Cultivation Using Coir Substrate and P or K Enriched Fertilizer Provides Higher Resistance to Drought in Ecologically Diverse Quercus Species.

Nursery cultivation practices can be modified to increase resistance to water stress in forest seedlings following field establishment, which may be increasingly important under climate change. We evaluated the morphological (survival, growth) and physiological (chlorophyll fluorescence, leaf water potential) responses to water stress for three ecologically diverse Quercus species (Q. robur, Q. pubescens, and Q. ilex) with varying traits resulting from the combination of growing media (peat, coir) and fertilization (standard, P-enriched, K-enriched). For all species under water stress, seedlings grown in coir had generally higher growth than those grown in peat. Seedlings fertilized with P performed better, particularly for survival; conversely, K fertilization resulted in inconsistent findings. Such results could be explained by a combination of factors. P fertilization resulted in higher P accumulation in seedlings, while no K accumulation was observed in K fertilized seedlings. As expected, the more drought-sensitive species, Q. robur, showed the worst response, while Q. pubescens had a drought resistance equal or better to Q. ilex despite being classified as intermediate in drought resistance in Mediterranean environments.

Effects of Silver Fir (Abies alba Mill.) Needle Extract Produced via Hydrodynamic Cavitation on Seed Germination.

This paper describes the antigerminant capacity of water extracts of silver fir needles created by means of hydrodynamic cavitation processes. Fir needles (2 kg fresh weight) collected in the winter were blended and crushed in ice, poured in water only (120 L) and processed in a controlled hydrodynamic cavitation device based on a fixed Venturi-shaped reactor. The A. alba water extract (AWE), comprising an oil-in-water emulsion of silver fir needles' essential oil (100% AWE), was diluted in distilled water to 75% and 50% AWE, and all aqueous solutions were tested as antigerminant against four weeds and four horticultural species and compared to control (distilled water). This study shows the effective inhibitory effect of pure AWE on germination, which mainly contains limonene (15.99 ng/mL) and α-pinene (11.87 ng/mL). Seeds showed delayed germination and inhibition but also a reduction in radicle elongation in AWE treatments as compared to control. This combined effect was particularly evident in three weeds (C. canadensis, C. album and A. retrofllexus) while horticultural species showed mainly effects on the radicle elongation as found in L. sativa, P. crispum and S. lycospermum, which showed on average 58%, 32% and 28%, respectively, shorter radicles than in the control. P. sativum was not affected by AWE, thus raising the hypothesis that seed characteristics and nutrition reserve might play a role in the resistance to terpenes inhibitory effect.

Critical evaluation of functional aspects of evaporation barriers through environmental and economics lens for evaporation suppression - A review on milestones from improved technologies.

Climate change models predict an increase in rainfall variability, leading to floods and drought events, hence intensifying the need for reservoirs. However, up to 50% of reservoirs' capacity is lost by evaporation, affecting their function of ensuring water availability and stability. Over decades biological, chemical and physical barriers "covers" were developed for inhibiting evaporation. Such barrier's efficiency and applicability are still a matter of discussion, given their economic efficiency, environmental consequences, and operational difficulties are accounted for. In this review, we discussed the efficiency, applicability, and environmental suitability of these covers. Compared to the physical covers, the chemical and biological solutions tend to be less efficient. However, the use of physical covers is multidisciplinary, involving climate, material, and hydrological sciences, and are more efficient. Among the physical covers, the use of suspended covers and free-floating elements decreases evaporation to the tune of 85 and 80.0%, respectively. However, the economic efficiency of free-floating elements remains an open question since all studies overlooked their water footprint (water used in the manufacturing process of these covers), which was found to be very high. The use of these covers decreases heat storage, gas exchange rate, and light availability that could adversely influence dissolved oxygen, water quality, aquatic organisms, and the water ecosystem's function. These ecological consequences have not yet been investigated. The exception is the suspended covers, which have had determinate effects on dissolved oxygen and algae growth. Due to light weight, floating elements' operation is unstable and vulnerable to move due to wind effects. Therefore, such covers must be engineered to increase their stability. Free-floating elements could provide a visible and scalable solution to evaporation suppression when considering their economic visibility, environmental effects, and stability against wind and wave effects under the field conditions. However, these covers can be viable only when water availability is the limiting factor in crop production. We found that studies at reservoir scale are highly limited, therefore, investigations at reservoirs' scale emphasizing ecological aspects, cover stability and cost efficiency, are urgently needed.

Usage of urban green space and related feelings of deprivation during the COVID-19 lockdown: Lessons learned from an Italian case study.

This study investigated perceptions and behavioral patterns related to urban green space (UGS) in Italian cities, during the period of national lockdown imposed due to the outbreak of SARS-CoV-2 in the spring of 2020. A survey was used to examine the responses of population groups in different municipal areas, comparing those in government-defined "red zones", mostly in the northern regions of the country, with "non-red zones" in the rest of the country, where the rate of infection was much lower. A total of 2100 respondents participated in the survey. The majority of respondents declared themselves to be habitual users of UGS, especially of parks or green areas outside the town - mainly visiting for relaxation and physical exercise, but also for observing nature. In the northern regions people more commonly reported the adoption of sustainable practices, in terms of the utilization of tools for "green mobility". During the lockdown, habits changed significantly: only one third of respondents reported visiting UGS, with frequent visits made mainly for the purpose of walking the dog. Other motivations included the need for relaxing, mostly in the red zones, and for physical exercise in non-red zones. The reduction in travel to urban parks was accompanied by increased visitation of gardens and other green spaces in close proximity, as social distancing and other regulations imposed restrictions on movement. In all regions, respondents who could not physically access UGS expressed a feeling of deprivation which was exacerbated by living in towns located in red zones, being a usual visitor of UGS and having no green view from the window. The extent to which these visitors missed UGS depended on the frequency of visitation before the pandemic and the UGS distance, as well as the type of previous activity. In fact, those activities that were most common before the pandemic were missed the most, reinforcing the importance of green areas for social gathering, sports, and observing nature - but simply "spending time outdoors" was also mentioned, even by those who visited UGS during the lockdown, as the time outdoors was not enough or not fully enjoyed. The feeling of missing UGS was only partially alleviated by the green view from the window - only a more open view to a natural landscape or adaptation to a view with little greenery reduced such feeling.

Effects of the COVID-19 pandemic on the use and perceptions of urban green space: An international exploratory study.

Urban green space (UGS) is an essential element in the urban environment, providing multiple ecosystem services as well as beneficial effects on physical and mental health. In a time of societal crisis these effects may be amplified, but ensuring that they are maintained requires effective planning and management - which is a complex challenge given the rapid changes in modern society and the need for continual adaptation. This study aims to identify the drivers that normally attract visitors to UGS, and to assess the effects of social isolation on the usage and perception of UGS during the COVID-19 pandemic. We conducted an online survey during the period in which restrictive measures were imposed in response to the pandemic (March-May 2020), in Croatia, Israel, Italy, Lithuania, Slovenia and Spain. Results showed that urban residents normally have a need for accessible UGS, mainly for physical exercise, relaxing and observing nature. The reduction in UGS visitation during the containment period was related to distinct changes in the motivations of those who did visit, with a relative increase in "necessary activities" such as taking the dog out, and a reduction in activities that could be considered non-essential or high-risk such as meeting people or observing nature. Behavioral changes related to proximity were also observed, with an increase in people walking to small urban gardens nearby (e.g. in Italy) or tree-lined streets (e.g. in Spain, Israel), and people traveling by car to green areas outside the city (e.g. in Lithuania). What the respondents missed the most about UGS during the pandemic was "spending time outdoors" and "meeting other people" - highlighting that during the COVID-19 isolation, UGS was important for providing places of solace and respite, and for allowing exercise and relaxation. Respondents expressed the need for urban greenery even when legally mandated access was limited - and many proposed concrete suggestions for improved urban planning that integrates green spaces of different sizes within the fabric of cities and neighborhoods, so that all residents have access to UGS.

Assessing the influence of topsoil and technosol characteristics on plant growth for the green regeneration of urban built sites.

Achieving urban regeneration through the creation of new green areas is a widely promoted strategy to improve the quality of life in densely built neighborhoods. "De-sealing" actions can compensate for the creation of new built-up areas, as demonstrated by the EU-funded Life + project 'Save our Soils for LIFE' (SOS4LIFE, LIFE15ENV/IT/000225), in which guidelines for de-sealing have been published. For the generation of new urban greening, it is important to know the characteristics of the soils used in order to better define the most appropriate landscaping decisions and management practices. In this study the physical and chemical characteristics of topsoils and technosols (soils enclosed under sealed surfaces) were assessed in relation to growth and leaf gas exchanges in two ornamental species (V. tinus and E. x ebbingei), in two partner municipalities of the project, Carpi and San Lazzaro di Savena (north-east Italy), during a three-year trial. Results of the study confirmed the dependence of plant growth on the chemical evolution of the soils, and identified the optimal soil moisture range based on soil texture and soil-plant water relationships. In addition, the technosols were found to actually be beneficial for plant growth, due to their high drainage capacity and nutrient content.

Microbiomes in Soils Exposed to Naturally High Concentrations of CO2 (Bossoleto Mofette Tuscany, Italy).

Direct and indirect effects of extremely high geogenic CO2 levels, commonly occurring in volcanic and hydrothermal environments, on biogeochemical processes in soil are poorly understood. This study investigated a sinkhole in Italy where long-term emissions of thermometamorphic-derived CO2 are associated with accumulation of carbon in the topsoil and removal of inorganic carbon in low pH environments at the bottom of the sinkhole. The comparison between interstitial soil gasses and those collected in an adjacent bubbling pool and the analysis of the carbon isotopic composition of CO2 and CH4 clearly indicated the occurrence of CH4 oxidation and negligible methanogenesis in soils at the bottom of the sinkhole. Extremely high CO2 concentrations resulted in higher microbial abundance (up to 4 × 109 cell g-1 DW) and a lower microbial diversity by favoring bacteria already reported to be involved in acetogenesis in mofette soils (i.e., Firmicutes, Chloroflexi, and Acidobacteria). Laboratory incubations to test the acetogenic and methanogenic potential clearly showed that all the mofette soil supplied with hydrogen gas displayed a remarkable CO2 fixation potential, primarily due to the activity of acetogenic microorganisms. By contrast, negligible production of acetate occurred in control tests incubated with the same soils, under identical conditions, without the addition of hydrogen. In this study, we report how changes in diversity and functions of the soil microbial community - induced by high CO2 concentration - create peculiar biogeochemical profile. CO2 emission affects carbon cycling through: (i) inhibition of the decomposition of the organic carbon and (ii) promotion of CO2-fixation via the acetyl-CoA pathway. Sites naturally exposed to extremely high CO2 levels could potentially represent an untapped source of microorganisms with unique capabilities to catalytically convert CO2 into valuable organic chemicals and fuels.

A tree from waste: Decontaminated dredged sediments for growing forest tree seedlings.

The sediments dredged from a waterway and decontaminated through a phytoremediation process have been used as substrates alternatively to the traditional forest nursery substrate for pot productions of holm oak (Quercus ilex L.) planting stocks. The substrates, made by mixing decontaminated sediments to agricultural soil at different degrees, were tested in order to evaluate their suitability as growth substrates. The experiment was carried out at the nursery of the Department of Agricultural, Food and Forestry Systems of the University of Florence (Italy). The experimental design consisted of four randomized blocks with six pots as replicates for each of the following treatments: 100% sediments, 66% sediments, 33% sediments, 100% agronomic soil and 100% traditional peat based substrate. In each pot, one holm oak acorn was seeded. Germination and both physiological and morphological traits of the seedlings were analysed during and at the end of the first growing season. Holm oak grown in phytoremediated sediments at higher concentrations showed germination levels comparable to those in the traditional substrate, and survival capacity (especially in 66% sediments) slightly higher than in 100% soil. Physiological performance of seedlings resembled that on the traditional substrate which required the addition of fertilizer, at least for the first growing season. Seedlings grown in mixed substrates with higher sediment concentrations occasionally showed better photosynthetic capacity with improved connectivity between the units of the photosystem II. At the end of the first growing season, height as well as the number of growth flushes of the seedlings grown in sole sediment or soil-sediment substrates were similar to what generally is observed for forest nursery stock of Quercus spp.. Regarding the root-system articulation and growth in depth, results in the mixed substrates were comparable to those for seedlings grown in the traditional forest nursery media, and higher than seedlings grown in 100% agronomic soil. According to our results, the reclamation of dredged sediments can provide appropriate nursery substrate for germination beds for forestry species.

Testing decontaminated sediments as a substrate for ornamentals in field nursery plantations.

When canals and harbours are dredged, huge amount of polluted sediments has to be stocked and transported to the landfill with incredibly high costs of management. Among the remediation techniques for the reclamation of polluted sediments and soils, phytoremediation represents a sustainable and effective technique though still not fully promoted or commercialized. In this study we have tested the suitability for plant nursing of a substrate resulting from sediments dredged from a canal and treated with phytoremediation. The experiment was set up in 2014. It aimed to test the physical, chemical and hydrological characteristics of two mixes of remediated sediments and agronomic soil (at 33% and 50% by volume) compared to control soil (100% agronomic soil), and to assess the growth of three ornamental species (Viburnum tinus L., Photinia x fraseri var. red robin, Eleagnus macrophylla Thunb.) together with the suitability for root balling. The mixed substrates produced good results in terms of water drainage, and were similar to the control in terms of soluble nutrients, guaranteeing and enhancing the aboveground and belowground growth of all the three species, especially V. tinus. In contrast, mixed substrates impaired root ball compaction with root ball breakage observed especially in 50% sediment/soil mix. Therefore, the use of remediated sediments in plant nursery can be limited to specific productions or practices.