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The determinants of the susceptibility to severe acute respiratory syndrome‐coronavirus‐2 (SARS‐CoV‐2) infection and severe coronavirus disease 2019 (COVID‐19) manifestations are yet not fully understood. Amino‐bisphosphonates (N‐BPs) have anti‐inflammatory properties and have been shown to reduce the incidence of lower respiratory infections, cardiovascular events, and cancer. We conducted a population‐based retrospective observational cohort study with the primary objective of determining if oral N‐BPs treatment can play a role in the susceptibility to development of severe COVID‐19. Administrative International Classification of Diseases, Ninth Revision, Clinical ModificationI (ICD‐9‐CM) and anatomical‐therapeutic chemical (ATC) code data, representative of Italian population (9% sample of the overall population), were analyzed. Oral N‐BPs (mainly alendronate and risedronate) were included in the analysis, zoledronic acid was excluded because of the low number of patients at risk. Incidence of COVID‐19 hospitalization was 12.32 (95% confidence interval [CI], 9.61–15.04) and 11.55 (95% CI, 8.91–14.20), of intensive care unit (ICU) utilization because of COVID‐19 was 1.25 (95% CI, 0.38–2.11) and 1.42 (95% CI, 0.49–2.36), and of all‐cause death was 4.06 (95% CI, 2.50–5.61) and 3.96 (95% CI, 2.41–5.51) for oral N‐BPs users and nonusers, respectively. Sensitivity analyses that excluded patients with prevalent vertebral or hip fragility fractures and without concomitant glucocorticoid treatment yielded similar results. In conclusion, we found that the incidence of COVID‐19 hospitalization, intensive care unit (ICU) utilization, and COVID‐19 potentially related mortality were similar in N‐BPs–treated and nontreated subjects. Similar results were found in N‐BPs versus other anti‐osteoporotic drugs. We provide real‐life data on the safety of oral N‐BPs in terms of severe COVID‐19 risk on a population‐based cohort. Our results do not support the hypothesis that oral N‐BPs can prevent COVID‐19 infection and/or severe COVID‐19; however, they do not seem to increase the risk. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The olive tree is not only the typical plant of the Mediterranean but it is also a tree that constitutes the only culture of global importance. From very old times through the centuries, the traditions of the great oil-growing areas of today were born and consolidated—Greece, Italy, and Spain. The olive tree and oil are an indispensable presence for our daily well-being, as well as a reminder of our oldest and truest history. Olive tree became a symbol of peace and value, an element of strength and purification, of resistance to the ravages of time and wars, the olive tree has always been a transcendent symbol of spirituality and sacredness.

The first step in planning the actions for climate change adaptation involves performing Climate Change Vulnerability Assessment (CCVA) to vulnerable populations and ecological systems. The study aims to perform a bibliometric analysis on the CCVA research field to identify how it was structured in terms of the mostly occurring research terms and their citation impact. A set of scientific papers related to CCVA (n = 8941) were retrieved via Elsevier’s Scopus database over the period 1996–2016 using specific keywords. The search was carried out in February 2017. The number of yearly papers published in CCVA research field increased after 2006, increasing more than six times in 2016. Our co-occurrences term analysis grouped four clusters related to (i) exposure, sensitivity, and quantitative methods for assessing CCVA, (ii) adaptive capacity and qualitative approaches, (iii) CCVA integrated approaches by combining participatory methods to quantitative ones, and (iv) collaboration and participation issues related to global change. The co-citation analysis showed that highly cited research terms were related to adaptation, exposure factors, and related changes and global change. This bibliometric analysis has provided an overall picture on the CCVA research field, particularly highlighting its utility for climate change adaptation.

Climate Change Vulnerability Assessment (VA) tools for forest ecosystems and forest-dependent communities are important for making decisions and understanding the impact of climate change on both social and natural systems. However, the tools are poorly coordinated, making it difficult for policymakers to carry out VAs properly. The aim of this study was to analyze VA literature worldwide to find representative case studies in terms of methods and tools applied and which have been successful in performing VAs on forests and forest-dependent communities. All successful VA studies analyzed had common characteristics such as significant funding, data availability and technical capacity. An additional characteristic was the development of an integrated approach that considered the vulnerability of both ecosystems and communities by combining qualitative and quantitative methods. Community members and relevant stakeholders were significantly involved in a participatory process that concluded with the identification of adaptation measures. The case studies also revealed how policymakers need to choose suitable methods and tools to undertake efficient assessment of vulnerabilities. They need to consider several aspects of the VA process such as subject matter, availability of resources, time and scale.

Microbial genetic, structural and functional diversity was assessed in response to arsenic (As) pollution in a former gold mine soil. Ester-linked fatty acid methyl ester (EL-FAME), quantitative PCR (qPCR), denaturating gradient gel electrophoresis (DGGE), enzyme activities and MicroResp techniques were used.Multivariate analysis showed that As bioavailability in soil was an important driver affecting microbial diversity. Microbial biomass assessed by EL-FAMEs and qPCR generally decreased under higher bioavailable As, as well as enzyme activities and C substrate utilization. Conversely, actinomycetes and fungal biomass increased along with total As content suggesting the selection of more resistant species.

The application of animal manure effluents in agriculture in combination with nitrification inhibitors should be beneficial for nutrient recycling, soil quality, plant productivity, and greenhouse gas emission and offer economic advantages to make them an alternative to conventional fertilizers. The present study aims to estimate the effects of the addition of bovine manure effluent alone or together with a nitrification inhibitor (3,4-dymethylpyrazol-phosphate (3,4 DMPP)) on the microbial community dynamics in a Mediterranean soil in an incubation experiment over 28 days. The application of the bovine manure effluent increased respiration, microbial biomass carbon, fungal and bacterial growth, and enzyme activities and changed the microbial community structure evaluated by the phospholipid fatty acid pattern. Adding the bovine manure effluent together with the nitrification inhibitor, although partly negating the positive effect of the effluent on soil microbial activity, still resulted in higher or similar growth and activity as in the control. Our results indicate that the addition of the nitrification inhibitor 3,4 DMPP together with a bovine manure effluent could be a promising solution to control the animal manure effluent application effects on soil microbiological properties and microbial dynamics, as well as counteracting direct inhibiting effects of 3,4 DMPP on the soil heterotrophic community.

The influence of light quality on growth and metabolic activity during pre-cultivation (in miniplug containers) of beech (Fagus sylvatica L.), holm oak (Quercus ilex L.) and wild cherry (Prunus avium) plants was investigated. Seedlings were grown in a growth chamber for a month under light-emitting diode (LED) light or fluorescent light. The LED lamps (Valoya) used in this study emitted a continuous spectrum thanks to a mixture of blue, green, red and far-red LEDs. Our results showed that plant response to light quality seems to be related to the plant species. In particular, in beech seedlings fresh and dry weight, shoot height and leaf area were greatest when plants were cultured under LED light, and lowest under fluorescent lamps. Furthermore, we found that LED-induced reduction of chlorophyll contents in beech and holm oak leaves resulted in an increase of the carboxylase capacity of Rubisco in the same plant species suggesting an improvement of light-use-efficiency in these plants. These results indicate that LED light may be suitable for the culture of plants in tightly controlled environments. The comparison of malondialdehyde levels between LED and fluorescent grown plants strongly supports this idea.

Among the bioindicators used to determine soil quality a vast interest is devoted to those related to soil biodiversity; in fact, the ability of a system to withstand stress and abiotic and biotic disturbances depends on its level of biodiversity which is the basis of the functionality of ecosystems. Functional diversity is widely used to gain insight into microbial performances, particularly in presence of a factor of disturbance. In this study we present the changes of microbial functional diversity and other soil chemical and biochemical properties following forest coppicing. The study was conducted in central Italy, in a natural reservation under Quercus cerris spp. plant cover; soils were sampled after three years from coppicing and in an aged coppice taken as control. Trees cutting provoked a decrease of soil total organic carbon (TOC) and a pH increase suggesting a priming effect on native organic matter and qualitative changes in soil solution composition. Microbial indicators (microbial biomass carbon, MBC), basal and cumulative respiration, and indexes (microbial and metabolic quotients) were significantly affected by forest management. Enzyme activities and microbial catabolic activity measured by means of community level physiological profile (CLPP) techniques (MicroResp and Biolog) increased in coppiced plots indicating higher decomposition processes promoted by plant debris and rhizodepositions released after cutting. The calculation of the diversity indexes using both techniques (enzyme activities and CLPP) suggested interesting speculations and perspectives on possible interpretations of these results.

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.

Soil enzymes are widely used as indicators of soil quality because they are sensitive to various land management practices. In particular, enzyme kinetic behaviour and the derived kinetic parameters ( V max and K m ) can be indirectly influenced by changes of soil structure, organic matter quantity and quality due to the addition of organic amendments to the soil. When measuring enzyme kinetics, the calculation of the specificity constant ( K a ), i.e.: the ratio V max to K m , is advisable to obtain additional information on the whole catalytic process. Many assays for a wide range of soil enzymes have been set up and they differ for the substrate used, incubation conditions and detection methods: the most widely used are those based on spectrophotometric and fluorimetric techniques. However, the comparative information between the two assays is poor. Therefore this study aimed to answer the following questions: (1) Can β-glucosidase kinetic parameters be considered reliable indicators in detecting changes due to soil management? (2) Can the specificity constant ( K a ) be considered an additional kinetic parameter useful as a new ecological indicator? (3) Do different analytical approaches give the same results? Both experimental approaches, fluorimetric and spectrophotometric, were effective in highlighting changes occurred under organic and conventional management indicating higher level of enzyme ( V max ) under organic cropping system. However the specificity constant ( K a ) demonstrated that organic management did not affect the whole catalytic behaviour of β-glucosidase. On the other hand, as regards the two analytical approaches, K a increased significantly using the fluorogenic substrate, 4-MUF-β- d -glucopyranoside, indicating a higher catalytic efficiency of the enzyme with the fluorimetric approach.

Five soils characterised by different agro-forest managements, typical of Mediterranean environment and with increasing human impact were chosen in Sardinia (Italy): two vineyards with different management systems, a rotation hay crop-pasture and a forest (Quercus suber L.). The study aimed to investigate the relationships between C storage and microbial functionality in soil under different managements. Pools of total organic C and microbial biomass C were determined, as well as the loss of organic C due to microbial respiration (basal and cumulative) and several microbial indices (metabolic, mineralization, and microbial quotient) as indicators of the microbial efficiency in the use of energy and the degree of substrate limitation for soil microbes. Enzymes were chosen on their relevance in the C (β-cellobiohydrolase, N-acetyl-β-glucosaminidase, β-glucosidase, α-glucosidase), N (leucine aminopeptidase), S (arylsulphatase) and P (acid phosphatase) cycling and were used as indicators of functional diversity in soil. Organic C pools and enzyme activities on average increased noticeably in soils with a lower human impact showing the highest values in forest and the lowest in the vineyards, following the trend of organic matter availability. The trend in functional diversity reflected the increase of microbial pool and organic C availability: the vineyards showed a lower Shannon’s diversity index, whilst pasture and forest sites reached the maximum levels of functional diversity. These soils showed an increase of microbial efficiency in the use of available resources and the decrease of substrate limitation for soil microbes.

In the past decade there has been increased scientific interest in organic farming, especially in comparison with conventional agriculture. The aim of this study was to investigate the effects of these two agricultural systems on the soil organic matter (SOM) quality evaluated according to a new methodological approach. In particular, a sequential solvent extraction and a linear gradient elution reversed-phase high performance liquid chromatography (RP-HPLC) were used to evaluate SOM hydrophobic/hydrophilic character. The selected areas for soil analysis were two adjacent fields located in Central Italy and cultivated for 8 years following organic and conventional management, respectively. This area was a cultivated arable land since last century. Soil was a Vertic Xerochrepts with sandy clay loam texture (USDA) and pH 7.6. The cation exchange capacity (CEC) was on the average 42 mequiv. 100 g(-1). Each soil sample has been subjected to three cycles of extraction with organic solvents (n-hexane, dichloromethane, ethyl acetate) using Soxhlet apparatus. The relative amounts of SOM extracted from conventional and organic soil by the most hydrophobic solvent ( n-hexane) were 45.4 and 28.9%, respectively; while dichloromethane was able to extract from the two soils 51.5 and 26.7% of SOM. The components of extracts have been separated by RP-HPLC using a linear acetonitrile gradient in water to elute organic compounds. The PCA analysis of RP-HPLC chromatographic profile has well discriminated the organic matter quality of soils under different managements on the basis of organic compounds polarity, evaluated by RP-HPLC. In organically managed soil, ethyl acetate extracts SOM components that span a wider range of hydrophobicity than the compounds extracted by this solvent from conventional managed soil, indicating that the organically managed soil had a more heterogeneous organic compounds, which could be originated from the continuous input of fresh plant residues. The wide variety of organic substances extracted with different solvents from this soil can also be due to the amphiphillic character of humic material. RP-HPLC technique may represent a powerful tool for a thorough analysis of SOM hydrophobic character, which is known to have substantial bearing on the formation of stable aggregates and the whole soil structural stability. (C) 2010 Published by Elsevier B.V.

Defoliation of grasses affects carbon (C) input from plants into the rhizosphere and so may affect C turnover in soil. We examined the effect of grassland's defoliation on root-derived CO2 efflux and microbial activity in Mediterranean Phaeozem. In situ partitioning of total CO2 efflux into root-derived and microbial-derived CO2 fluxes was performed by mesh-exclusion technique. Microbial basal respiration, N mineralization and the activity of enzymes involved in the cycling of C, N, P and S (also used to calculate microbial functional diversity) were measured in soils of defoliated and control plots. Cumulative CO2 efflux in defoliated plots was 18% lower in 2006 and equal to control plots in 2007. The contribution of microbial CO2 to total CO2 efflux from soil ranged from 71% to 86% without significant differences between defoliated and non-defoliated plots. The lack of correlation between root-derived CO2 and soil temperature after defoliation indicates that photoassimilate supply is the major determinant for root-derived CO2. Microbial-derived CO2 efflux was 20% lower in defoliated plots after accounting for temperature and humidity differences between the two treatments. Defoliation suppressed the activity of enzymes involved in the cycling of C, S and P and decreased basal respiration rates of soil microorganisms by 19%. In turn, defoliation stimulated activity of enzymes involved in the cycling of N, as indicated by the increase of potential nitrification rates and of leucine-aminopeptidase activity. Stimulation of N mineralization promotes a fast regeneration of defoliated plants. We confirm the presence of strong links between plant and microbial activity in a grassland community, as well as close coupling of aboveground photosynthetic activity with root-derived CO2.

In this work we propose the use of soil quality indicators with the aim of assessing the environmental impact of soil bioengineering works. This study was carried out in central Italy where soil bioengineering slope stabilization works were established using chestnut wood. In particular the goal of this study was to determine the occurrence of a wood-effect, that is changes of soil properties due to the presence of decomposing logs in two sites characterized by different time span since works setting up. The presence of the logs did not affect soil physico-chemical properties. Conversely, soil biochemical properties such as soil microbial biomass, basal and cumulative respiration activities as well as microbial indexes, were influenced by the presence of the logs confirming the role of these bioindicators as early predictors of changes occurring in soil. Although a general positive trend was observed for the biochemical properties at both sites with respect to the control soils, significant differences were recorded mainly at the site where works were established six years before soil sampling. Soil bioengineering slope stabilization works establish a positive feed-back which ultimately can benefit plants; in fact the increase in microbial mineralization activity can enhance nutrient cycling and thus promote adequate growth conditions for the plant cuttings used in the wooden-work.

Two management systems (conventional vs. organic) in a 3-years crop rotation (pea–durum wheat–tomato) were compared after 4 years in order to assess soil carbon (C) changes in a short-term period. Biochemical properties of soil, such as microbial biomass C and N (MBC and MBN), microbial respiration, N mineralization, dehydrogenase, chitinase, acid–phosphatase, arylsulfatase and β-glucosidase activities, were chosen as indicators of soil organic matter biochemical alteration. The main questions addressed in this study were (1) do soil biochemical properties discriminate between organic and conventional management systems in a short-term period? (2) Which biochemical indicator is more effective in predicting soil organic C accumulation in organically managed agricultural soils? A general increase of hydrolytic enzymes activities has been observed in soil under organic management. MBC, MBN and the MBC/TOC ratio ( q mic ) increased in organic soil under pea (100%, 50% and 100%, respectively) and durum wheat (55%, 28% and 42%, respectively), while the basal respiration per unit of microbial biomass ( q C O 2 ) decreased (48% and 40% under pea and durum wheat, respectively). Moreover, the specific activity of β-glucosidase was significantly lower under organic management of pea and durum wheat and was positively correlated with q C O 2 , suggesting a lower maintenance energy requirement of the microbial community. Soil microbial biomass and enzymatic activities were successfully used to detect short-term changes in soil and, taking into account its role in soil functioning, β-glucosidase resulted the most suitable indicator to predict organic C accumulation in soil under organic management in a Mediterranean environment.

Dry olive mill residue (DOR), the by-product of the two-phase extraction process, is very rich in organic matter and nutritionally relevant cations. For this reason, the agronomic use of this waste has been suggested although DOR exhibits significant phytotoxicity. The objective of this study was to investigate the impact of Paecilomyces farinosus on both organic matter modification and detoxification of this waste.Humification ratio in DOR colonized by the fungus for 20 weeks was increased by about 65% with respect to the abiotic control and humification index reached 0.38, a value that characterizes well-humified materials. High performance size-exclusion chromatography of humic acids from fungal cultures showed a marked increase in both weight-averaged and number-averaged molecular weights with respect to abiotic controls. Water-soluble phenols were reduced by 45% in 20-week-old P. farinosus cultures on DOR and mass-balance ultra-filtration showed that the relative abundance of the molecular weight fraction of phenols above 30 kDa increased from 31 to 72% suggesting the occurrence of polymerization.Experiments performed with alfalfa grown on soils containing 2.5% (w/w) of abiotic controls and fungaltreated DOR showed that phytotoxicity was totally suppressed in the waste that underwent fungal treatment. L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com

Important effects of elevated [CO2] on SOM are expected as a consequence of increased labile organic substrates derived from plants. The present study tests the hypotheses that, under elevated [CO2]: 1) soil heterotrophic respiration will increase due to roots-microbes-soil interactions; 2) the increased labile C will boost soil heterotrophic respiration, depending on N availability; 3) the temperature sensitivity of soil respiration will change, depending on nitrogen inputs and plant activity. To test these hypotheses, we measured the heterotrophic respiration of intact soil cores collected in a poplar plantation exposed to elevated [CO2] and two nitrogen inputs, at different temperatures. Additional physical (water content, root biomass) and biochemical parameters (microbial biomass, labile C) were determined on the same samples. The soil samples were collected at the POP-EuroFACE experimental site (Italy), where a Populus x euramericana plantation was exposed for 6 years to 550 ppm [CO2] (Free Air CO2 Enrichment) at two different nitrogen inputs (none or 290 kg ha−1). The higher heterotrophic respiration under elevated [CO2] (+30% on average) was driven by the larger pool of soil labile C (+57% on average). The temperature sensitivity of soil respiration was unaffected by elevated [CO2], but was positively affected by N fertilization. Our results indicate that only a fraction of the extra carbon fixed by photosynthesis in elevated [CO2] will contribute to enhanced carbon storage into the soil because of the contemporary stimulation of soil heterotrophic respiration. At the same time, the fraction remaining in the soil will enhance the pool of soil labile C.

Fertilization is required to maintain production of short rotation forestry plantations and an understanding of nutrient cycling processes is crucial in order to assess long-term sustainability of these systems. Fertilization can alter root biomass growth and turnover and the chemical and biochemical properties of the soil thus affecting soil carbon dynamics and soil quality. The present study was conducted in a short-rotation forest located in central Italy where three poplar clones were grown, during the second cycle, in presence and absence of nitrogen (N) fertilization. In the year 2002, the first year after coppice, 212 kg N ha−1 was supplied (Navarsol 20: 16 ammonium-N and 4 nitrate-N) while, in the years 2003 and 2004, 290 kg N ha−1 (ammonium nitrate 34: 17 ammonium-N and 17 nitrate-N) was supplied. On soil samples collected in spring and autumn, throughout the 3 years, several chemical and biochemical indicators were measured. Aim of the study was to determine: (1) the temporal variation of the soil quality indicators tested in the plantation, (2) the effects of a 3-years fertilization on soil microbial biomass and its activity, in terms of C mineralization and (3) the consequent changes in soil organic carbon, soil nitrogen and nutrient availability. A pronounced increase of soil organic matter content was evident due to the presence of the poplar plantation on a former arable soil. The results showed short- and medium-term effects of fertilization. Fertilization did not modify soil capacity to accumulate organic matter in the medium term, although a positive variation of SOC was observed at the beginning of the study, probably in relation to the type of the fertilizer supplied. At the end of the third year, the fertilization did not change soil nitrogen concentration although significant increases were observed in October 2002 and 2003. Nitrate-N was the principal mineral form of nitrogen that responded to the treatment (mean effect: +119%) while ammonium-N concentration was low and underwent to a microbial immobilization process though this was season-dependent. Microbial respiration was affected by N addition only in the short-term incubation while no effects were detected in the cumulative CO2 production over 10 days; this suggested a microbial selection towards microrganisms with a fast metabolism and more depending on nitrogen.

Photosynthetic stimulation by elevated [CO2] is largely regulated by nitrogen and phosphorus availability in the soil. During a 6 year Free Air CO2 Enrichment (FACE) experiment with poplar trees in two short rotations, inorganic forms of soil nitrogen, extractable phosphorus, microbial and total nitrogen were assessed. Moreover, in situ and potential nitrogen mineralization, as well as enzymatic activities, were determined as measures of nutrient cycling. The aim of this study was to evaluate the effects of elevated [CO2] and fertilization on: (1) N mineralization and immobilization processes; (2) soil nutrient availability; and (3) soil enzyme activity, as an indication of microbial and plant nutrient acquisition activity. Independent of any treatment, total soil N increased by 23% in the plantation after 6 years due to afforestation. Nitrification was the main process influencing inorganic N availability in soil, while ammonification being null or even negative. Ammonium was mostly affected by microbial immobilization and positively related to total N and microbial biomass N. Elevated [CO2] negatively influenced nitrification under unfertilised treatment by 44% and consequently nitrate availability by 30% on average. Microbial N immobilization was stimulated by [CO2] enrichment and probably enhanced the transformation of large amounts of N into organic forms less accessible to plants. The significant enhancement of enzyme activities under elevated [CO2] reflected an increase in nutrient acquisition activity in the soil, as well as an increase of fungal population. Nitrogen fertilization did not influence N availability and cycling, but acted as a negative feed-back on phosphorus availability under elevated CO2.

Soil C mineralization activity and microbial indices were measured in agricultural, forest and grassland soils, characterized by different managements in two adjacent fields: agricultural (conventional vs. organic), forest (conifer vs. broadleaf), grassland (naturally grazed grass vs. alfalfa ungrazed). The aim of the study was to determine if the land use and the management practices modified C mineralization activity and kinetics, microbial biomass size, microbial and metabolic quotients (Cmic/Corg ratio and qCO2). Land use induced significant changes in microbial biomass content, in most of the microbial indices, and in the cumulative CO2 production which showed the highest values for agricultural soils (300 μg C–CO2 g−1 28 d−1) and the lowest for grassland soils (120 μg C–CO2 g−1 28 d−1). In agricultural soils, a large availability of potentially mineralizable C (C0) was determined. Forest soils mineralization activity was mainly dependent on environmental factors such as aboveground tree species and soil pH which probably induced changes in microbial community structure and/or functionality. This could also explain the significant differences found on chemical, biochemical and microbiological properties of the two forest soils under the two managements. Grassland soils were characterized by a high stability of soil organic matter (SOM) and consequently a low mineralization activity. Although total nitrogen and soil C/N ratio varied between the two soils, the management practices did not affect C mineralization activity. In conclusion the results show that microbially mediated processes can be largely affected by land use confirming its role as a significant driver of soil C changes.

Background, Aims, and Scope The genetic structure and the functionality of soil microbes are both important when studying the role of soil in the C cycle in elevated CO2 scenarios. The aim of this work was to investigate the genetic composition of the fungal community by means of PCR-DGGE and the functional diversity of soil micro-organisms in general with MicroResp-based community level physiological profiling (CLPP) in a poplar plantation (POPFACE) grown under elevated [CO2] with and without nitrogen fertilization.

Dry olive mill residue (DOR) is a solid waste arising from the olive oil two-phase extraction system. The objective of the present study was to investigate the impact of an aerobic treatment of DOR with selected lignin-degrading fungi on both organic matter evolution and residual phytotoxicity of the waste. To this aim, several white-rot fungi, including Phlebia radiata, Coriolopsis rigida, Phanerochaete chrysosporium, Pycnoporus cinnabarinus, Poria subvermispora and Pleurotus pulmonarius were inoculated under axenic conditions for 2 and 20 weeks. The chemical composition and phytotoxicity of DOR were scarcely affected by fungi after 2 weeks incubation. By contrast, both a significant depletion of phenolic compounds and a partial removal of phytoxicity towards Lycopersicum esculentum plants were generally obtained after 20 weeks. The most effective fungus in degrading lignin, total phenols and in removing phytotoxicity was C. rigida. A high correlation was observed between phytotoxicity and phenols added to soil with the waste.

In the past decade, there has been increased scientific interest in the so-called organic farming, especially in comparison with conventional agriculture. Many recent studies compare these two fundamentally different systems for soil properties, in different regions of the world. In this study, two adjacent fields in Central Italy, one managed according to organic, and the other according to conventional farming methods, were studied to determine the effects of these two agricultural systems on soil quality indicators at the farm level. Chemical and microbiological properties were chosen as indicators of soil quality and were measured at soil depth intervals of 5–20 and 20–35 cm, after 7 years of organic certified and conventional management methods. The field under organic management showed significantly better soil nutritional and microbiological conditions; with increased level of total nitrogen, nitrate and available phosphorus, and an increased microbial biomass content, and enzymatic activities (acid phosphatase, protease and dehydrogenase). No consistent increase in total organic carbon was observed. Results of the study suggest that, over the period of 7 year, organic management method strongly affects soil quality indicators. Large differences between the two soils were found in terms of microbiological properties, which are sensitive soil indicators of changes occurred under the different farming systems.

This paper reports the results of a study carried out to evaluate the potentiality of combining selective solvent extraction and linear gradient elution reversed-phase high performance liquid chromatography (RP-HPLC) for characterizing soil organic matter on the basis of polarity of its constituting organic compounds. Such approach comprises the sequential extraction of soil organic matter with organic solvents of increasing polarity in a Soxhlet extractor and the subsequent separation of each extract by RP-HPLC. Accordingly, each soil sample has been subjected to cycles of sequential extraction with n-hexane, dichloromethane, ethyl acetate, and methanol. Each sample extracted by one of the four solvents have been dried in a rotary evaporator device at 40°C and then dissolved again in the proper volume of extraction solvent to obtaining sample solutions of concentration ranging from 5.0 to 15 mg ml−1. These sample solutions have been subjected to RP-HPLC separation using a Supelcosil LC-ABZ column that has been eluted by a linear acetonitrile gradient in water, having the same profile for all samples. The study has evidenced the possibility of producing highly repeatable chromatographic profiles, which are correlated to the polarity of organic solvents employed for extracting the organic matter in the Soxhlet extractor.

Biomass productivity and soil microbial responses to long-term CO 2 enrichment have been investigated in a Mediterranean natural forest ecosystem. Several biochemical parameters have been measured on soil samples taken from six open top chambers (OTCs), enclosing clumps of natural Mediterranean woody vegetation including: Quercus ilex L., Phillyrea angustifolia L., Pistacia lentiscus L. and Myrtus communis L. The CO 2 concentration of the air inside the OTCs was either ambient or ambient plus 350 μmol mol -1 (c. 710 ppm as mean daily value). Microbial C biomass, microbial respiration, dehydrogenase, β-glucosidase, acid phosphatase and protease activities, inorganic N and soluble P, were tested in order to evaluate soil microbial size and activity. Statistically correlated seasonal patterns have been identified in some biochemical parameters in response to climatic conditions, soil nutritional status and the physiology of the vegetative cover. In situ soil respiration and above- and below-ground productivity were also measured. Microbial responses to CO 2 enrichment were observed only at the beginning of the study and a general progressive reduction of the CO 2 effect was recorded as monitoring continued. These results are in agreement with data from literature regarding similar studies on natural complex communities.

Microorganisms are the regulators of decomposition processes occurring in soil, they also constitute a labile fraction of potentially available N. Microbial mineralization and nutrient cycling could be affected through altered plant inputs at elevated CO2. An understanding of microbial biomass and microbial activity in response to belowground processes induced by elevated CO2 is thus crucial in order to predict the long-term response of ecosystems to climatic changes. Microbial biomass, microbial respiration, inorganic N, extractable P and six enzymatic activities related to C, N, P and S cycling (β-glucosidase, cellulase, chitinase, protease, acid phosphatase and arylsulphatase) were investigated in soils of a poplar plantation exposed to elevated CO2. Clones of Populus alba, Populus nigra and Populus x euramericana were grown in six 314 m2 plots treated either with atmospheric (control) or enriched (550 μmol mol−1 CO2) CO2 concentration with FACE technology (free-air CO2 enrichment). Chemical and biochemical parameters were monitored throughout a year in soil samples collected at five sampling dates starting from Autumn 2000 to Autumn 2001. The aim of the present work was: (1) to determine if CO2 enrichment induces modifications to soil microbial pool size and metabolism, (2) to test how the seasonal fluctuations of soil biochemical properties and CO2 level interact, (3) to evaluate if microbial nutrient acquisition activity is changed under elevated CO2. CO2 enrichment significantly affected soil nutrient content and three enzyme activities: acid phosphatase, chitinase and arylsulphatase, indicators of nutrient acquisition activity. Microbial biomass increased by a 16% under elevated CO2. All soil biochemical properties were significantly affected by the temporal variability and the interaction between time and CO2 level significantly influenced β-glucosidase activity and microbial respiration. Data on arylsulphatase and chitinase activity suggest a possible shift of microbial population in favour of fungi induced by the FACE treatment.

An understanding of microbial biomass and microbial activity as part of belowground processes as affected by elevated CO2 is crucial in order to predict the long-term response of ecosystems to climatic changes. The ratio of biomass C to soil organic C (Cmic:Corg), the metabolic quotient (the specific soil respiration of the microbial biomass, qCO2), the C mineralization quotient (the fraction of total organic C mineralized throughout the incubation, qM), the microbial biomass change rate quotient (qC) and soil inorganic nitrogen content were determined on soil samples taken during 3 years (Fall 2000‐Fall 2003) in a poplar plantation exposed to increased atmospheric CO2 by means of FACE (Free Air CO2 Enrichment) technique and nitrogen fertilization. A competition for nitrogen between plants and microrganisms, stronger in FACE plots, induced a stress condition within microbial community. FACE treatment provided C for microbial growth (Cmic:Corg), but reducing nitrogen availability, led to a higher microbial loss over time (qC). Nitrogen fertilization decreased microbial mortality lowering energetic maintenance requirements (qCO2) and induced a short-term shift in favour of microrganisms more rapid in the use of the resources. The C mineralization quotient (qM) was not affected by either FACE nor fertilization treatment meaning that the fraction of total organic carbon mineralized during the incubation period did not vary significantly. # 2005 Elsevier Ltd. All rights reserved.

The chemical composition of leaves from transgenic tomato plants (RC332) showing tolerance to attack by some pathogens has been compared with those from untransformed control line (RIG). In addition, the respiration of soil amended with transgenic plant leaf residues was determined. The RC332 plants had the Gox gene coding d-glucose oxygen 1-oxido-reductase (GOD) enzyme. The chemical composition [soluble proteins, total nitrogen (N) and lignin contents] of the tomato leaves was determined to establish the quality of the organic residues entering the soil. The transgenic plants contained more nitrogen and insoluble lignin and less soluble protein than the control plants. Soil amended with leaves from the two lines had different respiration rates; both dried and fresh leaves from 130-day-old RC332 plants determined a lower soil respiration than untransformed material over the first 2 days of incubation. This difference was probably due to the larger lignin content or the smaller soluble protein con...

Liquid chromatography (LC) was employed in conjunction to mass spectrometry (MS) to develop a straightforward LC-MS procedure for monitoring the variation of functionalized nonpolar organic compounds during the development of an aerobic composting process of agricultural wastes. The LC separation was performed by a reversed-phase microbore HPLC octadecyl-silica column, which was eluted by a linear acetonitrile gradient in water. The reversed-phase HPLC column was connected on-line to a triploquadrupole mass spectrometer by an atmospheric pressure ionization interface. Weighed amounts of agricultural wastes sampled at different time intervals during the aerobic composting process were extracted by dichloromethane and analyzed by LC-MS. The resulting fingerprinting offered a means to monitor the variations of functionalized nonpolar compounds during the aerobic process and indicate the presence of compounds that are not degraded by the biotranformation, such as ursolic acid and β-sitosterol.

The aim of this research was to study in a field experiment the influence of different fertiliser applications on soil biological and physical properties. Vermicompost (VC) from biological sludge, stabilised dairy manure or mineral nitrogen fertiliser (NH4NO3) were applied to a corn crop (Zea mays L.) at 200 kg N ha−1. Soil enzyme activity (acid phosphatase, dehydrogenase and protease BAA) and CO2 production were measured as indices of soil biological activity. These measures of metabolic activity were correlated to soil physical properties such as soil porosity. The soluble fractions of C and N were taken as indicators of fertiliser effects on soil fertility. There were positive correlations between soil porosity, enzymatic activity and CO2 production in organic and mineral treatments. The addition of organic fertilisers improved soil physical and biological properties. The increase in macropores, ranging from 50–500 μm, in soil treated with organic fertilisers was mainly due to an increase in elongated pores, which are considered very important both in soil–water–plant relationships and in maintaining a good soil structure. Organic treatments stimulated soil biological activity probably due to an enrichment of soil organic matter. Mineral fertiliser enhanced soil porosity by increasing regular and irregular pores and caused a priming effect of native soil organic matter.

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 aim of this work was to compare the kinetic parameters of acid phosphatase (EC 3.1.3.2.) extracted from two forest soils under oak or pine. Soil was extracted with 4 mM CaCl2 and the extract was divided into two fractions by filtration: one >0.2 μm containing microbial cells and soil particulates, and the other 0.2 μm fraction had higher Km (0.26–0.82 vs. 0.12–0.39) and Vmax (0.07–0.79 vs. 0.06–0.16) values than the

Evolution of CO 2 was measured during a 24 h CHCl 3 fumigation at 25°C in eight different soils ( CO 2 F ) The cumulative production of such CO 2 was always lower than that evolved under the same conditions by unfumigated soils ( CO 2 NF ). However, for five of the eight soils, CO 2 F accounted for more than 50% of CO 2 NF . Neither CO 2 F nor CO 2 NF were singly or multiply correlated to soil pH, water holding capacity, Hg porosity and carbonate content, i.e. chemico-physical variables that could influence the release of CO 2 from soil. Also other considerations suggest that abiological evolution of CO 2 was likely to be negligible; thus, both CO 2 F and CO 2 NF were mostly of biological origin and, probably, the biomass surviving chloroform exposure, or partially lysed, was substantial. The ratio CO 2 F to CO 2 NF was taken as an indirect physiological assessment of the efficiency of CHCl 3 in lysing microbial cells as, in principle, the lower CO 2 F compared to CO 2 NF the more efficient the chloroform fumigation. This ratio was significantly multiply correlated with several combinations of independent variables, including a wide range of soil physico-chemical properties (Hg porosity, storage porosity, water holding capacity, sand, silt, organic C and carbonate contents) related to soil structure. These significant correlations were functionally confirmed because the dynamics of the CO 2 F evolution during fumigation was related to the relative structural stability of the soils. Other correlations seemed to indicate that the positive relationships reported earlier between clay content and organic C made extractable by CHCl 3 ( E C : from which biomass C is calculated in the FE method for estimating soil microbial biomass) could be largely dependent on the relative ability of chloroform to permeate pores in different soils. It is highly probable that the efficiency of CHCl 3 in lysing microbial cells is strongly influenced by the soil structural properties. This could be one of the reasons why the calibration procedures for calculating K C and K EC generate quite dissimilar values.

A stable acid phosphatase-polyresorcinol complex, retaining about 90% of the original enzymatic activity, was synthesized in the presence of peroxidase. The complex was disturbed by chaotropic agents, as 4 M urea, indicating that the enzyme linked the phenolic moiety by non-covalent bonds. The immobilized phosphatase was more stable than the free enzyme towards pH, temperature and proteolysis: however, when added to soil, free and immobilized phosphatase showed comparable stability. It appears that the polymerization conditions used, favouring the interaction between enzyme and polyphenol through secondary linkages, give rise to a fully active complex resembling those which naturally generate in soil.

Streptomycin and cycloheximide were added (3 and 2 mg g-1 dry soil, respectively) single and in combination to a forest soil to follow their possible degradation and their effects on soil mineralization-immobilization processes. After 0, 1, 2, 4, 7, and 10 days of incubation at 25°C and 60% water-holding capacity, measurements were taken of microbial biomass C and N, the evolution of CO2, exchangeable NH inf4 sup+ , 0.5M K2SO4-extractable organic C, and total N in both unfumigated and CHCl3-fumigated soil. The results indicated that during the first 2 days of incubation, soil microorganisms were killed by the antibiotics and/or by CHCl3 and used subsequently as a substrate by the survivors. Thereafter, surviving microorganisms probably also started to use biocidal molecules as an energy and nutrient source. The ratios of biomass C to biomass N and of CO2 evolved to net NH inf4 sup+ produced indicated that both biocides had non-target effects for most of the incubation. Thus, streptomycin and cycloheximide are not suitable in determining the relative contribution from fungi and bacteria to mineralization-immobilization processes in soils.

Fungal hydrolytic enzymes have a great potential due to the rapid development of enzyme technology and their industrial applications. A fluorimetric microplate assay has been developed for measuring activity of β-D-exoglucanase, β-D-glucosidase, α-D-glucosidase, β-N-acetyl-hexosaminidase, β-D-xylosidase in diluted culture broth samples. The substrates used are conjugates of the highly fluorescent compounds 4-methylumbelliferone (MUB) and thus product formation can be measured directly in the microplate without previous extraction and purification of the product. The developed system was evaluated on eight fungal strains isolated from shrub species (Tamarix) that can be used in phytoremediation. Depending upon the enzyme, each species exhibited different levels of enzymatic activities as well as different production profiles. The fluorimetric method could constitute an effective alternative to the pectrophotometric method to screen hydrolase-producing microbial strains.

A microcosm was assembled to physically separate soil from roots and was used to study both the impact of living roots on the soil–plant system during early stages of growth and plant responses to abiotic stress. Oat (Avena sativa L.) seedlings were grown in the microcosm unit for 44 days. Twenty-three days after planting, 0.154 mg CdSO4/g dry soil was added. Plants grown in Cd-treated microcosms showed considerable inhibition of shoot growth rates, and leaf chlorophyll content. Soil microbial biomass C and respiration increased with plant age, and most of the measured biochemical indicators decreased with increasing distance from the soil–root interface, thus demonstrating the rhizosphere effect, likely due to the quick assimilation of rhizodeposits by rhizosphere microflora. On the other hand, short-term Cd contamination sometimes had an inhibitory effect on soil respiration, qCO2, ATP content, and phosphatase activity, while stimulating microbial biomass, mainly at the rhizosphere level. The decrease in rhizosphere microbial activity observed after Cd application to soil may be due to a synergic effect of the metal directly on microbial cells and indirectly on plants, which reduced shoot growth rate and chlorophyll content, resulting in decreased availability of root exudates.

International audience; Chemical fractionation of copper in bulk soil and its distribution in the particle-size fractions were analyzed in a Cu-contaminated soil (674±122 μg Cu g−1, up to 1900 μg Cu g−1 in the clay fraction) sampled from a wood preservation site left untreated and subsequently treated with dolomitic limestone (DL, 0.2% w/w) and compost (CM, 5% w/w), singly and in combination (DL+CM). Soil enzymatic activities of leucine aminopeptidase, cellulase, N-acetyl-β-glucosaminidase, arylsulfatase, β-glucosidase, acetate esterase, butyric esterase, and acid phosphatase were determined. Chemical speciation showed that Cu was mostly present in the acid-soluble and reducible fractions in both untreated and treated soils, whereas treatments with DL and CM reduced the soluble and exchangeable Cu fractions, due to Cu precipitation and complexation, and increased Cu bound to soil organic matter. Analysis of the particle-size fractions showed that more than 80% of Cu was in the silt and clay fractions and that treatment with CM increased the concentration of Cu in the sand size fractions. Soil treatment with DL and CM, singly or in combination, increased hydrolase activities, mainly in the clay fraction, with the largest positive effects on N-acetyl-β-glucosaminidase, leucine aminopeptidase, and β-glucosidase activities. Overall, results confirm that (1) Cu in contaminated soils is mainly bound to the silt–clay fraction, (2) CM additions change its allocation in the particle-size fractions, and (3) treatments with DL and CM singly and in combination reduce Cu solubility and its inhibitory effects on soil enzyme activities.

Summary Three-day-old maize seedlings were transferred to fresh growth solution with or without spermidine (Spd), or had the primary root tip removed and were then transferred to fresh growth solution. Spd pretreatment resulted in 50 % inhibition of root extension in intact plants after 24 h, while no growth was detected in tipless roots. After 18 h of either treatment, K + uptake measurements taken from subapical segments of freshly cut roots (T o ) showed values higher than those obtained in freshly cut segments from control seedlings. The values were similar to those from washed control segments. Moreover, the roots from seedlings exposed to Spd pretreatment showed an increase in polyamine oxidase (PAO) and peroxidase (POD) activities. An earlier differentiation of xylem tissues and a stronger autofluorescence of vascular parenchyma, xylem vessels and rhizodermis were detectable in Spd-pretreated roots as compared with control roots. The same phenomena, except for the autofluorescence of vascular parenchyma, were observed in tipless roots. The reported effects suggest that both Spd pretreatment and tip removal induce a stress that may result in early differentiation, making roots less sensitive to the inhibiting effect of cutting injury on K + uptake.

Soil pH, total organic C, total N, exchangeable Al, available P, CO2 evolution, microbial biomass C and N, phosphatase and dehydrogenase activities were determined in acid soils sampled under spruce subjected to acid deposition, before and after liming. A slight decrease in pH values was observed from the edge of a tree canopy to the base of the trunk in acid soils. Liming drastically reduced exchangeable Al and increased CO2 evolution, microbial biomass, and the metabolic quotient. The microbial biomass C to total organic C ratio increased after liming but did not reach 2%, the average value considered valid in soils where the C content is in equilibrium, that is when C inputs are equal to C outputs. The microbial biomass C:N ratio decreased after liming, thus indicating that bacteria became predominant over fungi when soil acidity decreased. Dehydrogenase activity but not phosphatase activity was increased by liming. The decrease in phosphatase activity was not completely related to the increase in available P, but was also dependent on microbial growth and the decrease in acid phosphatase, the predominant component of acid soils.

The potential use for agronomic purposes of dry olive-mill residue (DOR), solid waste from the olive oil two-phase extraction process, might be impaired by its phytotoxicity. Although fungal treatments can detoxify DOR, long times are required for these processes. The objective of this study was to assess whether the addition of immobilized fungal inocula to DOR might improve colonization rates, thus reducing the time necessary for its detoxification and bioconversion. Inocula of Panus tigrinus CBS 577.79 and Phlebia sp. DABAC 9 immobilized on either chopped maize stalks or polyurethane sponge (PS) led to higher removals of both phenols and phytotoxicity from DOR than free inocula after 4 weeks of incubation. Best dephenolization (85%) was with PS-immobilized Phlebia sp., the use of which reduced germinability inhibition of Lepidium sativum and Lactuca sativa by 80 and 71.4%, respectively. Regardless of the type of inoculant, a low degree of humification was obtained.