1,721,065 research outputs found
Organic matter characteristics, biochemical activity and antioxidant capacity of soil amended with different organic materials.
No full textThe influence of pelleted cow manure (PCM), peat, municipal solid waste compost (MSWC), wet olive husk compost (WOHC) and green waste compost (GWC) on soil biochemical activity, antioxidant capacity (trolox equivalent antioxidant capacity (TEAC)) and the level of soil organic matter was evaluated in a short-term laboratory study. Peat was the most acidifying material, followed by GWC and PCM, reflecting the acidic characteristics of the compounds present in the aqueous and alkaline extracts of the amendments. Organic materials caused a marked increase of total and water-soluble organic carbon, total N, water- and alkali-soluble phenols in soil, with values generally reflecting the amount of organic matter present in the amendments. The breakdown percentage of C added expressed as CO2-C evolution for PCM was considerably the highest (18%) and for WOHC was considerably the lowest. The water-soluble organic carbon present in the amendments and soil total N acted as controllers of the rate of decomposition of organic C in soil. The highest TEAC was in peat soil, with 583.0 mM g−1, followed by PCM soil (450.2 mM g−1), while soils treated with compost had quite similar values (about 230 mM g−1). TEAC was strictly correlated with both alkali- and water-soluble phenols and water-soluble organic carbon. The level of ATP in PCM soil at the 60th day of incubation suggests that the PCM is the most effective amendment for increasing the activity of microbial biomass in soil
Utilizzo del compost nel processo di biorecupero di un suolo contaminato da idrocarburi: valutazione di parametri chimici e biologici
No full textUn’ indagine di laboratorio è stata realizzata al fine di valutare l’efficacia dell’utilizzo di compost durante il processo di biorecupero di un terreno inquinato da idrocarburi del petrolio. La sperimentazione è stata condotta attraverso l’uso di un ammendante compostato verde, applicato in diverse dosi (1%, 2% e 4%) ad un suolo agrario contaminato con gasolio per motori Diesel alla concentrazione di 10000 ppm. Sono state monitorate nel tempo le variazioni di alcuni parametri chimici, biologici e biochimici, per valutare l’efficacia del biorecupero del suolo inquinato da idrocarburi e individuare idonei parametri marcatori dei processi coinvolti nel risanamento. Per valutare la perdita di gasolio dovuta ad evaporazione è stato anche allestito un trattamento di controllo con suolo inquinato e sterilizzato.
I diversi trattamenti di biorecupero sono stati monitorati per circa 4 mesi con prelievi a 1, 7, 14, 30, 60 e 120 giorni. Oltre agli idrocarburi totali sono stati misurati, quali parametri chimici, il pH ed il C organico, come parametro biologico l’ATP del suolo, mentre dal punto di vista biochimico è stata determinata la lipasi.
I risultati indicano che si è verificata una perdita per evaporazione concentrata nella prima settimana di circa il 40% del gasolio presente nel suolo. L’applicazione dell’ammendante compostato verde ha stimolato in modo evidente il metabolismo del suolo poiché un importante indice di attività microbica, l’ATP, e l’attività enzimatica testata hanno mostrato valori superiori e diversi rispetto al suolo non trattato e inquinato.
Nonostante l’incremento metabolico di tutti i trattamenti con aggiunta di ammendante, il compost verde utilizzato nella sperimentazione ha fatto registrare un effetto positivo nella decontaminazione del suolo soltanto alla massima dose di applicazione (4%), con una diminuzione dei TPH dell’89%.
Il parametro che meglio ha rispecchiato il processo di biorecupero del suolo è stata la lipas
Bioremediation with compost of a diesel contaminated soil: monitoring by dehydrogenase activity and basal respiration
No full textThe effect of compost on hydrocarbon degradation was determined during a 120-d incubation period. An evaluation of soil basal respiration and dehydrogenase activity as a monitoring instrument for the bioremediation process of soil contaminated with commercial diesel-oil was carried out. Six soil samples were used: S (control, uncontaminated soil), CS (contaminated soil), CSS (contaminated and sterilized soil), CS1 (contaminated soil plus 1% compost), CS2 (contaminated soil plus 2% compost) and CS3 (contaminated soil plus 4% compost). The relationships between soil biological parameters and the levels of total petroleum hydrocarbons (TPH) residues were investigated. Results show a large loss of hydrocarbons since the first incubation period due to their volatilization. Sterilized soil control (SCS) showed, on the 7(th) day, a decrease in hydrocarbons of about 40% in weight. Successively, the decrease of TPH was 56% in the contaminated soil (CS). The amendment with compost significantly enhanced TPH degradation only when applied at the highest rate of 4%. At the end of incubation, CS3 achieved a 66% loss rate after volatilization. During the first 14 days of incubation, dehydrogenase activity of CS was significantly higher than S as a result of an efficient use of organic C of TPH. Amendment, particularly the 4% addition rate, increased the dehydrogenase activity of soil with respect to CS and S. The CS showed a rather higher basal respiration than S for the whole incubation period (24 days), so confirming the ability of microorganisms to use the organic C of TPH as a substrate. The incorporation of compost stimulated the basal respiration that increased with incremental addition of amendment. The presence of hydrocarbons exerted its negative influence on mineralization rate (k) of organic carbon, but it was weakened by the presence of compost. The trend of dehydrogenase activity and basal respiration were positively related with that of residual hydrocarbon in soil. Both biological activities can be considered as good qualitative indicators of biodegradation activity of TPH in soil
Soil quality under the energetic crop giant reed (Arundo donax L.), cropping sequence and natural grassland
No full textThe objective of this study was to determine, on the same pedological, topographic and climatic conditions, the effect of a continuous giant reed cropping (GR), a cropping sequence (CS) as well as of untilled native grassland (NG) on some soil quality characteristics. Between the examined parameters, total soil organic carbon (TOC), light fraction carbon (LFC), dissolved organic carbon (DOC) cumulative mineralized carbon (Cm), microbial biomass carbon (MBC), basal respiration, metabolic quotient (qCO2), potentially mineralizable carbon (C0), dehydrogenase (DHA), catalase (CA) and ß-glucosidase (GL) activities, as well as fluorescein diacetate hydrolysis (FDA), biological index of fertility (BIF) and initial potential rate of carbon mineralization (C0•k), were higher in the continuos giant reed cropping than in the cropping sequence. The C mineralization rate (k) was lower in GR than in CS, while the metabilc potential (MP) was similar in the two sites.
For what concerns the difference between GR and NG, this last usually considered as a reference or base line in evaluating attributes of soil quality, GR showed higher values for TOC, LFC, DOC and catalase activity. TOC and catalase, also for their analytical semplicity, may be suggested as the most suitable soil biochemical indicators for differentiating the effects of different crop management systems
Il biochar e il suo potere fertilizzante: una opportunità per l'uso ecosostenibile del suolo agrario.
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