Laser-Induced Breakdown Spectroscopy (LIBS) is a fast and reliable technique suitable for the simultaneous qualitative and quantitative analysis of major and trace elements in samples of various nature and origin. In last decades, the use of metal accumulator plants, in combination with compost, has become a cheap and sustainable alternative technique to lower soil contamination by toxic heavy metals. In the present work, the LIBS technique has been applied to measure the concentrations of selected elements, including Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Sr, and Zn, in two composts of different origin and nature and four accumulator plant species (Atriplex halimus, Brassica alba, Brassica napus, and Eruca vesicaria). The plant samples were analyzed either as bulk plant material or as specific organs (i.e., shoots and roots). The concentrations measured by LIBS were assessed by the complementary Induced Coupled Plasma - Optical Emission Spectroscopy (ICP-OES) technique. The significant correlation found between the data obtained by the two techniques (R = 0.732-0.999) supports the feasibility of LIBS for fast screening of major, trace and toxic elements in plant and compost samples. In conclusion, the LIBS technique shows promising for further applications in soil remediation as well as in agriculture.

Peatlands are archives of extreme importance for the assessment of past ecological, environmental and climatic changes. The importance as natural archives is even greater in the case of ombrotrophic peat bogs, where the only inputs are atmospheric in origin. Here we integrated previously published physical and chemical results regarding the solid and liquid phase of peat with a biomolecular microbiological approach to assess the relationships between chemistry and microbial biodiversity along a Swiss bog profile corresponding to approximately 2,000 years of peat formation. The structure of bacterial and archaeal communities was assessed through a polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach followed by sequencing of PCR-DGGE bands of interest. Both chemical and microbiological data showed a differentiation of properties along the peat profile, with three major zones identified. Both bacterial and archaeal profiles clustered according to the depth (i.e., age) of samples. Among bacteria, Acidobacteria were recovered primarily in the first layers of the profile, whereas methanogenic archaea were more commonly recovered in the deepest part of the core, corresponding to the occurring anoxic conditions. Finally, a number of sequences had low homologies with known species, especially in bacteria: this points to an almost unknown microbial community adapted to the extreme conditions of peat bogs, which are acidic, rich in dissolved organic C, and predominantly anoxic.

With 6.5 m of peat accumulated during the past ca. 15,000 years, Etang de la Gruère (EGr) represents the longest continuous record of atmospheric dust deposition in northern hemisphere. This paper presents a comparative study of the mineralogical composition of Sphagnum peat samples and their corresponding humic acids (HA) from a peat core collected at EGr bog. The purpose of this study was to better understand the dominant process responsible for the amount and distribution of mineral matter in ombrotrophic (i.e., rain-fed) peat. Specifically, the goal was to separate the relative importance of the changing rates of atmospheric mineral dust deposition (during the past two millennia) from the mineralization of organic matter (OM), for the distribution of the ash fraction of the peat profile. The results suggest that variations in ash content at EGr are mainly the result of an increase in the rate of supply of dust particles and cannot be attributed simply, or exclusively, to differences in the degree of OM decay: evidence is provided by both acid insoluble ash (AIA) profiles and the correlations among lithogenic elements (Al, Si, Ti, Y, and Zr), total ash content and AIA. Moreover, our findings suggest that part of the AIA occurring in peat extremely is stable, and is unaffected by the extreme chemical conditions used to extract the HA fraction: this may be partly due to the inherent stability of quartz and “heavy minerals” such as zircon and rutile, but organic coatings developed on mineral surfaces during peat diagenesis, or the formation of some other kind of organo-mineral complex, might also play a role. Consequently, testimonies of past dust depositions can be observed also into the recalcitrant HA fraction of the peat.

Residues of the marine plant posidonia (Posidonia oceanica, PO) beached in tourist zones represent a great environmental, economical, social and hygienic problem in the Mediterranean Basin, in general, and in the Apulia Region in particular, because of the great disturb to the bathers and population, and the high costs that the administrations have to bear for their removal and disposal.In the present paper, Authors determined the heating values of leaves and fibres of PO, the main offshore residues found on beaches, and, meantime, composted those residues with mowing and olive pruning wood. The final composts were characterized for pH, electrical conductivity, elemental composition, dynamic respiration index, phytotoxicity, fluorescence and infrared spectroscopic fingerprints.The aim of the paper was to investigate the composting and energy recovery of PO leaves and fibres in order to suggest alternative solutions to the landfill when offshore residues have to be removed from recreational beaches.The fibrous portion of PO residues showed heating values close to those of other biofuels, thus suggesting a possible utilization as source of energy.At the same time, compost obtained from both PO wastes showed high quality features on condition that the electrical conductivity and Na content are lowered by a correct management of wetting during the composting.

Although several studies have used bogs in order to reconstruct paleoclimatic conditions and the historical trends of pollutants, scientific literature is still rather controversial about the role of ombrotrophic bogs as reliable record of past environmental changes. Consequently, understanding whether all vegetational and climatic ginformationh are effectively preserved in peat deposits during humification becomes an essential aspect to be tested before using bogs as natural archives. The present work focuses on stable isotopic ratios, i.e., 13C/12C (ƒÂ13C), 15N/14N (ƒÂ15N) and 18O/16O (ƒÂ18O), and is based on the assumption that, if bogs are consistent archives of environmental changes, these types of ginformationh should be recorded also into humic acids (HA), i.e. the fraction of peat more recalcitrant and refractory to degradation. Thus, an 81-cm long peat core, covering the last 2000 years, was collected from the Etang de la Gruere bog (Jura Mountains, Switzerland), cut into 3 cm slices, and HA were isolated from each age dated layer. Stable isotopic ratios (ƒÂ13C, ƒÂ15N and ƒÂ18O) were then determined in bulk peat and corresponding HA samples. An increase in the humification degree and a decrease of the C/N ratio were observed along the profile. The ƒÂ13C of both peat and HA showed a significantly similar trend with depth (p=0.0001), and the same significant correlation was observed for the ƒÂ15N (pb0.0001). Also the ratio between ƒÂ13C and ƒÂ15N closely resembled the C/N ratio observed in the peat and in HA (pb0.0001), thus underlining that the trend of these isotopic ratios is preserved along the studied bog profile. Consequently, our data seem to support both the role of HA as recalcitrant, stable molecules with a long-term residence time, and the potential of ombrotrophic bogs to be used as garchivesh of vegetational changes occurring (at least) in the last 2000 years. Although a certain relationship (pb0.05) between peat and corresponding HA was found also for ƒÂ18O, our data did not allow the solving of the issue of its reliability as paleoenvironmental proxy.

Posidonia oceanica (L.). Del. is the main marine seagrass endemic of the Mediterranean Sea. From September on, leaves and rhizomes detach off the marine plant and accumulate on beaches in huge amount. Offshore residues represent an environmental, economical, social and hygienic problem because of the great disturb to the bathers and citizens and high costs that the public administrations have to support for managing them. Nowadays, current Italian legislation (D. L. n. 75/2010) allows the use of posidonia residues as raw material for the production of compost even though at a rate of 20% by weight. In an experiment posidonia residues have been used to produce green compost. This was used as a substrate for the cultivation of tomatoes in soilless subirrigation system. Plants grown on compost showed a lower production (18%) compared to perlite: peat (control), but fruits had the same quality characteristics (as dry matter and soluble solids). On the other hand, the same compost represented a viable alternative to peat when used for the production of lettuce transplants. In particular, lettuce seedlings grown on compost showed higher fresh and dry weight of leaves and roots, length and volume of the root system, and leaf area, if compared with those grown on peat alone.

Introduction Ash peaks along ombrotrophic bog profiles may arise from several different processes. In a recent paper, Leifeld and co-authors (Plant Soil 341:349–361, 2011) argued that ash peaks along the Etang de la Gruère (EGr) peat bog profiles are signs of previous periods of higher peat decomposition rather that an indication of periods of elevated dust inputs.

Posidonia (Posidonia oceanica [L.] Delile) is a marine phanerogam endemic of the Mediterranean basin. Senescent plant parts periodically detach from and accumulate along Mediterranean beaches, forcing the coastal municipalities to remove and manage somehow the large amount of beached biomass. In this research, a posidonia based compost (posidonia, 63% by volume - olive tree pruning residues, 21% - green waste, 16%) has been used as growing media component at different ratios (0, 25, 50, 75 and 100%), as a complement to a peat based commercial substrate, for nursery lettuce seedlings production. Growing media with increasing compost percentage showed higher pH, EC, air capacity and nutrients availability, but lower water holding capacity. The overall growth of the seedlings was enhanced by the compost presence in the substrate, with positively evidences for both roots and leaves. Posidonia based compost could represent an interesting alternative to peat as horticultural growing media component.

Melia azedarach fruit extracts have recently raised a substantial interest for their use in crop protection against phytoparasitic nematodes. The effect of M. azedarach on the root-knot nematode Meloidogyne incognita on cucumber, as well as the effect on the plant deference mechanism, is reported herein. Crushed fruits of M. azedarach, tested in the soil at the rates of 30 and 60 g kg−1, exhibited nematicidal activity similar to the one of fenamiphos (0.02 g a.i. kg−1) in terms of nematode population in roots and soil as well as reproduction rate. M. azedarach water extracts, rich in aldehydes, alcohols and carboxylic acids, showed nematicidal activity against M. incognita. Moreover, all M. azedarach treatments decreased the activities of catalase (CAT) and peroxidase (POX) involved in host H2O2 detoxification. Soil application of M. azedarach fruits could be favourably considered in the control of M. incognita on cucumber in a sustainable agriculture, since they act directly as nematicidals. Furthermore, M. azedarach elicits plant defence and helps the host to fight the nematodes infestation in an indirect way.

Laser Induced Breakdown Spectroscopy (LIBS) is a fast and multi-elemental analytical technique particularly suitable for the qualitative and quantitative analysis of heavy metals in solid samples, including environmental ones. Although LIBS is often recognised in the literature as a well-established analytical technique, results about quantitative analysis of elements in chemically complex matrices such as soils are quite contrasting. In this work, soil samples of various origins have been analyzed by LIBS and data compared to those obtained by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The emission intensities of one selected line for each of the five analytes (i.e., Cr, Cu, Pb, V, and Zn) were normalized to the background signal, and plotted as a function of the concentration values previously determined by ICP-OES. Data showed a good linearity for all calibration lines drawn, and the correlation between ICP-OES and LIBS was confirmed by the satisfactory agreement obtained between the corresponding values. Consequently, LIBS method can be used at least for metal monitoring in soils. In this respect, a simple method for the estimation of the soil pollution degree by heavy metals, based on the determination of an anthropogenic index, was proposed and determined for Cr and Zn.

BACKGROUND: Peat is the main component of growing media but is also a non-renewable resource; therefore European policy strongly encourages the use of peat alternatives such as compost. Posidonia is a Mediterranean seagrass that produces very conspicuous onshore deposits that can be composted. In this study, a commercial green compost and a Posidonia residue-based compost were tested in order to assess their potential use as substitutes or complements to peat. RESULTS: All macro and micro-element concentrations of the substrates were positively and significantly related to the percentage of composts in the growing media. Plant grown on peat showed higher content of P, Ca, K, Na, Cu, Mn, Zn and Fe, and a slightly higher biomass production in comparison to compost-based growing media. In contrast, plants grown on compost-based substrates showed lower uptake of Cd and Cr than peat. CONCLUSION: The results indicate that both composts can be used as a complement to the peat for substrate preparation, especially at a rate of 30%. The Posidonia-based compost showed better productive results in Comparison to the green one. Basil grown on the two compost-based media showed reduced absorption level of potentially toxic metals in comparison to peat.

Posidonia [Posidonia oceanica (L.) Delile] is a marine phanerogam endemic of the Mediterranean Sea that grows all along the coast forming extensive underwater meadows. Senescent posidonia leaves, together with fibers (residues of rhizomes and decomposed leaves), periodically accumulate along Mediterranean beaches, covering vast areas of coast. Removal and disposal of these large volumes of plant biomasses represent a high cost for local administrations. Therefore, in this experiment, beached residues of posidonia were composted with olive pruning and green wastes with the objective to assess the efficacy of posidonia-based compost (63% on a volume basis) as a peat replacement. The compost was then mixed with a peat-based commercial substrate at rates of 0% (C0, pure peat-based commercial substrate tested as control), 25% (C25), 50% (C50), 75% (C75), and 100% (C100, pure posidonia-based compost) v/v. Mixtures were used as growing media to produce lettuce seedlings for transplant. Two lettuce cultivars (8511RZ and Satine) were tested. Main physical and chemical properties of the five growing media, shoot and root fresh and dry weight, leaf area, root morphology, and elemental leaf tissue composition were studied. Growing media containing posidoniabased compost, C25 and C50 in particular, showed good physical properties. Increasing compost proportions in the mixtures resulted in enhanced: 1) availability of macro- and micronutrients in the growing media; and 2) overall growth parameters of lettuce seedlings, in particular for the cultivar Satine. In conclusion, posidonia-based compost shows a considerable potential as a peat substitute in horticultural substrates; posidonia residues are a low-cost renewable material. In growing media for lettuce seedlings production, posidonia-based compost could be used as a complement to peat at a rate of 25% or 50% to obtain optimal physical properties and to limit the negative effects of high B content, which are typical of posidonia residues.

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