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Purpose: The environmental impacts of the coffee industry are enormous, with large quantities of solid and liquid wastes generated globally. In the last years, measures have been implemented to valorize spent coffee grounds (SCGs) biowaste as a resource. The present study assessed the unexplored potential use of SCGs as a source of valuable humic substances (HS)-like materials, and linked their antioxidant properties to their chemical composition. Methods: Humic acid-like (HAL) and fulvic acid-like (FAL) were extracted from SCGs and characterized by elemental composition, UV-vis, FTIR, NMR and EPR spectroscopies. Their antioxidant capacity was determined in vitro through the ABTS decolorization assay and voltammetric techniques. Results: Elemental and spectroscopic characteristics were in the range of soil HS. Both HAL and FAL showed a high antioxidant capacity (2.29 ± 0.18 mmole− gHAL−1 and 3.63 ± 0.21 mmole− gFAL−1). The differences in the antioxidant and electrochemical responses of HAL and FAL are related to their chemical structure. Conclusion: The extraction of HS-like with remarkable antioxidant properties makes them a promising low-cost material to be upcycled in the agri-food system as natural fertilizer or novel antioxidants. Statement of Novelty: For the first time, we demonstrated the potential of spent coffee grounds to act as a low-cost source of humic-like substances with enhanced antioxidant capacity. [ABSTRACT FROM AUTHOR]

The removal of copper (Cu) in soils by green technology is less treated with urgency, as it is a plant micronutrient. We examined the efficiency of Cu shoot accumulation by herbaceous plants in Cu-contaminated and non-contaminated soils in Trhové Dusniky and Podles, respectively, in the Czech Republic. The total soil Cu content of 81 mg kg−1 in Trhové Dusniky indicated a slight contamination level compared to 50 mg kg−1, the permissible value by WHO, and < 35 in Podlesí, representing a clean environment. The Cu content was above the permissible value in plants (10 mg kg−1 by WHO) in herbaceous speciesat the control site without trees: Stachys palustris L. (10.8 mg kg−1), Cirsium arvense L. (11.3 mg kg−1), Achillea millefolium L. (12.1 mg kg−1), Anthemis arvense L. (13.2 mg kg−1), and Calamagrostis epigejos L. (13.7 mg kg−1). In addition, Hypericum maculatum Crantz (10.6 mg kg−1), Campanula patula L. (11.3 mg kg−1), C. arvense (15 mg kg−1), and the highest accumulation in shoot of Equisetum arvense L. (37.1 mg kg−1), all under the canopy of trees at the uncontaminated site, were above the WHO value. Leucanthemum Vulgare (Lam.) and Plantago lanceolata L. recorded 11.2 mg kg−1 and 11.5 mg kg−1, respectively, in the soil of the Cu-contaminated site. These herbaceous species can support the phyto-management of Cu-contaminated soils, especially E. arvense. Critical attention is well-required in the medicinal application of herbaceous plants in treating human ailments due to their Cu accumulation potentials above the threshold. Spontaneous surveys and analysis of Cu speciation in herbaceous species can reveal suitable plants to decontaminate soils and provide caution on consumable products, especially bioactive compounds. [ABSTRACT FROM AUTHOR]

Soil microbial biomass (SMB-C) is one of the most frequently used parameters for the assessment of soil quality, but no threshold values have ever been proposed. We challenged the problem of a reliable numerical estimation of the SMB-C based on the knowledge of physicochemical soil properties. The aim was to evaluate artificial neural network (ANN) modelling for the prediction of SMB-C from a range of physical and chemical properties. The dataset used is composed of 231 vineyard soils of widely different characteristics and exposed to different temperature and moisture regimes. Each soil was described by ten physicochemical parameters: sand, clay, soil organic matter, total N, C/N ratio, pH, EC, exchangeable Na, active lime and total Cu. The ANN followed the topology: one input layer (1 to 11 nodes), one hidden layer (2•n nodes) and one output node (SMB-C). Each soil sample was validated against the other 230 samples. The ANN model showed a much better fit than the linear model. The divergence between measured and predicted SMB-C was greatly restrained using the nonlinear approach, testifying the ability of the ANN to adapt to the highly variable dataset. The ANN analysis confirmed the primary importance of SOM for SMB-C prediction, being present in all of the best five models with the lowest root mean square relative error and in four out of five models with the lowest root mean square error. The prediction capability of SMB-C by ANN was limited at high SMB-C values, but the method can potentially be improved by expanding the dataset and introducing more parameters regarding soil physical properties and management. [ABSTRACT FROM AUTHOR]

At the end of October 2018, a storm of unprecedented strength severely damaged the forests of the eastern sector of the Italian Alps. The affected forest area covers 42,500 ha. The president of one of the damaged regions asked for help from the University of Padua. After eight months of discussion, the authors of this article wrote a consensus text. The sometimes asper debate brought to light some crucial aspects: 1) even experienced specialists may have various opinions based on scientific knowledge that lead to conflicting proposals for action. For some of them there is evidence that to restore a destroyed natural environment it is more judicious to do nothing; 2) the soil corresponds to a living structure and every ecosystem's management should be based on it; 3) faced with a catastrophe, people and politicians find themselves unarmed, also because they rarely have the scientific background to understand natural processes. Yet politicians are the only persons who make the key decisions that drive the economy in play and therefore determine the near future of our planet. This article is an attempt to respond directly to a governor with a degree in animal production science, who formally and prudently asked a university department called "Land, Environment, Agriculture and Forestry" for help before taking decisions; 4) the authors also propose an artistic interpretation of facts (uncontrolled storm) and conclusions (listen to the soil). Briefly, the authors identify the soil as an indispensable source for the renewal of the destroyed forest, give indications on how to prepare a map of the soils of the damaged region, and suggest to anchor on this soil map a series of silvicultural and soil management actions that will promote the soil conservation and the faster recovery of the natural dynamic stability and resilience. [ABSTRACT FROM AUTHOR]

Purpose: Humic acids (HA) have several environmental roles, but are particularly important in aquatic environments, being recognized as redox active natural organic matter (NOM) components. We examined NOM in recent sediments of a low-energy coastal environment which is free from inputs of dissolved terrestrial HA as their solubility is suppressed by bonding with Ca2+ ions. Our aim is to investigate the contribution of autochthonous versus terrestrial C sources to HA and their fractions along a river-coastal lagoon transect. Materials and methods: Surface sediments were collected along the Aussa River (R), in the central basin of the Marano and Grado Lagoon (L) and within a secluded lagoon fish farm (FF). Extractable NOM components were obtained by extracting sediments first with 0.5 M NaOH (free NOM) and then with 0.1 M NaOH plus 0.1 M Na4P2O7 (bound NOM). Extracts were separated into non-humic and humic fractions by solid phase chromatography. Organic carbon (Corg), total nitrogen (Ntot), δ13C, and δ15N were determined with an Isotope Ratio Mass Spectrometer (Thermo Scientific Delta V Advantage) coupled with an Elemental Analyzer (Costech Instruments Elemental Combustion System). Fourier-transform infrared (FTIR) spectra were recorded with a FT-IR100 PerkinElmer Spectrometer. UV-vis spectra were recorded at pH 7 by a Varian Cary Spectrophotometer. Results and discussion: Both NOM and HA display typical traits of terrestrial origin in river sediments and of a more marine (algal) origin in lagoon and fish farm sediments. This trend is evident in free HA, whereas bound HA seem more influenced by terrestrial inputs. A larger proportion (60–70%) of non-humic C was extracted by NaOH in all samples. Bound HA differ from free HA for their C/N ratios, which are higher and vary within a much narrower range. The changes in HA's 13C isotopic composition, FTIR spectra, and spectroscopic parameters (SUVA254, SR, and aromaticity) highlight a progressive mixing of terrestrial and marine substrates that either undergo in situ humification or are transported as materials sorbed onto suspended mineral particles. Conclusions: Our results highlight the existence of a complex, but continuous pattern of terrestrial and marine contributions to C sequestration and humification even in transitional environments where allochthonous humic C inputs are restricted due to insolubilization of humic substances by Ca2+. Along the examined transect, the NOM and free and bound HA appear well differentiated. Terrestrial inputs contribute to the bound HA fraction via transported mineral particles in all the samples, no matter the environment encountered. [ABSTRACT FROM AUTHOR]

Saltmarshes are recognised worldwide to be among the most complex ecosystems, where several environmental factors concur to sustain their fragile functioning. Among them, soil-plant interactions are pivotal but often overlooked. The aim of this work was to use a structural equation modelling (SEM) approach to get new insight into soil-plant interactions, focusing on the effect of plant traits and abundance on soil, and test the effect of soil and/or plants on the entire community, monitoring changes in plant richness. The target halophytes Limonium narbonense and Sarcocornia fruticosa were sampled in the Marano and Grado lagoon (northern Adriatic Sea). Basal leaves of L. narbonense and green shoots of S. fruticosa were used to estimate plant growth, while the abundance of both species was used as a proxy of species competition. SEM was applied to test relationships between predictors and response variables in a single causal network. The flooding period (hydroperiod) negatively affected plant growth and soil properties, whereas plants decreased the intensity of soil reduction. Flooding did not directly affect species abundance or diversity, whose changes were instead driven by plant traits. The direct relationships between plant traits and species richness highlighted that species competition could be even more important than environmental stresses in defining plant diversity and zonation. [ABSTRACT FROM AUTHOR]

Purpose: The relationship between soil properties and plant communities was investigated in a saltmarsh of the Grado and Marano lagoon (northern Italy), where hydrology and micromorphology strongly influence the features of the ecosystem. A multidisciplinary approach was used to assess the change of soil properties and plant communities in relation to the submergence of soil. Materials and methods: The plant community and soil profile surveys were both carried out along a transect in six sampling sites of the Gran Chiusa saltmarsh (Grado and Marano lagoon). The morphological and physicochemical parameters of soil profiles were investigated, and soils were classified according to Soil Taxonomy. The concentration of macronutrients in both soils and plants was analysed by inductively coupled plasma-optical emission spectrometry. Cluster and linear discriminant analysis were used to assist the interpretation of the data of plant communities and soil properties, respectively. The bioconcentration factor explored the macronutrient relationship between plant community and soil. Results and discussion: A high, middle and low zone were identified by clustering the different plant communities along the studied transect. Discriminant analysis showed how the increase in soil submergence supported the accumulation of S and Ca content and depletion of Fe and Na. The development of different plant communities was linked to both soil water saturation and to the capacity of halophytes to tolerate anoxic conditions or salinity, by extrusion or bioconcentration strategies. Conclusions: This study demonstrates that tide level plays an important role in the pedological development and chemical transformations along a soil hydrosequence. The micromosaic vegetation pattern may therefore represent a useful index of the hydrological and nutritional status of the underlying soils and could be used to predict changes in coastal ecosystems. [ABSTRACT FROM AUTHOR]

The fate of cyanides in soil is strongly influenced by the formation of Fe cyanides, which can interact with organic and inorganic colloids and precipitate as stable compounds. Scarce information is available on the capacity of humic acids to interact with cyano-complexes and thus affect the leaching and prevent the risk of contamination of watertable. Here we show that interaction between humic acids (HAs) and ferricyanide complex led to a formation of ferricyanide-humo micelles, and that the interaction did not imply changes in the original structure of ferricyanide complex. [ABSTRACT FROM AUTHOR]

An obituary for soil scientist David Jenkinson is presented.