Biochar and nanoparticle composites (nano-modified biochar) as next-generation soil amendments for sustainable salt stress management.

Nano-silicon and nano-calcium enriched biochars mitigated salt stress in safflower by enhancing ion homeostasis and root growth

Synergistic Approaches of Nanofertilizers and Soil Amendments on the Productivity of Rice and Some Soil Parameters to Achieve Sustainable Development Goals in Bangladesh: A Review

Rice-based agroecosystems in Bangladesh face mounting challenges from nutrient imbalance, declining soil organic matter, climate-related stress and inefficient fertilizer management. While intensive fertilizer use has raised productivity, it has also reduced nutrient use efficiency and degraded soil quality. Nanofertilizers and organic soil amendments have emerged as complementary strategies to improve nutrient management and soil health in rice systems. This review synthesizes 85 peer-reviewed field, pot and laboratory studies (2005-2025) from Bangladesh and comparable South Asian agroecosystems, evaluating the individual and combined effects of nanofertilizers and soil amendments (biochar, compost, green manure, lime) on rice productivity, soil properties, nutrient dynamics and environmental outcomes. Nanofertilizers improve nutrient use efficiency through controlled release, while amendments enhance soil organic carbon, microbial activity and nutrient retention. Combined application produces synergistic gains, with yield improvements of approximately 25-40% reported under specific experimental conditions. These integrated strategies reduce nutrient losses, strengthen soil function and support more efficient, climate-resilient rice production aligned with SDGs 2, 6, 13 and 15. Most available evidence, however, derives from short-term field and pot trials; long-term, multi-location studies are needed to evaluate nanoparticle fate, environmental safety, economic feasibility and farmer adoption under diverse rice-growing conditions before large-scale deployment.

Unraveling water-biochar synergy under cadmium stress: Coupled enhancement of photosynthetic physiology and bacterial community structure in maize seedlings.

Cadmium (Cd) is a highly toxic element that impairs plant growth and disrupts soil metabolism. Biochar is widely used to remediate Cd-contaminated soil; however, its immobilization performance may be altered by aging, particularly under different water regimes. In this study, a pot experiment was conducted to investigate the combined effects of biochar (0, 1.5%, and 3.0% w/w) and water management (50%, 60%, and 70% field capacity) on maize physiological responses, rhizosphere soil enzymatic activity, and bacterial communities in Cd-contaminated soil. Compared with deficit irrigation, full irrigation (70% θf) mitigated Cd-induced photosynthetic impairment more effectively. Antioxidant parameters responded differently to water and biochar: POD activity, SOD activity, and MDA content increased with increasing soil moisture, whereas CAT activity and GSH content decreased. The addition of biochar reduced POD and CAT activity, whereas the responses of SOD and GSH were V shaped. Soil moisture and biochar significantly influenced microbial community richness and diversity, and the M-B2 treatment (60% θf + 3% biochar) optimized bacterial diversity and promoted the enrichment of Sphingomonas (21.18%); these effects were linked to higher antioxidant enzyme activity. This pot-scale study provides reliable experimental evidence for the synergistic effects of water and biochar on maize seedlings under Cd stress and suggests a mechanistic framework that warrants further validation under field conditions.

Role of Plant Growth Regulators and Biological, Chemical, Nutrient, and Nanomaterial-Based Approaches in Mitigating Micro- and Nanoplastic Stress in Agroecosystems.

Evidence shows that stress mitigators can reduce MNPs-induced stress by improving rhizosphere microbial communities, increasing plant growth and photosynthetic efficiency, and regulating biochemical, transcriptomic, and metabolomic responses.

Biochar Beyond Soil: State of the Art and Future Perspectives of Foliar Applications

Biochar has traditionally been investigated as a soil amendment for improving fertility, carbon sequestration, and nutrient retention. However, recent advances in fine milling, colloidal stabilization, and nanotechnology have enabled the development of biochar-derived materials for foliar application. Unlike conventional soil application, foliar delivery enables direct interaction with leaf tissues, potentially providing faster physiological responses, improved resource-use efficiency, and complementary functions to existing plant biostimulants. This review critically evaluates the scientific basis, agronomic performance, and regulatory implications of foliar biochar applications across diverse crop systems. We synthesize and compare major formulation types, including finely milled suspensions, aqueous extracts, nano-biochar dispersions, and biochar-based composite carriers, based on their formulation characteristics, application methods, and reported biological effects. Across multiple crops, foliar biochar has been associated with enhanced chlorophyll content, improved gas exchange, strengthened antioxidant systems, better osmotic adjustment, and increased nutrient uptake, particularly under abiotic stresses such as salinity, drought, and heat. Mechanistically, these responses are linked to surface deposition effects, redox-active functional groups, modulation of leaf microclimate, and delivery of soluble bioactive compounds. Nevertheless, outcomes remain highly context-dependent, influenced by feedstock origin, pyrolysis conditions, particle size, formulation chemistry, dose, and crop species. Potential risks including phytotoxicity, nanoparticle exposure, environmental fate, and regulatory ambiguity especially for nano-scale formulations pose additional challenges for large-scale adoption. By integrating physiological, agronomic, environmental, and legislative perspectives, this review also highlights key barriers to commercialization, including formulation stability, limited field-scale validation, environmental safety, and regulatory uncertainty, while identifying research priorities needed to determine whether foliar biochar can become a scalable and scientifically validated biostimulant for sustainable agriculture.

Application of Beneficial Microbes to Enhance Agronomic Performance and Soil Health in Problematic Soils: Mechanisms, Challenges and Climate-resilient Agricultural Systems

Problematic soils, including saline, drought-affected, nutrient-deficient, acidic, and heavy metal-contaminated soils, represent major constraints to global agricultural productivity and soil sustainability. These unfavourable soil conditions disrupt nutrient availability, microbial activity, water uptake, and plant physiological processes, ultimately reducing crop growth and yield. Furthermore, prolonged environmental stresses often contribute to diminishing microbial populations, reducing the abundance and activity of beneficial microorganisms involved in nutrient cycling, soil fertility, and plant stress adaptation. Consequently, microbial inoculation has emerged as a promising eco-friendly strategy for restoring soil biological functions and improving agronomic performance under stressful environmental conditions. This review aimed to evaluate the application of beneficial microbes in problematic soils through bibliometric and systematic literature review approaches. Bibliometric analysis using VOSviewer revealed increasing research trends related to rhizosphere microbiology, plant growth-promoting rhizobacteria (PGPR), microbial diversity, diminishing microbial populations, salinity stress, drought stress, and sustainable agriculture. The systematic review demonstrated that beneficial microbes, including PGPR, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, arbuscular mycorrhizal fungi (AMF), and microbial consortia, significantly improve plant growth, nutrient uptake, chlorophyll content, stress tolerance, and crop productivity under various problematic soil conditions. In addition, microbial inoculation enhances soil health through improved nutrient cycling, microbial activity, soil enzyme activities, soil aggregation, and remediation of salinity and heavy metal toxicity. Despite challenges related to field performance variability, limited microbial survival, environmental variability, and insufficient farmer awareness, beneficial microbes remain promising biological agents for supporting sustainable and climate-resilient agricultural systems while reducing dependence on synthetic agricultural inputs.