The greatest challenge for the agriculture sector in the twenty-first century is to increase agricultural production to feed the burgeoning global population while maintaining soil health and the integrity of the agroecosystem. Currently, the application of biochar is widely implemented as an effective means for boosting sustainable agriculture while having a negligible influence on ecosystems and the environment. In comparison to traditional biochar, nano-biochar (nano-BC) boasts enhanced specific surface area, adsorption capacity, and mobility properties within soil, allowing it to promote soil properties, crop growth, and environmental remediation. Additionally, carbon sequestration and reduction of methane and nitrous oxide emissions from agriculture can be achieved with nano-BC applications, contributing to climate change mitigation. Nonetheless, due to cost-effectiveness, sustainability, and environmental friendliness, waste-derived nano-BC may emerge as the most viable alternative to conventional waste management strategies, contributing to the circular bioeconomy and the broader goal of achieving the Sustainable Development Goals (SDGs). However, it's important to note that research on nano-BC is still in its nascent stages. Potential risks, including toxicity in aquatic and terrestrial environments, necessitate extensive field investigations. This review delineates the potential of waste-derived nano-BC for sustainable agriculture and environmental applications, outlining current advancements, challenges, and possibilities in the realms from a sustainability and circular bioeconomy standpoint.

Improper disposal of organic waste leads to greenhouse gases, pollution, and health risks. Anaerobic digestion offers a sustainable solution by converting this waste into biogas and digestates, which contain valuable nutrients and stimulatory organic compounds that can be recycled to improve plant growth and support food production. Here we review the transformation of liquid and solid digestates into biostimulants by microalgal cultivation, vermicomposting, and insect-based bioconversion. These processes yield phytohormones, polysaccharides, betaines, humic substances, chitin, protein hydrolysates, and growth-promoting microbes, that enhance plant growth and resilience against environmental stresses. Due to the variability in digestate composition, we emphasize the need for optimized formulations, a deep understanding of synergistic interactions among bioactive compounds, and standardized extraction techniques to support broader applications.

Reducing mineral fertilizer inputs while maintaining crop productivity is a central challenge for sustainable grain legume production. This study evaluated whether biochar–biostimulant combinations could improve mungbean ( Vigna radiata L.) performance under reduced NPK fertilization. A polytunnel pot experiment was conducted using a completely randomized 2 × 4 factorial design with two NPK levels, 100% and 50% of the recommended dose, and four treatments: biochar alone, biochar + humic acid, biochar + Bacillus amyloliquefaciens , and biochar + Pseudomonas fluorescens . Biostimulant addition to biochar improved plant growth, pigment status, and antioxidant response, with the strongest responses observed under reduced NPK supply. Under 50% NPK, biochar + P. fluorescens increased grain yield by approximately 90% compared with biochar alone and maintained grain yield (4.00 g plant⁻¹) comparable to the 100% NPK biochar-only control (3.85 g plant⁻¹). It also enhanced nodulation, increased total chlorophyll by approximately 60%, and reduced malondialdehyde by approximately 50%. Grain weight was positively associated with nodule number and ascorbic acid content and negatively associated with H₂O₂ content. These findings support biochar-assisted P. fluorescens supplementation as a promising strategy for sustaining mungbean productivity under reduced NPK input, warranting further field validation for broader applicability.

Honey is a natural sweetener valued for its nutritional and potential health benefits. However, honey’s essential minerals and toxic metals can significantly impact its quality and safety. A total of 12 (n = 12) honey samples, including both local and imported, were assessed for concentrations of essential minerals (iron, zinc, and manganese) and toxic heavy metals (cadmium, chromium, and lead) using Atomic Absorption Spectrophotometry (AAS). The findings revealed significant variability in mineral content, with imported honey generally containing higher levels of iron and manganese. Zinc concentrations were similar between local and imported honey. Concerning toxic metals, cadmium levels in 4 local samples out of 6 and all imported (6) honey samples exceeded the maximum allowable limit. Health risk assessment using Target Hazard Quotient (THQ) and Hazard Index (HI) indicated no immediate non-carcinogenic risk (HI <1), though cadmium contributed the highest proportion to the HI, particularly in local honey. Chromium and lead levels were within safe limits for all samples. The study emphasizes the importance of regular monitoring and stringent quality control to ensure the safety of honey. Further research should investigate the sources of cadmium in local honey and develop mitigation strategies.

Postharvest losses of banana (25-40%) in tropical countries like Bangladesh necessitate effective, eco-friendly preservation strategies. This study evaluated the combined effects of hot water treatment (HWT: T₀=control, T₁=50°C/5min, T₂=55°C/5min) and organic extracts (O₀=control, O₁=propolis, O₂=neem, O₃=Aloe vera, O₄=garlic) on quality and shelf life of banana (cv. Amritsagar) using a two-factor CRD with three replications. Data were analyzed using two-way ANOVA, LSD post-hoc tests, correlation analysis, PCA, and hierarchical clustering. Among all treatments, T₁O₁ (50°C HWT + propolis) exhibited superior performance across all parameters, recording the lowest weight loss (9.72%), lowest decay incidence (11.0%), highest firmness (21.28), highest vitamin C retention (10.17 mg/100g), and longest shelf life (22 days)—a 60.9% extension over untreated control (13.67 days). Correlation analysis revealed strong negative relationships between shelf life and weight loss (r=-0.85) and decay (r=-0.90). PCA and hierarchical clustering confirmed T₁O₁ as a distinct, high-performing treatment cluster. Sensory evaluation rated T₁O₁ highest (8.28/9) vs control (6.67/9). These findings demonstrate that moderate HWT combined with propolis coating significantly improves postharvest quality and extends storage life of banana. This eco-friendly, cost-effective approach offers a sustainable alternative to synthetic chemicals for banana postharvest management in developing countries.