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Purpose The existence of black horizons (BHs) is often highlighted in European soils, and in the Po River plain of northern Italy. Nevertheless, BH chronological frameworks and genetic models are still debated. The present study investigated the genesis of BHs in the eastern Po Plain where they are buried at various depths. Materials and methods Soil sequences were investigated with a multidisciplinary approach integrating geomorphologic, stratigraphic, pedologic, geochemical, isotopic, palynological, and radiometric analyses. Results and discussion The formation of the studied BHs was scattered over time from the Last Glacial Maximum to at least the middle Holocene. The new data indicate that BHs developed when the landscape was dominated by coniferous forest during conditions that were totally different from the current pedoclimatic setting. The recurrent presence of black particles indicates that this vegetation cover was systematically affected by fire episodes that induced soil degradation and mineralization processes of the original organic compounds, thus contributing to darkening of the upper soil horizons. Conclusions BH formation clearly coincided with cold time lapses. Evidence for repeated fire events (natural or human-induced?) provides insights for the controversial debate on early anthropogenic impacts on the environment.

Carbon and nitrogen elemental (C-N, wt%) and isotopic ( δ 13 C- δ 15 N, ‰) investigation has been carried out on alluvial and deltaic soils from the Padanian plain (northern Italy), an area interested by intensive agricultural activities, to refine previous inferences on depositional facies, pedogenetic processes and anthropogenic influences. Soil analysis, carried out by EA-IRMS, have been focused on inorganic and organic fractions properly speciated by a thermally-based method, whereas further insights on the organic matter constituents have been obtained by sequential fractionation. The bulk EA-IRMS analyses reveal a remarkable compositional heterogeneity of the investigated soils (TC 0.89 to 11.93 wt%, TN 0.01 to 0.78 wt%, δ 13 C TC -1.2 to -28.2‰, δ 15 N -1.2 to 10.0‰) that has to be explained as an integration between inorganic and organic pools. The latter have been subdivided in Non-Extractable Organic Matter (NEOM, δ 13 C -16.3 to -28.6‰) and in extractable fractions as Fulvic (FA, δ 13 C -24.7 to -27.5‰, δ 15 N 0.6 to 5.7‰) and Humic (HA, δ 13 C -24.6 to -27.0‰, δ 15 N 1.0 to 9.7‰) Acids, which have been used to infer soil dynamics and Soil Organic Matter (SOM) stability processes. Results indicate that SOM at depth of 100 cm was generally affected by microbial reworking, with the exception of clayey and peaty deposits in which biological activity seems inhibited. Peaty and clayey soils display an organic fraction loss of ca. 20% toward the surface, suggesting deterioration possibly induced by intensive agricultural activities. These latter may be the cause of the ubiquitous losses of organic fraction throughout the investigated area over the last seventy years, evaluated by the comparison with historical data on corresponding topsoils. The obtained insights are very important because these soils are carbon (and nitrogen) sinks that are vulnerable and can be degraded, loosing agricultural productivity and potentially contributing to greenhouse gases fluxes.

The aim of the study was to assess if pedogenic processes such as mineral weathering and lessivage, other than organic matter accumulation, can affect soil microbial population and enzyme activities. This study examines six soil profiles located in a karst region of the North-Eastern Italian Alps and characterized by a vertical textural differentiation due to lessivage. For each soil, four pedological layers were recognized according to the dominant soil forming process: i) the top soil (Tp layer), formed by A and AB horizons, characterized by organic matter accumulation; ii) the subsurface eluviated layer (Elu layer), comprising AE and EB horizons; iii) the layer dominated by the in-situ mineral weathering (Wh layer), made by Bw horizons; iv) the deepest layer (Ls), subjected to clay illuviation and comprised by Bt horizons. In the upper layers (Tp and Elu), because of the low pH, weathering also occurred, as indicated by the presence of disordered smectite and by the high values of pedogenic Fe oxi-hydroxides to pseudo-total Fe ratio. The microbial biomass content and structure, and the enzyme activities significantly differed in the four pedological layers. The amount of microbial biomass was, as expected, most abundant in the Tp layer, where bacteria and actinomycetes abounded. Conversely, in Elu and Wh we observed a fungal-to-bacterial biomass ratio significantly higher than in Tp and Ls; in Elu, also the gram (+)/gram (−) ratio was the highest. In the upper layer, the interaction between enzymes and minerals like disordered smectite and pedogenic Fe-oxides appeared as responsible for the inhibition of the total enzyme activity per unit of organic C, and of the lipase activity. In Ls layer, where clay illuviation and high organo-minerals interaction occurred, the potential hydrolysis of organic matter was low, as revealed by the SEI/TOC ratio, the reduced lipase activity, and the inhibited activity of α-fucosidase and α-mannosidase. Even if the activity of most enzymes depends on the substrate availability, which decreases with soil depth, those involved in lipid degradation displayed the maximum activities in Elu and Wh layers, where a relative increase of the fungal population was observed. In conclusion, our findings showed that the soil functionality, expressed by the microbial community structure and enzymes activity, can vary according to organic matter–mineral interaction following the weathering and lessivage gradients along the soil profiles.

Rock-glacier sediment transfer and ice melting can impact surface waters located downstream. However, there is a lack of knowledge on the influence of rock-glacier dynamics on the geochemical, hydrochemical, and ecological characteristics of adjacent impounded surface waters. In the Col d'Olen area (Long-Term Ecological Research site, NW Italian Alps), an intact rock glacier terminates into a pond and solute-enriched waters originating from the rock glacier flow into the pond through a subsurface hydrological window. In this study, we performed geophysical and ground surface temperature measurements. Moreover, we sampled soils and sediments in different compartments of the investigated rock-glacier - pond system and we further sampled benthic invertebrates in the pond. Cold ground thermal regime, ground-ice presence, and coarse debris cover on the rock glacier together with its lithology (serpentinites) influence the rock-glacier geochemistry and ecology with respect to surrounding areas. Pond geochemistry is affected by transfer of trace-metal-enriched fine-grained debris and meltwaters from the rock glacier. Enhanced bioavailability of serpentinite-associated trace metals was proved, with concentrations of Ni and Cr in benthic invertebrates up to 384 and 110 mg kg−1 d.w., respectively, potentially exerting toxic effects on pond biota. The advancing movement of the rock glacier not only has delivered sediments to the pond, but it has progressively filled the valley depression where the pond is located, creating a dam that could have modified the level of impounded water. This process likely constituted a sediment trap in which serpentinitic rock-glacier sediments could be deposited at the pond bottom, with related geochemical and ecological implications. This study illustrates the importance of rock glaciers in influencing the characteristics of downstream freshwater bodies and highlights the need to improve our knowledge about climate-change-related impacts of rock-glacier dynamics on alpine headwaters.

A new analytical approach (Thermally Based Separation, TBS) for the characterisation of inorganic (IC) and organic (OC) carbon pools in alluvial soils has been tested. The method does not involve any chemical pre-treatment of samples and relies on different thermal stabilities of IC and OC pools, which can be accurately determined with an EA-IRMS analytical system. Elemental (C, g/kg) and isotopic (δ13C, ‰) carbon data were used to check the reliability of the TBS method by calculating the mass balances using the measured IC and OC fractions and total carbon (TC). TBS was applied to 7 soil samples from the Padanian alluvial plain (NE Italy) that were collected from different depths and characterised by textural/geochemical heterogeneity. The method allowed for a mean carbon elemental recovery of 99% (SD = 2%), and mean isotopic deviation (Δ13C) between theoretical (δ13COC XOC + δ13CIC XIC)/(XOC + XIC) and measured δ13CTC of 0.2‰ (SD = 0.3‰). A comparison of TBS with other conventional methods for carbon separation provided insights into the possible effects of sample acidification on the soil organic pools. The results suggest a higher robustness of TBS compared to conventional methods in the determination of organic and inorganic carbon pools in soils. This is because TBS bypasses any possible fractionation derived from the hydrolysis of soil organic matter and therefore accurately determines the carbon isotopic composition of the OC and IC fractions. TBS appears to be more robust than conventional methods and is independent from the IC/OC ratio of the samples, from the unpredictable complexity of soil organic matter and from the arbitrary application of the acidification routine. On this basis, TBS represents a very promising approach for a correct and complete characterisation of soil carbon pools.

Urban agriculture is increasingly popular for social and economic benefits. However, edible crops grown in cities can be contaminated by airborne pollutants, thus leading to serious health risks. Therefore, a better understanding of contamination risks of urban cultivation is needed in order to define safe practices. The present study addresses the determination of potentially toxic elements (PTEs) risk in horticultural crops grown in urban gardens of Bologna, Italy. Seven experiments were conducted between June 2015 and November 2015, using the following crop species: tomato (Lycopersicon esculentum), sweet basil (Ocimum basilicum), onion (Allium cepa), lettuce (Lactuca sativa), black cabbage (Brassica oleracea), fennel (Foeniculum vulgare) and radish (Raphanus sativus). Plants were grown either on soil or on a soilless system filled with peat. Among studied species, radish grown on soil presented the highest accumulation levels for all PTEs under study. The adoption of soilless system reduced PTEs accumulation in most considered species. Accordingly, daily PTE intake presented a decrease of 80% for chromium, 38% for copper, 100% for cobalt, 53% for lithium, 27% for molybdenum, 78% for nickel, 55% for lead and 98% for vanadium in soilless grown vegetables.

A sedimentary sequence comprising a Late Bronze age archaeological site located in the alluvial plain between Bologna and Ferrara (Northern Italy) was studied from geochemical, pedological and palynological points of view. Sediment geochemistry (in particular, the high content of Cr) indicates the existence of a thin set of Po River deposits coeval to the Bronze Age site, lying among alluvial sediments delivered from the Apennine chain. The soil corresponding to this chronological interval is also characterised by anomalous content of phosphorous and chalcophile elements (mainly Cu and Zn) that are clearly related to anthropogenic activities. The results were critically discussed to reconstruct the geomorphological and regional palaeo-hydrographic settings to support the existence of an unknown buried Po River course active during the late Middle Bronze Age in the southern part of the alluvial plain. The 14C and pollen analyses corroborate this interpretation, also providing clues on the genesis of more superficial peaty horizons. On the whole, the results provide fresh insights on the occurrence of ancient human settlements in the southern Po River alluvial plain.

The aim of this research was the understanding of a peculiarly expanded soil sequence in Bologna (i.e., Roman Bononia, Etruscan Felsina), one of the most important archaeological poles for Etruscan colonisation and settlement in northern Italy. The uppermost part of the chronological sequence dating from the Bronze Age up to medieval and modern times was analysed for the first time from geochemical and pedological viewpoints. The integration of archaeological, stratigraphical and pedological data supported by soil chemical analysis, a fundamental key for reconstructing a correct evolutionary sequence, made it possible to recognise seventeen buried Soil Units (ancient Technosols, Anthrosols and Cambisols) characterised by different kinds and degrees of intensity of anthropogenic influence. In some cases, the results show a relatively severe element concentration (Cu, Sn) mainly characterising the Iron Age (Etruscan and Villanovan) stratigraphic units, representing an ancient industrial pollution linked to local dispersal of melting activity dump products generated in near-site surrounding areas. Therefore, a comparison was possible between natural blank and anthropogenically polluted geochemical values for some local soils.

We evaluated the influence of the rhizosphere, soil depth, and altitude on the amount and nature of the density separated soil organic matter (SOM) pools. Samples were collected from the A and AB horizons of European beech (Fagus sylvadca L.) forest soils located at two altitudes (800 and 1000 m) along 1 degrees of latitudinal gradient in central Italy, by using altitude as a proxy for air temperature change. Specifically, we hypothesized that: i) larger amount of labile organic matter, comprising of fresh plant and organism residues and easily degradable molecules, was allocated in the rhizosphere than in the non-rhizosphere soil, and the temperature had a stronger effect on the C pools of the rhizosphere than in that of the non-rhizosphere soil. At both altitudes, we found more organic C (OC) associated with the light fractions of the rhizosphere than in those of the non-rhizosphere soil and, specifically in the rhizosphere free light fraction, larger OC concentrations were observed at 1000 m than at 800 m above sea level. These higher amounts of OC have been attributed to roots, which are one of the main source of particulate organic matter, and their activity and turnover increase when the environmental conditions become more restrictive, as it happens at higher altitude. Conversely, no effect related to rhizosphere and altitude on the OC associated to the heavy fraction was found. The recalcitrance of the OC of the heavy fraction has been ascribed both to its protection due to the tight bounds to mineral particles and to its degradation degree, as indicated by delta C-13 values, which were greater than those of the light fractions. The similar C-14 signature and the presence of recent C in all the density fractions of rhizosphere and non-rhizosphere soil of both A and AB horizons suggested the occurrence of a rapid incorporation of fresh organic matter into the mineral horizons, followed by occlusion into aggregates and adsorption on mineral surfaces. Further, the lack of different Delta C-14 values between the fractions at 800 and 1000 m could indicate that a temperature change of 1 degrees C is not sufficient to induce marked changes in SOM cycling.

The aim of this study was to examine the effects of selected metal (Ag, Co, Ni) and metal oxide (CeO2, Fe3O4, SnO2, TiO2) engineered nanoparticles on basil (Ocimum basilicum L.). Seedlings, grown in soil mixture (20% sandy soil, 80% peat), were exposed to nanoparticles once per week, for 4 weeks with solutions at 100 μg mL−1 of nanoparticle component metal, to simulate a chronic exposure to NPs supplied with irrigation. At the end of the experiment (4 weeks), (i) morphological and physiological parameters of basil (e.g. dry weight, gaseous exchange), (ii) nanoparticle component metal taken up by the basil plant (namely, Ag, Ce, Co, Fe, Ni, Sn and Ti) and (iii) the content of nutrients (Ca, Mg, K, Na, P and S) in different basil organs were evaluated. The results indicated that the nanoparticle component metal was mainly accumulated in the basil roots. However, despite the capability of plant to exclude potentially toxic elements, Ag, CeO2, Co and Ni NPs component metal translocate from the root to the shoot reaching the leaves, the edible part of the plant. Notably, also in the relative short exposure there was an accumulation of Ca in roots, suggesting that the modification of metabolic pathway in plants could be aimed at counteracting the membrane damage generated directly or indirectly by nanoparticles.

Soil organic matter (SOM) pools and soil available calcium (Caexch) were monitored during a 4-year period in an experimental chestnut stand treated for the restoration of timber production. In 2004 the stand was cut and stumps were grafted. Before the forestry operations, the biocycling process seemed to contrast soil nutrient loss, returning Ca to mineral soil through plant activity. Therefore, we hypothesized that the regrowing vegetation after forestry operations would supply Ca to the soil surface and maintain a certain soil fertility level. In fact, from 2005, a progressive recovery of 460 mg Caexch kg−1 year−1 at the soil surface was found, corresponding to about 5 % of the Ca of the leaf litter (8,605 mg Ca kg−1, chestnut leaves sampled in 2007). However, the Caexch seemed to depend on the humified C (r200.858; p

The aim of the study was to examine soil microbial activity and functional diversity in different parts of coastal landscapes influenced by recurring saltwater intrusion in the Ravenna area (Italy). For this reason, seven profiles were selected in the San Vitale Pinewood, in low-lying interdune spot and next to dune crests and swales. Soils were classified as Typic Psammaquent, Typic Ustipsamment, Aquic Ustipsamment and Sodic Psammaquent. Chemical, physical and biochemical properties of soil horizons, such as microbial biomass metabolic quotient and enzyme activity, were determined to examine the effects of soil salinity and sodicity levels on microbial activity and functional diversity. The various soils and horizons could be split into distinct groups based on Differential Function Analysis of their properties. Cellulase, xylosidase and arylsulfatase showed a peak of their activity in surface horizons of sodic soils. α-glucosidase activity also was high in deeper horizons of those soils. Moreover, functional diversity, evaluated through calculation of Shannon's diversity index, was higher in the surface and deeper horizons of saline soils than non-saline soils. Conversely, soil with shallow water-table showed similar enzyme activity to soil located in the highest spots of the dune system. However, the highest values of specific activity (per unit of organic carbon) recorded in the deep horizons of the Typic Ustipsamment soil suggested more efficient hydrolytic activity of organic substrates due to oxygenation of soil. In conclusion, hydromorphic conditions in these soils influence the efficiency of organic substrate hydrolysis while soil salinity and sodicity increase both biochemical activity and functional diversity of microbial communities.

In Brazil, more than 80% of population today lives in urban areas. Consistently, growing concerns about the quality and cost of food and food insecurity have increased interest in producing food locally as well as in urban community or allotment gardens. Urban horticulture, besides its recognized role in improving social relations and healthiness of diet, may pose some risks on human health. Urban gardeners may be exposed to chemical risks associated with pesticides and fertilizers, as well as ingestion of metal(oid)s due to air and water pollution and contamination. In the urban environment, vehicle emissions are considered one of the main sources of contamination of metal(oid)s, and consistently, plants grown nearby roads can present high levels of lead, zinc, chrome, nickel and tin in their tissues. Metal(oid)s, which can cause chronic diseases, are transported into the human body through food consumption. The present study analyzed the metal(oid)s contamination in urban gardens compared to a rural farm. Ions analysis was conducted on lettuce and chives collected in allotment gardens and in a rural farm in the Brazilian city of Teresina (Piaui). In plants from rural and urban gardens cadmium, arsenic and nickel were found below the detection limits. Plants grown in allotment gardens resulted to be more exposed to copper, zinc, molybdenum and antymony than those cultivated in the rural farm. On the other hand, reduced values of lead, strontium and barium were observed in plant samples obtained from urban allotments as compared to the rural farm. Furthermore, the metal(oid)s content was lower than in the Brazilian wholesale vegetables cited in the literature. Accordingly, urban vegetables grown in the city of Teresina resulted to be safe for human consumption.

The extensive use of silver nanoparticles (SNPs) as antimicrobial in food, clothing and medicine, leads inevitably to a loss of such nanomaterial in soil and water. Little is known about the effects of soil contamination, in particular, on microbial cells, which play a fundamental ecological role. In this work, the impact of SNPs on forest soil has been studied, investigating eco-physiological indicators of microbial biomass and microbial diversity with culture-dependent and independent techniques. Moreover, SNPs bioavailability and uptake were assessed. Soil samples were spiked with SNPs at two different concentrations (10 and 100 μg g(-1)dw) and incubated with the relative controls for 30, 60 and 90 days. The overall parameters showed a significant influence of the SNPs on the soil microbial community, revealing a marked shift after 60 days of incubation.

The aim of the present study was to investigate the microbial activity along forest brown soil profiles sequence developed on different lithological substrates (carbonate or non-carbonated cement in sandstone formations) at different altitudes. The main question posed was: does carbonate affect the biochemical activity of brown soil profiles at different altitudes? For the purpose of this study, four soil profiles with different amounts and compositions of SOM developed on different lithological substrates were selected: two with carbonate (MB and MZ) and the other two with non-carbonated cement in the sandstone formations (MF1 and MF2). Chemical and biochemical properties of soil were analysed along soil profiles in order to assess the SOM quantity and quality, namely total organic C (Corg), water extractable organic C (WEOC) and humification indices (HI, DH, HR). Microbial biomass (Cmic and Nmic) content, as well as the specific activities of acid phosphatase, β-glucosidase and chitinase enzymes were chosen as indicators of biochemical activity. The soil biochemical properties provided evidence of better conditions for microorganisms in MB than in MF1, MF2 and MZ soil profiles, since patterns of microbial biomass content and activity might be expected in response to the amount and quality of organic substances. The different lithological substrates did not show any clear effect on soil microbial biomass content, since similar values were obtained in MF1, MF2 (with non-carbonated cement) and MZ (with carbonate). However, the specific activities of acid phosphatase (per unit of Corg and per unit of Cmic) were higher in soils with no carbonate (MF1 and MF2) than in soils with carbonate (MB and MZ). In conclusion, the biochemical activity along brown soil profiles was mainly regulated by different soil organic matter content and quality, while the two different lithological substrates (with carbonate or non-carbonated cement in the sandstone formations) did not show any direct effect on microbial biomass and its activity. However, the activity of acid phosphatase per unit of C was particularly enhanced in soil with non-carbonate cement in the sandstone formations.

The aim of the study was to analyse the pedological, chemical and biochemical properties of soil in order to assess the effect of plant cover species (chestnut, Douglas-fir and mixed vegetation) on soil processes. The selected area under Douglas-fir reforestation was homogeneous for climate, morphology and parent material. The study involved three soils: under chestnut forest (CS), Douglas-fir reforestation (DF) and the transition zone (T). A soil profile differentiation occurred after 50 years of Douglas-fir plantation. The thickness of soil horizons at the surface varied, and the OH horizon in Tsite was fourfold thicker than that in DF site. The A1 mineral horizon in T site was also thicker than that in DF site. The Munsell value of mineral horizons was significantly lower in DF than CS site. Morphological differences (thickness and colour) probably reflect soil organic matter quality changes: in DF higher values of humification index were found in surface layers (OF/OH or OH and A1) and lower in deep organo-mineral and transition horizons (A2 and BA or AB) with respect to CS site. Also, a slight increase of weathering process was observed under Douglas-fir reforestation. The morphological, chemical and biological properties of soil were effective to assess the impact of various vegetation types on soil organic matter properties related to pedogenetic process. The various methodological approaches allow studying soil processes using a small–medium spatial scale sampling scheme. The aim of the study was to analyse the pedological, chemical and biochemical properties of soil in order to assess the effect of plant cover species (chestnut, Douglas-fir and mixed vegetation) on soil processes. The selected area under Douglas-fir reforestation was homogeneous for climate, morphology and parent material. The study involved three soils: under chestnut forest (CS), Douglas-fir reforestation (DF) and the transition zone (T). A soil profile differentiation occurred after 50 years of Douglas-fir plantation. The thickness of soil horizons at the surface varied, and the OH horizon in T site was fourfold thicker than that in DF site. The A1 mineral horizon in T site was also thicker than that in DF site. The Munsell value of mineral horizons was significantly lower in DF than CS site. Morphological differences (thickness and colour) probably reflect soil organic matter quality changes: in DF higher values of humification index were found in surface layers (OF/OH or OH and A1) and lower in deep organo-mineral and transition horizons (A2 and BA or AB) with respect to CS site. Also, a slight increase of weathering process was observed under Douglas-fir reforestation. The morphological, chemical and biological properties of soil were effective to assess the impact of various vegetation types on soil organic matter properties related to pedogenetic process. The various methodological approaches allow studying soil processes using a small–medium spatial scale sampling scheme.

This study aimed to evaluate the role of different plant covers on brown soil profile development changing SOM stability in the epipedons. In particular, two brown soils (Eutric Cambisols), located in Monghidoro at the Italian Apennines, were analysed in order to test the hypothesis that plant cover affects the brown soil profile development under eutric qualifier changing SOM stability and soil pH. Also we verified if soil biochemical activities and microbial biomass size could be promoted by factors supporting Eutric Cambisols development. The two soil profiles were formed under coniferous (Mcon) and beech cover (Mbeech), respectively; both of them had similar lithology, morphology, exposition, slope and elevation. The development of soil profiles was evaluated by the determination of their physical, chemical and biochemical properties, while SOM stability of the epipedons was assessed through the determination of some properties of humic substances by thermal (TG-DSC) and spectroscopic (FTIR) analysis, humification indexes and eco-physiological indicators such as microbial quotient (Cmic:Corg) and metabolic quotient (qCO2). The Corg content decreased along both soil profiles. The epipedon of Mbeech soil was richer in SOM that in turn showed a higher level of humification than Mcon. The pH value, CEC and the concentrations of all earth-alkaline cations were also higher in Mbeech than in Mcon soil profile. Differences in soil reaction and SOM quality seemed to affect weathering process, since the content of all Al forms (amorphous—Alo, crystalline—Ald and linked to SOM—Alp) increased as the soil pH decreased, and the Fe forms increased as the humification level of SOM increased. Nevertheless, the active iron ratio (Feo/Fed) calculated in the two soil profiles did not highlight significant differences between them in terms of podzolitation intensity. The activity of hydrolytic enzymes (β-glucosidase, cellulase and chitinase) was higher in Mbeech soil than in Mcon soil profile. The activity of all enzymes, on mass basis, decreased along both soil profiles, while the specific activity (per unit of organic carbon), increased only in the endopedons of Mbeech. Although biochemical properties were not correlated with physical and chemical properties of soil profile, significant correlations were observed between enzyme activity and the soil organic carbon or nitrogen content. As far as the epipedons SOM quality is concerned, the content of humified C, the microbial biomass carbon (Cmic), as well as the Cmic:Corg were higher in Mbeech than in Mcon, whereas the qCO2 was lower in Mbeech than in Mcon. Also the FTIR and TG-DSC analysis showed differences on HAs and FAs hydrophilic character and thermal stability between epipedons of Mbeech and Mcon. The SOM quality of epipendon under coniferous resulted in a more recalcitrant and hydrophobic composition than that of epipedon under beech. In conclusion the type of plant cover (coniferous vs. beech-tree) affected the weathering of the pedogenetic substrate changing the SOM properties and soil pH. Even if the beech-tree cover promoted SOM accumulation in soil profile, which represented the organic substrates for microbial biochemical activities, the weathering of soil under coniferous appeared more marked than beech-trees covered soil. Consequently, soil biochemical activity of microbial biomass along soil profile was not promoted by factors supporting weathering processes.

Rhizodeposition plays an important role in nitrogen (N) cycling within ecosystems, but it is understudied in agroecosystems, especially in orchards. In this study, we quantified N flux from peach root to soil in two soils with different texture. Seedlings were grown for 1 year in sand and fertilized with 15N-enriched ammonium nitrate. Trees were then transplanted into pots filled with a coarse-textured (CT) or a fine-textured (FT) soil with natural 15N abundance. The isotopic mass balance technique was applied to quantify the uptake and the release of N by roots. At the end of the experimental year tree growth was 431 g tree−1 in CT soil and 188 g tree−1 in FT soil, and root N concentration was 0.98% in CT soil and 0.73% in FT soil. Leaf chlorophyll was always higher in trees grown in CT than in FT soil. Nitrogen uptake in CT soil was more than double that in FT soil (4471 mg tree−1 vs. 2106 mg tree−1), but its allocation was not affected by soil texture (57% aboveground and 43% belowground). Nitrogen flux from roots to soil was 453 and 412 mg N tree−1 year−1 for trees in CT and in FT soil, respectively, 70% of which transferred in the winter. Our data suggest that root mortality is more important than root exudation in N transfer from roots to soil. Rhizodeposition was similar for both soils but tree growth was greater in CT soil than in FT soil. As a consequence, trees in FT soil allocated belowground (root biomass and rhizodeposition) a higher proportion of the absorbed N compared to trees in CT soil. Data also indicate that rhizodeposition can account for a major fraction (25–41%) of the photosynthate flux to the root system and therefore it should be considered to accurately estimate BNPP. A deeper knowledge of the belowground orchard processes is necessary to understand a balanced tree nutrient uptake. Rhizodeposition can also contribute to nutrient mobilization, heavy metal detoxification, root exploitation of soil, and drought tolerance. This work can thus provide information enabling horticulturists to develop management practices to optimise tree growth.

The N uptake by crops, soil distribution and recovery of 15N labelled urea-N (100 kg N ha-1) were investigated in a sorghum-wheat rotation in two silty clay soils (Foggia and Rieti Casabianca) and one silt loam soil (Rieti Piedifiume) under different mediterranean conditions. Non-exchangeable labelled NH4-N represented an important pool at both Rieti sites with higher values (p

The aimof thework was to propose a newmethodological approach that relates soilmicrobial functional diversity to soil development under different moisture regimes. As soil evolution proceeds through an increasing niche separation we expect a link between functional diversity and soil development. Shannon's (H') and Gini (D) diversity indices were calculated using eight enzyme activities (β-cellobiohydrolase, N-acetyl-β-glucosaminidase, β-glucosidase, α-glucosidase, acid phosphatase, arylsulfatase, xylosidase and butyrate esterase) in order to assess functional diversity at different scales, from soil horizons (α-diversity) to soil profiles (β-diversity) under different moisture regime (γ-diversity) and belonging to different taxonomic levels. In addition, the ratio of acid phosphatase to chitinasewas calculated as a potential index of soil development. Eight soil profileswere selected: four in Northwestern Italian Alps orNorthern Apennines with Udic soil moisture regimes (TypicHaplocryod, MollicHaplocryept, Lithic Dystrudept, Lithic Cryorthent) and four in Northeastern Italy where in two cases the water table near the soil surface strongly affects the Ustic soil moisture regime, and intrazonal Aquic regime or Aquic conditions develop (Typic Haplustept, Typic Ustipsamment, Aquic Ustipsamment, Typic Psammaquent). D ranged from 50 to 95%, while the H' ranged from 3 to 2.4 in Lithic Cryorthent and Typic Psammaquent, respectively. Under Udic moisture regime an inverse relationship between soil profile development and the diversity index was observed. However the lowest the diversity in the profile, the highest the variability of the values obtained within horizons in the soil profile suggesting a link between differentiation of soil horizons and biochemical properties. The Aquic conditions interfere in establishing the relationship between soil profile development and themicrobial functional diversity since H' and D increased in Typic Psammaquentwith respect to Typic Haplustept (H' from 2.4 to 2.6 and D from 52.2 to 60.4). Finally, the phosphatase/chitinase ratiowas related to soil development since the lowest values were obtained in the upper horizons of Typic Haplustept, Typic and Aquic Ustipsamment (from 2.0 to 4.0), while the highest values were obtained in deep horizons of Typic Haplocryod and Lithic Dystrudept (e.g. 39.2 in Bs2 and 28.0 in Bw1). In conclusion, microbial functional diversity assessed using Shannon or Gini diversity indices and phosphatase/chitinase ratio measured at different scales from soil horizons to soil profiles under differentmoisture regime and belonging to different taxonomic levels, may represent a new approach to establish the interrelationship between pedogenetic processes, soil development and soil microbial functions. © 2012 Elsevier B.V. All

The amount of interlayer NH 4 + -N and net mineralization of organic N were measured at periodic intervals, over a period of 10 months, in soil samples collected from a peach orchard which had been subjected to different rates of N fertilizer application. Two different groups of soil samples, designated sampling 1 and sampling 2 were collected. Soils of sampling 1 were collected from sites where the soil was heavily penetrated by tree roots and those of sampling 2 were collected from sites where the soil remained free from tree roots. In sampling 1, during the 10-month period, the concentration of interlayer NH 4 + -N showed significant variations, while in sampling 2 no significant variation was found. In sampling 1 the amount of NH 4 + -N released from the interlayers of the clay minerals were not influenced by the N fertilizer application rate. Changes in the interlayer NH 4 + -N concentrations were related to variation in net N mineralization and immobilization rates as well as to plant uptake N. It is concluded that, in our experiment, the dynamics of interlayer NH 4 + -N in soil were influenced by the spatial distribution of the tree roots and organic N mineralization, while N application influenced seasonal variation but not the total interlayer NH 4 + -N released during the experiment.

Laboratory incubation experiments were conducted to study the influence of increasing concentrations of N-(n-butyl)phosphorothioic triamide (NBPT) on NH3 volatilization and rate of urea hydrolysis and evolution of mineral N in Ozzano, Rimini and Carpi soils with different physicochemical characteristics. Low concentrations of NBPT reduced NH3 losses due to volatilization after urea fertilization and the effectiveness of the inhibitor was related to the soil characteristics (e.g. high concentrations of organic C and sand). After 15 days of incubation, no significant reductions of losses were found for any of the NBPT concentrations employed in Rimini soil. The application of NBPT led to a considerable reduction of the formation of nitrite. This process was completely annulled with the highest dose of NBPT (0.5% w/wurea) in the Carpi soil after 15 days. In Rimini soil, however, the use of NBPT was less effective in influencing nitrite formation. The use of NBPT favoured accumulation of nitrate proportional to the NBPT concentration employed while it had no influence on the NH inf4 sup+ fixation by 2:1 layer silicates. The data obtained support previous evidence that NBPT is effective in reducing the problems encountered in using urea as fertilizer. However, environmental conditions and soil physicochemical characteristics may have an important influence on the effectiveness of NBPT.

We studied the turnover of interlayer NHinf4sup+in three soils cropped with sugar beet. The three soils chosen for this study (Carpi, Cadriano, and Ozzano) are typical of the soils in the Po Valley where sugar beet is grown. The variation in interlayer NHinf4sup+content during the growing season was significant and very similar for the Carpi and Cadriano soils, while there was no significant variation in the NHinf4sup+content in the Ozzano soil during the same period. The turnover of interlayer NHinf4sup+in the Carpi and Cadriano soils was high, and appeared to cover a substantial amount of the N requirement of the crop. The turnover in these two soils showed a significant decrease during the initial phase followed by a period during which the pool of interlayer NHinf4sup+was replenished and reached the initial levels again. The spatial distribution of the root system, the pattern of N uptake by the sugar beet crop, and the processes of immobilization-mineralization of organic N all have an influence on the mechanisms of adsorption and release of interlayer NHinf4sup+. The release of interlayer NHinf4sup+, and thus its availability for plant uptake, was greater at the beginning of the growing season. The physicochemical characteristics of the soils, the K concentration, and the types of clay minerals present were found to be important in determining the dynamics of interlayer NHinf4sup+turnover of soils.

Five different procedures for the oxidation of organic carbon were compared in order to determine the most suitable method for use as a pretreatment before the determination of fixed NH4‐N in soils. Three of the procedures involved a method based on the use of a solution containing 0.1M Na4P2O7, 0.1M NaCl, and 6% H2O2, applied for three different periods of time, 10 days, 20 days, and whatever number of days are required until frothing no longer occurs. This third period of time is designated as NF (no frothing). The remaining two procedures involved a method based on the use of a 3M NaOCl solution applied for two different periods of time, 3‐cycles and 5‐cycles. Two of the procedures, the NF treatment with H2O2+NaCl+Na4P2O7 and the 5‐cycle treatment with NaOCl, were found to give the must efficient removal of organic C. The amount of residual N in the soil after the NF treatment was highly correlated with the amount of residual N in the soil after the 5‐cycle treatment. It is concluded that the ...

Changes in soil porosity and microstructure are discussed for a silty clay soil and a sandy loam soil following the surface application of livestock effluents and composts from sewage sludges and urban refuse. Porosity measurements were carried out on large, thin-sections of undisturbed soil samples by means of scanning electron microscopy, light microscopy and electro-optical image analysis. The organic materials significantly increased the micro- and macroporosites of the two soils. Micro-morphometric measurements showed that the increase in microporosity was mainly due to the elongated micropores associated with newly formed microaggregates. The increase in macroporosity was due to enlarged pores ranging from 50–500 μm, which are considered the most important both in soil-water-plant relationships and in maintaining a good soil structure. The increase of porosity in the topsoil was accompanied by a reduction in the presence of surface crusts, thus indicating that such organic materials play an important role in improving soil structure.

A given tolerance value on the declared nutrient content of fertilizers is permitted by some national laws. A statistical method to assess systematic exploitation of tolerance values by single nutrient fertilizer producers is proposed. Production of superphosphate was selected as the case study. The method was tested on a yearly production, on randomly selected samples, and on a generated series of samples; it was found to be simple and reliable. The method is theoretically expected to be more reliable than the Wilcoxon test recommended by French law for normal distributions; it appears to fit better than the Wilcoxon test to uneven production of fertilizers.

Exchangeable NH4, organic N, and fixed NH4, were followed in three soil layers (0–25, 25–50, and 50–75 cm) of plots under conventional and minimum tillage in a 10—year field experiment. The main effect of both tillage treatments was a marked increase of fixed NH4 during the first two years which was attributed to the heavy application of N fertilizers because soils were not fertilized prior to the experiment. Due to spatial variability of soil composition, a statistically significant increase over the 10—year was observed for total and fixed NH4 only in the surface layer of conventionally tilled soils, probably due to thorough mixing caused by intense cultivation. In this layer the organic N pool did not appear to vary with the years, while the fixed NH4 pool was influenced by N fertilization. A general trend was a uniform increase of the ratio between fixed NH4 and total N. Under conventional tillage, the trend was similar for the three soil layers while the reduced amount of fixed NH4 present i...

Subsurface drainage systems have been installed in about 10000 ha of agricultural land in the flat part of the Emilia-Romagna Region in northern Italy. Nitrate loss in drainage water from a representative farm in this area was measured for three consecutive years (1986, 1987, 1988). During this period a total of 369 water samples were collected, filtered at 0.45 µm and analyzed. The nitrate concentration exceeded the limits for surface water set by Italian law regarding water pollution (90 mg NO3−L−1 = 20 mg N L−1) in 84% of the samples. The greatest nitrate loss was recorded during the winter and early spring when drainage was high. After this period loss of nitrate, via drainage water, progressively decreased. This was attributed to a decrease in the amount of drainage water and increase in crop uptake of N. The average annual nitrate loss via drainage water was around 200 kg of NOinf3sup− ha−1. Annual nitrate losses of this order of magnitude (≊ 50 kg N ha−1) indicate an urgent need for implementation of management practices directed towards achieving considerable reductions in these losses.

The objectives of the study were to test the electrofocusing technique to determine its suitability as a method for the characterization of organic fertilizers from a qualitative point of view and identification of the organic matrix in an unknown fertilizer; no laboratory methods for this purpose are presently available. Analytical electrofocusing (EF) is shown to fulfill these objectives and may be easily adopted as a routine manual procedure. A solution of sodium hydroxide was chosen as the extractant because it allows comparisons between various types of humified materials and permits the evolution of organic matter to be followed during “maturation” of the fertilizer itself. The organic fertilizers considered included many nitrogen-rich waste materials, mostly of animal origin. They are divided into different groups according to origin and EF profiles.

An enzymatic approach to assess the stability of organic matter extracted from organic fertilizers and amendments is proposed. The use of 0.1M NaOH plus 0.1M Na4P2O7 previously suggested as a suitable extractant solution for soil organic matter was also found satisfactory for the extraction of organic matter from organic fertilizers and amendments, especially when the temperature was raised to 65°C. The presence of nonhumified compounds in the extracts from organic fertilizers may interfere considerably during fractionation of organic carbon. An enzymatic hydrolysis with lipase, lysozyme and pronase, added sequentially to the extracts, led to an appreciable reduction in the interference. The interference was further reduced by carrying out a successive acid hydrolysis with 3N H2SO4; in this case the DH values (percentage of humified fractions with respect to total extractable carbon) were reduced to less than 10% in all organic fertilizers, but remained higher than about 70% in organic amendments.

New humification parameters are proposed for characterizing soils and organic fertilizers or amendments. They include an index, a degree and a rate of humification, all devised to assess the ratio between humified and non-humified materials. The separation of the two types of materials is essentially performed by extraction and fractionation on solid polyvinylpyrrolidone.

Resumption of growth in deciduous fruit trees in spring depends largely on the re-mobilisation of nitrogen (N) from reserves in perennial organs. Root nitrogen uptake starts before re-mobilisation is finished. Uptake may take place as either nitrate or ammonium. As uptake rates may differ significantly between both sources, we assessed uptake and partitioning of N labelled with 15N. A part of the trees was girdled to test the hypothesis that root N uptake depends on availability at root level of phloem transported carbohydrates.

Potentially mineralizable nitrogen and interlayer ammonium-nitrogen pools of the soil were determined. The mineralization process has an influence on fixation and release of interlayer ammonium. During long-term incubation for determining of the potentially mineralizable nitrogen of soil, the mineralized nitrogen could be affected by the realease of inorganic nitrogen from the other pools, particularly from the interlayer ammonium-nitrogen pool.

Aims of this work were to understand the effects of metal oxide (CeO2, Fe3O4, SnO2) engineered nanoparticles (NPs) on microbial biomass and to evaluate their availability and distribution among soil particles. Two organ-mineral horizons (A1 and A2) of Epileptic Cambisol were polluted with NPs at rates of 0, 10 and 100 mg kg1 of dry soil of Ce, Fe and Sn and incubated for 7 and 60 days at 60% WHC and at 25 C. Both microbial biomass C and N were not statistically affected by NPs pollution whereas the microbial C/N ratio increased with Fe3O4 and SnO2-NPs probably due to the predominance of microbial communities such as ectomycorrhizae. The metabolic quotient (qCO2) significantly (P < 0.001) increased in polluted soils indicating microbial stress or changes in the bacterial/fungal biomass ratio. The CHCl3- labile amounts of free Ce and Fe were found in soil polluted with CeO2 and Fe3O4, indicating these elements were taken up by soil microorganisms. The chemical methods used for NPs bioavailability were not adequately sensitive to evaluate availability of elements in nanoparticles, and the best evaluation was from the wateresoil partition coefficient (log Kd) showing a low solubility of NPs. Nanoparticles were found in soil small aggregates (2e53 and

The aim of this work was to characterize dry atmospheric deposition after the washing of broad leaves and conifer foliage. To assess this method different sites chosen on the basis of different exposure to both point (e.g. waste incinerator plant (WIP), local crafts) and widespread (e.g. roads, agricultural practices) sources of anthropogenic pollution. The principal components analysis (PCA), performed on the major and trace elements identified after leaf washing, extracted four factors. F2 was lithogenic while the other three were anthropogenic. The enrichment factor (EF) highlights that Cd, Cu and Zn had a purely anthropogenic origin. The sites were grouped according to the predominant source of exposure and the synthetic index of enrichment (SIE) showed a decrease as follows: downwind from WIP > max exposure to WIP > min exposure to WIP > road > craft > rural zone. The leaf area allows to calculate the annual flow of elements and the deposition flux in the study area varied for Cd from 0.07 to 0.55 mg m-2, for Co from 0.1 to 0.48 mg m-2, for Cr from 0.63 to 3.7 mg m-2, for Cu from 14.5 to 32.27 mg m-2. The Cd flux in the Bologna area was lower than in some industrial zones of the World and the lowest values were found in the rural zones and under a minimum exposure to the incinerator plant, while the highest values were near the roads and under maximum exposure to the incinerator. The direct analysis of the leaf-washing water allows to discriminate the anthropogenic or geogenic metals deposited on the leaves using multivariate statistical analysis. It is also possible to predict the flow of metals in different areas of investigation.

Nanoparticles (NPs) types diffused into the environment are increasing, giving potential damages to terrestrial ecosystems. In this work we investigated the nanoparticles toxicity as pure metal and two oxides (Co, SnO2 and CeO2) on earthworm survival (Lumbricus rubellus). A concentration of 5000 mg kg-1 dry soil of each NP was compared to the chronic dose of 10 mg kg-1. The interaction between NPs and soil microbial biomass was also studied in 7 days length incubation. No mortality was observed at the end of the experiment, but high concentration of Co was found in the 5000 kg-1 dry soil treated. Despite low solubility of all NPs (solid-liquid partition coefficient > 2.8 log l kg-1) pure metal NPs were (Co) more soluble than the metal oxides nanoparticles (SnO2 and CeO2).

The suburban area of Bologna city in southeast portion of Po Valley (Northern Italy) is characterized by high emission from industrial, urban, agriculture and traffic sources. The presence of an urban waste incinerator get inhabitants to require answers about impact of its emissions on the environmental quality related to human health. The concentrations of some pollutants (Ba, Cd, Co, Cr, Cu, Ni, Pb, V and Zn) were determined in topsoil, plants and mosses tissues sampled in sites selected according to different falling out conditions, due to the incinerator and other sources of atmospheric emissions that affect the monitoring area. No correlation was found between metal content and the distance of the incinerator plant. The pollution load index (PLI) calculated for soil and moss indicated a low environmental pollution, while highest values in sites downwind of incinerator and in craft area indicate a moderate pollution.

In a building site located near the historic centre of the city of Bologna (Italy), archaeological and geopedological studies supplemented by chemical and physical analyses of the soil made it possible to identify 17 pedogenic cycles. These cycles, distributed in a continuous chronosequence from Reinassance period back to the Bronze Age, show a persistent anthropogenic presence as demonstrated by the different distributions of P2O5 and CaCO3, by the concentrations of some elements (Cu, Pb, Sn) and by the presence of fragments of charcoal, brick and ceramics, which overall reach the highest values during the Iron Age (Etruscan and Villanovan). According to the WRB taxonomic system, the soil units of the pedogenetic cycles belong to the groups of Anthrosols, Cambisols and Technosols.

A public property site, situated on an alluvial terrace of the Idice Stream (Emilia Romagna Region-Italy) was contaminated by a layer of waste, constituted by vitrified fly ashes and ceramic materials produced by an incinerator of municipal solid waste. The waste had high contents of heavy metals which exceeded the Italian legal concentration limits for Cd, Cu, Pb and Zn (D. Lgs. 152/06, all. 5, tab.1). The in-situ remediation of the area was possible. In this study, alternative materials than the Portland cement were tested for the environmental restoration and the further naturalization of the area. Leaching tests were carried out treating the ashes with different concentrations of hydrated lime (CaOH2) and also with lime at 20% concentration and smectic marlstone. At the end of the leaching test, most of the heavy metals in the waste were immobilized in the waste by the lime/marlstone treatment.

Soil is a complex heterogeneous system whose physical, chemical and biological properties regulate interactions with the chemical species which reach its surface. Soil chemistry is an essential tool for understanding and predicting these interactions. Soil is able to immobilize and transform organic and inorganic molecules by different mechanisms, such as complexing and redox reactions. This behaviour gives soil detoxifying capacities towards pollutants which accumulate in the environment. Pollution by heavy metals is regulated by their solubility in soil solution which in turn depends on soil pH and redox properties and metal speciation. Organic and inorganic colloidal soil fractions can promote the immobilisation, degradation, and diffusion of organic molecules such as agrochemicals, solvents, hydrocarbons and other chemicals which reach the soil by anthropic activities. Predicting the fate of xenobiotics in soil, water, air, and plant ecosystems, the recycling of biomass and the decontamination of polluted soils are of major concern to soil chemistry.

The growing shortage of water combined with the sharp increase in population and the development of large cities due to rapid urbanization are different aspects of an important problem, and the competition among the various consumers of water increases concerns about the protection of the environment and health. Agriculture represents the greatest burden on the availability of water and most international projects dealing with water reuse are aimed at this sector. The reuse of water for irrigation cannot overlook certain risks for human health and the environment which depend on the quality of the recycled water, its use, soil characteristics and climatic conditions. Urban wastewaters, if separated from those of industrial origin, contain concentrations of organic and inorganic compounds that present only limited problems for human health in the case of reuse for irrigation. On this basis, the present study examines various characteristics of wastewaters coming from different urban wastewater treatment plants and surface water bodies situated in the eastern Po basin and in particular the Provinces of Bologna and Ferrara. The application of multivariate statistical methods can allow us to interpret the large and complex matrices of analytical data obtained during monitoring campaigns. In particular, cluster analysis, which discriminates data on the basis of the degree of similarity among different classes of quality, was able to characterize the quality of the wastewaters of the various plants. Moreover, it was possible to distinguish different types of water in the surface water bodies of the sub-basins in the Provinces of Ferrara and Bologna.

In the last decades the Aral Sea, located in Central Asia on the boundary between Kazakhstan and Uzbekistan, experienced a dramatic shrinking, divulged even in newspapers and magazines. Such an ecological catastrophe, renamed the “Aral Sea Crisis”, was triggered by the artificial diversion of the rivers of the basin during the Soviet period, in order to irrigate new cotton fields. Nowadays, notwithstanding the fulfilment of several environmental restoration projects and a wide scientific literature about the process, the general balance about the water body, in particular its Uzbek side, is still critical. This paper, after a synthesis concerning the causes and the consequences of the ecological disaster, analyses the geopolitical implications connected to the deterioration of the environmental quality in the region and to water management in Post-Soviet Central Asia, underlining, in the case of the Aral Sea Basin, the criticities linked to its fast transition from an internal basin to an international one. Finally, Central Asian water-related old programs and future scenarios are discussed.

The present work of nanocotoxicity wants to propose a new plant model starting from the rice plant. The model takes into consideration the impact of engineered nanoparticles (Ag, Co, Ni, CeO2, Fe3O4, TiO2) on rice plants that were weakened by infections of Xanthomonas oryzae pv oryzae bacteria. The results indicate that some NPs increase the rice sensitivity to the pathogen while others decrease the virulence of the pathogen towards rice. No-enrichment in component metal concentration is detected in above organs of rice, with exception of Ni-NPs treatment. An imbalance of major elements in infected rice crops treated with NPs was investigated., EQA - International Journal of Environmental Quality, Vol 16 (2014)

Knowledge on the impact of engineered nanomaterials (ENMs) on both human and environment health is scarce. Several studies sustain that soil is the environmental compartment designed to be the major recipient of engineered nanoparticles (NPs). With the aim of investigating the impact of commercially relevant NPs on soil functioning, we compared the effect of Ag and Co NPs, as well as cobalt and silver ions, on soil microbial community in the presence of Lumbricus rubellus. Earthworms specimens were placed in a rich-C soil and fed with horse manure spiked with Ag-NPs, Co-NPs, Ag+ and Co++ for a total amount of 10 mg of single pollutant kg−1 soil. At the end of acute exposure (4 weeks) to pollutants, the following analyses were performed: soil metal contents, soil microbial biomass C (MBC) and nitrogen (MBN) , basal respiration, specific respiration (qCO2), phospholipid fatty acids (PLFAs). The pollutants introduced with the food in the soil-earthworm system affected the microbial activity increasing basal respiration and qCO2, while MBC and MBN content decreased. PLFAs of soil were affected by both pollutant NPS and ions supplied. The fatty acids significantly affected by treatments were C18:1w7 and C18:2w6,9 in soil. These results suggested that NPs could induce stress on soil microorganisms.

This geochemical study is focused on the easternmost part of the Po River alluvial plain in Northern Italy, which is interested by widespread agricultural activities, investigating a reclaimed sector of the Province of Ferrara, known as "Valle del Mezzano" (Mezzano Low Land, hereafter reported as MLL) characterized by peat-rich soils. The chemical-mineralogical characterization of these reclaimed soils is important to compare the local geochemical backgrounds with those recorded in other sectors of the River Po plain and to monitor if the observed concentration exceeds critical thresholds. The reported analyses include (a) measurement of the soil salinity, (b) nutrient evaluation, (c) major and trace element concentrations carried out on bulk soils, (d) tests of metal extraction with both aqua regia and EDTA to highlight the distinct elemental mobility and (e) phyto-toxicological measurement of heavy metal concentrations in plants (Lactuca sativa acephala) grown on the studied soils. The results indicate (1) high soil salinity, often with drastic increase of sodium and chloride along the soil profiles, (2) high nitrogen content (in part related to anthropogenic activities) on superficial horizons and nitrate decrease along the soil profiles and (3) comparative enrichments in heavy metals with respect to other soils of the province, which indicate that peat deposits are effective in trapping metals from anthropogenic sources. This, in turn, implies potential geochemical risks for the agricultural activities. In this regard, specific concerns are related to the high nickel and arsenic content of MLL soils due to the mobility of these elements and their attitude to be taken up by plants.

Soils are complex matrices and their geochemical investigation necessarily needs reliable Certified Reference Materials (CRMs), i.e. standards, to support analytical precision and accuracy. In particular, the definition of soil multi-element CRMs is particularly complex and involves an inter-laboratory program that employs numerous analytical techniques. In this study, we present the results of the inter-calibration experiment focused on the certification of two new soil standards named AMS-ML1 and AMS-MO1. The two soils developed on sandstone and serpentinite parent materials, respectively. The experiment involved numerous laboratories and focused on the evaluation of soil physicochemical parameters and geochemical analyses of major and trace elements by X-ray fluorescence (XRF) and Inductive Coupled Plasma techniques (ICP-OES and ICP-MS). The data was statistically elaborated. Three levels of repeatability and accuracy in function of the different analytical methods and instrumentation equipment was observed. The statistical evaluation of the results obtained by ICP-OES on Aqua Regia extracts (i.e., Lilliefors test for normally, Grubbs test for outliers, Cochran test for outliers in variances and ANOVA) allowed to computed some certified values for the two proposed soil standards. This preliminary study will represent the first step of a more thorough intercalibration ring-test involving a higher number of laboratories, in order to propose the investigated matrices as CRMs., EQA - International Journal of Environmental Quality, Vol 15 (2014)

The aim of the study was to determine the effect of mature Douglas-fir reforestation (DR) on nutriens and C stocks in mineral soils compared with beech forests (BF) at two altitudes in North Apennine, Italy, at around (1) 1028 and (2) 1281 m a.s.l.