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Monitoring crop responses to drought is crucial for understanding the progressive impact of drought on food production and identifying management practices that can enhance agricultural resilience. This study combined drone-based multispectral data (MD d ) with laboratory determination over multiple pilot farms to identify the main soil physical and chemical parameters correlated with a crop health index (SVI- Standardized Vegetation Index), which compares the Normalized Difference Vegetation Index (NDVI) at the observed time to historical (NDVI at similar dates in previous years) values. Significant relationships were found between MD d and selected soil properties for different crops. Differences found at the plot scale were primarily related to texture, organic carbon and total nitrogen content, resulting in heterogeneous responses to droughts. The performance of the proposed indicators was further validated for the same crops by extending the findings across similar climatic regions in Europe, using satellite-based multispectral data (MD s ) and field-based soil data from LUCAS (Land Use/Cover Area frame statistical Survey Soil) for 2018, as well as MD s and digital soil data from SoilGrids 2.0 for 2022. Varying drought magnitudes were also considered. The method effectively identified drought-prone areas and distinguished crop health across varying drought intensities, making it a valuable tool for drought monitoring and agricultural planning., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Climate and time are among the most important factors driving soil organic carbon (SOC) stability and accrual in mineral soils; however, their relative importance on SOC dynamics is still unclear. Therefore, understanding how these factors covary over a range of soil developmental stages is crucial to improve our knowledge of climate change impact on SOC accumulation and persistence. Two chronosequences located along a climate gradient were investigated to determine the main interactions among time (age) and climate (precipitation and temperature) on SOC stability and stock with depth. Considering a common depth (0-15 or 0-30 cm), in the drier chronosequence, the older soil showed the highest SOC stock, while the younger exhibited the lowest carbon accumulation. Considering the whole profile, the SOC stock increased with age. In the wetter chronosequence, the younger soil showed the highest SOC stock considering a common depth, whereas, when the entire profile is taken into account, the older one accumulated 2-3 times more SOC than the others. In both chronosequences, significant stocks of SOC (∼42 %) were accumulated below 30 cm. Soil organic matter stability, assessed by thermal analysis and heterotrophic respiration, increases with depth and age only in the drier chronosequence. Soils from the wetter chronosequence were instead characterized by a greater quantity of labile and/or not-stabilized SOC; here, the amorphous Fe/Al-rich secondary mineral weathering products showed an essential predictor function of SOC storage, although they do not seem to be involved in SOC stabilization mechanisms. Otherwise, the interaction of SOC with fine particles, short-range order minerals, and organo-metal complexes represent the significant stabilization mechanisms in soils from drier climate. The results highlighted how the age factor plays an unassuming role in geochemical processes influencing SOC dynamics; however, climate determines different trajectories of soil development and SOC dynamics for a given soil age. Thus, soil age shows a key role in SOC stabilization especially in drier climatic conditions, while wetter conditions determine an accumulation of a higher yet more labile amount of SOC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Peatlands play a crucial role in carbon (C) sequestration and biodiversity conservation. However, these environments are highly vulnerable, and Europe has lost >60 % of its peatland habitat in recent decades. Cattle grazing and trampling contribute to peatland degradation, which generally result in a shift from moss-dominated vegetation to vascular plants and in lower C sequestration rates. Overgrazing poses also a significant threat to habitat integrity and biodiversity, especially in the Alpine area, where close-to-pristine mires with high ecological integrity are becoming extremely rare. Thus, a more in depth understanding of how cattle grazing and trampling are threatening Alpine mires is strongly needed for a sustainable management and conservation of these habitats. The objective of this study was to examine the impact of grazing on the physical, chemical, and biological characteristics of peat, with a focus on diatoms. To answer such a question, seven 50-cm deep cores were collected from mires located in the Adamello-Brenta Nature Park (North of Italy) along a grazing-induced disturbance gradient. Results indicated that grazing primarily affected at least the upper 15 cm of the peat, resulting in increased density and reduced water content, due to compaction, and lower C-to‑nitrogen ratio, possibly caused by both cow manure inputs and increased peat mineralization. Moreover, almost 200 diatom taxa were recorded across the 7 cores, with several of them falling under threat categories in the Red List for central Europe. The higher percentage of eutraphentic species in highly-grazed areas was related to the increase in nutrients caused by cattle manure. Finally, intense grazing increased the share of taxa that are more likely to survive in environments with unstable water availability (= aerial species). We showed that diatom data, supported by physical and chemical parameters, can be a refined tool to inform mire protection and rehabilitation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Natural and human-induced environmental changes deeply affected terrestrial ecosystems throughout the Holocene. Paleoenvironmental reconstructions provide information about the past and allow us to predict/model future scenarios. Among potential records, peat bogs are widely used because they present a precise stratigraphy and act as natural archives of highly diverse organic remains. Over the decades, several techniques have been developed to identify debris occurring in peat, including their morphological description. However, this is strongly constrained by the researcher's ability to distinguish residues at the species level, which typically requires many years of experience. In addition, potential contamination hampers using these techniques to obtain information from organisms such as fungi or bacteria. Environmental DNA metabarcoding and shotgun metagenome sequencing could represent a solution to detect specific groups of organisms without any a priori knowledge of their characteristics and/or to identify organisms that have rarely been considered in previous investigations. Moreover, shotgun metagenomics may allow the identification of bacteria and fungi (including both yeast and filamentous life forms), ensuring discrimination between ancient and modern organisms through the study of deamination/damage patterns. In the present review, we aim to i) present the state-of-the-art methodologies in paleoecological and paleoclimatic studies focusing on peat core analyses, proposing alternative approaches to the classical morphological identification of plant residues, and ii) suggest biomolecular approaches that will allow the use of proxies such as invertebrates, fungi, and bacteria, which are rarely employed in paleoenvironmental reconstructions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

A 3-m thick sediment sequence, found in a limestone mine located in the south of Italy at a depth of ca. 25-30 m from the current ground level, was investigated. Samples from 5 layers were analysed by X-ray diffraction, elemental analysis, Inductively Coupled Plasma Mass Spectrometry and micromorphology. Microbial DNA was analysed by 16S rRNA gene metabarcoding. The main mineral compounds found in the 5 layers were calcite (70-80%) and clay minerals in layers #1 and #5, goethite (75%) and hematite in layer #2, manganese (66%) and iron oxides in layer #3, and almost exclusively goethite in layer #4. Micromorphology data allowed to shed light in understanding whether these sediments formed by subsequent weathering of carbonates and silicates or by migration of soil sediments from the surface, or also by the accumulation of shallow marine sediments occurring between the middle Pliocene and the lower Pleistocene, when the extreme western sector of this area underwent strong subsidence. From the microbiological point of view, upon the 16S rRNA gene analysis, these 5 layers appear to cluster in three groups. Overall, such a distribution suggests that, both in the top (#1) and in bottom layers (#4 and #5), different communities would have undergone in situ reproduction and colonization exploiting metabolically the substrate, whereas the two mid layers would have received bacterial convection by passive transport of percolating waters. At the same time, micromorphological data show that each layer preserved its distinct features to be related to the environmental condition at the time of deposition. The chemical, mineralogical and micromorphological features of the layers and the known physiology of the microbial taxa thereby encountered highlight the possible role of the latter in elucidating the occurrence of certain mineral species as well as the biogeochemistry of elements like Mn and Fe in sediment layers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The Fe(II)-catalyzed transformation of ferrihydrite into highly crystalline forms may represent an important pathway for soil organic matter (SOM) destabilization under moderately reducing conditions. However, the link between redox-driven changes in soil Fe mineral composition and crystallinity and SOM chemical properties in the field remains elusive. We evaluated abiotic Fe(II)-catalyzed mineralogical transformation of Fe (oxyhydr)oxides in bulk soils and two particle-size SOM fractions, namely the fine silt plus clay (<20 μm, FSi + Cl) and fine sand (50-200 μm, FSa) fractions of an agricultural soil unamended or amended with biochar, compost, or the combination of both. After spiking with Fe(II) and incubating for 7 days under anoxic and sterile conditions at neutral pH, the FSa fractions (Fe(II):Fe (III) molar ratios ≈ 3.3) showed more significant ferrihydrite transformations with respect to FSi + Cl fractions (Fe(II):Fe (III) molar ratios ≈ 0.7), with the consequent production of well-ordered Fe oxides in most soils, particularly those unamended or amended with biochar alone. Nonetheless, poorly crystalline ferrihydrite still constituted about 45% of the FSi + Cl fractions of amended soils after reaction with Fe(II), which confirms that the higher SOM and clay mineral content in this fraction may possibly inhibit atom exchange between aqueous Fe(II) and the solid phase. Building on our knowledge of abiotic Fe(II)-catalyzed mineralogical changes, the suppression of ferrihydrite transformation in FSi + Cl fractions in amended soils could ultimately lead to a slower turnover of ferrihydrite, possibly preserving the carbon sequestration potential associated with this mineral. Conversely, in both bulk soils and FSa fractions, the extent to which mineral transformation occur seemed to be contingent on the quality of the amendment used., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Soil organic matter (SOM) protection, stability and long-term accumulation are controlled by several factors, including sorption onto mineral surfaces. Iron (Fe) has been suggested as a key regulator of SOM stability, both in acidic conditions, where Fe(III) is soluble, and in near-neutral pH environments, where it precipitates as Fe(III) (hydr)oxides. The present study aimed to probe, by sorption/desorption experiments in which Fe was added to the system, the mechanisms controlling Fe(III)-mediated organic carbon (C) stabilization; fine silt and clay (FSi + Cl) and fine sand (FSa) SOM fractions of three soils under different land uses were tested. Fe(III) addition caused a decrease in the organic C remaining in solution after reaction, indicating an Fe-mediated organic C stabilization effect. This effect was two times larger for FSa than for FSi + Cl, the former fraction being characterized by both low specific surface area and high organic C content. The organic C retained in the solid phase after Fe-mediated stabilization has relatively low sensitivity to desorption. Moreover, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy indicated that Fe-mediated organic C stabilization can be mainly ascribed to the formation of complexes between carbohydrate OH functional groups and Fe oxides. These results demonstrate that the binding of labile SOM compounds to Fe(III) contributes to its preservation, and that the mechanisms involved (flocculation vs. coating) depend on the size fractions., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Arsenic (As) occurs in soils mostly in inorganic forms, whereas the organic forms usually occur only in trace amounts. Peatlands are waterlogged, generally anoxic, organic soils representing the first step in coal formation; the contribution of organic vs. inorganic As species in this environment has received little research attention. Here, 57 peat samples collected throughout a 4-m deep, free-floating mire were analysed for total As and for its organic species, including dimethylarsinic acid (DMA), methylarsonic acid (MA), trimethylarsine oxide (TMAO) and arsenobetaine (AB), by HPLC-ICPMS. Aqueous trifluoroacetic acid was used as extractant, resulting in an average extraction efficiency of almost 80%. Total As concentration throughout the profile ranged between 0.2 and 9.8mg/kg peat (mean: 1.4±1.2mg/kg peat ). Organic As species (DMA+MA+TMAO+AB) accounted, on average, for 28±10% of total As (range: 6-51%), and for 37±13% of the extracted As (range: 7-64%). The relative abundance of organoarsenicals generally followed the order DMA>TMAO~MA≫AB. A positive correlation (p<0.001) was found among all organic As compounds, whereas their concentrations were negatively correlated with total sulfur content. The submerged zone (bottom 300cm) showed average and maximum concentrations of organoarsenic compounds that were almost twice those found in the top 100cm. This study shows that significant proportions of methylated As species occur even in peat samples characterized by low total As concentration (mostly <2mg/kg). Finally, this work provides the first evidence of organoarsenic species in free-floating mires, i.e., a globally distributed but scarcely investigated ecosystem., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Water samples were collected on the Athabasca River (AR), upstream and downstream from bitumen mines and upgrading facilities, to identify changes in water quality due to industrial activities in this region of northern Alberta, Canada. Starting upstream of Fort McMurray and proceeding downstream ca. 100km, waters were collected in duplicate at 13 locations on the main stem of the river, as well as 5 tributary streams, using ultraclean sampling protocols developed for polar snow and ice. To estimate potential bioaccessibility, trace elements of concern (Ag, Cd, Pb, Sb, Tl) were determined in the dissolved fraction (<0.45μm) along with metals known for their enrichments in bitumen (V, Ni, Mo, Re) and those found mainly in ionic (Li, Sr) or colloidal forms (Al, Co, Cr, Fe, Ga, Mn, Th, Y). Analyses were performed in the metal-free, ultraclean SWAMP lab using quadrupole and sector-field ICP-MS. Concentrations of Ag, Cd, Pb, Sb and Tl were extremely low, not significantly more abundant downstream of industry and probably reflect "background" values. In contrast, V, Ni, Mo and Re concentrations were all significantly (p<0.05) greater downstream of industry. However, chloride also increased downstream, due to natural inputs of saline groundwaters and it is unclear whether the increases in V, Ni, Mo and Re are due to natural or anthropogenic inputs to the river. Although it had been claimed that the industrial development of the Athabasca Bituminous Sands (ABS) is a significant source of Ag, Cd, Pb, Sb and Tl to the river, our study failed to find any evidence to support this. Here we provide a first, robust (accurate and precise) description of baseline values for these trace elements in the AR, and suggest that V, Ni, Mo and Re are more valuable tracers for environmental monitoring and source assessment., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The bracken fern Pteridium aquilinum (L.) Kuhn, one of the most common plant species on Earth, produces a wide range of secondary metabolites including the norsesquiterpene glucoside ptaquiloside (PTA). Several studies are present in literature about eco-toxicological aspects related to PTA, whereas results about the effect of growth conditions and soil properties on the production and mobility of PTA are sometimes conflicting and further investigations are needed. The aim of the present work is to investigate the occurrence and possible fate of PTA in soils showing different physical and chemical features, and collected in several areas of the South of Italy. The PTA content was determined in both soil and fern samples by GC-MS; both the extraction protocol and recovery were previously tested through incubation studies. Soils samples were also characterized from the physical and chemical points of view in order to correlate the possible influence of soil parameters on PTA production and occurrence. PTA concentration in P. aquilinum fern seemed to be significantly affected by the availability of nutrients (mainly P) and soil pH. At the same time, PTA concentration in soil samples was always undetectable, independent of the PTA concentration in the corresponding Pteridium samples and pedo-climatic conditions. This seems to suggest the degradation of the PTA by indigenous soil microbial community, whereas incubation studies underlined a certain affinity of PTA for both organic colloids and clay/silt particles., (Copyright © 2014 Elsevier B.V. All rights reserved.)