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Mobilization and plant uptake of chromium after application of tannery sludge derived fertilizers: 2-year trials in north Italy.
No full textAn organo-mineral fertilizer containing both mineral NP and organic N materials, the last one prepared by composting sewage sludges and skins residues from a leather processing industry, was compared with a mineral NP fertilizer and a control without added N. Field (wheat, maize and rice) and lysimeter (rice) trials were performed on the same randomised complete block design.
Cr(VI) concentration in the organo-mineral fertilizer was <0.4 μmoles, in accordance to Italian Rules, and before and after cropping Cr(VI) content of experimental soils was <1 μmoles, threshold law limit, beyond which the oxidation of Cr(III) to Cr(VI) most likely occurs. It s believed that pH and OM are the main factors affecting the fate of chemical forms of Cr in the soil-plant system, shifting the equilibrium of Cr reactions in the soil to the more reduced and insoluble form.
Throughout the 2-year experiment, total Cr concentration in the soils did not exceed the controls, but it was observed a significant (p<0,01) increase of the soil available Cr fraction (extracted by K2HC6H5O7) after wheat and maize cultivation, probably due to the more acid conditions of the rhizosphere in the upland than in the wetland soils.
Cr concentrations ≤1 ppm were observed in wheat plants, as Pratt (1966), with no correlation of plant Cr with soil Cr both as total (Adriano, 2001) and potentially soluble forms; significant differences (p<0.05) were observed for Cr between straw and grain, the former higher than the latter, irrespective of the treatment. A multivariate analysis (two-tails SKN with Pearson coefficients) showed an inverse correlation straw/grain (p<0.05; r = -0.592, df = 8), which can be regarded as a barrier effect , as stated by Smith and Huyck (1999). In maize grain Cr concentration was less than the instrumental detection limit and in stalks no significant difference was observed between treatments, suggesting the presence of a barrier effect too.
The evaluation of Cr mobility in the soil-plant system, as measured by soil-plant transfer factors, gave very low values (0.002-0.003 for wheat and 0.006-0.009 for maize) irrespective of the treatments, confirming the very low mobility of this metal as stated by Sauerbeck (1989).
In rice plants the tannery sludge derived fertilizer determined a consistent and significant (p<0.01) increase of Cr concentration in roots, showing that total and potentially soluble Cr(III) in the flooded soil was not correlated with root accumulation. In spite of this, Cr was not significantly translocated to the straw and the grain, indicative of a transport barrier through the upper parts of the rice plant. Accordingly, soil to plant transfer factors of chromium were similar to those of the comparing treatments, ranging from 0.003 to 0.01, throughout the 2-year experiment. Only the values obtained for Cr total uptake (g ha-1) in the upper part (grain + straw) were similar or greater than those of the mineral NP treatment.
In the lysimeter study, when the heavy metal distribution was expressed as a percentage in plant parts, the main accumulation was found in the roots, i.e. 80% of total plant Cr, and only about 7% in the grain, independent of Cr treated and untreated tanks. Lysimeter study also showed that total dissolved Cr in leachate samples, collected during the growing season, was unaffected by the application of the tannery sludge derived fertilizer.
Although Cr uptake by grain crops, such as wheat, maize and rice, seems to be unaffected after 2-years application of the tannery sludge derived fertilizer and the relatively inert nature of Cr(III) in soil chemistry, showed by the very low solubility and strong soil-plant barrier, longer-term field studies are recommended to verify if bound chromium could be released to soluble forms and becoming a threat for water quality through potential leaching
Food traceability using the 87Sr/86Sr isotopic ratio mass spectrometry
No full textToday, food traceability, needs to develop suitable “robust “ analytical methods, in terms of the precision and of the reliability of results, which can support modern legislative tools, aimed at guaranteeing food authenticity and origin and trying to avoid possible frauds. This review paper highlights the most recent results obtained with the use of the 87Sr/86Sr isotopic ratio technique, when applied to the traceability of the origin of different foods for human consumption, such as vegetables, beverages, dairy products, meat and fish products. The instrumental techniques, with the relative methodologies and the quality of the final results, will be examined and commented
Uso del modello RothC per descrivere la dinamica della SOC nella gestione di pratiche di fertilizzazione in un inceptisuolo franco-limoso del nord Italia
No full textLo scopo del presente lavoro è valutare l’idoneità del modello RothC a simulare la dinamica del carbonio organico del suolo (SOC) su 12 anni di pratiche di fertilizzazione organica e/o minerale in un Inceptisuolo di un’azienda sperimentale della regione Emilia-Romagna, sita a Gariga di Podenzano (PC), nella Pianura Padana (Nord Italia), con rotazione pomodoro, mais ed erba medica.
Il modello ha consentito di descrivere le dinamiche della SOC in presenza di letame (aumenti significativi), borlanda (diminuzioni lievi) e nessun apporto organico (diminuzioni significative) evidenziando l’importanza della fertilizzazione organica, in particolare letame, per mantenere buoni livelli di SOC
Effetti di 3 anni di somministrazione di liquami suinicoli su contenuti e distribuzione del Kscamb in 3 diversi pedotipi della pianura piacentina
No full textel bilancio nel sistema suolo-pianta del potassio apportato
continuativamente per un triennio con applicazioni di 60 t N ha-1 anno-1 con
liquami suinicoli, effettuate in epoche diverse dell’anno, su una
monocoltura di mais (Zea Mais L.), per confronto con 2 tesi ad esclusivo
apporto di azoto minerale ed un testimone non fertilizzato. Le prove sono
state effettuate sui 3 pedotipi in altrettante aziende site nella pianura
piacentina, caratterizzati da differenti valori di potassio scambiabile, pH,
sostanza organica, carbonati e a differente tessitura
Application of Roth Carbon model over 50 years under a rotation tomato-maize on a silty loam soil
No full textStarting from the management data from 10 ten years of fertilization practices on a silty-loam soil where RothC model proved to be suitable to simulate SOC dynamics (see Symposium 7.8), the model was applied to simulate the SOC trend over 50 years, on the same soil type under a baseline climate generated with LarsWG5, assuming a biennial rotation tomato-maize with additions of 50 t ha-1 and 40 t ha-1 of FYM respectively. Since the behaviour of SOC in RothC is affected mainly by the clay content, four clay classes were identified to verify the effectiveness of the proposed rotation for SOC increase: clay10 (<10%clay); clay15 (10-15% clay); clay 20 (15-20% clay); clay 25 (20-25% clay). For clay 10 a significant decrease of SOC was observed (-6.0 ± 2.2 t ha-1); for clay 15 a nearly steady-state (-1.1 ± 0.9 t ha-1); for clay 20 (+5.2 ± 2.2 t ha-1) and clay 25 (+10.8 ± 4.7 t ha-1) a significant increase of total C. Results have shown that under these specific pedoclimatic conditions, the proposed rotation has increased the SOC levels only at higher clay contents in comparison with the traditional rotation (including maize, tomato and alfalfa with and without organic inputs)
Cap 37 (Ottica ondulatoria) e Cap 38 (Figure di diffrazione e polarizzazione) nella 5° ed. di FISICA di Serway & Jewett
No full textTopics dei paragrafi tradotti:Cap 37: L'esperimento di Young della doppia fenditura; Modello di analisi:interferenza delle onde; Distribuzione dell'intensità nella figura di interferenza da doppia fenditura; variazione di fase dovuta alla riflessione; interferenza in lamine sottili; l'interferometro di Michelson. Cap 38.Introduzione alle figure di diffrazione; figure di diffrazione da fenditure sottili; risoluzione di singole fenditure e di aperture circolari; il reticolo di diffrazione; diffrazione di raggi X da cristalli; polarizzazione delle onde luminose
Soil and sediment analysis by spectroscopic techniques. Part II: determination of trace elements by ICP-MS
No full textUna nuova procedura per ridurre i valori di elementi potenzialmente tossici contenuti in fanghi di depurazione urbana
No full textScopo di questo lavoro è presentare i risultati di uno studio concernente la messa a punto di una nuova procedura chimico-fisica (brevetto n° PC2012A000008 del 22/03/2012) realizzata per ridurre le concentrazioni di alcuni elementi potenzialmente tossici in fanghi di depurazione urbani ottenuti tramite digestione anaerobica e per disidratarli efficientemente, rimuovendo l’acqua in essi contenuta con un aumento dei solidi totali, allo scopo di ridurre il volume totale dei fanghi finali e per recuperare elementi nutritivi utili in vista di un loro riutilizzo diretto, o per impiegarli come componenti e/o precursori di nuovi prodotti fertilizzanti da utilizzare in agricoltura.
Un trattamento Fenton-simile (classico Fenton + ulteriore acidificazione a pH 2) si è dimostrato essere più idoneo del trattamento Fenton classico (pH 3,5) per ridurre il contenuto dei metalli, tranne il Pb, con valori medi di riduzione di Zn (77%), Ni (63%), Cd (15%) e Cr (10.5%), per togliere l’acqua dai fanghi aumentando così la quota di solidi totali (44%) e per consentire di mantenere accettabili valori di Corg nel fango (26,4 g/kg) rispetto ad un valore iniziale di Corg di 28,1 g/kg.
I risultati delle prove eseguite in impianto pilota a scala di laboratorio posseggono tutte le peculiarità per poter essere estese in modo soddisfacente ad una scala industriale
A Chemical-Physical procedure to reduce levels of potentially toxix elements (PTEs) in municipal sewage sludges
No full textThe current waste policy in EU aims at reducing the amounts of sludges to be disposed in landfill, encouraging their energy reuse (e.g. energy source, fertilizers, etc.). In this perspective a reduction of potentially toxic elements (PTEs) and water is welcome, in view of a more sustainable reutilization of sludges, e.g. in agriculture. Aim of this work was to set up a chemical-physical procedure, named modified Fenton process (patent n° PC2012A000008 of 22/03/2012), which was able to improve the reduction of some PTEs (Zn, Ni, Cu, Pb, Cd and Cr) and water in municipal sewage sludges from anaerobic digestion, better than a conventional Fenton process, avoiding significant decreases of total organic carbon (TOC)
Effect of three years of pig slurry application on the distribution and contents of exchangeable K in three different soil types in the plain of Piacenza
No full textVariations in exchangeable K (Kexch), amount of recovery of K in the soil, of the uptake and of K recovery in the crops, and the amounts of unaccounted-for K in the soil-plant system, have been determined for three soil types with different textures, CEC, pH, and lime content. These soils were fertilized with pig slurry for three consecutive years, in different periods, at a constant rate of 60 t N ha-1 year-1 in experimental plots cropped with maize (Zea Mais L.).
The increases of soil Kexch observed for soil 3 (clay with ΔmaxKexch estimated 162.6 mg kg-1) showed values significantly (P<0.01) greater than the other two soils (soil 2 silty-clay-loam with a value estimated for ΔmaxKexch 72.6 mg kg-1 and soil 1, silt-loam with estimated ΔmaxKexch 38.1 mg kg-1). The difference in the estimated cumulated amounts of Kexch among the three soil types is due to the different clay content, C.E.C. and to the higher slope values present in soils 1 and 2 respect to soil 3 too. For soil 3 only a significant inverse correlation (P<0.01 and r = -0.945) was observed between ΔKexch and K applied with slurry. The amounts of K taken up by the crops were only slightly correlated with the applied K: soil 2 (r = 0.804; tot. rec. = 33.3 % K), soil 1 (r = 0.785; tot. rec. = 35.6 % K) and soil 3 (r = 0.581; tot. rec. = 39.8 % K).The values of unaccounted-for K were, on average, significantly lower (P<0.01) for soil 3 (17.4 %) compared to soil 1 (58.3 %) and soil 2 (59.5 %). Only for soil 3 a significant correlation (P<0.05) was found with the amount of applied K (r = 0.957)
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