William Trenti

Vegetation strongly influences soil formation, yet its effect on Rare Earth Element (REE) distribution and fractionation across treeline ecotones remains insufficiently constrained. The present study investigated how contrasting plant communities, Vaccinium myrtillus heathlands and Picea abies forests, affect pedogenetic pathways and REE behavior in sandstone-derived soils of the Northern Apennines (Italy). Six soil profiles were characterized for bulk geochemistry, selective Fe–Al extractions, particle-size distribution, and REE concentrations. Principal component analysis and hierarchical clustering identified pedogenetic drivers and horizon groupings. Under Vaccinium myrtillus, thick acidic organic horizons promoted organo-metal complexation and incipient podzolization, whereas Picea abies soils showed thinner organic layers and enhanced mineral weathering, leading to Bw development with higher silt–clay contents and elevated Al/N ratios. These pathways were captured by Fe–Al indicators and the Spodic Index. REE distributions showed vegetation-related differences in surface horizons and Eu–Ce anomalies, but they did not reproduce Fe–Al pedogenetic clusters, reflecting strong parent-material control. The coexistence of podzolic and cambic pathways at the treeline highlights pronounced spatial heterogeneity and vegetation effects. Plant composition may redirect pedogenesis, influencing nutrient cycling and metal mobility. Additionally, these findings emphasize the need to integrate multivariate statistics with established pedogenetic indicators when evaluating geochemical properties in mountain soils.

Vegetation strongly influences soil formation, yet its effect on Rare Earth Element (REE) distribution and fractionation across treeline ecotones remains insufficiently con-strained. We investigated how contrasting plant communities, Vaccinium myrtillus heathlands and Picea abies forests, affect pedogenetic pathways and REE behavior in sandstone-derived soils of the Northern Apennines (Italy). Six soil profiles were charac-terized for bulk geochemistry, selective Fe–Al extractions, particle-size distribution, and REE concentrations. Principal component analysis and hierarchical clustering identified pedogenetic drivers and horizon groupings. Under Vaccinium myrtillus, thick acidic organic horizons promoted organo-metal complexation and incipient podzolization, whereas Picea abies soils showed thinner or-ganic layers and enhanced mineral weathering, leading to Bw development with higher silt–clay contents and elevated Al/N ratios. These pathways were captured by Fe–Al indicators and the SpodicIndex. REE distributions showed vegetation-related differences in surface horizons and Eu–Ce anomalies but did not reproduce Fe–Al pedogenetic clusters, reflecting strong parent-material control. The coexistence of podzolic and cambic pathways at the treeline highlights pro-nounced spatial heterogeneity and vegetation effects. Plant composition may redirect pedogenesis, influencing nutrient cycling and metal mobility. Additionally, our findings emphasize the need to integrate multivariate statistics with established pedogenetic in-dicators when evaluating geochemical properties in mountain soils.

Ink disease, caused by the soil-borne pathogens Phytophthora cambivora and Phytophthora cinnamomi, is threatening sweet chestnut (Castanea sativa) groves across Europe. This study investigates whether the morphology of soil and related properties influence the development of ink disease throughout the entire soil profile. In a C. sativa stand in Northern Italy, soil pits were excavated near symptomatic (INK1, 978 m a.s.l.) and healthy trees (INK2, 988 m a.s.l.; INK3, 998 m a.s.l.) along an altitudinal transect. The slope gradients at these sites were 3%, 9%, and 30%, respectively. Soils were classified as Luvisols. Results suggest that the lower slope position and gentler gradient of INK1 may have facilitated the downslope transport of clay and water from INK2 and INK3, leading to increased clay accumulation throughout the INK1 soil profiles. This, in turn, enhanced saturated hydraulic conductivity (Ks) and the wilting point (WP), favoring water retention in deeper horizons, where Phytophthora DNA was detected. Indeed, INK1 had a higher WP (14.9%) compared to INK2 (11.7%) and INK3 (8.2%), and exhibited the highest Ks (25.1%), significantly exceeding values in INK2 (4.6%) and INK3 (6.5%). The presence of the pathogen in INK1 appeared to affect microbial functionality, as indicated by the dominance of contact (~20%) and medium-distance ectomycorrhizal (~60%) exploration types over long-distance ones. Overall, our findings highlighted the key role of soil processes, particularly clay and water redistribution, in shaping microbial communities and soil-borne pathogen dynamics through their influence on edaphic properties.

As protection and conservation of habitats gain importance in the environmental policies of many countries, knowledge of the spatial distribution of soil types is increasingly needed to manage natural and semi-natural lands. Mountainous areas have high environmental variability, and this complexity can make the study of such landscapes particularly challenging. Recently, digital soil mapping (DSM) has gained popularity with the increasing availability of data layers that, together with soil observations and machine learning techniques such as random forests, allow the production of accurate soil maps. In this study we used random forests with recursive feature elimination to map the distribution of soil types in two protected natural parks in the mountains of northern Italy. We used 108 soil pedon observations and an optimal subset of five covariates (elevation, diffuse insolation, NDVI, slope, and distance from lakes) to make several predictions of soil functional group distribution. The final soil map created using the modes of the predictions was accurate (Kappa index = 0.82) and could be confidently used by land managers, while identifying the leading pedogenetic factors in this landscape. Furthermore, running several predictions allows the mapping of soil transition zones and complex areas which might require more careful management. Knowing which covariates are more influential in this landscape allows the optimization of soil survey efforts in similar areas.

The present study applied a GIS-based methodology for assessing soil diversity in a protected mountain area of Italy. Using QGIS, morphological (i.e., altitude and slope), lithological, climatic, and land use layers were intersected to delineate 16 land units (LUs), each representing relatively homogeneous conditions for soil formation, according to Jenny’s equation. To obtain the soil map units, a total of 112 soil profiles were analyzed, including 79 from previous studies and 33 that were newly excavated during 2023–2024 to fill gaps in underrepresented LU types. Most soils were classified as Inceptisols/Cambisols, occurring in both Dystric and Eutric variants, mainly in relation to lithology (i.e., arenaceous or pelitic facies). Alfisols, Umbrisols, and hydromorphic soils were also identified. The physicochemical properties showed marked variability among LUs, with sand content ranging from 39 to 798 g kg⁻¹, pH from 4.4 to 7.9, and organic carbon content from 1.6 to 6.1%. This LU-based framework allowed efficient field sampling, if compared to grid-based surveys, while retaining information on fine-scale pedodiversity. No quantitative accuracy assessment (e.g., boundary precision, internal homogeneity metrics) was conducted, even if the spatial coherence of the delineated LUs was supported by the distribution of soil profiles, which provided empirical validation of the LU framework.

Ink disease caused by the soil-borne Phytophthora cambivora and Phytophthora cinnamomi is threatening sweet chestnut (Castanea sativa) groves in Europe. This study aims to explore whether soil morphology and its related properties influence the development of chestnut ink disease considering the whole soil depth. In C. sativa stand in Northern Italy, along a small altitudinal transect, soil profiles were dug close to ink diseased plants (INK1 at 978 m a.s.l.) and healthy plants (INK2 988 m a.s.l. and INK3 at 998 m a.s.l.) and each soil horizon evaluated for its properties. Further, INK1, INK2 and INK3 had a slope of 3, 9 and 30 %, respectively. The results showed that the lower slope position of INK1 combined with the lower slope gradient than INK2 and INK3 might have promoted the transport of clay particles and water from the latters to the former. Such process allowed the accumulation of clay within the whole INK1 soil profile increasing the saturated hydraulic conductivity and the wilting point. Such soil features might promote the water accumulation within the deeper soil horizons of INK1 which would explain the presence of Phytophthora spp. DNA. The presence of the root pathogen in INK1 might have affected the microbial functionality as observed by the higher abundance of the contact and medium-distance exploration ectomycorrhizal fungal community than the long-distance types. Finally, such study highlighted the pivotal role of soil processes (i.e., clay and water transport) to shape the soil microbial community and soil-borne pathogens because of the changes of edaphic properties.

Ink disease caused by the soil-borne Phytophthora cambivora and Phytophthora cinnamomi is threatening sweet chestnut (Castanea sativa) groves in Europe. This study aims to explore whether soil morphology and its related properties influence the development of chestnut ink disease considering the whole soil depth. In C. sativa stand in Northern Italy, along a small altitudinal transect, soil profiles were dug close to ink diseased plants (INK1 at 978 m a.s.l.) and healthy plants (INK2 988 m a.s.l. and INK3 at 998 m a.s.l.) and each soil horizon evaluated for its properties. Further, INK1, INK2 and INK3 had a slope of 3, 9 and 30 %, respectively. The results showed that the lower slope position of INK1 combined with the lower slope gradient than INK2 and INK3 might have promoted the transport of clay particles and water from the latters to the former. Such process allowed the accumulation of clay within the whole INK1 soil profile increasing the saturated hydraulic conductivity and the wilting point. Such soil features might promote the water accumulation within the deeper soil horizons of INK1 which would explain the presence of Phytophthora spp. DNA. The presence of the root pathogen in INK1 might have affected the microbial functionality as observed by the higher abundance of the contact and medium-distance exploration ectomycorrhizal fungal community than the long-distance types. Finally, such study highlighted the pivotal role of soil processes (i.e., clay and water transport) to shape the soil microbial community and soil-borne pathogens because of the changes of edaphic properties.

Ink disease caused by the soil-borne Phytophthora cambivora and Phytophthora cinnamomi is threatening sweet chestnut (Castanea sativa) groves in Europe. This study aims to explore whether soil morphology and its related properties influence the development of chestnut ink disease considering the whole soil depth. In C. sativa stand in Northern Italy, along a small altitudinal transect, soil profiles were dug close to ink diseased plants (INK1 at 978 m a.s.l.) and healthy plants (INK2 988 m a.s.l. and INK3 at 998 m a.s.l.) and each soil horizon evaluated for its properties. Further, INK1, INK2 and INK3 had a slope of 3, 9 and 30 %, respectively. The results showed that the lower slope position of INK1 combined with the lower slope gradient than INK2 and INK3 might have promoted the transport of clay particles and water from the latters to the former. Such process allowed the accumulation of clay within the whole INK1 soil profile increasing the saturated hydraulic conductivity and the wilting point. Such soil features might promote the water accumulation within the deeper soil horizons of INK1 which would explain the presence of Phytophthora spp. DNA. The presence of the root pathogen in INK1 might have affected the microbial functionality as observed by the higher abundance of the contact and medium-distance exploration ectomycorrhizal fungal community than the long-distance types. Finally, such study highlighted the pivotal role of soil processes (i.e., clay and water transport) to shape the soil microbial community and soil-borne pathogens because of the changes of edaphic properties.

Ink disease caused by the soil-borne Phytophthora cambivora and Phytophthora cinnamomi is threatening sweet chestnut (Castanea sativa) groves in Europe. This study aims to explore whether soil morphology and its related properties influence the development of chestnut ink disease considering the whole soil depth. In C. sativa stand in Northern Italy, along a small altitudinal transect, soil profiles were dug close to ink diseased plants (INK1 at 978 m a.s.l.) and healthy plants (INK2 988 m a.s.l. and INK3 at 998 m a.s.l.) and each soil horizon evaluated for its properties. Further, INK1, INK2 and INK3 had a slope of 3, 9 and 30 %, respectively. The results showed that the lower slope position of INK1 combined with the lower slope gradient than INK2 and INK3 might have promoted the transport of clay particles and water from the latters to the former. Such process allowed the accumulation of clay within the whole INK1 soil profile increasing the saturated hydraulic conductivity and the wilting point. Such soil features might promote the water accumulation within the deeper soil horizons of INK1 which would explain the presence of Phytophthora spp. DNA. The presence of the root pathogen in INK1 might have affected the microbial functionality as observed by the higher abundance of the contact and medium-distance exploration ectomycorrhizal fungal community than the long-distance types. Finally, such study highlighted the pivotal role of soil processes (i.e., clay and water transport) to shape the soil microbial community and soil-borne pathogens because of the changes of edaphic properties.