling (Pires et al., 2017). These changes negatively impact soil health by reducing its natural ability to retain water and nutrients and sequester carbon, ultimately impacting food and fibre production. While soil structure can often recover relatively quickly, changes in texture are longer to reverse (Pagliai et al., 2004). Significant textural changes are less common, typically occurring due to erosion and depositional processes. The effects of these changes on soil health are often more challenging to address in short term (Rosenbloom et al., 2001). 2.4 Soil pH Soil pH or soil reaction is an indication of the acidity or alkalinity of soil and is measured in pH units (Figure 6) 3 , 4 . Soil pH can vary from very acidic (3-4) to very alkaline (8-9) and is a key indicator of soil health. It influences many other soil properties, including nutrients availability and biological activity. For instance, nutrients like nitrogen, phosphorus, potassium, and iron are more accessible to plants and organisms within specific pH ranges. Furthermore, most organisms, including plants and microorganisms, thrive best within a certain pH range, so extreme acidic or alkalinity can negatively impact their populations. 3 https://www.snexplores.org/article/scientists-say-ph 4 https://www.soilquality.org.au/factsheets/soil-ph-south-austral Figure 6: Indicative values of pH within a logical context aimed at their proper interpretation 19 The main causes of soil acidity are factors such as climate, rainfall, litter composition, and carbonic acid generated during SOM decomposition and root respiration. Additionally, hydrogen ions (H⁺) are released during organic matter breakdown and nitrification process. Soil pH is also influenced by the type of bedrock; for instance, soils formed from siliceous rocks (e.g., granites, slates, or quartzites) are typically acidic, whereas alkaline soils are common in regions with calcareous rocks, such as limestone and dolomite. Alkalinity in soils mainly results from the weathering of calcareous rocks, salinization in arid and semi-arid regions due to irrigation, and the use of lime in agriculture to improve fertility. Major land-use changes, such as converting forests to farmland, can also affect soil pH. Land use and management practices greatly influence soil pH. Vegetation type plays a key role, with boreal forests in Finland showing pH values between 3.8 and 4.9. Generally, forest soils tend to have lower pH levels compared to agricultural fields; however, agricultural practices significantly affect the latter. As a result, converting land from forest or grassland to cropland can cause noticeable changes in soil pH over time, ultimately impacting soil health. Figure 7 (Ballabio et al., 2019) illustrates the significant influence of geochemical composition of soil parent material. Areas with carbonate rocks show higher pH levels, especially where soil erosion amplifies the effect of parent material, such as around the Mediterranean Sea. This results in neutral to alkaline soils in much of Spain, southern France, Italy, and Greece. Similar geological impacts are seen in northern France and parts of the UK. However, climate can sometimes override the parent material’s influence; for instance, heavy rainfall in Ireland and north-eastern Spain leaches nutrients, creating acidic soils. Vegetation also plays a role in shaping soil pH: forested areas, particularly coniferous forests, tend to lower pH due to fewer base cations returning from litter. In contrast, steppe grasslands, like Hungary's Chernozem plains, can raise topsoil pH by enriching it with calcium ions from loess deposits. At a smaller scale, the difference in pH between forested and cultivated soils can be particularly pronounced. Assessing soil pH is a straightforward and rapid method to gauge soil health from a chemical perspective. However, pH values must be interpreted considering local factors such as climate, vegetation and dominant rock types. Rapid fluctuations in pH can cause lasting harm to soil biology, particularly to microbial communities, which can disrupt nutrient and carbon cycling, reduce nutrient availability to plants, and overall harm soil health (Dewangan et al., 2023). These changes are often associated with over-fertilization and prolonged fertilizer use in agricultural soils (Semenov et al., 2023), deforestation in forested areas (Amoakwah et al., 2021), and inadequate waste management in urban soils (Rahmonov et al., 2022). Addressing these challenges requires sustainable land management practices that consider the implications of soil pH on different land uses. 20 2.5 Soil biodiversity Soil biodiversity is the “variation in soil life, from gene to communities, and the ecological complexes of which they are part, that is from soil micro-habitats to landscapes” (Convention on Biological Diversity, CBD). This concept is used to express the number of species and their abundance including bacteria, fungi, protists, nematodes, arthropods, earthworms and mammals, which are categorized by size into micro-, meso-, macro-, and megafauna. Soil biodiversity plays a crucial role in delivering key ecosystem services, including nutrient cycling, water flow and storage, regulation of soil erosion, pests and disease management, maintaining soil structure, and detoxifying pollutants 5 . These services are critical for agriculture, water quality, climate regulation, and overall ecosystem health. Three ways are feasible for studying microbial diversity: • Direct observation and counting: some microbes can be grown in vitro by using specific growth media and then identified through microscopy. Problem is that only a 5 https://esdac.jrc.ec.europa.eu/themes/soil-biodiversity Figure 7: Spatial distribution of soil pH in the European Union 21 tiny percentage of microorganisms are capable of growing in artificial conditions; • Functional assays: different biochemical techniques allow to detect functional activities carried out by specific enzymes of soil microorganisms; • DNA sequencing: this approach represents the new age in studying soil biodiversity. For most taxa, it relies on direct extraction of DNA from soil and identification of microorganisms through the sequencing of some portions (barcode regions) of their genomes. This strategy is recently grown thanks to the new sequencing technologies (next generation sequencing - NGS) allowing to obtain an unprecedented amount of data (number of DNA sequences) in a short time. Assessing soil biodiversity requires different methods based on the organism group and the data type needed, such as species abundance or their role in soil functions. For example, invertebrates like earthworms can be directly observed, while identifying microorganisms like bacteria and fungi requires laboratory analysis. This process involves extracting DNA from soil samples and sequencing it to identify microbial taxa. Among soil invertebrates, earthworms are considered as valuable indicators of soil health due to their species-specific preference and tolerance towards soil quality, climate, and food (Bartlett et al., 2010). Earthworm population is affected by seasonal and climatic variations, with their activity picking in spring and autumn 6 , and also is related to soil properties and agricultural practices (Bartz et al., 2024). As earthworms preferences are for humid soils and temperature from 0 to 30 degrees, during cold or heat waves periods, earthworms tend to burrow deeper into the soil for a resting state or to move to a more humid site. Addtitionnaly, in the mediterranean area, it might be found low number of earthworms due to dry conditions. In forests, the number of earthworms can be reduced due to acidic soils, as pH values move towards pH 5 and they mostly disappear at pH 4.5. It is important to note that in most boreal forest ecosystems, earthworms are invasive species and some healthy soils, such as peat soils or low-fertility coniferous forest soils, may have very few or no earthworms. In ECHO, soil biodiversity will be assessed both on-site and off-site: • On-site by counting earthworms, as their presence can reveal much about the soil structure and quality. However, being scientifically correct, numbers of earthworms are only relevant when you identify the species present. • Off-site by using DNA-based sequencing techniques to examine the taxonomic composition of the microbial community. The loss of soil biodiversity, often driven by human activities, negatively impacts soil health by reducing the number of organisms, eliminating key species, disrupting their interactions, and disturbing the natural balance of the soil food web. The loss of species that play similar roles in the soil significantly affects essential processes like SOM decomposition, nutrient cycling, and plant-microorganism interactions, which are crucial for plant nutrient uptake (Soil Biodiversity, ESDAC). As a result, human-induced changes that reduce microbial activity can cause irreversible damage, diminishing the soil’s ability to resist pests, store water, 6 https://www.nrcs.usda.gov/sites/default/files/2022-10/Earthworms.pdf 22 absorb nutrients, and sustain nutrient cycling and fertility. The relationship between soil biodiversity and land use is closely intertwined, as different land-use types have distinct impacts on soil biodiversity, as follows: 1. Agricultural land: • Intensive agriculture often leads to a reduction in soil biodiversity due to practices such as monocropping, the use of agrochemicals, soil compaction from machinery, and frequent tillage. These activities disturb the soil habitat, reduce organic matter inputs, and disrupt microbial and invertebrate communities. • Sustainable agriculture practices like crop rotation, organic farming, reduced tillage, and cover crops can promote soil biodiversity by enhancing habitat variety and increasing organic matter inputs, fostering a healthier soil ecosystem. 2. Forestry: • Natural or managed forests tend to have higher soil biodiversity (but typically few earthworms) compared to agricultural land, as they often have continuous organic matter inputs from leaf litter and less disturbance. The variety of plant species supports diverse soil microbial and faunal communities. • deforestation or unsustainable forestry practices can reduce soil biodiversity by disrupting these communities, altering nutrient cycling, and increasing soil erosion. 3. Urban areas: • Urban soils typically have lower biodiversity due to soil sealing (paving over soil surfaces), compaction, pollution, and the reduction of green spaces. However, urban green areas like parks and gardens can serve as a source of biodiversity. 4. Grasslands and pastures: • Natural grasslands often support high levels of soil biodiversity due to the perennial root systems that contribute to soil organic matter and promote habitat stability. • overgrazing or conversion to intensive pasture can lead to soil degradation, loss of vegetation cover, and reduced biodiversity due to compaction, erosion, and nutrient imbalances. 5. Wetlands: • Wetland soils support unique and specialised soil biodiversity due to their waterlogged conditions, which create anaerobic environments. They play a crucial role in carbon sequestration and nutrient cycling, though if anoxic conditions, it can result in methanogenesis and therefore increase greenhouse gas emissions. • Drainage of wetlands for agriculture or urban development can drastically alter soil biodiversity, reducing the presence of species adapted to these conditions and leading to habitat loss. In summary, land use plays a critical role in shaping soil biodiversity. Practices that disturb the soil or reduce organic inputs tend to lower biodiversity, while those that enhance 23 habitat complexity and promote organic matter can boost it. Sustainable management across all land uses is crucial to maintaining soil biodiversity and its associated ecosystem services. 2.6 Vegetation cover, forest cover, landscape heterogeneity ECHO will evaluate the impact of vegetation on soil health using three key indicators: vegetation cover, forest cover, and landscape heterogeneity. Vegetation cover is critical for preventing soil compaction, reducing erosion risk, and limiting CO2 emissions, which can result from the rapid oxidation of SOM when soils are exposed. It also promotes soil biodiversity, with plant roots contributing to improved soil structure, aeration, water infiltration, and organic matter content (Tahat et al., 2020). Forest cover, which measures tree density in a given area, provides essential ecosystem services, including carbon sequestration, water purification, erosion control, flood and drought mitigation, and disease reduction (Karjalainen et al., 2010). Landscape heterogeneity is another key indicator, reflecting the spatial distribution of different habitats within a landscape. It serves as a measure of ecological integrity, affecting biodiversity and the delivery of ecosystem services, including essential soil functions (Stein and Kreft, 2015). This concept is based on the niche theory (Vandermeer, 1972), which posits that a greater number of species can coexist when more ecological niches are available. This principle applies to soil habitats, where diverse fungi, bacteria, and micro-, meso-, and macrofauna thrive. Additionally, connectivity between forest patches is vital for maintaining ecosystem services, such as ensuring continuous wildlife habitats. The interpretation of these indicators varies depending on the type of land use, whether urban, agricultural, or forested. Urban soils are often heavily influenced by human activities but may be more protected in areas like urban parks. Degradation of urban soils can reduce their ability to sequester carbon, regulate temperatures (reducing urban heat islands), filter pollutants, manage floodwaters, support wildlife, and provide recreational space. In agricultural soils, vegetation cover is often removed, typically through herbicide use, which exposes the soil to erosion and accelerates the loss of organic matter through oxidation. However, more recently, the use of cover crops has been shown to mitigate this problem. In forested areas, the main threats include reductions in tree numbers due to wildfires, windstorms, timber harvesting, pest-induced mortality, and land reclamation activities, like road construction and the use of heavy machinery. The key land degradation issues facing the EU today include poor vegetation cover, landscape homogeneity, and land-use mismanagement. A lack of vegetation cover has been shown to significantly increase soil loss during rainfall, reduce soil's capacity for flood regulation, and release large amounts of carbon into the atmosphere. Landscape simplification, driven by both intensive agriculture and land abandonment, reduces biodiversity and weakens nature's ability to prevent wildfires and control pest spread. Landuse mismanagement, including overgrazing, deforestation, excessive fertilizer use, inappropriate irrigation, and urban sprawl, can cause irreversible damage to soil biodiversity and integrity, jeopardizing soil health for future generations. 24 3. Field protocols Although various methods could be considered for soil analysis based on the indicators outlined in the Mission Soil Implementation Plan, ECHO activities have been simplified and tailored for citizen use. This approach emphasizes its primary role in citizen science and engaging also younger participants, who, with adult support, can follow and understand the activities. In ECHO, citizens will collect data both directly through on-site field activities and indirectly via laboratory-based (off-site) analyses to evaluate the indicators described earlier. The detailed protocols in the following sections are designed to guide citizens in assessing soil health at their chosen location. The field protocols are a supplement to the handbook derived from D2.3, providing a deeper understanding of the theory behind each protocol for assessing the eight soil health indicators. 3.1 On-site activities 3.1.1 Selecting the sampling site and time As a citizen science project, ECHO allows each participant to independently choose their sampling location. If you have any doubts about the area you’ve selected, feel free to contact the ECHO team or your designated ECHO Ambassador for guidance. Choosing the right sampling location is crucial to ensure accurate and meaningful results. A well-chosen site helps capture the true characteristics of the soil, reflects local conditions, and provides valuable data to assess soil health effectively. It is best to avoid sampling when the soil is too wet, such as after heavy rainfall, or too dry, such as during summer heat waves. In colder regions, don’t sample when soil is frozen and covered with snow in winter and usually saturated by water in spring. Rather, it is recommended to collect samples in the summer months for more representative results. Please note that one ECHO kit is designed for a single complete sampling. The materials inside are limited to one sampling. If collecting soil samples as a group of citizen scientists, please ensure that: 1. You complete one sampling, following all the required steps through the ECHO App, before opening another kit. 2. It is important to ensure that the distance between sampling sites is at least 50 meters. Practical advice Before collecting any soil samples, make sure you have the necessary authorization to sample the chosen site, especially if it is not your own property. If the sampling site is inaccessible (e.g., due to barriers or restricted zones) do not take any risks, and instead, choose 25 an alternative site. Also avoid sampling in fragile environments (e.g. legally protected areas) which are sensitive to disturbances and vulnerable to degradation. 3.1.2 GPS coordinates Once you have selected your sampling location, it is important to record the GPS coordinates, as this helps us identify the area’s specific context and characteristics, complementing the data you collect. Additionally, it enables better mapping of soil health across regions, facilitates comparisons between different locations, and ensures the reproducibility of the study, contributing to the creation of a citizen science-generated soil map. The GPS coordinates saved on the map will indicate an area, not an exact point. If you are in an area without an internet connection, you can save the coordinates offline. If you need help with recording your GPS coordinates, contact us in advance or reach out to your ECHO Ambassador. Your coordinates will only be shared once you have given authorization through the ECHO App, and they will only be used for the duration of the sampling. 3.1.3 Vegetation cover, forest cover, landscape heterogeneity Describing vegetation, forest cover, and landscape heterogeneity is essential as it provides context for understanding soil health and its interaction with the surrounding environment. Such information helps assess how land use and biodiversity influence soil conditions. Additional data collected through the ECHO app supports this step, offering valuable insights to enrich the analysis. Try to take clear, high-quality pictures that really capture the surroundings. If you are unsure about anything, feel free to reach out to us or your ECHO Ambassador for help. The ECHO App will ask for permission to access your camera so you can take the photos. Once you give permission, the app will only use the camera for sampling, and your photos will be shared for that purpose only. Conduct a thorough walk around the site to identify any potential sources of contamination or disruptions, such as nearby roads, traffic, and industrial facilities. Additionally, if you have any prior knowledge of the area, include relevant details about waste disposal sites, agricultural activities, pesticide use, standing water, or indications of recent flooding. Please provide any other pertinent information that can help describe the surrounding landscape in the comments. The more comprehensive the information, the better. Photos will be used to support environmental assessments. They help assess the density and health of plant species, and document signs of soil degradation or erosion. Photos also aid in identifying visible biodiversity, analysing land use patterns, and observing human activities in the area. Additionally, they contribute to creating visual maps of the landscape 32 3.2 Off-site activities Not all indicators from the Mission Soil Implementation Plan can be simplified for onsite analysis. Therefore, we will need you to send soil samples to the laboratories of ECHO scientists (UNIBZ lab), allowing us to conduct more accurate analyses using laboratory equipment and expertise. Specifically, the laboratory will analyse your soil samples for two indicators: soil biodiversity (bacteria and fungi) and heavy metals. For soil biodiversity (bacteria and fungi), soil should be placed in a plastic container with a preservation solution (see 3.2.1). For heavy metal analysis, it is sufficient for the soil to be field-moist, with a spoonful placed in a plastic bag (see 3.2.2). Your role in collecting and sending the samples is essential to the success of the overall site evaluation. 3.2.1 Soil biodiversity in terms of bacteria and fungi The soil sample for biodiversity analysis (bacteria and fungi) must be stored in a preservation solution to prevent degradation during shipping to the unibz laboratories, where DNA will be extracted and microbial diversity sequenced. This solution ensures that the DNA remains intact and viable for accurate analysis. The provided plastic tube already contains this solution and is ready to be filled with soil. The preservation solution is not harmful, and a datasheet from the company provides full details about it (available via the ECHO App). However, handle the tube carefully, wear gloves for safety, and avoid drinking the solution. Keep the kit out of reach of unsupervised children to prevent accidental ingestion. How to collect a soil sample for off-site soil biodiversity assessment (Figure 14): 1. Put on gloves and keep them on throughout the entire procedure for your safety when using the preservation solution and to prevent contamination of the sample. 2. Take the small plastic tube that contains the preservation solution. 3. Open the tube and use the wooden spoon to collect the mixed soil, filling the tube to the top, until the mixture reaches 5 mL. 4. Close the tube carefully and shake it gently for 15 seconds to mix the soil with the preservation solution, ensuring that all the soil is in contact with the solution. 5. Place the small plastic tube in the plastic bag marked with the QR code from your toolkit. Figure 14: Procedure to collect a soil sample for off-site biodiversity assessment 33 3.2.2 Heavy metals and soil nutrients As ECHO follows a citizen science approach, there is no simple method available for on-site assessment of soil nutrients and heavy metals. Heavy metals and essential plant nutrients are both elements that play significant roles in the environment and plant growth, but they differ in their functions and potential impacts on living organisms. Essential plant nutrients are elements required by plants for growth and development. These nutrients are divided into macronutrients (N, P, K, Ca, Mg, S) and micronutrients (Fe, Mn, Zn, Cu, B, Mo, Cl, Ni). While macronutrients are required in large quantities, micronutrients are needed in trace amounts. These nutrients support essential plant functions, including photosynthesis, cell division, nutrient uptake, and overall metabolism. They are typically non-toxic when present in appropriate amounts. On the other hand, heavy metals are a group of naturally occurring elements that have high atomic weight and density. As heavy metals we can include the following elements: Arsenic (As), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Lead (Pb), Nickel (Ni), Zinc (Zn). Excessive levels of heavy metals in soils can hinder plant growth and accumulate in the food chain, posing risks to human and animal health. This is why we need to analyse these elements in our laboratory, where ECHO experts will use a micro-X-Ray Fluorescence (µXRF) technique. Note that with the µXRF, the nutrients B and N cannot be measured. The citizen science approach means that participants help collect data, but more complex analyses require specialised equipment and expertise. Please use the small plastic bag (the one without QR code) for collecting the soil sample for this analysis (Figure 15). How to collect the soil sample for off-site heavy metals and soil nutrients assessment: 1. Open the small plastic bag and start collecting soil with the wooden spoon; 2. Fill the plastic bag completely (6 full spoonfuls of soil) and close it carefully; 3. Place the plastic bag containing the soil sample into the larger plastic bag already containing the sample tube for biodiveristy analysis, and marked with the QR code, and seal the bag. Figure 15: Procedure to collect soil sample for off-site heavy metals and nutrients assessment 34 Figure 16: Sample shipment process Once the sample arrives for analyses, the soil will be oven dried at 105°C until constant weight is reached before being analysed for total heavy metals and nutrients concentration by µ-X-ray fluorescence. 4. Site cleanup and sample shipment Once you have collected the two soil samples for off-site indicator analysis (the tube for soil microbial diversity and the plastic bag for heavy metals and nutrients) and placed inside the larger plastic bag marked with the QR code, they are ready to be sent to the laboratory for analysis (Figure 16). To do this, schedule an appointment with your nearest ECHO Ambassador to hand over the bag containing both samples. To find your nearest ECHO Ambassador, simply search on the ECHO App through the list of Ambassadors available in your area. The ECHO Ambassador will then scan the QR code on the plastic bag and will plan the shipment to the UNIBZ laboratory with the ECHO partners . Upon arrival, ECHO experts will scan the QR code to confirm receipt and proceed with the next steps. Your sample will be assigned a specific code that allows you to access your results through ECHOREPO. The results will be available once the analysis is complete. Using this code, you can access your data in ECHOREPO. Once the results are ready, you will receive detailed instructions on how to retrieve them. E C H O S O I L . E U 5. References Amoakwah, E., Rahman, M.A., Nketia, K.A., Djouaka, R., Didenko, N.O., Islam, K.R. (2021) Impact of deforestation and subsequent land-use change on soil quality. Eurasian Journal of Soil Science 10: 150-160. Ball, B. C., Batey, T., Munkholm, L.J. (2007). Field assessment of soil structural quality – a developmentof the Peerlkamp test. Soil Use and Management 23, 329-337. Ballabio, Cristiano, et al. "Mapping LUCAS topsoil chemical properties at European scale using Gaussian process regression." Geoderma 355 (2019): 113912. Bartlett, M.D., Briones, M.J.I., Neilson, R., Schmidt, O., Spurgeon, D., Creamer, R.E. (2010) A critical review of current methods in earthworm ecology: From individuals to populations. European Journal of Soil Biology 46: 67-73. Bartz, Marie Luise Carolina, et al. "Earthworms as soil health indicators in no-tillage agroecosystems." European Journal of Soil Biology 121 (2024): 103605. Bordoloi, R., Das, B., Yam, G., Pandey, P.K., Tripathi, O.P. (2019) Modeling of water holding capacity using readily available soil characteristics. Agricultural Research 8: 347-355. Lehmann, J., Bossio, D.A., Kögel-Knabner, I. et al. The concept and prospects of soil health. Nat Rev Earth Environ 1, 544–553 (2020). https://doi.org/10.1038/s43017-020-0080-8 Bronick, C.J., Lal, R. (2005) Soil structure and management: a review. Geoderma 124: 3-22. Cachada, A., Rocha-Santos, T., Duarte, A.C. (2018). Chapter 1 - Soil and Pollution: An Introduction to the Main Issues. In: Duarte, A. C., Cachada, A., Rocha-Santos, T. Soil Pollution. Academic Press: pp. 1-28. David Raj, A., Kumar, S., Kalambukattu, J.G., Chatterjee, U. (2024). Land degradation and its relation to climate change and sustainability. In: Chatterjee, U., Shaw, R., Kumar, S., Raj, A. D., Das, S. Climate Crisis: Adaptive Approaches and Sustainability. Springer: pp. 121-135. Dewangan, S., Kumari, L., Minj, P., Kumari, J., Sahu, R. (2023) The effects of soil pH on soil health and environmental sustainability: A review. Journal of Emerging Technologies and Innovative Research 10: 611-616. ESDAC. (2024a) EUSO Dashboard. Retrieved from: https://esdac.jrc.ec.europa.eu/esdacviewer/euso-dashboard/. Accesed on 30/10/2024. ESDAC. (2024b) Soil Organic Carbon Content. Retrieved from: https://esdac.jrc.ec.europa.eu/themes/soil-organic-carbon-content. Accesed on 30/10/2024. European Commission. (2023) Proposal for a Directive of the European Parliament and of the Council on Soil Monitoring and Resilience (Soil Monitoring Law). COM/2023/416 final. FAO, UNEP. (2021) Global Assessment of Soil Pollution: Report. Rome. Ferreira, C.S.S., Keesstra, S., Destouni, G., Solomun, M.K., Kalantari, Z. (2024). Soil Degradation in the Mediterranean Region: Drivers and Future Trends. Environmental Sustainability in the 36 Mediterranean Region: Challenges and Solutions. Springer: pp. 81-112. Franzluebbers, A.J. (2002) Water infiltration and soil structure related to organic matter and its stratification with depth. Soil and Tillage Research 66: 197-205. IUSS Working Group WRB. (2022) World Reference Base for Soil Resources. International soil classification system for naming soils and creating legends for soil maps. 4th edition. Vienna. Jansson, C., Faiola, C., Wingler, A., Zhu, X.-G., Kravchenko, A., De Graaff, M.-A., Ogden, A.J., Handakumbura, P.P., Werner, C., Beckles, D.M. (2021) Crops for carbon farming. Frontiers in Plant Science 12: 636709. Karjalainen, E., Sarjala, T., Raitio, H. (2010) Promoting human health through forests: overview and major challenges. Environmental Health and Preventive Medicine 15: 1-8. Krull, E.S., Skjemstad, J.O., Baldock, J.A. (2004) Functions of soil organic matter and the effect on soil properties. Cooperative Research Centre for Greenhouse Accounting Canberra. Lal, R. (2004) Soil carbon sequestration to mitigate climate change. Geoderma 123: 1-22. Lehmann, J., Kleber, M. (2015) The contentious nature of soil organic matter. Nature 528: 6068. Montanarella, L., Panagos, P. (2021a) The relevance of sustainable soil management within the European Green Deal. Land Use Policy 100: 104950. Montanarella, L., Panagos, P. (2021b) Soil security for the European Union. Soil Security 4: 100009. Pagliai, M., Vignozzi, N., Pellegrini, S. (2004) Soil structure and the effect of management practices. Soil and Tillage Research 79: 131-143. Pires, L.F., Borges, J.A., Rosa, J.A., Cooper, M., Heck, R.J., Passoni, S., Roque, W.L. (2017) Soil structure changes induced by tillage systems. Soil and Tillage Research 165: 66-79. Prăvălie, R., Borrelli, P., Panagos, P., Ballabio, C., Lugato, E., Chappell, A., Miguez-Macho, G., Maggi, F., Peng, J., Niculiță, M., Roșca, B., Patriche, C., Dumitrașcu, M., Bandoc, G., Nita, I.-A., Birsan, M.-V. (2024) A unifying modelling of multiple land degradation pathways in Europe. Nature Communications 15: 3862. Pulido-Fernández, M., Schnabel, S., Lavado-Contador, J.F., Miralles Mellado, I., Ortega Pérez, R. (2013) Soil organic matter of Iberian open woodland rangelands as influenced by vegetation cover and land management. Catena 109: 13-24. Pulido, M., Schnabel, S., Lavado Contador, J.F., Lozano-Parra, J., Gómez-Gutiérrez, Á., Brevik, E.C., Cerdà, A. (2017) Reduction of the frequency of herbaceous roots as an effect of soil compaction induced by heavy grazing in rangelands of SW Spain. 158: 381-389. Rahmonov, O., Czajka, A., Nádudvari, Á., Fajer, M., Spórna, T., Szypuła, B. (2022) Soil and vegetation development on coal-waste dump in southern Poland. International Journal of Environmental Research and Public Health 19: 9167. Rosenbloom, N.A., Doney, S.C., Schimel, D.S. (2001) Geomorphic evolution of soil texture and 37 organic matter in eroding landscapes. Global Biogeochemical Cycles 15: 365-381. Semenov, V., Lebedeva, T., Zinyakova, N., Sokolov, D., Semenov, M. (2023) Eutrophication of arable soil: The comparative effect of mineral and organic fertilizer systems. Počvovedenie 1: 58-73. Stein, A., Kreft, H. (2015) Terminology and quantification of environmental heterogeneity in species-richness research. Biological Reviews 90: 815-836. Tahat, M.M., Alananbeh, K.M., Othman, Y.A., Leskovar, D.I. (2020) Soil health and sustainable agriculture. Sustainability 12: 4859. Tóth, G., Hermann, T., Szatmári, G., Pásztor, L. (2016) Maps of heavy metals in the soils of the European Union and proposed priority areas for detailed assessment. Science of the Total Environment 565: 1054-1062. Vandermeer, J.H. (1972) Niche theory. Annual Review of Ecology and Systematics 3: 107-132. Xiao, S., Ou, M., Geng, Y., Zhou, T. (2023) Mapping soil pH levels across Europe: An analysis of LUCAS topsoil data using random forest kriging (RFK). Soil Use and Management 39: 900-916. Yudina, A., Kuzyakov, Y. (2023) Dual nature of soil structure: The unity of aggregates and pores. Geoderma 434: 116478.