Session 9.1: Quantifying sustainability and impacts of solutions for soil management and health

The transition towards sustainable agricultural systems requires robust methods to evaluate the multidimensional impacts of Integrated Pest Management (IPM) innovations on soil and plant health. Within the Horizon Europe project MultiSoil (Multifunctional Soil Biodiversity: Unlocking Potential for Healthy Cropping Systems), we develop an integrative assessment framework to evaluate IPM innovations across social, economic, environmental, and resilience dimensions. The framework is applied to practices, such as organic amendments, soil-enhancing microbes, and diversified cropping systems, across diverse European pedoclimatic regions. 
The approach consists of (1) a socio‑economic assessment, including cost‑benefit analysis and farmer adoption studies (2) environmental impact modelling, including a Life Cycle Assessment (LCA) related to soil health, with primary field data and models such as Yasso and (3) a risk and resilience assessment, to evaluate the capacity to withstand environmental, economic, and social stressors along value chains. The framework advances current methods by linking ecological processes (e.g. soil health, pest dynamics) with socio-economic outcomes (e.g. profitability and resilience). This enables the identification of impact hotspots, trade-offs, and innovation potential across diverse contexts.
The results provide a comprehensive evidence base on the sustainability and risks of soil health-related IPM innovations. It supports decision-making and helps stakeholders evaluate the sustainability and scalability of innovations, contributing to the transition towards low-input, resilient farming‑systems and improved soil and plant health.
Funding: Horizon Europe Research and Innovation Programme.

Soil health is a key component of sustainable land management, yet its assessment remains challenging due to the complexity of soil systems and the need to integrate environmental, social, and economic dimensions. The INTERESH project addresses this challenge through a series of experimental actions to be carried on in Apulia, Italy. Through the development of the INTERESH Performance Metrics (IPM), a flexible framework designed to support the definition and implementation of Key Performance Indicators (KPIs), it will be possible to evaluate soil health and land use performance along the project.
The IPM framework provides a structured, stepwise methodology that guides stakeholders in defining indicators based on land characteristics, land use practices, and desired outcomes. It integrates three core sustainability pillars-environmental, social, and economic-allowing for a holistic evaluation of land management systems. 
The framework will be applied to the INTERESH experimental actions under Mediterranean agricultural conditions. These include the implementation of Nature-Based Solutions in olive orchards through the reuse of organic residues and fungal-based systems, and the use of precision fertigation techniques in tomato production to optimize water and nutrient use. Indicators assessed include soil organic carbon, water and nitrogen use efficiency, soil moisture, crop yield, and plant survival, alongside qualitative measures such as farmer perception and operational feasibility. In this work, we present the process that led to the development of the IPM and its main characteristics.
Funded by the European Union under the GA 101216898.

Benchmarking soil health measurements is vital to understand the variability of soil health in a landscape and understand the state of the soil within a land use system. However, a comprehensive way to benchmark soil health in Europe is currently missing, despite the fact that over sixty percent of the European soils have been documented "unhealthy". It is important to benchmark soil health measurements in their respective local context and, at the same time, assess the state of a particular field or plot in relation to the variability found in the landscape. 
There are different ways to design soil sampling campaigns to capture regional variability throughout a landscape. Here we present a methodology to benchmark soil health measurements through the development of Empirical Cumulative Distribution Function curves per soil health indicator. Different sampling designs are tested to assess the applicability to construct ECDF curves that reflect the spatial heterogeneity found in a landscape. We compare a stratified random sampling approach for different land uses throughout Europe with random sampling design approaches. 
The results show the methodology is able to Benchmark different soil health indicators throughout different pilot sites in Europe. With a predefined set of strata, we can effectively capture spatial variability across the landscape and benchmark different soil health indicators. The performance of the stratified random sampling approach varies across land-use types, working better in some than in others. These findings can guide future soil health benchmarking campaigns across Europe in selecting appropriate sampling approaches and benchmarking methodologies.

The concept of a critical Soil Organic Carbon (SOC) threshold defines the minimum SOC level needed to maintain essential soil functions, including structural stability, water retention, nutrient cycling, and crop productivity. Traditionally, a "rule of thumb" of 2% SOC has been applied in temperate regions. However, recent research shows that critical thresholds are highly soil-type and context dependent. Indicators such as the SOC:clay ratio (≈0.10–0.13) and the Dexter clay:carbon index are widely used to assess structural vulnerability, yet European-scale evaluations reveal that fixed thresholds can misclassify soils due to pedoclimatic variability and extreme soil types.
Alternative approaches compare SOC with soil-type-specific reference distributions (Observed/Typical SOC ratios), identify meta-analytical breakpoints in SOC concentrations (commonly 10–20 g C kg⁻¹), or integrate satellite-based productivity proxies.
This talk synthesizes ten recent European studies on critical SOC thresholds, confirming substantial regional variation and the limitations of universal cutoffs. Danish research testing the clay:carbon hypothesis supports mineral–organic interaction mechanisms but finds no single universal threshold. Structural risks generally appear below ~10–15 g SOC kg⁻¹, depending on texture and mineralogy.
Current efforts focus on developing site-specific SOC thresholds for Danish soil texture classes (JB numbers) and relating current SOC levels to attainable potentials. Practical management strategies, including ley inclusion, residue management, reduced tillage, and organic amendments, are presented to promote favorable SOC levels. This initiative is practice-oriented: its goal is to help farmers realize the agronomic and resilience benefits of higher SOC, rather than to support carbon credit schemes.

The GroundWork project addresses the urgent challenge of soil degradation in Europe, where 60–70% of the soils are currently in poor condition, threatening food security, ecosystem services, and climate resilience. By tackling key Soil Mission objectives (conserving soil organic carbon stocks, preventing soil erosion, improving soil structure habitat and fostering soil literacy), GroundWork focuses on transforming livestock-based farming through regenerative practices that restore soil health while maintaining productivity. It establishes a network of five Living Labs (LL) across diverse European regions (Portugal, Germany, Sweden, Belgium, and Serbia), engaging farmers, researchers, policymakers, and other stakeholders in a participatory co-creation process. Within these real-world experimental settings, GroundWork develops, tests, and scales Regenerative Livestock Grazing Practices, such as rotational grazing, silvopasture, cover cropping, and improved manure management. A key innovation of the project is the development of the Ecosystem-Mediated Management Approach, a holistic framework for assessing soil health, environmental impacts, animal welfare, and farm sustainability. The Beira Interior LL will work with 15 farmers to address critical challenges like soil erosion, overgrazing, water scarcity, and biodiversity loss in pasture and agroforestry systems. Pilot studies will be designed in a tailor-made fashion in order to adapt to their context, with the support of the quintuple helix of innovation. The LL promotes knowledge exchange, farmer training, and soil literacy to support rural revitalisation. By integrating traditional practices with innovative regenerative approaches, the project aims to demonstrate scalable solutions that contribute directly to the broader objectives of the EU Soil Mission.

Bio-based fertilizers production from organic waste or by-products are increasingly recognized as a key strategy within EU policies, such as EU Soil Strategy for 2030. This approach promotes circular economy principles, reduces waste disposal, and recycles nutrients into agricultural systems. In this scope, this study aims to evaluate the agronomic efficacy and sustainability impacts of two organic amendments composed of 80% animal by-products (chicken manure) and 20% vegetable residues, formulated as powdered and granulated products. The assessment was conducted through controlled pot experiments using lettuce as a model crop, applying five amendment rates (0-40 t/ha) with five replicates per treatment.
Results demonstrated a pronounced field response, with biomass increasing by approximately 5-6 times relative to the control, particularly at 20 t/ha for powdered material and 40 t/ha for granulated amendment. In addition, plant nutrient concentration increased with application rate. Total nitrogen rose from 1.23% (control) to 5.32% (powdered) and 2.55% (granulated) in 40 t/ha treatment. Potassium concentrations reached up to 8%, while phosphorus increased to 0.4%, compared to 0.21% in control, indicating a marked improvement in soil fertility status. Heavy metal concentrations in lettuce remained below quantification limits (e.g., Cd < 1.55 mg/kg, Cr < 3.35 mg/kg), confirming the environmental safety of the amendments.
Overall, these findings demonstrate that organic amendments can enhance crop productivity and improve soil nutrient status while supporting circular nutrient flows. This study provides quantitative evidence supporting the agronomic and environmental benefits of organic soil improvers in climate-resilient agriculture.

As the European Union shifts toward a circular economy, there is growing interest in using seaweed materials and their industrial residues as organic fertilizers and soil improvers. However, seaweed may contain high levels of potentially toxic elements (PTEs) such as arsenic (As) and cadmium (Cd), as well as elevated potassium (K), which can threaten soil health and food safety if not properly managed.
To assess these risks and benefits, a field experiment was conducted over two growing seasons (2023–2024) on a grass-clover ley in Norway. Seven types of seaweed materials, including sludges, meals, and fermented products, were applied at rates matching the Norwegian 10-year regulatory maximum in a single dose (1.6–4 kg DM m⁻²). The study measured dry matter yields and concentrations of macronutrients and PTEs in the above-ground plant material (APM).
Seaweed application generally boosted dry matter yields. However, high K inputs caused mineral imbalances: the K to calcium and magnesium ratios in APM exceeded safe levels for ruminants in the first season, indicating a high risk of grass tetany if used as feed. As concentrations and total uptake in APM increased significantly with higher application rates (R² = 0.72). In contrast, Cd uptake was not significantly affected.
In conclusion, seaweed-derived materials can enhance crop yields but must be applied cautiously to avoid fodder mineral imbalances and As accumulation in the food chain. Blending seaweed with other nutrient-rich residues, such as fish bones, is recommended for more balanced marine-based fertilizers.

Background and aims
Acidic-coarse granitic-soils dominate North and Central Portugal, their productivity being limited by nutrient
limitations and Al/Mn toxicity, low water retention causing drought stress, and soil hardness. Al3+/Mn2+ induce
immobilization and antagonize Ca2+/Mg2+ uptake, high sand content limits water retention, and hard-setting creates a
cement-like structure limiting root growth. We hypothesized that biochar incorporation would alleviate these three
limitations and improve pasture productivity and quality.

Methods
10 plots with woody biochar (4% w/w) and 10 controls in randomized block design field experiment.

Results
Contrary to common findings, biochar alleviated nutrient limitation and improved soil nutrient status not by
increasing available nutrients (except K+), rather by decreasing antagonist soil metal concentrations, their antagonism
on Ca2+/Mg2+ uptake, and their ratios against available P. Liming effect caused Al3+ decrease, while decrease of Mn2+
and Fe2+/Fe3+ is not fully clear. Biochar increased available K, total N, and SOM, while increasing K/decreasing Mn
grass uptake, increasing forb N and S uptake, and diluting legume Mg and Zn tissue content. Root zone SMC
increased (31%), but decreased in deep layers of biochar treatment, whereas extreme drought stress was completely
eliminated during critical flowering period. Biochar reduced hardness (29-68%) in deep layers but not in top-soil,
and increased aboveground productivity from 6 to 9 t ha−1, increasing grass and legume, but not forb biomass, and
increasing protein yield (52%).

Conclusion
Biochar offers a multifunctional solution for acidic-coarse drought-affected granitic-soils, reducing needs for costly
separate measures (dolomitic limestones/mechanical treatments/irrigation) while substantially increasing fodder
quantity and quality.

This presentation synthesises evidence from long-term compost trials to highlight its effects on soil fertility and health. It presents compost as a long-term soil amendment supporting soil health, nutrient recycling, and sustainable soil management, alongside a 20-year nutrient and cost projection comparing two compost application rates with a mineral-only fertilisation baseline. Key soil health indicators include soil organic matter and carbon, soil biology, nutrient supply, water retention and structure, crop yield, and overall soil quality.
Indeed, compost application is often overlooked as a strategy for improving soil health and reducing dependence on mineral fertilisers, as its value is frequently assessed using short-term metrics that fail to capture cumulative soil and nutrient dynamics. This leads to underestimation of compost-derived organically bound nitrogen and the gradual release of phosphorus (P₂O₅) from soil-bound and organic pools over longer time horizons.
Results show that repeated compost application supports sustained nutrient supply and cumulative soil health improvements. Organic matter inputs enhance structure and aggregation, improve the soil's capacity to store and cycle nutrients, increase water-holding capacity, and promote biologically mediated nutrient cycling, while supporting higher yields and improved crop quality. Over 20 years, compost enhances soil fertility, resilience, and overall function, while reducing mineral fertiliser requirements.
These findings highlight the importance of long-term soil health indicators in nutrient management and demonstrate compost's role as a foundational component of sustainable fertilisation strategies that integrate productivity, soil health, and ecosystem service provision.

Hungary's diverse soil and climate conditions create a challenging environment for agriculture, highlighting the need for farming approaches that reduce soil degradation and strengthen climate resilience. Regenerative agriculture is increasingly recognised as a pathway to restore soil health, while alternative nutrient management strategies may additionally support climate mitigation efforts. This preliminary study investigates farmers' attitudes toward regenerative transitions in Hungary and examines the economic implications of adopting alternative nutrient management practices.
In an attitude survey we have targeted farmers already shifting to regenerative systems, exploring the tendencies in mineral fertiliser use, the uptake of alternative nutrient sources, and the range of applied regenerative techniques. Insights from preceding qualitative interviews enriched the interpretation of findings, and national statistics provided context on the prevalence of regenerative practices.
To assess the economic and environmental impacts of regenerative nutrient management, we incorporated Farm Accountancy Data Network (FADN) data and developed three complementary indicators: a low-input index reflecting farm-level structural and cost characteristics; a biodiversity index capturing crop system and management diversity; and a carbon credit potential estimating the extent of GHG emission reductions. In parallel, we mapped carbon farming programmes currently available in Hungary, analysing their interaction with input-use strategies, mitigation incentives, and bioeconomy development.
Overall, this pilot study highlights that regenerative nutrient management offers both environmental benefits and potential economic returns, but adoption is influenced by knowledge transfer, incentive structures, return-on-investment, and policy conditions. Strengthening these elements will be essential to advance circular, regenerative farming systems in Hungary.

Terra Preta de Índio (TPI), or Amazonian Dark Earths, comprises ancient anthropogenic soils characterized by persistent high fertility, elevated organic carbon stocks, and high biological diversity, making it a valuable model for sustainable soil management. Inspired by this system, we assessed whether TPI-like amendments can provide a sustainable soil management solution from a microbial perspective. In a factorial greenhouse experiment using an acidic, nutrient-poor tropical Latosol, we tested the individual and combined effects of biochar, manure, the earthworm Pontoscolex corethrurus, and maize on bacterial communities across bulk soil, roots, and the earthworm gut. Compartment-specific microbiome profiling based on high-throughput 16S rRNA gene sequencing examined responses across the soil-plant-animal continuum.
Bacterial communities were strongly compartmentalized but connected by a shared core microbiome. Amendment effects propagated unevenly across compartments, highlighting the interconnected yet non-uniform nature of the soil-plant-fauna continuum. Bulk soil communities responded primarily to manure-associated changes in soil chemistry, root-associated communities were comparatively buffered, and the earthworm gut showed distinct sensitivity to amendment-induced shifts. The more complete TPI-inspired treatment generated non-additive microbiome responses across compartments and was associated with the strongest plant performance.
Overall, results indicate that TPI-inspired amendment strategies can reorganize microbiomes across the interconnected soil-root-fauna continuum and support biologically mediated pathways relevant to sustainable soil management in low-fertility tropical soils. More broadly, these findings show that such amendments can propagate unevenly across interconnected compartments, generating compartment-specific and not fully predictable microbiome outcomes.