Search Results (1,796)

Second-, third-, and fourth-generation biofuels represent an important response to the challenges of clean energy supply and climate change. In this context, the Horizon 2020 “TO-SYN-FUEL” project aimed to produce advanced biofuels together with phosphorus from municipal wastewater sludge through a combination of technologies including a Thermo-Catalytic Reforming system, Pressure Swing Adsorption for hydrogen separation, Hydrodeoxygenation, and biochar gasification for phosphorous recovery. This article presents the environmental performance results of the demonstrator installed in Hohenberg (Germany), with a capacity of 500 kg per hour of dried sewage sludge. In addition, four alternative scenarios are assessed, differing in the source of additional thermal energy used for sludge drying: natural gas, biogas, heat pump, and a hybrid solar greenhouse. The environmental performance of these scenarios is then compared with that of conventional fuel. The comparative study of these scenarios demonstrates that the biofuel obtained through wood gasification complies with the Renewable Energy Directive, while natural gas remains the least sustainable option. Heat pumps, biogas, and greenhouse drying emerge as promising alternatives to align biofuel production with EU sustainability targets. Phosphorus recovery from sewage sludge ash proves essential for compliance, offering clear environmental benefits. Although sewage sludge is challenging due to its high water content, it represents a valuable feedstock whose sustainable management can enhance both energy recovery and nutrient recycling. Full article

Closed hydroponic systems for strawberries (Fragaria × ananassa Duch.) are infrequently used because the crop is highly sensitive to salt accumulation and prone to root diseases, resulting in yield reduction. This study investigated semi-closed hydroponic systems using various drainage recycling ratios (30%, 50%, and 70% of drainage EC) to determine their impact on yield, fruit quality, and antioxidant properties. Recycling at moderate levels (30–50%) effectively maintained ionic balance, particularly with respect to K/N and K/Ca ratios, which enabled stable yields and increased fruit weight similar to the control (open hydroponic system) group. Conversely, a high recycling ratio (70%) led to ionic imbalances—characterized by increased K/N ratios and higher concentrations of Na⁺, Cl⁻, and SO₄²⁻—that were associated with decreased fruit size. Measures of antioxidant capacity, such as total phenol and flavonoid content, ferric reducing antioxidant power, and DPPH activity, were not significantly influenced by the recycling ratio alone. Nevertheless, the relatively elevated antioxidant activity observed at the 70% recycling level indicates a mild ionic and osmotic stress response likely caused by increased salt concentration. Changes related to the cropping system season, rather than ion variations from recycling, exerted a stronger influence on antioxidant accumulation. In summary, moderate drainage recycling facilitates optimal fruit production without negatively affecting quality, while excessive recycling may increase antioxidant activity but leads to reduced yields. The results provide practical recommendations for optimizing nutrient reuse in semi-closed strawberry hydroponic systems. Full article

Sustainable development requires implementation of eco-friendly practices and a circular approach in both agricultural and industrial systems. This study evaluated winery flotation wastewater (WFW) as a cultivation substrate for Bacillus sp. 10/R isolated from grapevine rhizosphere for sustainable biostimulant production. The bacterial isolate was characterized by 16S rRNA sequencing and biochemical tests, showing the highest similarity with Bacillus mojavensis and Bacillus halotolerans. Plant growth-promoting traits were assessed via assays for hydrolytic enzymes, ACC (1-aminocyclopropane-1-carboxylate) deaminase, and IAA (indole acetic acid) production, as well as for phosphate solubilization. The isolate was cultivated in WFW, including monitoring of biomass growth, enzymatic activity, and substrate composition changes. The resulting cultivation broths based on WFW (WFW-CB) and nutrient broth (NB-CB) were tested as barley seed treatment at five dosages, using sterile media and water as controls. The results have displayed strong pectinase (EAI–enzyme activity index 2.79) and cellulase activity (2.33), moderate xylanase (1.75) and ACC deaminase activity (growth zone 54.67 ± 0.58 mm), and moderate IAA production (9.66 µg/mL). Biomass content has increased by two log units within 48 h (up to 9.06 log CFU/mL), with stable pectinase activity (~2.2 U/mL). Germination assays revealed that 10% WFW-CB and 50% WFW enhanced germination indices and biomass, whereas undiluted WFW and WFW-CB inhibited germination. These results indicate that WFW is a suitable substrate for Bacillus sp. 10/R cultivation, linking industrial wastewater valorization with plant biostimulant production in a circular economy framework. Full article

Amidst the rapid development of renewable energy, wind power, as a major renewable energy source, has raised ecological concerns regarding its impacts on ecosystems and biodiversity. Insects, as direct displays and feedback of the environment, have become a hot topic in ecology and conservation biology research due to the impact of environmental changes on them. So this study investigates the effects of wind power density on insect diversity and their mechanisms in the Ningxia desert steppe wind farms. The results indicated that minimal disturbance marginally increased insect aggregation at low wind power densities (2 turbines/km²). However, higher wind power densities caused pronounced insect population declines toward turbines (6, 11 turbines/km²), and with the increase in wind power density, the number of insects decreased significantly. Increased wind power disturbance led to decreases in soil total nitrogen (TN), total carbon (TC), nitrate nitrogen (NO₃⁻-N), and soil moisture content (SM) and a significant decrease in total phosphorus (TP). While direct impacts on vegetation were relatively minor and irregular, vegetation height exhibited strong positive correlations with soil nutrient depletion, suggesting that wind-induced soil degradation indirectly constrains plant growth. Consequently, the effect of wind power on insects is mediated through coupled vegetation–soil interactions. These findings underscore the necessity of integrating ecological thresholds into wind farm management protocols. Full article

The growing challenge of managing end-of-life creosote-treated railroad ties, along with the increasing demand for effective water treatment solutions, has highlighted the potential of converting railroad tie biomass into functional biochar through pyrolysis. Pyrolysis temperatures ranging from 250 °C to 700 °C were evaluated to determine their influence on biochar yield, physicochemical properties, and adsorption performance for nitrate and phosphate. The findings revealed that increasing pyrolysis temperature enhanced biochar surface area and porosity, reaching 454.9 m²/g at 700 °C. Elemental analyses showed maximum carbonization at 550 °C, with carbon content peaking at 80%, reflecting the development of more stable aromatic structures. SEM and FTIR analyses confirmed these structural changes, including the emergence of extensive pore networks and aromatic frameworks. Biochar produced at 600 °C demonstrated high nitrate (80%) and phosphate (79%) removal efficiencies, following Freundlich isotherm models. Magnesium-modified biochar further improved nitrate adsorption, reaching 90% removal at 5 ppm. Importantly, polycyclic aromatic hydrocarbons in the biochar decreased significantly at higher temperatures, ensuring environmental safety. This work demonstrates the dual environmental benefits of converting hazardous railroad tie waste into value-added biochar for nutrient removal in water treatment applications, offering a sustainable and scalable solution for circular waste management. Full article

Sustainable fertilization strategies are critical under climate change and the European Green Deal, particularly for Mediterranean cereal systems. Organic fertilizers derived from agro-industrial residues offer promising alternatives to conventional mineral inputs. This study evaluated RecOrgFert, a novel fertilizer composed of sulfur–bentonite and citrus-processing residues, in comparison with NPK (15-15-15) and horse manure across two years in Central Macedonia (Greece) and Apulia (Italy). Using a randomized complete block design, soil chemical and biological properties, plant growth, yield, and grain quality were assessed. RecOrgFert outperformed conventional fertilizers by enhancing soil fertility—raising organic matter 25–27% above control and further increasing it from 2023 to 2024 (up to +75% in Italy, +38% in Greece)—while improving cation exchange capacity, enzymatic activity, and soil water content. Wheat grown with RecOrgFert showed higher protein (up to 15.2%), antioxidant activity (DPPH > 37%, ABTS⁺ > 26%), and phenolic and flavonoid content, with yields comparable to NPK. The unique sulfur and orange-residue composition distinguish RecOrgFert from standard fertilizers, promoting nutrient cycling, microbial activity, and bioactive compound accumulation. It represents a novel, circular, and climate-smart solution aligned with EU sustainability and circular economy objectives. Full article

Nitrogen (N) is the most important macro-nutrient for plant growth and development, which not only results in the highest cost in crop production but may also lead to environmental pollution. Hence, there is a need to develop N and use efficient genotypes, a prerequisite for which is a better understanding of N stress adaptation. Here, responses of two contrasting linseed accessions at the seedling stage were assessed for N stress-induced changes in twelve phenotypic traits and for gene expression profiling in the roots. The results showed that nine out of twelve phenotypic traits were affected under N stress conditions, and include total root length (TRL), root tips (RT), shoot dry weight (SDW), root dry weight (RDW), root-to-shoot ratio (R/S), plant nitrogen content (PNC), shoot nitrogen content (SNC), root nitrogen content (RNC), and nitrogen use efficiency (NUE). For example, under N stress, the TRL, RDW, SDW, PNC, SNC, and RNC showed reductions of 7.1, 7.6, 16.0, 43.7, 43.3, and 38.7%, respectively. The N-efficient (NE) genotype outperformed the N-inefficient (NI) genotype for all root and shoot traits and NUE under N stress and N normal conditions. Transcriptome analysis identified 1034 differentially expressed genes (DEGs) under the contrasting N conditions and uncovered the opposite responses of the two linseed genotypes to N starvation at the gene expression level. DEGs included 153 transcription factors distributed in 27 families, among which ERF, MYB, NAC, and WRKY were the most represented. In addition, DEGs involved in N absorption and transport, root development, amino acid transport, and antioxidant activity were found to be differentially expressed. The candidate genes identified in the current study are purported for their roles in N metabolism in other crops and might also play a pivotal role in N stress adaptation in linseed, and therefore could be useful for further detailed research on N stress response in linseed, paving the way toward developing N-efficient linseed cultivars with improved root system architecture. Full article

Although the role of biochar in enhancing soil quality has been extensively studied, its specific effects on the changes of soil bacteria and fungi in greenhouse tomato under mulched drip irrigation are not yet fully understood. In order to understand the above-mentioned changes, a two-year experiment on greenhouse tomatoes with mulched drip irrigation was conducted. The objective of this experiment was to explore the relationship between different irrigation levels (W1: 50–70% of the field capacity W2: 60–80% of the field capacity, and W3: 70–90% of the field capacity) and different biochar application rates (B0: 0 t/ha, B1: 15 t/ha, B2: 30 t/ha, B3: 45 t/ha, and B4: 60 t/ha) on soil bacteria and fungi. The results demonstrated that the soil bacterial Chao index was influenced by biochar application and water-biochar interactions, while the soil fungal α-diversity index and bacterial and fungal β-diversity were predominantly impacted by the irrigation level. The random forest modelling indicated that soil bacterial biomarkers were predominantly rare genera, while fungal biomarkers contained both dominant and rare genera. In comparison with the B0 treatment, biochar application resulted in an enhancement of the abundance of bacterial biomarkers associated with nutrient cycling, including Galbibacter (400.90–2216.22%) at the W3 levels. The B4 treatment at both W3 and W2 levels reduced the relative abundance of the pathogenic fungus Aspergillus sp., but the rest of the biochar treatments enhanced it by 4.69–108.16% and 55.86–213.30%, respectively. The Mantel test demonstrated that soil water content was the most significant influencing factor for all soil bacterial and fungal biomarkers. Biochar application significantly altered major bacterial biomarker functions in mulched drip irrigation, while fungal biomarker functions were mainly affected by irrigation levels and water-biochar interactions. At the W3 level, biochar application significantly reduced the relative abundance of Saprotroph–Symbiotroph by 83.44–97.92%. These results serve as a reminder of the critical importance of soil health sustainability in integrated crop management decisions and provide valuable insights for improving soil quality under mulched drip irrigation. Full article

Litter nutrient stoichiometry and its drivers are important for understanding nutrient cycling in desert ecosystems, plant adaptation strategies, and the sustainability of ecosystem functions. However, little is known about the spatial variation in litter nutrient stoichiometry and its environmental drivers in desert shrubs. This study focused on two Nitraria species (N. tangutorum Bobrov and N. sphaerocarpa Maxim) in Northwestern China, analyzing leaf litter N, P, and K stoichiometry, their spatial variation, and environmental drivers. Nutrient concentrations and stoichiometric ratios did not differ significantly between the two species. The average N contents in the litters of N. tangutorum and N. sphaerocarpa were 11.363 mg g⁻¹ and 11.295 mg g⁻¹, respectively. The P contents were 0.591 mg g⁻¹ and 0.611 mg g⁻¹, whereas the K contents were 17.482 mg g⁻¹ and 16.255 mg g⁻¹, respectively. With the changes in geographic and climatic factors, the same nutrient elements of the two Nitraria species showed inconsistent variation patterns. Both species showed low P concentration, indicating high P resorption and possible P limitation, reflecting nutrient vulnerability in desert ecosystems according to the scaling exponents among elements. In litter, the residual nutrient contents ranked as K > P > N, suggesting strong N resorption but low K resorption, especially for N. sphaerocarpa. N was mainly influenced by latitude, P by soil properties, and K by mean annual temperature. Moreover, litter stoichiometric ratios of N. tangutorum were relatively stable, whereas those of N. sphaerocarpa were more sensitive to environmental variables. In conclusion, the two Nitraria shrubs exhibited differential nutrient use strategies under nutrient restriction, providing insights into nutrient cycling and supporting sustainable management of desert ecosystems. Full article

Silicon (Si) has emerged as a promising tool for mitigating the negative effects of biotic and abiotic stresses, such as caused by heavy metals, on plants. The aim of the study was to summarize knowledge about the mechanisms underlying the interaction between silicon and cadmium. This review first discusses silicon compounds in plant physiology, then examines mechanisms of silicon–cadmium interaction, including antioxidant defense, metal chelation, nutrient transport, molecular responses, subcellular changes, and future directions. Recent studies show that various forms of Si, such as conventional Si and Si-nanoparticles (Si NPs), can have various effects on the ability of a plant to absorb and utilize Si for protection. Silicon, taken up mainly as soluble orthosilicic acid (H₄SiO₄) and Si NPs, can be absorbed by plants and subsequently deposited predominantly in cell walls. It has been found that Si and Si NPs increase the activity of antioxidant enzymes, including CAT, SOD, and POD, in plants under cadmium (Cd) stress. Furthermore, Si reduces the expression of Cd transport-related genes, including OsNRAMP5 and OsHMA2 in rice. It has also been shown that supplementation with Si and Si NPs in plants under Cd stress reduces the Cd content in their tissues and changes the uptake of elements necessary for the proper functioning of the plant organism. Furthermore, Si supplementation increases the content of pectins, which are involved in the binding and neutralization of Cd. The following overview highlights the importance of both Si and SiNPs in neutralizing the harmful effects of Cd on the environment and agriculture. Full article

Climate change, marked by increasing temperatures and unpredictable rainfall, presents a significant challenge to the sustainable cultivation of runner beans (Phaseolus coccineus L.). These conditions underscore the urgent need for efficient resource management. Therefore, it is crucial to establish suitable irrigation regimes and nutritional conditions for runner bean cultivars. Furthermore, since genotype performance is strongly influenced by water availability and nutrient supply, understanding their interactive effects is essential for developing technologies that are adapted to climate change and sustain high yields of garden beans. In this context, the individual and combined effects of three runner bean cultivars (Cozia1, Cozia2, and Cozia3), two irrigation regimes (2000 and 2500 m³·ha⁻¹), and three fertilisation strategies (chemical, organic, and unfertilised) on some physiological, morphological, and biochemical parameters were assessed in this study. The field experiment was carried out in the north-eastern part of Romania over two consecutive growing seasons, following a randomized split–split plot design with three replications. The results showed that genotype had the most significant influence on the majority of traits, highlighting its dominant role over fertilization and irrigation. Under chemical fertilization and 2500 m³·ha⁻¹ irrigation, Cozia2 achieved the highest grain yield (3427.60 kg·ha⁻¹) and pod number (48.13), while Cozia1 combined with chemical fertilization under 2000 m³·ha⁻¹ irrigation recorded the highest total phenolic content (0.47 mg GAE·100 g⁻¹ d.w.). Among cultivars, Cozia2 was highly responsive to fertilisation and irrigation variation, showing both the highest and lowest values for pod number, seed weight, and seeds per pod depending on treatment. Notably, the highest photosynthetic assimilation rates were observed in Cozia2 × IR2 × UF and Cozia3 × IR1 × OR combinations. Based on the results of this study, Cozia3 under chemical fertilization is best suited for high yields under limited water (2000 m³·ha⁻¹), while Cozia2 is best suited when chemical fertilization is combined with higher irrigation (2500 m³·ha⁻¹). However, in the context of organic cultivation, Cozia3 is identified as the most suitable cultivar. Full article

The narrow margin for irrigation error in aeroponics necessitates advanced control strategies beyond fixed timer-based approaches. This study evaluates a plant-driven irrigation method based on real-time leaf turgor feedback in aeroponic romaine lettuce (Lactuca sativa L. var. longifolia) cultivation. A leaf thickness–turgor sensor was interfaced with an Arduino Mega 2560 to activate misting events dynamically. Two identical aeroponic systems were operated in a fully controlled environment: a conventional timer-based control (TC) system applying mist every 10 min and an Arduino-controlled (AC) system triggered by turgor changes. Over two independent 37-day cultivation cycles, the AC strategy reduced total water use by an average of 15.9% and pump activations by 17.2% while improving water use efficiency by 17.8% and nutrient use efficiency for N, P, and K by an average of 17.8%, with no statistically significant differences in shoot biomass, height, or yield. Although root dry weight was significantly higher under TC, the AC treatment led to a 45.0% reduction in leaf nitrate accumulation and non-significant increases in phenolic content. These findings demonstrate the potential of turgor-responsive irrigation for enhancing sustainability, resource use efficiency, and the quality of produce in aeroponic systems, thereby supporting its broader integration into controlled-environment agriculture (CEA). Full article

Due to its complex composition and toxicity, the waste liquid from hydrothermal carbonization (HTC) poses a serious environmental challenge that must be addressed before disposal. In this study, the photochemical treatment of HTC liquid in a microreactor flow system was investigated. The effects of wavelength, the presence of atmospheric oxygen, oxidizing agent (H₂O₂) and catalyst (FeSO₄), residence time and pH on the efficiency of the photo-treatment were investigated. In addition, the influence of the addition of deep eutectic solvent (DES) on photo-treatment was studied. The results showed that the photochemical treatment was more efficient at 365 nm than at 420 nm, and that the acidic conditions gave better results than the basic ones. UV₃₆₅ treatment in the presence of H₂O₂ (at a dosage of 1 vol%) resulted in removal efficiencies of 31.6% for COD, 17.6% for TOC, 16.9% for NH₄-N and 17.2% for PO₄-P. The addition of FeSO₄ caused coagulation/flocculation effects, but improved phosphorus removal. The addition of DES resulted in slight discolouration of the liquid and proved unsuccessful in COD removal. The GC-MS analysis and 3D-EEM spectra showed significant changes in the fate of organics and in the fluorescence intensity of aromatic proteins and humic acid-like substances. Photochemical treatment in a microreactor flow system in the presence of H₂O₂ under the selected operating conditions reduced the content of organics and nutrients in the HTC liquid, but the process liquids still showed toxic effects on the organisms V. fischeri and Daphnia magna. Full article

Plant traits could help in designing feasible strategies to mitigate global change in inland wetlands, but the correlations between plant traits and carbon emissions in coastal wetlands remain unclear. Here, we investigated the plant traits (including nutrient, structural, and biomass traits) and environmental conditions (including climate and soil properties) and determined the soil carbon emissions (methane (CH₄), carbon dioxide (CO₂), and their temperature sensitivities (Q₁₀ value)) from the soils of 90 coastal herbaceous wetlands differing in land use types along China’s coastline. We further tested how environmental conditions affected plant traits and how these traits then altered carbon emissions. We found that plant traits had a greater effect on CH₄ and CO₂ emissions than on their Q₁₀ values, with nutrient traits being the key drivers in coastal herbaceous wetlands in China. In general, coastal herbaceous wetlands with larger leaf C and N contents combined with a lower leaf N:P ratio tended to have higher CH₄ emission; those with larger leaf C and P contents combined with a lower leaf N:P ratio tended to have higher CO₂ emission; and those with higher leaf N content and N:P ratio combined with a lower leaf C:P ratio tended to have higher Q₁₀ values of both CH₄ and CO₂. Notably, the predictive power of plant traits in coastal herbaceous wetlands varied significantly across heterogeneous environments influenced by climate and land use. Our results highlight the critical role of plant nutrient traits in driving soil carbon emissions and provide practical insights into understanding coastal carbon dynamics under pressures from climate and land use changes (e.g., coastal reclamation and plant invasion). Full article

Pinellia ternata, a traditional Chinese herb, suffers from soil degradation and nutrient imbalance, which significantly decrease both yield and quality. Here, the application of microbial organic fertilizer (MOF) in the cultivation of P. ternata results in high yields and quality under two soil conditions, whether grown in greenhouse or open-field environments. The application of MOF enhanced seedling emergence rates and photosynthetic efficiency, significantly improving various agronomic traits, and increasing the content of flavonoids and total alkaloids in tubers, with a stronger effect observed at a dosage of 75 g/m². Moreover, available phosphorus, available potassium, catalase, and urease levels were significantly improved. Further, 16S and ITS sequencing revealed that bacteria diversity was not affected by all treatment, while the fungi unweighted UniFrac index showed significant decline in the MOF treatment. The abundance of bacterial Acidobacteriota and Proteobacteria varied with continuous cropping soil, whereas abundance of fungi Ascomycota, Basidiomycota, and Mortierellomycota was changed in the first cropping of P. ternata. These findings suggest that applying MOF improves the microbial communities of the rhizosphere soil of P. ternata, enhancing soil enzyme activities and decomposing organic and inorganic matter. This, in turn, contributes to the yield and quality of P. ternata. Full article