Search Results (749)

Phosphorus scarcity and inefficient fertilizer utilization highlight the need for sustainable phosphorus recovery and reuse strategies. In this study, a Zn/Fe-layered double hydroxide (Zn/Fe-LDH)-kelp-derived biochar (KBC) composite (Zn/Fe-LDH@0.5KBC) was synthesized via co-precipitation for phosphate capture and subsequent reutilization as a slow-release fertilizer. The incorporation of KBC improved the dispersion of LDH nanosheets and generated a hierarchical porous structure with a specific surface area of 122.13 m²/g. As a result, Zn/Fe-LDH@0.5KBC exhibited a high phosphate adsorption capacity of 132.52 mg P/g and reached adsorption equilibrium within 240 min. Kinetic and isotherm analyses indicated that phosphate adsorption was dominated by chemisorption and was best described by the Sips model. Comprehensive scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses revealed that phosphate removal occurred through synergistic mechanisms, including electrostatic attraction, interlayer anion exchange, surface complexation, and metal phosphate precipitation. The P-loaded composite exhibited diffusion-dominated phosphorus release in soil and significantly enhanced pak choi growth. Compared with the control, labile phosphorus increased from 2.8% to 6.8%, while moderately labile phosphorus increased from 6.3% to 14.1%, indicating improved phosphorus availability. These findings demonstrate an effective strategy for integrating phosphate recovery from wastewater with agricultural reuse and provide insights into the development of multifunctional adsorbent-fertilizer systems for circular phosphorus management. Full article

Iron overload is a recognized risk factor for female reproductive dysfunction, yet the underlying cellular and molecular mechanisms remain incompletely understood. In this study, the effects of iron overload on ovarian granulosa cells were investigated, and a protective role of the steroid biosynthesis pathway against ferroptosis was identified. A mouse model of ovarian iron overload was established by daily gavage of ferric citrate (FC, 120 mg/kg for 40 days). Iron-overloaded female mice exhibited disrupted estrous cycles, reduced serum estradiol levels, impaired antral follicle development, and decreased pregnancy rates and litter sizes. Metabolomic analysis of freshly isolated granulosa cells revealed significant depletion of unsaturated glycerophospholipids and fatty acids, along with reduced antioxidants such as glutathione, vitamin E, and coenzyme Q6, and enrichment of the ferroptosis pathway. Transcriptomic analysis showed marked upregulation of genes involved in steroid biosynthesis, including Hmgcr and Fdft1, and their master transcription factor Srebf2. In cultured KK1 granulosa cells, FC treatment increased intracellular Fe²⁺ and reactive oxygen species, decreased glutathione content and NADPH/NADP⁺ ratio, elevated malondialdehyde levels, and induced lipid peroxidation and plasma membrane rupture, all of which were attenuated by the iron chelator deferoxamine. Knockdown of Srebf2 suppressed Hmgcr and Fdft1 expression, exacerbated lipid peroxidation, and increased membrane damage in iron-overloaded cells, confirming that SREBF2-driven steroid biosynthesis acts as an endogenous anti-ferroptotic mechanism. Collectively, these findings demonstrate that iron overload triggers ferroptosis in granulosa cells, leading to follicular arrest and reduced fertility, and that activation of the steroid biosynthesis pathway counteracts ferroptosis, likely through the production of protective intermediates. This study provides a mechanistic basis for iron overload-induced female infertility and identifies the steroid biosynthesis pathway as a potential therapeutic target. Full article

Red mud (RM) can be used as a fertilizer for large-scale disposal, but its low phosphorus content limits its high-value utilization. This study prepared composites of RM and biogas residue (BR) via co-pyrolysis, and adsorbed phosphorus from biogas effluent to increase the phosphorus content. The results show that composites with 25% BR addition and that were pyrolyzed at 600 °C had the highest phosphate adsorption capacity. Composites with a dosage over 50 g·L⁻¹, pH at 3, and initial phosphate concentration lower than 30 mg·L⁻¹ achieved a theoretical maximum phosphorus adsorption capacity of 2.877 mg·g⁻¹. The surfaces of the composites were enriched with functional groups, such as Fe-O, and this formed the complex of FePO₄ for phosphate adsorption incrementation. RM-BR adsorption of phosphate satisfied the pseudo-second-order kinetic equation, and the adsorption constant was up to 0.9949. The adsorption results of phosphorus by the composites can also be well fitted by the Langmuir models (R² = 0.969 and 0.991), indicating that the composites were more inclined to a monolayer adsorption mode. Thus, chemical precipitation was the major way for phosphate adsorption. Furthermore, the environmental impact of the biogas slurry that was disposed of with the composites in this study was lower compared to the traditional coagulation precipitation process. Above all, this study established a practical method for adsorbent preparation of RM for phosphorus recovery from biogas slurry. Full article

Nanoscale zerovalent iron (nZVI) has shown promise for soil remediation. This study examined the impact of this nanomaterial on barley and wheat grown in alkaline soil throughout a complete growth cycle, to assess its potential as a fertilizer and to understand its behavior in an uncontaminated matrix. A greenhouse experiment was conducted in which barley and wheat plants were grown in soil treated with a commercial nZVI slurry at 0 and 5% (equivalent to 0 and 8 g kg⁻¹). Physiological parameters were monitored throughout the growth cycle, and plants were harvested after five months. Biomass production, impact on root and leaf ultrastructure, and the concentrations of Fe and other nutrients were determined in several plant tissues. Soil physicochemical properties were not adversely affected by nZVI application, and an increase in Fe availability was observed regardless of the species, from 1 mg kg⁻¹ to 5.2 and 6.6 mg kg⁻¹ in barley and wheat soils, respectively. However, this increase did not translate into higher Fe accumulation in plant tissues at the end of the growth cycle, nor did it enhance plant growth in either species. Therefore, under the experimental conditions evaluated, the application of nZVI as an iron fertilizer cannot be recommended. Notably, both crops exhibited a greater sensitivity to nZVI during early stages of development, as evidenced by significant reductions in chlorophyll content and increased oxidative stress. These initial adverse effects were progressively alleviated as plant growth advanced, with no detectable alterations in cellular ultrastructure, allowing both species to complete their growth cycle. Full article

Anthocyanin is the primary determinant of visual quality in red-fleshed apples. Iron (Fe) contributes to alleviating chlorosis and improving fruit quality, including anthocyanin accumulation. However, the mechanism linking Fe nutrition to anthocyanin content remains unclear, particularly in red-fleshed cultivars. Here, we evaluated how foliar Fe application influenced anthocyanin and soluble sugar contents in apple flesh and investigated the associated transcriptional responses using RNA-seq. Fe increased leaf chlorophyll content and promoted the accumulation of soluble sugars and anthocyanins in fruits grown in calcareous soil. RNA-seq analysis identified 323 differentially expressed genes (DEGs) in response to Fe treatment. Specifically, multiple DEGs were associated with sugar biosynthesis and transport, anthocyanin biosynthesis, and phytohormone biosynthesis. Based on RNA-seq and physiological analyses, we proposed that Fe may promote anthocyanin accumulation through three putative mechanisms: (i) elevating sugar levels via increased leaf chlorophyll content, thereby providing substrates and signals; (ii) activating key anthocyanin structural genes and related transcription factors; and (iii) stimulating ethylene and brassinosteroid biosynthesis and signaling pathways involved in anthocyanin accumulation. This work provides new insight into the Fe-mediated regulatory network underlying anthocyanin accumulation, offering a practical basis to refine fertilization strategies for fruit quality improvement in red-fleshed apples. Full article

Compost derived from macadamia husks provides a sustainable alternative for improving soil fertility, nutrient uptake, and crop productivity. This study evaluated the effects of different macadamia husk compost (MHC) application rates on nut yield, nut quality, and leaf nutrient concentration in macadamia trees. Compost application significantly (p < 0.05) increased leaf potassium (K), magnesium (Mg), and zinc (Zn) concentrations, with the highest values recorded at 12 t ha⁻¹. Other nutrients (N, P, Ca, Cu, Mn, Fe, and B) were not significantly affected. Nut yield increased with compost application, with the highest yield observed at 12 t ha⁻¹ (63.10 kg tree⁻¹), followed by 8 t ha⁻¹, 4 t ha⁻¹, and the control. Similarly, nut-in-shell yield improved with increasing compost rates. Compost application enhanced key nut quality parameters, including sound kernel recovery, total kernel recovery, and first grade nuts, while maintaining insect damage and immature nuts within acceptable industry standards. Overall, nut quality improved in 2022 compared to 2021. These findings demonstrate that macadamia husk compost is an effective organic amendment for improving yield, nut quality, and selected leaf nutrient concentrations, contributing to sustainable macadamia production. Full article

This study evaluated the effects of peat-based organomineral fertilizers with different compositions and Bacillus spp. inoculation on the growth and nutrient accumulation of loose-leaf lettuce grown under summer and winter conditions. Two independent greenhouse experiments were conducted using a randomized complete block design with eight treatments: no basal fertilized control (T1); conventional mineral fertilization (T2); peat-based organomineral fertilizers containing 50% (T3), 40% (T4), or 30% peat (T5); and the corresponding formulations supplemented with Bacillus subtilis, Bacillus megaterium, and Bacillus aryabhattai (T6–T8). All fertilized treatments were standardized to supply the same P rate. Multivariate analyses revealed a strong effect of fertilization strategy on plant growth and nutritional status. In both seasons, fertilized treatments significantly outperformed the control, while organomineral fertilizers performed similarly to or better than conventional mineral fertilization. The greatest shoot fresh mass and nutrient accumulation were observed in formulations containing lower peat proportions and higher mineral nutrient density, particularly when combined with Bacillus spp. inoculation. In the summer experiment, the 40% peat formulation supplemented with Bacillus spp. (T7) produced the highest shoot fresh mass (197.57 g plant⁻¹), whereas in the winter experiment the highest value was obtained with the 30% peat formulation supplemented with Bacillus spp. (T8; 157.86 g plant⁻¹). These treatments also exhibited greater accumulation of macronutrients and micronutrients, particularly N, P, K, Fe, Mn, and Zn. The results indicate that the performance of peat-based organomineral fertilizers was influenced by the balance between the organic matrix and mineral fraction, as well as by seasonal growing conditions. In addition, Bacillus spp. inoculation was associated with improved performance of formulations with greater mineral nutrient density but did not compensate for less favorable fertilizer compositions. Under the conditions evaluated, peat-based organomineral fertilizers containing lower peat proportions and supplemented with Bacillus spp. performed similarly to or better than conventional mineral fertilization and promoted greater lettuce growth and nutrient accumulation than the non-fertilized control. These findings are limited to a single lettuce cultivar grown in pots under greenhouse conditions across two seasonal experiments conducted at one location. Full article

Agronomic biofortification represents an effective strategy to counteract hidden hunger in humans. Salts and synthetic chelates are widely used as foliar or root applications for enriching vegetables with mineral nutrients. Recently, biochelates have been proposed as a sustainable alternative to synthetic chelates, especially peptide-based biochelates that combine the beneficial role of peptides as biostimulants and chelating agents. This study investigated the impact of multiple foliar applications of two peptide-based biochelates for enhancing Fe and Zn in leaves of hydroponically grown lettuce. No significant differences were observed in the fresh and dry weight of lettuce shoots, leaf pigments, leaf antioxidant activity and leaf macronutrient profile, while a significant increase in biochelate treatments was observed in leaf Fe and Zn concentrations in comparison with untreated control (+38.1% and +44.1%, respectively). Leaf concentration of Fe and Zn in biochelate treatments allowed to estimate that 100 g of biofortified fresh lettuce shoots per day in the human diet can contribute to Population Reference Intake from 7.9 to 11.5% for Fe and from 3.3 to 3.9% for Zn. Moreover, Zn-peptide treatments reduced nitrate concentration with respect to control and Fe-peptide (−9% and −11%, respectively), increasing the quality of lettuce leaves. Overall, peptide-based biochelates proved to be a promising, environmentally friendly fertilizer for lettuce biofortification, enhancing Fe and Zn concentration without impairing yield and leaf quality. Full article

Excess phosphate in aquatic environments can trigger eutrophication and pose risks to ecosystem integrity and public health, even though phosphate is indispensable for plant growth. Herein, we report the fabrication of Zr-LDHs-PS hydrogel microspheres by in situ cross-linking zirconium–magnesium–iron layered double hydroxides (ZrMgFe-LDHs) with Polyvinyl alcohol (PVA) and sodium alginate (SA). The resulting bead-type adsorbent was designed to enable efficient phosphate capture from water while facilitating subsequent, controlled phosphate release. Benefiting from the cross-linking granulation strategy, the microspheres mitigate typical limitations of powdered adsorbents, including compaction, aggregation, and poor separability. General characterization (SEM, FT-IR, XPS, XRD, BET, TG, and zeta potential) elucidated the microstructure and surface chemical composition. The Zr-LDHs-PS microspheres exhibited a maximum experimental adsorption capacity of 51.313 mg/g. Kinetics data were best fitted by the pseudo-second-order model, and adsorption isotherms were subjected to the Freundlich model, pointing to heterogeneous, multilayer adsorption. Importantly, high phosphate selectivity was preserved despite the coexistence of competing anions (Cl⁻, NO₃⁻, and CO₃²⁻). After adsorption, the spent beads released phosphate gradually in water, highlighting their potential for dual functionality. Collectively, these results demonstrate that Zr-LDHs-PS hydrogel microspheres are promising candidates for extraction-based phosphate removal and resource recovery, with prospects for repurposing slow-release phosphate fertilizers to support sustainable plant nutrition. Full article

Iron deficiency is a major global health concern, primarily attributable to inadequate dietary intake and limited absorption of iron. Foliar fertilization of vegetables like bell pepper (Capsicum annuum) may increase their iron content. When especially rich in ascorbic acid, intestinal iron absorption might be improved even further. However, iron content in foods and/or bioaccessibility after in vitro digestion alone would be unreliable predictors of iron bioavailability. Consequently, it seems to be necessary to reconsider digestion models and bioavailability evaluation. The objective of this study was to establish a mucin-enhanced in vitro digestion model to assess the bioavailability of non-heme iron from food matrices in combination with the widely utilized Caco-2 model of intestinal iron absorption. Compared with Fe(III), incubation with 20 µM and 200 µM Fe(II) sulfate increased ferritin formation (normalized to total protein (TP)) in differentiated Caco-2 cells by 80% and 130%, respectively. Furthermore, no loss of cellular viability was observed across the tested Fe(II) and Fe(III) concentrations (20–2000 µM). Three in vitro digestion models (DIN, DIN-lite, and DIN+G), differing mainly in digestive enzyme content, were evaluated for iron bioaccessibility and bioavailability. Only DIN-lite and DIN+G were compatible with Caco-2 cells. Although DIN-lite yielded 25% higher bioaccessible iron than DIN+G, both models resulted in comparable ferritin formation in Caco-2 cells. The DIN+G/Caco-2 model was applied to bell pepper cultivars (‘Ferrari’, ‘Morbidelli’, and ‘Jack Miller’), treated with foliar Fe(II) sprays during cultivation, achieving up to 3.9-fold increased iron content. However, this increase did not translate into enhanced in vitro iron bioavailability in the bell pepper pericarp. Consistent with previous studies, these findings indicate that iron content and bioaccessibility alone are insufficient predictors of iron bioavailability in plant-based foods. At the same time, the mucin-enhanced DIN+G/Caco-2 model proved to be a suitable approach for investigating iron bioavailability in plants. Full article

The Fukushima nuclear accident caused widespread radiocesium contamination, and subsequent decontamination reduced soil fertility by removing nutrient-rich topsoil. Although biological amendments have been widely investigated for soil improvement, their potential to restore crop productivity in decontaminated Fukushima soils remains poorly understood. This study evaluated a Bacillus-based biofertilizer (Yume-Bio) and an Aspergillus fermentation product (kouji) as biological amendments for restoring crop productivity in decontaminated soils. Pot and field experiments were conducted to assess their effects on the growth, mineral nutrition, and seed yield of Perilla frutescens grown in decontaminated Fukushima soils. In pot experiments, Yume-Bio showed no significant effects on plant growth, although slight root improvement was observed. In contrast, application of kouji alone or in combination with Yume-Bio significantly enhanced plant growth, increasing leaf number by 112% and improving biomass production. Nutrient accumulation was also promoted, with total N and Fe increasing by 170% and 194%, respectively. In field experiments at two sites in Fukushima, treatment effects were limited and generally non-significant. These results indicate that kouji has potential to enhance plant growth under controlled conditions, while the effectiveness of biological amendments under field conditions remains site-dependent, highlighting the need to optimize application strategies under heterogeneous soil conditions. Full article

Soil salinization poses a significant global challenge to agriculture and the environment, leading to decreased soil fertility and hindered crop growth. Therefore, the development of effective and environmentally friendly soil improvement strategies is crucial for sustainable agriculture. In this study, a range of eco-friendly, versatile, and highly absorbent hydrogels for soil enhancement were created using itaconic acid (IA) as a hydrophilic monomer. Furthermore, their effectiveness and application in agriculture were thoroughly evaluated. The nano-iron-loaded IA-based hydrogels (nano-iron (III) oxide (nano-Fe₂O₃)/Poly itaconic acid (PIA)-Acrylamide (AM)/Sodium alginate (SA)) hydrogels demonstrated exceptional water absorption and retention capabilities. They exhibited remarkable soil conditioning properties by leveraging carboxyl groups for electrostatic adsorption of saline ions and the porous structure created by the crosslinked network. These features not only significantly facilitated gradual regulation of pH levels and salinity but also effectively enhanced organic matter in saline–alkali soil. Meanwhile, nano-Fe₂O₃ simultaneously served to stabilize the hydrogel structure and enhance crop nutrient absorption. Wheat cultivation trials demonstrated that the hydrogels notably enhanced the growth of 7-day-old wheat seedlings. The degradation rates of the hydrogels can be adjusted by varying the IA amount, allowing for the continuous release of small organic molecules to enhance soil quality, aligning with various crop growth cycles. Overall, these hydrogels function as environmentally friendly and versatile soil conditioners, offering significant potential for enhancing agricultural soil quality and expanding into related fields. Full article

Plant growth-promoting rhizobacteria (PGPR) foster sustainable and environmentally friendly agriculture by promoting plant growth and development. PGPR colonize the root rhizosphere, rhizoplane and root tissues, where they drive organic matter turnover and nutrient cycling, thereby increasing the (phyto)availability of essential macro- (P, N, K, S, Ca, Mg) and micronutrients (Fe, Zn, Mn, Mo, Co, Ni, Cu, B). This process relies on various mechanisms, including acid secretion (rhizospheric acidification and metal chelation), siderophore production (binding Fe, Zn, and other metals) and hydrolytic enzyme-mediated catalysis (phosphatases, phytases). Some of these microorganisms can also modulate the phytohormonal balance, reshaping root architecture and enhancing nutrient uptake, and even can alleviate abiotic stress or serve as biocontrol agents, contributing to pathogen resistance. Even though plant cultivation practices relying solely on synthetic fertilizers rapidly increase crop yield and productivity, they eventually result in crops poor in essential micronutrients and trace elements. This may contribute to micronutrient malnutrition in the human population. On the contrary, PGPR enhance both crop yield and nutritional quality. Therefore, in utilization with other nutrient sources, PGPR provide a promising and scalable approach towards advancing environmentally sustainable agriculture systems. Full article

Excessive chemical fertilization in maize production has reduced fertilizer-use efficiency and increased pressure on soil quality, whereas reducing fertilizer input without yield loss remains challenging. This challenge has shifted attention toward strategies that improve crop nutrient acquisition and utilization under lower fertilizer supply. Harpin protein-based enzyme complexes may provide a regulatory approach, but their field performance under reduced fertilization remains unclear. A two-year field experiment was conducted from 2023 to 2024 using two maize cultivars, Heyu236 and Fuyuan2. In 2023, the harpin protein-based enzyme complex was applied at 200-fold and 300-fold dilutions under conventional fertilization to identify effective spraying concentrations. In 2024, the same two concentrations were evaluated under conventional fertilization and 15%, 30%, and 45% fertilizer reductions. In the 2023 concentration screening trial under conventional fertilization, the enzyme complex increased kernels per ear by 5.6–9.7% and tended to increase the yield by 0.4–17.2% (not significant). In 2024, under reduced fertilization, enzyme application combined with 30% fertilizer reduction produced a stable yield response. In particular, the 300-fold dilution combined with 30% fertilizer reduction increased kernels per ear by 18.1% and 13.2% and grain yield by 16.9% and 9.5% in Fuyuan2 and Heyu 236, respectively. Soil analyses showed that the enzyme treatment mainly improved nutrient availability, as reflected by higher available P, available K, alkali-hydrolyzable N, organic matter, and available Cu, Zn, Fe, and Mn in the soil. These findings suggest that the harpin protein-based enzyme complex helped maintain maize yield under moderate fertilizer reduction by improving kernel formation and soil nutrient availability. Among the tested treatments, foliar application at 300-fold dilution combined with 30% fertilizer reduction showed the greatest potential for reducing fertilizer input while sustaining maize productivity. Full article

Morus alba L. fruit extract (MFE), which is rich in cyanidin 3-glucoside (C3G), demonstrates antioxidant properties and pharmacological effects, but its reproductive safety remains poorly understood. Polyphenols modulate steroidogenesis, spermatogenesis, and sperm acrosome integrity; therefore, toxicity assessment is needed for use. This study aimed to evaluate the antioxidant profiles and subchronic reproductive effects of MFE. MFE was standardized using high-performance liquid chromatography (HPLC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. Male rats were administered MFE (250 or 500 mg/kg BW) for 56 days. Assessments included computer-assisted sperm analysis (CASA), testosterone, seminal fructosamine, and testicular CYP11A1 and androgen receptor (AR) expression. Acrosomal status was determined using PNA lectin staining. The results showed that MFE contained C3G (119.42 mg/g), antioxidant capacity (DPPH IC₅₀: 0.101 mg/mL; FRAP: 465.01 µmol Fe (II)/g), and total contents (phenolics: 41.15 mg GAE/g; flavonoids: 3.15 mg CE/g; anthocyanidins: 11.04 mg C3G/g). MFE did not alter testicular histology and seminiferous stages VII-IX. High doses significantly increased sperm concentration, while both doses reduced sperm beat cross frequency. Testosterone, fructosamine, and CYP11A1/AR expressions showed increasing trends. Significantly, high doses induced a precocious acrosome reaction. In conclusion, MFE has no reproductive toxicity and pro-fertility effects on sperm quantity or androgenic markers, supporting safe subchronic use. Full article