196,309 research outputs found
High resolution chemical stratigraphies of atmospheric depositions from a 4 m depth snow pit at dome C (East Antarctica)
No full textIn this work, we present chemical stratigraphies of two sampling lines collected within a 4 m depth snow pit dug in Dome C during the Antarctic summer Campaign 2017/2018, 12 years after the last reported snow pit. The first sampling line was analyzed for nine anionic and cationic species using Ion Chromatography (IC); the second sampling line was analyzed for seven major elements in an innovative way with Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) after sample pre-concentration, allowing the study of deposition processes of new markers especially related to crustal source. This coupled analysis, besides confirming previous studies, allowed us to investigate the depositions of the last decades at Dome C, enriching the number of the detected chemical markers, and yielding these two techniques complementary for the study of different markers in this kind of matrix. As a result of the dating, the snow layers analyzed covered the last 50 years of snow depositions. The assessment of the accumulation rate, estimated about 9 cm yr−1, was accomplished only for the period 1992–2016, as the eruption of 1992 constituted the only tie-point found in nssSO42− depth profile. Na, the reliable sea salt marker, together with Mg and Sr, mainly arose from marine sources, whereas Ca, Al and Fe originated from crustal inputs. Post-depositional processes occurred on Cl− as well as on NO3− and methanesulfonic acid (MSA); compared to the latter, Cl− had a more gradual decrease, reporting a threshold at 2.5 m for the post-depositional process completion. For NO3− and MSA, instead, the threshold was shallower, at about 1 m depth, with a loss of 87% for NO3− and of 50% for MSA
Co-application of wood distillate and biochar improves soil quality and plant growth in basil (Ocimum basilicum)
No full textBackground: Nowadays, an ever-increasing attention toward eco-friendly and sustainable agricultural practices, such as the use of biological fertilizers that do not alter the ecological balance of soil, has been grown worldwide. Aim: To evaluate the effect of wood distillate (WD), biochar (B), and their combination (BWD) in increasing soil biomass, soil biological activities, and plant growth in basil (Ocimum basilicum L.) by determination of plant biomass. Methods: Plants of basil were cultivated in greenhouse with three different amendments. WD was applied at a 1% dilution through fertigation. B was applied at a rate of 2% (w/w) corresponding to 34 t ha–1. Organic carbon (OC), dissolved organic carbon (DOC), soil microbial biomass carbon (MB-C), and enzymatic activities (dehydrogenase, phosphatase, arylsulfatase, β-glucosidase, and urease) were determined at the end of the cultivation period (4 weeks) in bulk soil and in the rhizospheric soil. The alteration index three (AI3), which calculates the balances between three enzymes and potentially allows to quantify in relative terms the differences between soils due to different management practices, was also determined. Results: WD and B significantly increased OC and MB-C content, whereas B preferentially retains soil DOC species and the organic substance of the WD in the BWD treatment. Phosphatase and urease activities were the most increased with the combination of the two amendments. AI3 in controls suggests that the application of WD and B at the right doses promotes the activity of soil microorganisms, enhancing the soil biological quality. Conclusion: The presence of the two organic sources increased the availability of nitrogen and phosphorus, with a positive response in terms of basil dry biomass. WD and B have been confirmed as suitable and sustainable amendments for potential application in crops cultivation
Il biochar e il suo potere fertilizzante: una opportunità per l'uso ecosostenibile del suolo agrario.
No full textUsing Biochar and Vermiwash to Improve Biological Activities of Soil
No full textThe recycling of key nutrients and bioenergy from waste materials is a goal of sustainable agriculture. The co-application of biochar and a vermicompost solution (vermiwash) could enhance the positive effects of both materials on soil biomass and biological activities. Tomato plants were grown in soil amended with biochar, mixed at a rate of 2% w/w, and vermiwash, applied through fertigation at a rate of 25 mg per plant, alone (B and V) and in combination (BV). Organic C, dissolved organic C (DOC), soil biomass C, and some enzymatic activities were determined at the start (T0) and the end (T100) of the cultivation period in bulk soil and rhizosphere soil. B and V significantly increased the organic C and soil biomass contents. In addition, B retained the DOC species derived from the soil and, in the BV treatment, also the humic substance of the vermiwash. Generally, all the parameters achieved higher values in the rhizosphere than in the bulk soil. The altered soil index three (AI3) of enzyme activities suggests that applying V and B is helpful for the soil microorganisms. Synergisms between B and V were low in the bulk soil and clearly evident in the rhizosphere
Effects of combined biochar and vermicompost solution on leachate characterization and nitrogen balance from a greenhouse tomato (Solanum lycopersicum) cultivation soil
No full textBoth biochar (B) and vermicompost (V) can provide the soil with soluble organic matter. We evaluated the effect of B in reducing nitrate and dissolved organic carbon (DOC) losses from soil via leaching together with the effect of B combined with V solution (vermiwash) in increasing the efficiency of plant nitrogen. Tomato plants (Solanum lycopersicum L.) were cultivated in a greenhouse with soil under three different amendments (B, V and a mix BV). B was applied at a rate of 2% w/w corresponding to 34 t ha−1. V was applied at 25 mg per plant through fertigation. Leachate and soil were monitored in terms of nitrates and DOC throughout the trial (120 days), and plants and fruits were monitored in terms of nitrogen balance index (NBI) and dry matter biomass. B and BV significantly decreased NO3–_N content in the leachate in all recovered times by 66.8% and 71.3%, respectively. In contrast, the absence of biochar in the V treatment led to a 38.1% increase in NO3–_N concentration. Similar results were found for DOC content. The dry biomass of plants increased in B and BV treatments by 19.5 and 28.7%, respectively. The dry biomass of tomato fruits was enhanced by 18.5, 12.1, and 37% in V, B and BV treatments, respectively. Synergisms were found between the char material and complex organic compounds derived from the vermicompost process in terms of safeguarding the quality of the soil, the underground water, and the sustainability of crops. © 2021 Taylor & Francis Group, LLC
Biochar impact on the estimation of the colorimetric-based enzymatic assays of soil
No full textThis study was carried out in order to assess the influence of biochar applications on
the estimation of colorimetric-based
enzymatic assays and to verify the effectiveness
of the most common methods. Since most methods used to determine enzymatic
activities in the soil are based on colorimetry, biochar may absorb substrates and/
or coloured products thereby distorting the analytical result. Biochar was added to
two soils, with different textures and cation exchangeable capacities, at a rate of
2% (w/w), and seven enzyme activities were determined following standard methods.
The biochar amendment lowered the spectrophotometer reading of the activity
of FDAase and dehydrogenase in the sandy soil. In the three enzymatic activities
based on p-nitrophenol
production (β-glucosidase,
phosphatase and arylsulphatase),
the addition of biochar did not change the enzyme assays. The biochar led to an
overestimation in terms of the protease and urease activities in the sandy soil. In the
clay loamy soil, biochar did not change the response of any of the enzyme activities
tested. A biochar dose of up to 2% only guarantees the effectiveness of the most common
spectrophotometric methods for not excessively sandy soils
Tra scienza, arte e diletto. Collezioni naturalistiche nella Toscana di Cosimo III
No full textSi tratta dell'intervento presentato al convegno "La Toscana dell'età di Cosimo III: un modello di assolutismo europeo" organizzato dal Dipartimento di Storia moderna e contemporanea dell'Università di Pisa e dall'Istituto Universitario Europeo (Pisa-San Domenico di Fiesole, 4-5 giugno 1990
Integrative Effect of UV-B and Some Organic Amendments on Growth, Phenolic and Flavonoid Compounds, and Antioxidant Activity of Basil (Ocimum basilicum L.) Plants
No full textThe application of organic amendments, biochar, and wood distillate (WD), as well as the exposure to UV-B radiation, are two sustainable ways to enhance soil fertility and increase plant nutraceutical quality, respectively. However, they have always been studied separately, without testing the eventual synergistic or antagonistic effect when applied together. The present study investigated the effects of biochar (2% w/w), WD (1:100), and their combination (BWD) on some biometric and biochemical parameters of basil plants (Ocimum basilicum L.) exposed to different doses of UV-B radiation (0, 1, 2 h d−1; UV-B irradiance of 1.36 W m−2) in controlled conditions. Root and stem length and weight were not affected by soil amendments, while 1 h d−1 UV-B increased the length (+28%) and weight (+62%) of the aerial part. When combining the above- and below-ground factors, a decrease in root length was observed in the 2 h d−1 UV-B-treated plants in both WD (−36%) and BWD (−39%) treatments. The co-application of below- and above-ground treatments generally decreased phenolic and flavonoid concentration in both fully expanded leaves and vegetative shoot apices. This preliminary study highlights an antagonistic action of the combination of the investigated factors, at these doses, on the plant growth and metabolism that should be considered
Effetti del biochar sulla mineralizzazione della sostanza organica del suolo: prove di laboratorio.
No full textUna potenziale via di abbattimento dei livelli crescenti di CO2 nell'atmosfera è l'uso della pirolisi per convertire la biomassa vegetale in una forma più stabile di carbonio (biochar), che può poi essere applicato al suolo.
Allo scopo di valutare l'interazione tra biochar e sostanza organica del suolo e di mettere in evidenza eventuali priming effects indotti dal materiale, è stata effettuata un’incubazione di breve periodo, in laboratorio, trattando un suolo con dosi di applicazione di 0, 2, 4, 6, 8 e 10% in peso, misurando per 21 giorni la respirazione microbica mediante lo sviluppo di CO2.
Gli effetti del biochar sulla mineralizzazione della sostanza organica nativa (priming effect) sono stati valutati attraverso la comparazione tra il rilascio di CO2 dal suolo (controllo) e quello misurato nelle miscele di biochar e suolo. A tal fine è stata calcolata una retta di regressione con i dati cumulativi di C-CO2 emesso dalle miscele biochar–suolo rispetto al C fornito con il materiale, che ha permesso di stimare il C-CO2 emesso ad una dose di applicazione pari a zero. Il valore ottenuto è stato infine confrontato con il corrispondente dato misurato nel controllo, ottenendo così il priming ratio.
I risultati mostrano che dal suolo ammendato con biochar è stata rilasciata una maggior quantità di carbonio sottoforma di CO2 rispetto al controllo, con aumenti lineari rispetto alla quantità di C aggiunto.
L’assenza di priming effect, confermato dal valore prossimo a 1 del priming ratio, indica che l’incremento di CO2 non proviene da un maggior rilascio di carbonio della sostanza organica nativa e quindi che una frazione del carbonio del biochar viene perduta per respirazione microbica. La perdita di C da parte del biochar, pari a circa 0.006%, è tuttavia molto modesta e, vista la netta tendenza alla diminuzione nell’entità della mineralizzazione già durante la breve durata dell’incubazione, è presumibile che le perdite di C del materiale nel lungo periodo siano nettamente inferiori alla quantità dell’elemento aggiunto al suolo con l’ammendamento. Considerato il lunghissimo tempo medio di residenza nel suolo del carbonio del biochar, il modesto rilascio di carbonio per respirazione microbica non pare quindi compromettere la capacità del materiale di contribuire al sequestro di C nell’ecosistema suolo
I gesuiti e il principe. Il modello francese nella politica dell'assistenza di fine Seicento
No full textGrazie a ricerche effettuate negli archivi francesi, si attribuisce la paternità delle iniziative assistenziali in Francia e in alcuni Stati italiani alla fine del XVII secolo al gesuita Chaurand, anziché al suo allievo Guevarre
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