Soil Degradation and Soil Quality in Western Europe: Current situation and future perspectives

Abstract: The extension and causes of soil chemical, physical and biological degradation, and of soil loss, varies greatly in different countries in Western Europe. The objective of this work was to review these issues, the strategies for soil protection, and the future perspectives for soil quality evaluation, under the light of present legislation for soil protection. Agriculture and forestry are responsible for many of them, especially for physical degradation, erosion and organic matter loss. Land take and soil sealing have increased in the last decades and can enhance these problems. In agricultural land, conservation farming, organic farming and other soil-friendly practices have been seen to have site-specific effects, depending on the characteristics of soils and the particularities of land uses and land users. No single soil management strategy suitable for all regions, soil types and soil uses exists. Except for soil contamination, specific legislation for soil protection is lacking in the region. The development of a Thematic Strategy for Soil Protection in the European Union has produced valuable information and the development of networks and databases. However, soil degradation is addressed only indirectly in environmental policies, and through the Common Agricultural Policy of the European Union, which encourages farming practices supporting soil conservation. Despite these efforts, there is still a need for soil monitoring networks and decision-support systems based in soil quality optimization in the region. The pressure to European soils will continue in the future, and a clear regulatory framework is needed.JRC.H.5-Land Resources Managemen

Soil degradation and soil quality in Western Europe: current situation and future perspectives

The extent and causes of chemical, physical and biological degradation of soil, and of soil loss, vary greatly in different countries in Western Europe. The objective of this review paper is to examine these issues and also strategies for soil protection and future perspectives for soil quality evaluation, in light of present legislation aimed at soil protection. Agriculture and forestry are the main causes of many of the above problems, especially physical degradation, erosion and organic matter loss. Land take and soil sealing have increased in recent decades, further enhancing the problems. In agricultural land, conservation farming, organic farming and other soil-friendly practices have been seen to have site-specific effects, depending on the soil characteristics and the particular types of land use and land users. No single soil management strategy is suitable for all regions, soil types and soil uses. Except for soil contamination, specific legislation for soil protection is lacking in Western Europe. The Thematic Strategy for Soil Protection in the European Union has produced valuable information and has encouraged the development of networks and databases. However, soil degradation is addressed only indirectly in environmental policies and through the Common Agricultural Policy of the European Union, which promotes farming practices that support soil conservation. Despite these efforts, there remains a need for soil monitoring networks and decision-support systems aimed at optimization of soil quality in the region. The pressure on European soils will continue in the future, and a clearly defined regulatory framework is needed.The FORRISK project (Interreg SUDOE IVB, project SOE3/P2/F523) is acknowledged for partially funding this work

Low-quality carbon and lack of nutrients result in a stronger fungal than bacterial home-field advantage during the decomposition of leaf litter

Decomposition of litter is a key biochemical process that regulates the rate and magnitude of CO2 fluxes from biosphere to atmosphere and determines soil nutrient availability. Although several studies have shown that plant litter decomposition accelerated in their native compared to a foreign environment, that is, a home-field advantage (HFA) for litter degradation, to date HFA has only been considered in terms of respiration or litter mass loss. The competitive success of the decomposer micro-organism will be determined by its ability to transform used OM into population growth. Therefore, we hypothesized that HFA for microbial growth would be more pronounced than that for decomposition. We also expected that HFA effect for decomposition and microbial growth would increase with lower quality litter, which the fungal role in litter decomposition would be more dominant than that of bacteria, and that HFA effects would strengthen with more pronounced differences between ‘home’ and ‘away’ environments. We designed a 2-month microcosm reciprocal transplant experiment with litter from two sites with contrasting climates (Atlantic and Sub-Mediterranean climates) and including three tree species (Quercus robur, Pinus sylvestris and Fagus sylvatica). We found a stronger HFA for microbial growth than for decomposition, that the nutrient content and C-quality of litter influenced the microbial HFA and that interactions between bacterial and fungal communities during litter decomposition modulated the HFA for litter degradation. Low litter nutrient content, strong nutrient limitations and low C-qualities all favoured fungal over bacterial decomposers, and our results suggest a dominant functional role of the fungal community and gave rise to HFA effect for fungal growth but that this translated to only marginal implications for overall decomposition of litter. A free Plain Language Summary can be found within the Supporting Information of this article

Potential indicators of soil quality in temperate forest ecosystems: a case study in the Basque Country

• Assessment of forest sustainability requires reliable soil quality indicators. The present study evaluated the use of several potential such indicators in forests in the Basque Country under different types of management, involving: (i) species change and (ii) heavily mechanised forest operations. • Five adjacent forest stands were selected for study: (i) two unmanaged forests (Quercus robur, Fagus sylvatica) and one (40-year-old) Pinus radiata plantation, to investigate the effect of species change; and (ii) a chronosequence of mechanised radiata pine plantations (3 and 16 years old), to investigate heavy mechanisation. • Several physical, chemical and biological parameters were analysed in the mineral soil. Species change could not be assessed with chemical parameters, but parameters related to organic matter indicated the disturbance caused by heavy mechanisation. The Least Limiting Water Range was a good indicator of soil physical degradation induced by heavy mechanisation. Biological parameters proved sensitive indicators: (i) the fungal phospholipid fatty acid biomarker 18:2$\omega$6 for species change; and (ii) the ratio of Gram-positive/Gram-negative bacteria for heavy mechanisation. Nevertheless, these parameters are complementary, and monitoring programmes should include physical, chemical and biological parameters. • Further studies are required to assess natural boundaries of variation in soil quality indicators, and their resistance and resilience.Indicateurs potentiels de la qualité des sols dans les écosystèmes forestiers tempérés : une étude de cas dans le Pays Basque. • L'évaluation de la durabilité des forêts nécessite des indicateurs fiables de la qualité des sols. La présente étude a évalué l'utilisation de plusieurs de ces indicateurs potentiels dans les forêts du Pays Basque sous différents types de gestion, comprenant : (i) le changement des espèces et (ii) les opérations forestières fortement mécanisées. • Cinq peuplements forestiers voisins ont été sélectionnés pour l'étude : (i) deux forêts non gérées (Quercus robur, Fagus sylvatica) et une plantation (âgée de 40 ans) de Pinus radiata, pour examiner l'effet des changements d'espèces, (ii) une chronoséquence de plantations mécanisées de Pinus radiata (âgées de 3 et 16 ans), pour enquêter sur la mécanisation lourde. • Plusieurs caractéristiques physiques, chimiques et biologiques ont été analysées dans le sol minéral. Le changement d'espèce ne peut être évaluée avec des paramètres chimiques, mais les paramètres liés à la matière organique ont indiqué des perturbations causées par la forte mécanisation. Le Least Limiting Water Range est un bon indicateur de la dégradation des sols induite par la forte mécanisation. Paramètres biologiques qui se sont révélés des indicateurs sensibles : (i) le biomarqueur acide gras phospholipide fongique 18$:$2$\omega$6 pour le changement d'espèces, (ii) le rapport bactérien Gram-positive/Gram-negative pour la mécanisation lourde. Néanmoins, ces paramètres sont complémentaires, et des programmes de suivi devraient inclure des paramètres physiques, chimiques et biologiques. • D'autres études sont nécessaires pour évaluer les limites naturelles de la variation des indicateurs de la qualité des sols, de leur résistance et de leur résilience

Wood ash and biochar addition to forests do not shift soil microbial functional diversity in the short term

Community level physiological profiles (CLPP) performed by the MicroResp method are reliable ecological indicators to assess soil microbial functional diversity. Functional diversity provides a great insight to microbial roles in ecosystems, and it is regulated among others, by soil physicochemical properties. The application of biochar or wood ash to forest soils is often employed to improve soil structure and soil hydraulic properties, increase soil organic matter stocks, neutralise acidity and restore nutrients. We hypothesized that addition of new carbon sources (biochar and wood ashes) may induce a change in the microbial functional diversity. Two experimental sites were established on acidic soils: one on a loamy soil (SOC% 3.9; pH: 4.8) and another on a sandy loam soil (SOC% 10.8; pH: 3.8). CLPP were performed using MicroResp system in surface (0-5 cm) soil samples. The carbon sources used were selected on the basis of their ecological relevance to the soil microbial community. CLLP data of each experimental site was ordinated by principal component analysis. The first two ordination axes (explaining more than 70% of the variance) were selected and their relation with soil hydraulic and nutritional properties, soil structure and microbial biomass carbon was analysed. The major findings of this study may be summarised as follows: a) In the short term, a shift in the microbial substrate use profile for wood ash and biochar additions was not observed, b) the soil microbial community responded most strongly to the addition of carboxylic acids and carbohydrates in both experimental sites, and c) in the loamy soil the first axis of the PCA was related with pH and the second one to the mean weight diameter of soil aggregates, and in the sandy-loam site, the first axis was related to the available water content and the second one to the mean pore diameter

Mineral control of organic carbon storage in acid temperate forest soils in the Basque Country

International audienceAbstract Soil carbon dynamics is strongly controlled by depth globally, with increasingly slow dynamics found at depth. The mechanistic basis remains however controversial, limiting our ability to predict carbon cycle-climate feedbacks. Here we combine radiocarbon and thermal analyses with long-term incubations in absence/presence of continuously 13 C/ 14 C-labelled plants to show that bioenergetic constraints of decomposers consistently drive the depth-dependency of soil carbon dynamics over a range of mineral reactivity contexts. The slow dynamics of subsoil carbon is tightly related to both its low energy density and high activation energy of decomposition, leading to an unfavourable ‘return-on-energy-investment’ for decomposers. We also observe strong acceleration of millennia-old subsoil carbon decomposition induced by roots (‘rhizosphere priming’), showing that sufficient supply of energy by roots is able to alleviate the strong energy limitation of decomposition. These findings demonstrate that subsoil carbon persistence results from its poor energy quality together with the lack of energy supply by roots due to their low density at depth

Red para la innovación en la selvicultura y los sistemas de integración de riesgos en la gestión forestal

La forêt, en plus de ses fonctions économiques reconnues par tous les acteurs du milieu rural tels que le développement de l'emploi rural et le marché local du bois pour la transformation ou pour l'énergie, rend de nombreux autres services. Cependant, de multiples risques sont identifiables et doivent être gérés dans et pourront éventuellement être aggravés par les changements climatiques: futures sécheresses favorables aux pathogènes et ravageurs ainsi qu'à la propagation des incendies, et le risque de la modification du vent. Le projet FORRISK se focalisera ainsi sur les risques en forêt dont l'intensité est modulée par le changement climatique. L'histoire des forêts du sud de l'Europe nous rappelle que pour de nombreux problèmes, une approche seulement nationale n'a pas de sens. C'est-à-dire, les risques concernés, les réponses à apporter peuvent être soit au niveau technique soit au niveau de l'organisation des institutions. Pour cette raison, FORRISK vise à coordonner et mettre en réseau trois communautés différentes que sont les acteurs politiques, les gestionnaires et les scientifiques, dans le but d'obtenir que la gestion des risques soit partie intégrante des décisions prises à tous les niveaux du secteur forestier. Cela permettra d'initier une plateforme européenne sur les risques forestiers en facilitant des recommandations et des informations pertinentes à tous les niveaux. Pour y parvenir, le projet analysera et comparera les outils institutionnels, les systèmes et organisations liés à la gestion de risques dans les régions étudiées. Ensuite, FORRISK développera sur le terrain des techniques de lutte écologique, génétique et sylvicole, dont les résultats feront l'objet de guides de bonne pratique. Les outils produits consisteront à des cartes de risques à l'échelle régionale ou subrégionale, ainsi que à des modèles informatiques permettant de faire des diagnostics sur le terrain et de modéliser la propagation du fomès dans les peuplements de pin maritime. Ainsi, décideurs politiques, gestionnaires et scientifiques auront entre leurs mains des outils adaptés à la gestion de nombreux risques menaçant la forêt dans leurs régions