Soil fertilization with fertilizers derived from renewable sources is a topic of great interest in terms of the sustainable management of organic waste. To optimize the management of nitrogen supplied to the soil with digestates, it is necessary to deepen knowledge on the process of mineralization of organic nitrogen over time. In this research, a laboratory incubation system was utilized to study the impact of various digestate sources on nitrogen mineralization processes in soils and nitrogen mineralization kinetics. Six types of digestates of different origins and composition were administered to soil and the soil samples were placed under controlled conditions. The release of N was determined by measuring ammonium-N and nitrate-N concentrations in leachates during a 12-week period of incubation. The nonlinear regression technique was used to fit the cumulative leaching of total N to the Stanford and Smith first-order kinetic model during the incubation period. The results showed that the differences between digestates, nitrogen and organic carbon concentration, and C/N ratio influenced both ammonification and nitrification processes in the soil and the nitrogen mineralization kinetics. The processing of the statistical data highlighted that the potentially mineralizable nitrogen (MPN) followed first-order kinetics.

A peculiar solid olive mill waste called Pat & egrave; Olive Cake (POC), produced by decanters of latest generation, and its derivative solid extract from centrifugation called 'pellet' were evaluated as soil amendments on a pot cultivation of ryegrass in sub-acid and sub-alkaline soils. Characterization of POC and pellet was performed to determine their main chemical characteristics and phytochemical profile by conventional methods, NMR and HPLC to evaluate their suitability for agronomic applications. In both soils, POC and pellet were applied and contrasted to (i) half dose of POC and pellet added of mineral nitrogen (N) and phosphorous (P) to correct the C:N ratio and to balance the phyto-nutritive formula, (ii) commercial mineral and organo-mineral fertilizers and (iii) untreated soil (Control). During the ryegrass annual cycle, the vegetative responses and the N concentration were monitored in the epigeal biomass. At the end of the experiment, soil samples were taken from the pots to determine the main physicochemical characteristics and to carry out genomic and enzymatic investigations. Both soils treated with POC and pellet supplemented with N and P showed a significant increase in biomass productions compared to Control (+36.32%) and to commercial fertilizers (+14.34% and + 16.41%, respectively, to mineral and organo-mineral fertilizers). In all treatments, higher cumulative biomass productions were observed in the sub-acid soil (+7.02%). In both soils, abundance and structure of fungi and bacteria communities showed no difference compared with the Control. Furthermore, enzymatic analysis indicated that microbial activity was not adversely affected by POC and pellet treatments. Our results indicate that POC and pellet can be used as soil amendments, contributing to reduce the use of chemical fertilizers and implementing circular economy and sustainability.

The aim of this work was to verify the existence of a threshold effect in the capacity of Brassica napus to bioaccumulate cadmium in roots in soil artificially over-polluted with cadmium and to translocate it to the shoots at flowering and maturation. The cadmium effects on biomass production, on cadmium uptake and on morphological parameters were also investigated and the bioconcentration factor (BCF) and the translocation factor (TF) were also elaborated. Pot experiment was carried out in controlled conditions. The soil was contaminated with two concentrations of cadmium (50 and 100 mg kg(-1) soil) administered to soil as cadmium sulphate. Plants were collected at flowering and maturation. The cadmium concentration of the plant and soil was determined after acid digestion by Inductively Coupled Plasma (ICP). Cadmium uptake was calculated for each growth stage. The results showed that the B. napus tolerate and bioaccumulate cadmium during the entire life cycle without a threshold effect but the behaviour of cadmium in plants was different in flowering and maturation. The higher cadmium removal by shoots was found at flowering while, at maturation, the oilseed rape seems to be more active in bioaccumulating cadmium in roots. Positive linear correlation coefficient was found between cadmium in soil and shoot removals both for contamination levels and for phenological stages.

The aim of our study was to verify the effect on plant growth and biomass production of a new olive mill by-products named "Pate Olive Cake" (POC) generated by a multi-phase decanter (MPD) technology. POC is an olive mill by-product consisting of olive pulp, olive skin and vegetative water. The POC was treated with Eco-sustainable Separation and Extraction Technologies according to the methods developed and standardized by the ENEA Casaccia Research Center. In CREA Research Center for Agriculture and Environment (CREA-AA), methodologies and measurement protocols were applied both for the evaluation of different fractions of POC through biological laboratory assays to highlight their nutritional, biostimulant and toxic properties and trough experimental pot tests for the evaluation for agronomic use, from the perspective of the circular economy. Several studies have been carried out on the effects of oil mill products on the biological fertility of the soil but not on the POC. In the present work the first results obtained are reported and discussed for the adoption of protocols for the evaluation of different POC fractions through laboratory bioassays. This study was conducted within the Lazio Innova ABASA project, CUP B81G18000770002 (Agricultural By-products into valuable Assets for Sustainable Agriculture).

Olive oil production generates high amounts of liquid and solid wastes. For a long time, such complex matrices were considered only as an environmental issue, due to their polluting properties. On the other hand, olive mill wastes (OMWs) exert a positive effect on plant growth when applied to soil due to the high content of organic matter and mineral nutrients. Moreover, OMWs also exhibit antimicrobial activity and protective properties against plant pathogens possibly due to the presence of bioactive molecules including phenols and polysaccharides. This review covers the recent advances made in the identification, isolation, and characterization of OMW-derived bioactive molecules able to influence important plant processes such as plant growth and defend against pathogens. Such studies are relevant from different points of view. First, basic research in plant biology may benefit from the isolation and characterization of new biomolecules to be potentially applied in crop growth and protection against diseases. Moreover, the valorization of waste materials is necessary for the development of a circular economy, which is foreseen to drive the future development of a more sustainable agriculture.

The aim of this research was to verify the effects of the mineral (F) or organic fertilization (compost, C or manure, M) on the productivity and the nutritional characteristics of zucchini (Cuearbita pepo L.) and on the soil residual fertility. The plants were grown in open fields and harvested at consumer's maturation time (June and July). The nutrient contents and some quality indexes were determined using chemical analyses. Magnetic resonance imaging spectroscopy (MRI) was utilized to study water distribution and the morphology in differently fertilized zucchini. The highest productivity was reached using the amendment with compost. The amendment with manure caused the increase in the total organic carbon concentration of soil with respect to the compost or mineral fertilization. Few significant differences were determined in nutrient contents of differently fertilized zucchini. No differences were highlighted in the internal morphology of the vegetables as demonstrated by MRI spectroscopy.

The aim of this research was to investigate the relationship among leaf mineral nutrition, soil chemical fertility, presence of phytoplasma in fruit trees and susceptibility of the plant to become infected. In the experimental farm, pear and apricot orchards were cultivated, in separate areas far 30 metres each other and since 1997 they resulted respectively infected by 'Candidatus Phytoplasma pyri' and by 'Candidatus Phytoplasma prunorum'. In 1999 whole collections of these two species had been eradicated and substituted with new plants of the same species. Four pear plants had been selected in the old collection and had been covered by anti-aphid tissue. These pear plants (three infected by the phytoplasma and one healthy) and four healthy apricot plants were analysed for the presence of phytoplasma, for the nutritional status of leaves as well as for the soil chemical fertility. This study was carried out in two years, from May 2006 to September 2007. The results showed a Fe/Mn ratio unbalanced in the pear infected plants compared with the pear healthy ones. The pear leaves of the healthy plant didn't show any disequilibrium, while those of the infected plants showed the unbalanced ratio Fe/Mn either when the molecular test for phytoplasma detection was still negative. The apricot leaves, always resulted free from phytoplasmas, showed a K/Mg imbalance.

The objective of this research was to verify the effects of the amendment with distiller's residue Compost on soil fertility, the nutrients accumulation and the yield in profitable vegetables of high consumption, such as broccoli (Brassica oleracea var. italica Plenck), endive (Cichorium indivia L.), lettuce (Lactuga saliva L.) and Roman artichoke (Cynara scolymus L.). The crop session was made following an experimental randomized design with four treatments: T (no fertilization): F. mineral fertilization: C. compost derived wine-producing residues; CF. integrated organic-mineral fertilization.The results showed that the amendment with distiller's residue compost (C) caused the increase of both organic matter content and yield in perennial crop (artichoke). Conversely, in seasonal crops the integrated fertilization (CF) determined a higher productivity only in the first year of administration, with no effect on the soil organic matter content. The different fertilization practices adopted provided benefits to the mineral nutrition status of the horticultural crops. with no significant difference among the treatments.

The work focused the application of an image analysis technique to determine corn leaves morphology as objective indicator of the growth performance of corn (Zea mays) resulting from the urban residual fertilization. The analyses were related to six fertilization plots: original soil; chemical fertilizer (160 and 200 kg ha(-1) of nitrogen); organic fertilizer (32 t ha(-1)) and two different doses of urban residues (sewage sludges) (7.5 and 22.5 t ha(-1), this last amount corresponds to is the maximum level permitted from the Italian law in three year of fertilization). Those tests were realized by full randomized plots, with two three repetitions for each treatment. Measurements were performed for the first year of the trials in the period proximate to harvest (Rome, Italy - July 2000). Four plants for each plot were harvested and stripped of all leaves, whose RGB images were acquired by a digital photo camera (Kodak Ltd). Image analysis was performed first through the separation of RGB channels into single monochromatic 8-bit distribution, than the blue channel images, the most informative, were then submitted to enhancement, low pass filtering to reduce noise, threshold of binarization (based on statistical parameter affected on Gaussian grey levels distribution), binary morphology and object measurement. For ach single leaf the length, the width, the area were measured. The test results indicated positive and significant responses in relation between the crop growth (leaves area, length and width greater) and the different doses of urban residues (sewage sludges).

The aim of this research was to investigate the capability of Brassica napus to bioaccumulate zinc and copper from artificially contaminated soil at the flowering and maturation phenological stage. The trial was set up in a greenhouse and the plants were cultivated in pots. The agricultural soil utilized was contaminated with zinc and copper sulfate (300 and 600 mg/kg, respectively). The soil and plant samples were simultaneously collected during the flowering (8 weeks after seeding) and maturation (harvest time, 1.3 weeks after seeding) stages, and the heavy metal concentrations were then analyzed. The production of vegetable biomass and the length of the roots were measured. The results showed that B. napus accumulated zinc and copper and translocated these elements in different ways in the harvestable parts of the plants. The zinc bioaccumulation was higher than that of copper. At flowering, zinc was mainly accumulated in the shoots (stems + leaves). Copper was particularly accumulated in the roots, during the entire life cycle. Taking into account the biomass production, the highest heavy metal removal by the shoots (above-ground parts) occurred at the flowering stage for both zinc and copper. The high bioavailability of zinc and copper in the soil did not severely affect the root length and the biomass production.

The capability of Brassica napus to accumulate soil cadmium, zinc and copper was investigated. The removals of cadmium, zinc and copper from soil by plants, in the fifth week of growth, were calculated by multiplying the heavy metal concentrations by the vegetable biomass production. Plants were cultivated in pots on artificially contaminated soil (50 mg/kg Cd, 600 mg/kg Zn and 600 mg/kg Cu). In contaminated soil, Brassica napus did not show any upper threshold to the absorption of Cd and Zn, hence the removal of these metals from soil was higher than that of the control. In contrast, Cu absorption was poor and the removal of copper from soil did not differ between contaminated soil and control. The results showed that Brassica napus would most likely be more effective in removing cadmium and zinc than copper from the soil.

The effects of medium-term applications of liquid, dehydrated and composted sewage sludges on a silty learn soil were studied in a field trial in northern Italy. Once per year, randomized plots were added of liquid, dehydrated and composted sewage sludges. A sequential extraction of Zn, Cu, Ni and Pb from sludge and soil samples was performed after six years of sludge application to evaluate the heavy metal distribution in the different sewage sludges and their influence on the pool of potentially bioavailable metals in amended soils. Comparison of metal fractions in the three sludges (liquid, dehydrated and composted sludge) showed that the process of composting altered the chemical forms between the metals and the organic matrix, resulting in a shift of metals from the residual to the more labile and potentially bioavailable forms, In particular, an increase of the EDTA-extractable Zn, Ni, Pb and Cu. was observed, as well as a significant increase of the NaOH-extractable Cu. With regard to soil, heavy metals were found mostly in the residual form (HNO3-extractable) and at the sixth year of sludge amendment, except for zinc, the soil fractionation of heavy metals was not affected by the amendment practices. A significant increase of the potentially bioavailable fractions (EDTA and NaOH-extractable) of Zn was observed.

The purpose of this research was to evaluate the influence of different amounts of cupper and zinc applied to an agricultural soil on the behavior of exchangeable cations (Ca++, Mg++, Na+ and K+), in relation to two different open systems: one carried out in a laboratory with use of chromatography columns and one using a pot cultivation of Hordeum vulgare. As regards the laboratory experience, the highest degree of cation leaching was found in the treatments receiving only Cu. Oppositely, the lowest degree of leaching was found in the control. On the other hand, the application of both Cu and Zn resulted in an amount of cation leaching lower than the amounts resulting from each of the two heavy metals alone. As regards the Mitcherlich experiment, all the treatments resulted in a decrease of the CEC in comparison to the control, due to the addition of these two metals. Besides, all the treatments with both Cu and Zn showed a decrease in biomass yield relatively to the control, particularly in the treatments in which the metals had been applied at sowing. In both experiment it was found a negative synergism of the two metals added to the systems: as regards the laboratory experience, the treatment receiving Cu + Zn together, showed the lowest concentration of cations leached in the percolates; as regards the Mitcherlich pots experiment, the treatment receiving the two metals together at sowing showed the lowest biomass yield..

During June 1996, 1-month-old sunflower plants (Helianthus annuus. L.) of the cvs. Blue Mix and Romsun × 590, grown at the experimental farm of the Istituto Sperimentale per la Nutrizione delle Piante (Montelibretti, Rome), showed symptoms of wilting, and then gradually dried out. Discolored areas were observed on the crown, where whitish, fan-shaped mycelia were occasionally present. A fungus was isolated on potato dextrose agar from surface-disinfested, diseased stem fragments. It also developed from diseased stem segments incubated in moist chambers. In both cases, round sclerotia developed after 9 days at room temperature. The fungus was identified as Sclerotium rolfsii Sacc. The fungus has been deposited in the ISPaVe collection (no. ER 883). To test pathogenicity, 20-day-old sunflower seedlings of the cvs. Blue Mix and Romsun × 590 were grown singly in an autoclaved peat/soil mixture in 20-cm-diameter plastic pots in a greenhouse at 30 ± 3°C. Plants were inoculated by placing five sclerotia of isolate ER 883 near the crown of each plant about 5 mm below the soil surface. For each cultivar, 10 plants were inoculated and 10 were left uninoculated. Wilting symptoms and stem discoloration appeared after 12 days. Sclerotia were produced at the stem base of some inoculated plants. All inoculated plants died after 20 days. S. rolfsii was consistently reisolated from all the inoculated plants, while no symptoms or signs were observed on the uninoculated plants. This is the first report of S. rolfsii on sunflower in Italy and has important implications for the use of sunflower in crop rotation. An unusual rainy period delayed planting of sunflowers by 1 month in 1996 and this could have favored the disease.