Above- and below-ground morpho-physiological traits indicate that biochar is a potential peat substitute for grapevine cuttings nursery production.

The growing demand for grapevine planting materials, due to growing global viticulture, is promoting research studies to improve vineyard sustainability. In greenhouse nurseries, peat is the most common growing medium component used although is an expensive and non-renewable material. Indeed, the reduction of peat exploitation is receiving great attention, and currently, several materials are being investigated as peat substitutes for composing the cultivation substrates. Biochar, a carbon-rich, recalcitrant charred organic co-product of the pyrolysis or gasification process, has emerged as a potentially promising replacement for soilless substrates in nursery plant material propagation. Although several studies carried out at greenhouse nurseries have shown that biochar, can improve plant growth, only a few studies have focused on the production of grapevine plant material. To fulfil this knowledge gap and push forward the sustainability of the nursery sector, we evaluated above and below-ground morpho-physiological traits of one-year-old potted grapevine cuttings growing with 30% volume of four different biochar types (i.e., from pyrolysis and gasification) mixed with commercial peat. The present study shows that biochar can be used in growing media mixes without adverse effects on roots, improves soil water retention and leaf water potential, and improves the effects on soil microbiology.

Long term effect of biochar on soil plant water relation and fine roots: Results after 10 years of vineyard experiment.

Biochar is widely suggested to improve soil physical properties and soil-water-plant interactions. Furthermore, the application of biochar to the soil can alter the dynamics of the roots and, in turn, affect the performance of the plant. Nevertheless, the long-term evolution of these effects is unknown and of critical importance because biochar persists in soil for centuries. The results of this work are part of a long-term study in the vineyard started in 2009 and still ongoing. In this work, the effect of applying biochar to soil on the plant-water relationships of Vitis vinifera, soil properties and fine root traits is evaluated 10 years after application. Even after 10 years, the ecophysiological measurements indicated an increase in soil water content and a significant increase in the water status of the plants in the plots treated with biochar. Independently of the diameter class considered, both doses of biochar led in the entire 40 cm of soil to a general reduction of the fine-root standing biomass and length, which is probably due to the lower need for fine root foraging. Moreover, the SRL did not show differences among different treatments. When fine-root traits were analysed along the soil depth at 10 cm intervals, we noted that both length and biomass were significantly higher in the control plant only in the upper soil layers (20 cm) and SRL was significantly higher only in the upper 10 cm of soil. These findings underscore how control plants plastically respond to the lower content of water in the soil by decreasing the fine-root cost-to-benefit ratio, especially in the topsoil layer. Research on the effect of biochar in viticulture can provide an effective contribution to the mitigation of climate change by increasing the water status of the soil and plants even 10 years after its application.

Seasonal and diurnal variations of greenhouse gases in Florence (Italy): Inferring sources and sinks from carbon isotopic ratios.

In this study, the results of a continuous monitoring of (i) CO2 fluxes, and (ii) CO2 and CH4 concentrations and carbon isotopic ratios (δ13C-CO2 and δ13C-CH4) in air, carried out from 7 to 21 July 2017 and from October 10 to December 15, 2017 in the city centre of Florence, are presented. The measurements were performed from the roof of the historical building of the Ximenes Observatory. CO2 flux data revealed that the metropolitan area acted as a net source of CO2 during the whole observation period. According to the Keeling plot analysis, anthropogenic contributions to atmospheric CO2 were mainly represented by vehicular traffic (about 30%) and natural gas combustion (about 70%), the latter contributing 7 times more in December than in July. Moreover, the measured CO2 fluxes were about 80% higher in fall than in summer, confirming that domestic heating based on natural gas is the dominant CO2 emitting source in the municipality of Florence. Even though the continuous monitoring revealed a shift in the δ13C-CO2 values related to photosynthetic uptake of atmospheric CO2, the isotopic effect induced by plant activity was restricted to few hours in October and, to a lesser extent, in November. This suggests that urban planning policies should be devoted to massively increase green infrastructures in the metropolitan area in order to counterbalance anthropogenic emissions. During fall, the atmospheric CH4 concentrations were sensibly higher with respect to those recorded in summer, whilst the δ13C-CH4 values shifted towards heavier values. The Keeling plot analysis suggested that urban CH4 emissions were largely related to fugitive emissions from the natural gas distribution pipeline network. On the other hand, δ13C-CH4 monitoring allowed to recognize vehicular traffic as a minor CH4 emitting source.

Chemical, biochemical, and microbiological properties of soils from abandoned and extensively cultivated olive orchards.

The abandonment of olive orchards is a phenomenon of great importance triggered mainly by economic and social causes. The aim of this study was to investigate some chemical, biochemical, and microbiological properties in a soil of a southern olive grove abandoned for 25 years. In order to define the effect of the long-term land abandonment on soil properties, an adjacent olive grove managed according to extensive practices was taken as reference (essentially minimum tillage and no fertilization). Soil organic matter, total nitrogen, and pH were significantly higher in the abandoned olive grove due to the absence of tillage and the natural inputs of organic matter at high C/N ratio which, inter alia, increased the number of cellulolytic bacteria and stimulated the activity of ß -glucosidase, an indicator of a more advanced stage of soil evolution. The soil of the abandoned olive orchard showed a lower number of total bacteria and fungi and a lower microbial diversity, measured by means of the Biolog method, as a result of a sort of specialization trend towards low quality organic substrates. From this point of view, the extensive cultivation management seemed to not induce a disturbance to microbiological communities.

Impact of biochar application to a Mediterranean wheat crop on soil microbial activity and greenhouse gas fluxes.

Biochar has been recently proposed as a management strategy to improve crop productivity and global warming mitigation. However, the effect of such approach on soil greenhouse gas fluxes is highly uncertain and few data from field experiments are available. In a field trial, cultivated with wheat, biochar was added to the soil (3 or 6 kg m(-2)) in two growing seasons (2008/2009 and 2009/2010) so to monitor the effect of treatments on microbial parameters 3 months and 14 months after char addition. N(2)O, CH(4) and CO(2) fluxes were measured in the field during the first year after char addition. Biochar incorporation into the soil increased soil pH (from 5.2 to 6.7) and the rates of net N mineralization, soil microbial respiration and denitrification activity in the first 3 months, but after 14 months treated and control plots did not differ significantly. No changes in total microbial biomass and net nitrification rate were observed. In char treated plots, soil N(2)O fluxes were from 26% to 79% lower than N(2)O fluxes in control plots, excluding four sampling dates after the last fertilization with urea, when N(2)O emissions were higher in char treated plots. However, due to the high spatial variability, the observed differences were rarely significant. No significant differences of CH(4) fluxes and field soil respiration were observed among different treatments, with just few exceptions. Overall the char treatments showed a minimal impact on microbial parameters and GHG fluxes over the first 14 months after biochar incorporation.

Multispectral Imaging System for the Mapping of Pigments in Works of Art by use of Principal-Component Analysis.

Image spectroscopy (IS) is an important tool for the noninvasive analysis of works of art. It generates a wide sequence of multispectral images from which a reflectance spectrum for each imaged point can be recovered. In addition, digital processing techniques can be employed to divide the images into areas of similar spectral behavior. An IS system designed and developed in our laboratory is described. The methodology used to process the acquired data integrates spectral analysis with statistical image processing: in particular, the potential of principal-component analysis applied in this area is investigated. A selection of the results obtained from a sixteenth-century oil-painted panel by Luca Signorelli is also reported.

Lossless image compression by quantization feedback in a content-driven enhanced Laplacian pyramid.

In this paper, the effects of quantization noise feedback on the entropy of Laplacian pyramids are investigated. This technique makes it possible for the maximum absolute reconstruction error to be easily and strongly upper-bounded (near-lossless coding), and therefore, allows reversible compression. The entropy-minimizing optimum quantizer is obtained by modeling the first-order distributions of the differential signals as Laplacian densities, and by deriving a model for the equivalent memoryless entropy. A novel approach, based on an enhanced Laplacian pyramid, is proposed for the compression, either lossless or lossy, of gray-scale images. Major details are prioritized through a content-driven decision rule embedded in a uniform threshold quantizer with noise feedback. Lossless coding shows improvements over reversible Joint Photographers Expert Group (JPEG) and the reduced-difference pyramid schemes, while lossy coding outperforms JPEG, with a significant peak signal-to-noise ratio (PSNR) gain. Also, subjective quality is higher even at very low bit rates, due to the absence of the annoying impairments typical of JPEG. Moreover, image versions having resolution and SNR that are both progressively increasing are made available at the receiving end from the earliest retrieval stage on, as intermediate steps of the decoding procedure, without any additional cost.