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Negative plant–soil feedback (PSF) arises when localized accumulations of pathogens reduce the growth of conspecifics, whereas positive PSF can occur due to the emergence of mutualists. Biochar, a carbon-rich material produced by the pyrolysis of organic matter, has been shown to modulate soil microbial communities by altering their abundance, diversity, and activity. For this reason, to assess the long-term impact of biochar on soil microbiome dynamics and subsequent plant performance, we conducted a PSF greenhouse experiment using field soil conditioned over 10 years with Vitis vinifera (L.), without (e.g., C) or with biochar at two rates (e.g., B and BB). Subsequently, the conditioned soil was employed in a response phase involving either the same plant species or different species, i.e., Medicago sativa (L.), Lolium perenne (L.), and Solanum lycopersicum (L.). We utilized next-generation sequencing to assess the abundance and diversity of fungal pathogens and arbuscular mycorrhizal fungi (AMF) within each conditioned soil. Our findings demonstrate that biochar application exerted a stimulatory effect on the growth of both conspecifics and heterospecifics. In addition, our results show that untreated soils had a higher abundance of grape-specialized fungal pathogens, mainly Ilyonectria liriodendra, with a relative abundance of 20.6% compared to 2.1% and 5.1% in B and BB, respectively. Cryptovalsa ampelina also demonstrated higher prevalence in untreated soils, accounting for 4.3% compared to 0.4% in B and 0.1% in BB. Additionally, Phaeoacremonium iranianum was exclusively present in untreated soils, comprising 12.2% of the pathogens' population. Conversely, the application of biochar reduced generalist fungal pathogens. For instance, Plenodomus biglobosus decreased from 10.5% in C to 7.1% in B and 2.3% in BB, while Ilyonectria mors-panacis declined from 5.8% in C to 0.5% in B and 0.2% in BB. Furthermore, biochar application was found to enrich the AMF community. Notably, certain species like Funneliformis geosporum exhibited increased relative abundance in biochar-treated soils, reaching 46.8% in B and 70.3% in BB, compared to 40.5% in untreated soils. Concurrently, other AMF species, namely Rhizophagus irregularis, Rhizophagus diaphanus, and Claroideoglomus drummondii, were exclusively observed in soils where biochar was applied. We propose that the alleviation of negative PSF can be attributed to the positive influence of AMF in the absence of strong inhibition by pathogens. In conclusion, our study underscores the potential of biochar application as a strategic agricultural practice for promoting sustainable soil management over the long term. [ABSTRACT FROM AUTHOR]

A byproduct from orange juice processing known as pastazzo represents a significant organic waste stream. Rich in essential oils and known for its inhibitory effect on plant germination, pastazzo could serve as a valuable input for agricultural purposes. This study assesses the effects of a 40% w/v orange pastazzo water extract (OPWE) produced by hydrodynamic cavitation on the germination of two species, one of economic interest (Lactuca sativa L.) and one common weed (Chenopodium album L.). Three dilutions of OPWE in water (25%; 50%; 75%) were compared to a control treatment in four experiments, using (i) seeds in Petri dishes; (ii) seeds in commercial substrate; (iii) C. album seeds and transplanted L. sativa in commercial substrate; and (iv) other weeds in an open-field plantation of L. sativa. Highly rich in limonene, OPWE applied at higher concentrations in Petri dishes caused the effective inhibition of germination in C. album and a germination delay in L. sativa. Similar results were observed in the germination of the two species in commercial substrate, with none of the dilutions affecting L. sativa biomass. In the field experiment, despite a relatively low number of weeds in the control treatment, higher OPWE concentrations reduced the number of grasses and forbs, largely confirming the inhibitory effects. We conclude that OPWE produced with hydrodynamic cavitation, an efficient and affordable method of extraction, represents an effective crop treatment due to the species-specific effects of its constituent limonene on plant germination. Further tests are essential to understand the extent to which OPWE interacts with other species and types of substrate. [ABSTRACT FROM AUTHOR]

The contribution of animal waste storage on GHG emissions and climate change is a serious issue for agriculture. The carbon emissions that are generated from barns represent a relevant source of emissions that negatively affect the environmental performance measures of livestock production. In this experiment, CO2 and CH4 emissions from different animal wastes, namely, digestate, slurry, and manure, were evaluated both in their original form and with a biochar addition. The emissions were monitored using the static camber methodology and a portable gas analyzer for a 21-day period. The addition of biochar (at a ratio of 2:1 between the substrates and biochar) significantly reduced the emissions of both gases compared to the untreated substrates. Slurry exhibited higher emissions due to its elevated gas emission tendency. The biochar addition reduced CO2 and CH4 emissions by 26% and 21%, respectively, from the slurry. The main effect of the biochar addition was on the digestate, where the emissions decreased by 45% for CO2 and 78% for CH4. Despite a lower tendency to emit carbon-based gases of manure, biochar addition still caused relevant decreases in CO2 (40%) and CH4 (81%) emissions. Biochar reduced the environmental impacts of all treatments, with a GWP reduction of 55% for the digestate, 22% for the slurry, and 44% for the manure. [ABSTRACT FROM AUTHOR]

Introducing plants in the design of biophilic indoor environments is fundamental for improving human health, well-being, and performance. Previous studies showed that the phenotype of the model plant Arabidopsis thaliana grown under LED-sourced CoeLux® lighting systems was characterized by low biomass production rates, a small leaf area, and a low lamina-to-petiole length ratio, suggesting the onset of a strong shade avoidance syndrome. Therefore, it is essential to identify new strategies to improve plant growth under these peculiar light conditions. In the present work, we investigated the effects of two growing media (i.e., low-fertility soil and soil-less substrate), solid and liquid fertilizers, manure, biochar, perlite, mirror reflection of light, and a 24 h photoperiod on A. thaliana plants growing under CoeLux® lighting systems at a light intensity of 30 μmol m−2s−1. We found that the biochar soil amendment to low-fertility soil increases both the above-ground plant biomass and leaf area. Furthermore, the application of a mirror behind the plants and a continuous photoperiod improves not only the biomass and the leaf area but also the lamina-to-petiole length ratio. The combination of different beneficial treatments can further boost plant growth in the low-intensity light environment characterizing the CoeLux® biophilic lighting systems. [ABSTRACT FROM AUTHOR]

Biochar soil amendment can improve growing medium water and nutrient status and crop productivity. A pot experiment was conducted using Solanum lycopersicum var. cerasiforme plants to investigate the effects of biochar amendment (20% application rate) on a soilless substrate, as well as on plant growth, fruit yield, and quality. During the experiment, substrate characteristics, plant morphological traits, and root and leaf C/N content were analyzed at three sampling points defined as early stage (36 days after germination), vegetative stage (84 days a. g.), and fruit stage (140 days a. g.). Fruit morphological traits, titratable acidity, lycopene, and solid soluble content were measured at the end of the experiment. Biochar ameliorated substrate characteristics (Nav increase of 17% and Ctot increase of 13% at the beginning of the study), resulting in a promotion effect on plant root, shoot, and leaf morphology mainly at the vegetative and fruit stages. Indeed, at these two sampling points, the biochar-treated plants had a greater number of leaves (38 and 68 at the vegetative and fruit stages, respectively) than the untreated plants (32 and 49, respectively). The biochar also increased leaf area with a rise of 26% and 36% compared with the values measured in the untreated plants. Moreover, the amendment increased twofold root length, root surface area, and root, stem, and leaf biomasses in comparison with untreated plants. Regarding plant productivity, although fruit morphology remained unchanged, biochar increased flower and fruit numbers (six times and two times, respectively), acidity (75%), lycopene (28%), and solid soluble content (16%). By unveiling promoting changes in morphological traits, fruit number, and antioxidant content occurring in cherry tomato plants growing in a biochar-treated soilless substrate, it could be possible to highlight the importance of biochar for future applications in the field for enhancing plant production and fruit quality in a sustainable agriculture framework. [ABSTRACT FROM AUTHOR]

Most urban greening interventions involve soil de-sealing and management to enhance fertility. Management typically requires translocating fertile topsoil to the site, which comes at great environmental costs. We hypothesized that de-sealed urban soils would undergo an increase of their fertility without exogenous topsoil application. We assessed experimental plots with de-sealed soil with topsoil, and de-sealed soil without topsoil. Both treatments were vegetated with two ornamental shrub species and irrigated. Soil fertility was analyzed by chemical (total and organic carbon) and biological indicators of soils (biological quality index and microbial activities). Since metal contamination is related to urban de-sealed soil, we also monitored the concentration of Zn, Cu and Pb in soil and detected it in plant leaves. The results demonstrate that de-sealed urban soils rapidly restore their biological quality and fertility. Restoration of de-sealing soils can contribute to the recent growing interest reclamation of urban soils for improving the urban environment quality through the restoration of soil functions and related ecosystem services. Overall, the results of this study demonstrate that de-sealed soils can improve their functionality and can contribute to the recent growing interest in reclamation of urban soils for improving the urban environment quality. [ABSTRACT FROM AUTHOR]

Light quality and nutrient availability are the primary factors that influence plant growth and development. In a research context of improving indoor plant cultivation while lowering environmental impact practices, we investigated the effect of different light spectra, three provided by light-emitting diodes (LEDs), and one by a fluorescent lamp, on the morpho-physiology of Pisum sativum L. seedlings grown in the presence/absence of biochar. We found that all morpho-physiological traits are sensitive to changes in the red-to-far-red light (R:FR) ratio related to the light spectra used. In particular, seedlings that were grown with a LED type characterized by the lowest R:FR ratio (~2.7; AP67), showed good plant development, both above- and belowground, especially when biochar was present. Biochar alone did not affect the physiological traits, which were influenced by the interplay with lighting type. AP67 LED type had a negative impact only on leaf fluorescence emission in light conditions, which was further exacerbated by the addition of biochar to the growing media. However, we found that the combination of biochar with a specific optimal light spectrum may have a synergetic effect enhancing pea seedling physiological performances and fruit yield and fostering desired traits. This is a promising strategy for indoor plant production while respecting the environment. [ABSTRACT FROM AUTHOR]