Soil health monitoring requires multiple indicators and continuous measurements

Moss and mushrooms.

This post was originally published on Luke website.

A major new law on soil health in Europe is being prepared in the European Union, and scientists report that one of the proposed indicators is not fit for purpose.

Operational monitoring of soil carbon is vital to improve soil-based ecosystem services, as stated in the Paris Climate Agreement and other national commitments. As a significant proportion of Europe’s soils are unhealthy, new regulation is needed. The European Union is committed to improving soil health and is currently developing a new Soil Monitoring Law that will establish monitoring a set of different soil health indicators.

HoliSoils and Benchmarks researchers are actively contributing to the ongoing process on this European Soil Monitoring Law by testing one of the proposed indicators. A recent publication shows that the ratio of soil organic carbon to clay (SOC:Clay), proposed as part of the new law to measure soil carbon loss, is not a reliable indicator for soil health.

Single indicator and its threshold value does not adequately reflect the diversity of European soils

The joint publication by EU funded HoliSoils and Benchmarks projects assessed the feasibility of the SOC:Clay indicator by evaluating its performance using data from the pan-European 2009 LUCAS soil survey. The results were also compared with changes in soil carbon stocks reported by countries to the UNFCCC.

Based on these findings, the researchers concluded that the SOC:Clay indicator proposed by the European Commission in the Soil Monitoring Law does not adequately monitor soil carbon status. They demonstrated that the use of this single indicator and its proposed threshold value of 1:13 for all soils under different land cover, management practices and climatic conditions, cannot account for the diversity of European soils, management practices, and climatic conditions.

The results also show that the SOC:Clay indicator provides an inconsistent conclusion on the proportions of non-healthy soils identified by using the SOC:Clay indicator when compared to changes in soil carbon stocks reported by national greenhouse gas (GHG) inventories. GHG inventories estimate changes in soil carbon stocks through repeated measurements or modelling. However, the proposed indicator, which would be based on the sampling and analysis of soil samples taken at a single point in time, may have therefore temporal limitations.

Soil monitoring indicators and tools need further development

The proposal for the Soil Monitoring Law has been discussed and voted on by the EU Parliament, after which it will be subject to further trilogue negotiations which will remain the responsibility of the next Parliament after the EU elections in June. Trilogue brings together the representatives of the European Parliament, the Council of the European Union and the European Commission and aims to reach a provisional agreement on the legislative proposal.

“The sustainable production of ecosystem services relies on healthy soils. To achieve this across Europe, as outlined in the Soil Monitoring Law, various actions must be taken in different regions. In addition to the indicators to be determined at the EU level, national tools are also necessary to monitor soil status and maintain soil health that meet the needs of different actors” says Raisa Mäkipää, Research Professor at Luke, HoliSoils project coordinator.

HoliSoils and Benchmarks researchers are committed to providing scientific input to the ongoing process of developing the new Soil Monitoring Law that best supports Europe’s important promise of healthy soils.

HoliSoils partners preparing numerous products in project’s penultimate year 

The HoliSoils project annual meeting gave consortium partners and stakeholder representatives the chance to discuss HoliSoils’ results and potential products in detail. 

HoliSoils is already in its penultimate year, and this year’s gathering brought into focus the depth of work being carried out in the project, from soil and forest management strategies, biophysical research linked to disturbance and to microbiological processes, to modelling, data and monitoring frameworks for greenhouse gas emissions (GHG).  

A detailed session focused on the various maps being developed through the project, and how the wealth of information will be accessible to potential end users. 

Two poster sessions allowed participants to dive more deeply into the research being carried out in the project. Many of the project’s post docs shared their work on specific research questions, and there was a second session focussing on experimental studies being carried out at the project’s test sites around Europe, as well as at the one from Uruguay. 

The HoliSoils Stakeholder and End-user Advisory Board (SEAB) has been instrumental in helping partners consider how different stakeholder groups in the project might use their findings and results. Their active engagement has made a real difference and in the dedicated panel session at this year’s meeting, the ten members who participated (nine in person and one online!) did not disappoint, sharing useful insights, critical questions and offering valuable advice in a fruitful conversation with the consortium. 

The consortium and SEAB members were also treated to two extremely interesting field excursions, the first to witness experiments being carried out on a peatland GHG site, the second to visit Kranzberg drought experiments in planted forests of spruce and beech, where one of the HoliSoils test sites is located. 

The fruits of all this labour will become available as results are published, via publications, web portals, updated modelling tools and recommendations for policy and practice. The challenge now and until the end of the project is to make sure that HoliSoils products reach as many people as possible so that all its stakeholders can benefit. 

Stay up to date with HoliSoils products as they become available: the HoliSoils toolkit is continuously updated and our repository in Zenodo already has many papers, with more added as they come out! 

Join HoliSoils at EGU 2024!

EGU session

From 14 to 19 April, scientists and early career researchers worldwide will meet at the General Assembly 2024 of the European Geosciences Union (EGU 2024) in Vienna, Austria, and online to engage in discussions on various aspect of geoscience.

The management of agricultural and forest soils in meeting global change mitigation goals” session will be filled with contributions from researchers involved in the HoliSoils project. On the morning of Friday 19, oral presentations will take place in Room -2.2, followed by poster session in Hall X3 in the afternoon.

If you plan to be there, don’t miss this chance to get unique insights from HoliSoils research!

Discover all the details about the session SSS9.11!

Time to get serious about forest soil

HoliSoils researcher at work.

Originally published in in Spanish.

European legislation on forests and climate and the forthcoming legislation on soil quality place particular emphasis on the importance of the soils that support our forests. These soils store more carbon and biodiversity than the trees they feed and are full of water and nutrients that provide a myriad of services. The European Union warns that, in general, degraded soils reduce the provision of ecosystem services such as food, timber, nutrient cycling, carbon sequestration, pest control or water regulation – a loss that costs the EU billions of euros every year. After the degradation of urban, industrial and agricultural soils, forests can be a lifeline against impacts such as climate change.

In the forests of Gamiz, a council of the city of Vitoria (Álava) located in the foothills of the Vitoria Mountains, work is being carried out as part of what is considered “the largest research project in Europe on the central, though little understood, role of forest soils in the fight against climate change”. This is what is stated in HoliSoils, an acronym for Holistic management practices, modelling & monitoring for European forest soils, a project of the EU’s Horizon 2020 programme in which 20 European universities and research centres are participating, including four Spanish ones.

The work being carried out in Gamiz includes that done by Jorge Curiel, the principal researcher in Spain at HoliSoils, who also leads the working group dedicated to the vulnerability of soils to climate change. He stops for a moment to talk to us: “We have three plots with a common design where we test, on the one hand, how different types of wood extraction affect the soil, such as 50% thinning and clear-cutting – cutting down all the trees in a forest area – and, on the other, how we can accelerate soil recovery with two treatments: in one we leave the soil bare and in the other we use the remains of the cutting, which are broken up and spread to create a layer that protects it and accelerates its recovery”.

An important part of this work is to analyse the carbon sequestration achieved by forest management taking into account different soil treatments. Forest soils store more carbon than trees, thanks to the combined action of dead wood, litter and the innumerable associated fauna, flora, and fungal communities, including other important micro-organisms such as protists, bacteria, and archaea.

Forest soils: champions of carbon sequestration

Gonzalo Almendros, research professor at the Department of Biogeochemistry and Microbial Ecology of the National Museum of Natural Sciences (MNCN/CSIC), highlights this value in figures: “In general, soils contain 2,500 petagrams of carbon (one petagram is equivalent to one thousand trillion grams), that is, more than three times the amount of atmospheric carbon and four times the amount stored in the biomass of plants and animals. Therefore, the interest in forest soils lies in the fact that they constitute a reservoir of carbon in slowly biodegradable forms, which is not actively exchanged with CO2 in the atmosphere”.

But there is a risk that climate change will accelerate this loss of soil carbon, as Pablo García-Palacios, a scientist at the Consejo Superior de Investigaciones Científicas at the Instituto de Ciencias Agrarias (ICA-CSIC), pointed out in a study published in June 2021 in the journal Nature: “Until now, the size of the carbon pool has been balanced annually between carbon losses from soil respiration and gains from carbon fixation by plants. However, anthropogenic warming is disturbing this balance”.

HoliSoils, like other European projects working in the same direction (DrySom, Benchmark, Atlantis, etc.), seeks to halt the loss of valuable forest soil, which is why not only research centres are involved in it, but also associations of forest owners, the European Environment Agency, the United Nations Convention on Climate Change and the FSC forest certification seal. Dozens of forest plots in various countries with different climates, tree species and management are serving as test laboratories.

Undergrowth in Peñacaballera, Sierra de Béjar, Salamanca. Photo: Javier Rico.

Every soil is a world

Each soil is different depending on all these factors: climate, altitude, trees, type of management, slope… There is nothing like taking a look at some of the almost 2,900 entries on the blog Un universo bajo nuestros pies (A universe beneath our feet) to make sure of this. It is the work of Juan José Ibáñez, senior scientist at the Desertification Research Centre (CSIC-University of Valencia), who constantly repeats that “soil is a very fragile and non-renewable resource”. There are soils dominated by leaf litter, in others by the herbaceous stratum, in others by scrub, and in some there is more moss, or rocky and stony ground, or a bit of everything. Ibañez even claims the value of dead wood: “The fall of a tree is essential for the maintenance of the dynamics of forest ecosystems and their soils”.

In this variety of soils and their composition also lies the ability to adapt to impacts such as those induced by climate change. Ana Rey, MNCN/CSIC scientist and expert in forest ecology, says: “Preliminary results of a study we are carrying out in Mediterranean forests on different types of soils indicate that forests with soils that are in principle more unfavourable seem to be less susceptible to drought, because they have already developed an adaptation to extreme conditions. Therefore, although they grow less, they are more resilient”. According to Jorge Curiel, “in the Iberian Peninsula, the most fragile forests are on steeper slopes, with more erosion potential, which increases depending on the type of management they have”.

Curiel is also a research professor at one of the centres participating in HoliSoils, the BC3 (Basque Centre for Climate Change). He says that all the work carried out (types of felling, soil treatments, placement of sensors, analysis of carbon sequestration, inventory of organisms, measurement of soil health parameters) “serves, first, to generate evidence that what is being done so far is not correct and, second, to generate more responsible management practices focused on soil conservation”.

Time to get serious about forest soil

Raisa Mäkipää, coordinator of HoliSoils and research professor at the Natural Resources Institute of Finland, stresses: “Soils really matter, but they have not been studied enough, especially forest soils. By learning more about how they trap and release CO2, countries can help ensure that their forests can adapt to and mitigate climate change”.

In the meantime, the EU has also got down to work. On 5 July 2023, the European Commission (EC) presented the proposal for a Directive of the European Parliament and of the Council on soil monitoring and soil resilience. The main objective is to achieve a healthy state of EU soils by 2050. It recognises that soil degradation costs us tens of billions of euros per year by affecting basic ecosystem services that provide important economic benefits: food, timber, carbon sequestration, pest control, erosion control, etc.

The variety of soils and their composition also determines the capacity of forests to adapt to impacts such as those induced by climate change. Photo: Javier Rico.

Without departing from the economic line, the proposed directive mentions: “The availability of healthy and fertile soils and land is crucial for the transition to a sustainable bioeconomy and can therefore help to increase and preserve land values”. In an article in The Conversation, Jorge Curiel and four other BC3 researchers stress that “the bioeconomy should take into account forest soil conservation”, but he warns: “We cannot expect the bioeconomy to cover all the production and business niches that are currently covered by other materials such as concrete or petroleum derivatives because, like these, natural resources are not infinite”.

One of the mainstays of the forest bioeconomy is the extraction of biomass for energy production. The Spanish Biomass Association (Avebiom) they state: “The companies that carry out works of exploitation and extraction of this biomass must comply with the requirements imposed by the EU Renewable Energy Directive, and they are doing so, many of them with the help of the European certification system SURE (Sustainable Resources Verification Scheme)”. In addition, they consider that removing biomass from forests for energy recovery “contributes to increasing the resilience of our forests to increasingly dangerous forest fires and climate change. Keeping the destructive power of fires and forest stress at bay is also a way of caring for soils and biodiversity”.

No planting for planting’s sake

Ana Rey considers how we should deal with reforestation very important: “When we talk about reforestation, about planting trees, we must remember that a forest is not just trees, because sometimes we ignore the complexity of forests and the many ecosystem services they provide, including the great importance of the soil. We have to take into account the type of soil we plant in and the species we plant”. Almendros stresses: “Each situation has to be studied separately, taking into account climate, soil type and the quality of pre-existing organic matter.”

Much remains to be done. The EC itself, in its proposal for a directive on soil monitoring and resilience, estimates: “More than 60% of European soils are unhealthy and scientific evidence shows that they are being further degraded due to unsustainable land management, pollution and overexploitation, combined with the impact of climate change and extreme weather events”.

PhD course on Advanced Measurements and Analyses of GHG Fluxes

Students at university

A PhD course on Advanced Measurements and Analyses of Greenhouse Gas Fluxes from Soils and Ecosystems will take place in Copenhagen between 26 and 30 August 2024.

The course is hosted by the Department of Geosciences and Natural Resource Management of University of Copenhagen with the support of AnaEE-ERIC (Analysis and Experimentation on Ecosystems).

The course will offer post-graduate students the possibility to develop their skills in measuring and analysing the exchange of GHG’s between the soil and the ecosystem and the atmosphere using the latest chamber technologies. Participants will gain hands-on experience with analisers, experiments, and state-of-the-art software.

The application deadline is on 1 August 2024. Don’t miss this opportunity: seats are limited.

Read all the details about this course!

Webinar: Forests in changing climate

Finnish forest


Friday 22 March 2024

9.00 am – 12:30 pm (EET, Helsinki time)

Online: Microsoft Teams


Natural Resources Institute Finland
Forestry and Forest Products Research Institute (FFPRI)


On 22 March this HoliSoils webinar will offer engaging discussions on current research topics relating to forests growth, greenhouse gas exchange, ecosystem services and climate change by researchers from Forestry and Forest Products Research Institute, FFPRI (Japan) and Natural Resources Institute Finland, Luke (Finland).

The webinar will include insightful segments on:

  • Luke and the HoliSoils project (Aleksi Lehtonen)
  • Topographically high-resolution mapping of catchment-scale soil carbon dioxide and methane fluxes using machine learning analysis with the DEM-derived covariates (Shoji Hashimoto)
  • Drought response of the boreal forest carbon sink is driven by understorey–tree composition (Martínez García Eduardo)
  • Assessment of climate mitigation pathways for shrinking and aging tree plantations in Japan – Simulated synergies and trade-offs between carbon removal and other forest ecosystem services (Jumpei Toriyama)
  • Environment-induced growth changes in forests of Finland revisited – a follow-up using an extended data set from the 1960s to the 2020s (Harri Mäkinen)
  • Challenges in Distinguishing Between Biotic and Abiotic Soil Enzyme Activities (Taiki Mori)
  • The high climate benefits return of peat preservation policies (Lorenzo Menichetti)

Click here to join the webinar!

HoliSoils in the spotlight of the Horizon Magazine

forest soil

‘Soils really matter but they are understudied, especially forest soils.’ This quote by Raisa Mäkipää, HoliSoils’ coordinator from the Natural Resources Institute Finland (Luke), opens a new piece in the Horizon Magazine featuring HoliSoils. This publication gives visibility to inspiring innovations and science insights coming from research projects funded by the EU.

The piece dives into the HoliSoils’s work in the Dobroč test site, where Michal Bošela from the Technical University in Zvolen and his team are exploring the difference in forest soils between monocultures and old-growth forest with its mix of tree species.

Check out the full piece on the Horizon Magazine!

Become Luke’s new Principal Scientist in forest soil science

Mushroom in a forest

HoliSoils’ project coordinator Natural Resources Institute Finland (Luke) is looking for a Principal Scientist to strengthen soil research in the institute. The selected candidate will work to develop and lead Luke’s research on carbon and nutrient cycling processes in forest soils on mineral soil sites, and how these processes are controlled.

The research will focus on soil carbon and nutrient cycling processes, nutrient availability, and organic matter quality. The objective is to better understand the linkages between these factors, and their significance both for the biomass production of forest ecosystems and for the environmental and climate impacts. The main focus should be on the response of soil processes and properties to forest management in changing environment and climate.

The position of Principal Scientist is permanent. The tasks include planning and leading research projects and working in those, as well as developing both field and laboratory methods connected to the research topics. The Principal Scientist is expected to publish at international scientific level, acquire research funding and be active in both national and international collaboration networks.

The deadline for applications is 23 February 2024, 16:00 Finnish time.

Read all the details on this opportunity & discover how to apply!

Dive into the NBSOIL Soil Academy!


You can now register to the NBSOIL Soil Academy, a free Massive Open Online Course (MOOC) that aims to co-create and test a learning pathway for soil advisors. The course is designed for anyone facing soil-related challenges, including soil advisors, researchers, and policy-makers. It emphasises Nature-based solutions (NBS) in sustainable soil management.

The key features of this MOOC are:

  • Dynamic Learning: effectively apply a variety of NBS.
  • Audience: open to all with a stake in soil management.
  • Collaboration: foster connections with professionals.
  • Educator-Friendly: materials adaptable for academic use.
  • Accessible Resources: all resources are available from Day 1, and the course is free.

Find out more and learn how to enroll!

HoliSoils finds proposed soil health indicator lacking

Distribution of the soil organic carbon (SOC) and clay content for different land covers (cropland, forest, and grassland).

As MEPs discuss a major new law for soil health in Europe, HoliSoils researchers report that one of the proposed soil health indicators is not fit for purpose.

HoliSoils researchers are actively contributing to the current discussion on EU soil monitoring law Soil health – European Commission by testing one of the proposed soil health indicators.

In a pre-print of a forthcoming publication, project coordinators Raisa Mäkipää and Aleksi Lehtonen, with other consortium members and in collaboration with researchers from the Horizon Europe Benchmarks project, have found that the organic carbon-to-clay ratio, proposed as part of the new law for measuring soil carbon, is not a reliable indicator of soil health.

The operational monitoring of soil carbon is vital for improving soil-based ecosystem services, as identified in the Paris Climate Agreement and other national commitments. As substantial fractions of European soils are unhealthy, new regulation is needed. The European Union is committed to enhancing soil health, and the European Commission is currently defining a new Soil Monitoring Law, recommending the monitoring of soil carbon loss, among other soil health indicators.

The study for publication, carried out through the HoliSoils and Benchmarks projects, evaluates the feasibility of the proposed soil carbon loss indicator by assessing its performance using the EU-wide 2009 LUCAS soil survey data. The results are also compared with the soil carbon stock changes reported by countries to the climate convention (UNFCCC).

Results reveal that differences in the soil organic carbon (SOC) and clay content at European scale is in fact greater than that of the data used to develop the proposed indicator. Furthermore, the variation in SOC content was influenced not only by clay content but also by climate and land-use. Other observations included discrepancies between the soil carbon stock changes reported by the national GHG inventories and the proportions of degraded soils identified by using the soil health indicator.

These findings led the researchers to conclude that the indicator proposed by the European Commission for the Soil Monitoring Law cannot adequately monitor the loss of soil carbon. A single indicator such as SOC:Clay ratio, with one threshold value for all soils across various land covers, management practices, and climatic conditions, is unable to respond to the variety of soils, climates and uses across Europe, and is thus inappropriate for monitoring soil carbon loss.

The EU Soil Monitoring Law will next be discussed by MEPs and stakeholders in the EU Parliament on 31 January 2024: Soil Monitoring for Better Knowledge – Renew Europe (  HoliSoils researchers remain committed to continue providing scientific knowledge to inform this ongoing process for a new soil monitoring law that will best support Europe its important pledge for healthy soils. 

Read the full pre-print!


Mäkipää, Raisa and Menichetti, Lorenzo and Martínez-García, Eduardo and Törmänen, Tiina and Lehtonen, Aleksi, Is the Organic Carbon-to-Clay Ratio a Reliable Indicator of Soil Health?. Available at SSRN: or