Editorial for the Second <scp>EJP SOIL</scp> Special Issue: “Climate‐Smart Sustainable Agricultural Soil Management for the Future II”

EJP SOIL (2020–2025) was a European Joint Programme on Agricultural Soil Management, launched to address key societal challenges such as climate change and future food security. The programme aimed to enhance the understanding of agricultural soil management by creating synergies in research, strengthening research communities, and raising public awareness (https://ejpsoil.eu/). While the first Special Issue of EJP SOIL, “Climate-smart sustainable agricultural soil management for the future I”, focused primarily on early-stage work—comprising 10 surveys, 8 reviews, and 4 research articles—this second Special Issue presents a deeper dive into experimental findings. It highlights predominantly research articles (18), complemented by topic-specific reviews (2) and surveys (2), as well as short communications (2) and one methods article, drawing on results from ongoing projects. The contributions are structured around five core themes that form the backbone of EJP SOIL. The first and perhaps most comprehensive theme is Sustainable Land Management, which encompasses the evaluation of management options, mitigation of soil threats, and the status and role of soil biodiversity (Figure 1; reproduced from Towards climate-smart sustainable management of agricultural soil, 2025 by Laroche et al., licensed under CC BY 4.0). The second theme, Climate Change Mitigation, has received increasing attention in the context of the EU's Carbon Removal Certification Framework (CRCF), particularly regarding carbon farming. This includes studies on soil organic carbon (SOC) sequestration processes and potentials, the development of robust Monitoring, Reporting, Verification (MRV) methodologies, and assessments of trade-offs among SOC, nitrogen, and phosphorus. The third theme, Climate Change Adaptation, addresses the growing need for resilient farming systems. Here, scientific evaluations of management options support farmers in responding to extreme weather events and shifting climatic conditions. The fourth theme, Soil Information Assessing and Monitoring, has gained political relevance since the adoption of the EU Soil Monitoring Law in November 2025. Together with the establishment of the European Soil Observatory (EUSO) and the upcoming launch of new ESA satellites in 2028, this area is advancing rapidly. Key aspects include the development of soil health frameworks and indicators, innovative data acquisition methods, and harmonized soil information systems across Europe. Finally, the fifth theme, Fostering Adoption, focuses on bridging science and practice. It includes the evaluation of support tools, stakeholder engagement strategies, policy and incentive analyses, and the promotion of capacity building and education. The overarching aim of the EJP SOIL program—and of this Special Issue in collaboration with the European Journal of Soil Science—is to support climate change adaptation and mitigation through improved soil management. In doing so, it contributes to food security, enhanced ecosystem services, and stronger soil education across Europe. The 25 articles in this special issue provide valuable insights into the programme's core themes. Together, they help lay the foundation for better soil management in the years ahead. Over the last years, soil has become more recognized both in terms of its deteriorating quality and increasing degradation, but also as a potential part of the solution toward the ambitious goals of European political initiatives, such as the European Green Deal or the Common Agricultural Policy (Keesstra et al. 2024). Besides the efforts to make European agriculture more sustainable, there is a strong need for an additional rethink regarding which management practices deem meaningful to reduce, for instance, the environmental pressure associated with the pursuit of a more efficient (and often also more intensive) agriculture. Frequently suggested attempts toward more sustainable management practices are, for instance, the shift from conventional tillage to reduced or no-till, as well as the implementation of cover crops to ensure soil coverage and to reduce nitrate leaching and erosion. The primary reason for tillage is the incorporation of crop residues and weeds and the loosening, mixing and aeration of the soil. While this certainly impacts biological (Ocvirk et al. 2025; Spiegel et al. 2025), chemical (Spiegel et al. 2025) and physical (ten Damme et al. 2025) soil properties, reported differences between tillage treatments are often limited to the topsoil (0–10 cm) and little to no significant differences are found for deeper soil layers (e.g., Spiegel et al. 2025; ten Damme et al. 2025). However, what is often overlooked is the heterogeneity of soil and weather conditions, which are hard to capture by single experiment studies. The study of ten Damme et al. (2025) took advantage of the wide spread of the EJP SOIL consortium by including seven long-term field experiments (LTEs) along a European pedo-climatic gradient considering different tillage treatments. The authors found that differences in soil structural parameters between the seven LTEs were often larger than between tillage treatments. Nevertheless, a higher compactness and probably longer anoxic conditions under no-till can be expected to increase the chances for denitrification and thus nitrous oxide (N2O) emissions. This assumption is supported by the study of Ocvirk et al. (2025) who found higher aggregate stability, as well as higher SOC content in all soil aggregate size fractions in the topsoil after 20 years of non-inversion tillage compared to conventional tillage. This implies conditions that potentially promote denitrification, and thus, N2O emissions. Nevertheless, regardless of the practice (tillage or not) soil structure is significantly impacted by any kind of intervention. This makes it rather difficult in modeling studies, in particular, if the models do not account for the change in soil structure and, consequently, soil hydraulic properties through management practices. A closer look at this has been taken by Turek et al. (2025) who set up four agro-hydrological models with 18 different soil hydraulic descriptions derived from pedotransfer functions (PTFs). The authors found that the variance in model outputs was strongly influenced by the models and less by the PTF. Also, the sensitivity of the models to the choice of PTF depended on the type of hydrological approach that was used by the models. The authors therefore recommend using an ensemble of PTFs and, consequently, a range of soil hydraulic properties, which will help to cover regional soil heterogeneity. Cover crops are sown between two main crops to reduce periods of bare soil or undersown in a main crop to increase the species richness in the field (Oberholzer et al. 2024). Different strategies, that is, cover cropping systems, exist, and while “permanent soil cover” implies that the cover crop biomass is harvested but not incorporated into the soil, “double cover cropping” means that a summer cover crop is being terminated by incorporation into the soil and followed by a winter cover crop. Assuming that different cover cropping strategies have different effects on soil organic matter dynamics, Oberholzer et al. (2024) studied six fields in Eastern Switzerland over a 9-month period. The authors observed a high variability over time and between the fields, rather than differences between strategies. However, based on their results, the authors confirmed earlier studies stating that higher below-ground carbon inputs, as present under permanent soil cover, seem more important for the build-up of SOC stocks than above-ground biomass input given by the double cover cropping. The usage of cover crops as a measure to prevent erosion is particularly well-known in hilly regions and cropping systems, such as vineyards. However, vine-producing regions are often water-limited, making the establishment of a permanent soil cover between the rows questionable due to competition for water with the main crop. Vineyards are usually located at rather steep slopes, which is one of the reasons for the shallow soils with poor organic carbon content (e.g., Garcia et al. 2018), making inter-row management even more important with regard to potential benefits for soil quality improvement. Using 78 vineyards in four European countries, Liebhard et al. (2024) showed that “low-intensity management,” that is, low tillage intensity and cover crops, showed a long-term increase in SOC and soil physical properties compared with more intense inter-row management. The only exception was vineyards in highly water-limited regions where the establishment of temporary cover crops did not result in increased soil quality. The authors recommend that alternating low-intensity inter-row management rather than intense tillage for weed control might be a feasible alternative to a permanent soil cover, which might be particularly well-taken in water-limited regions. Overall, the results presented in this Special Issue clearly highlight that there is no such thing as a silver bullet when it comes to sustainable soil management, but pedo-climatic conditions must be considered, not to mention social, cultural, and financial differences between regions and farms. Increasing SOC stocks is one of the most prominent options for contributing to climate change mitigation and several studies that are part of this special issue contributed to an improved understanding on this aspect. For example, the pre-treatment of exogenous organic matter—such as composting or pyrolysis—substantially influences long-term soil carbon storage, as predicted by Keel et al. (2025) using numerical modeling. Similarly, crop rotation choices also strongly affect whether SOC increases or decreases over time. Concretely, by comparing data from 30 field experiments across Europe, Panagea et al. (2025) found that increasing the proportion of forage legumes in a rotation led to SOC gains of up to 0.44 Mg h a−1 yr−1, whereas rotations with grain legumes resulted in SOC losses of −0.48 Mg h a−1 yr−1. The largest SOC increases occurred at sites with initially low SOC stocks and with the highest shares of forage legumes in the rotation. Yet, even within a single crop species, substantial variation exists in its capacity to contribute to climate change mitigation, for example through differences in potential carbon inputs into soil via roots. When assessing variability in root biomass among 10 winter wheat varieties grown at 11 European sites ranging from Norway to Spain, site conditions emerged as the dominant factor influencing root biomass (Heinemann et al. 2025). Site conditions similarly affected root colonization by arbuscular mycorrhizal fungi (Veršulienė et al. 2024). Moreover, root–shoot ratios varied considerably in response to precipitation patterns within the same varieties, indicating that climate-change–induced alterations in hydrological regimes may influence both the amount and proportion of carbon transferred to soils via roots. From a process perspective, soil microorganisms play a central role in SOC transformation, yet their contributions are still insufficiently understood. When evaluating microbial growth, respiration, and carbon use efficiency (CUE) in soils from eight experimental sites across Europe, Schroeder et al. (2025) found no overall effects of crop diversification on these microbial parameters. Microbial CUE was, however, strongly influenced by seasonal dynamics. This highlights also the inherently dynamic nature of SOC processes and demonstrates the constraints and limitations on actively managing SOC stocks given their strong dependence on environmental conditions. While carbon sequestration strategies aim to mitigate climate change, it is equally important to address how agricultural soils can adapt to its impacts. Climate change adaptation requires a detailed understanding of how cropping systems respond to increasing climatic stresses such as drought, heat, and extreme rainfall. The modeling approach by Coucheney et al. (2024) demonstrates how modifying crop root traits can strengthen adaptive capacity at the field scale. Their long-term simulations show that deeper and more effective root systems not only enhance soil water uptake and reduce runoff but also support higher yields and increased soil organic matter stocks—indicating that crop breeding can play a pivotal role in building resilience to future climatic variability. Complementing this crop-focused perspective, long-term field evidence from Lang et al. (2025) highlights how diversified rotations and manure-supported ley systems can buffer soils against carbon loss, particularly in sandy, drought-prone soils. However, their findings also warn that gains in topsoil carbon can be offset by losses at depth, underscoring the need for adaptation strategies that target the whole soil profile. At a broader management level, Heller et al. (2025) provide tools through the SoilManageR framework to track soil management intensity and its consequences for soil quality indicators. Such harmonized indicators are essential for assessing whether adaptation strategies effectively maintain soil functions under shifting climatic conditions. Together, these studies show that climate change adaptation requires an integrated approach that combines crop genetic improvements, diversified management, and robust monitoring tools to sustain soil health under future climate pressures. The European Soil Monitoring Law has passed the EU parliament and has to be implemented by the member states in the coming years. While this is a great chance for detecting and regenerating degraded soils in general, much scientific work is needed to identify meaningful descriptors and thresholds, harmonized methods and representative sampling designs. In this special issue, the reader will find a collection of seven studies, covering a broad range of soil monitoring related topics. Globally, the largest soil threat is the loss of fertile topsoil via soil erosion, while its quantification in the field remains challenging. Schmaltz, Callewaert, et al. (2025); Schmaltz, Schmid, et al. (2025) conducted a controlled lab experiment to test how certain boundary conditions affect the accuracy of an almost 100 years old method to quantify runoff: the tipping bucket method. While accuracy did not vary with soil type, the authors highlighted the limitation of the method for heavy rainfall events, which are likely to become more frequent with climate change. The most often applied way to quantify water erosion at scale is the universal soil loss equation. As with every model, the accuracy of this equation depends on the quality of input data. In another study by Schmaltz, Callewaert, et al. (2025); Schmaltz, Schmid, et al. (2025), two different erosion models in two different central European areas and different farm sizes are used to test the effect of spatial resolution on model accuracy. The authors finally advocate for accurate, high-resolution soil and management data for more effective soil conservation. Another threat is soil compaction, which can lead to plant inaccessible soil layers as well as water stagnation. Here, the first soil compaction map of Ireland is published by Shahrokh et al. (2025), presenting a large proportion of Irish mineral topsoils as compacted with a bulk density threshold of 1.4 g cm−3. Soil organic carbon is crucial for many soil functions, yet its accurate quantification in space and time poses challenges. A novel analytical solution to distinguish organic and inorganic carbon using Rock Eval thermal analysis coupled to isotope ratio mass spectrometry (Hazera et al. 2025), but also advances in multispectral earth observation of bare soils to detect soil organic carbon contents are presented here (Wetterlind et al. 2025). Despite considerable advances in the field of soil sensing in the last decade, classical sampling will remain the core of assessing and monitoring soils. For the harmonization of data from different sources, it is important to quantify potential sampling biases. In the study of Del Duca et al. (2025), an Italian sampling protocol was compared to the European LUCAS sampling design. For most assessed parameters, they found a high comparability between the two, while for some parameters the differences were significant. This highlights that even within one monitoring system, a constant sampling approach is crucial to produce reliable data. Finally, Mason et al. (2025) covered a very relevant topic for making a change for the better: the stakeholders' perspective on soil threats and how they compare to scientific indicators. They identified stakeholder perception as an important complementary tool for exploring soil threats, also because scientific indicators based on individual soil properties are usually not holistic enough. What stands from this collection of rather methodological articles, is the fact that the accurate assessment and monitoring of such a diverse medium as soils on a national to continental scale requires a spirit of innovation and harmonization. Adopting climate-smart sustainable soil management practices across European agricultural systems remains a complex challenge. As demonstrated above, there is no one-size-fits-all solution for sustainable soil management. Instead, effective strategies must be tailored to local pedo-climatic conditions and take into account the diverse social, cultural, and economic contexts across regions and farming systems. This is further corroborated by the following five studies on the implementation of sustainable soil management. As explored by Pulido-Moncada et al. (2025), stakeholder perceptions in Denmark underscore the critical need for site-specific knowledge, long-term interdisciplinary research, and stronger science–policy–practice linkages. Farmers remain concerned about the practicality, profitability, and regulatory clarity of soil health practices—pointing to knowledge gaps not only in science but in stakeholder communication and engagement. A central theme across multiple papers is the potential of decision support tools (DSTs). While Warren Raffa et al. (2025) provide a landscape assessment of 115 DSTs across Europe and highlight their moderate adoption, they also stress the importance of user-friendly interfaces, alignment with farmers' goals, and integration of multiple soil processes. Complementing this, Jouini et al. (2025) offer stakeholder-driven insights from participatory across four They that adoption is often by and of regional and limited studies to the need for and DSTs that address the of The of whether education systems are future soil to support such is by et al. Their of European higher education that soil science is often and on Despite growing for soil collaboration and tools remain a need for and broader Finally, et al. (2025) a framework ecosystem soil and farm Their the trade-offs and synergies that and a for ecosystem into models. Together, these papers that adoption is not a matter of awareness It requires tailored tools, change, and participatory that the diverse and contexts of European agriculture. This second Special Issue in demonstrates the potential of to understanding of soil processes and management impacts under climatic conditions. on the scientific the third Special Issue is It will this by further scientific into soil managing and policy At the same it will look by and into strategies for better soil management. and and and and and and This research was in the framework of the European Joint Programme for SOIL climate-smart sustainable management of agricultural by the European research and innovation programme and by European The data are in with the of the Special