Aug 2026· Horticulturae· Vol 12, pp. 1042· 0 citations· 142 references
Abstract
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.
Biochar has emerged as one of the most promising nature-based strategies for improving soil quality, enhancing crop productivity and supporting climate-smart agriculture. However, the agronomic performance of biochar remains highly variable because its effects are governed by complex interactions among feedstock characteristics, pyrolysis conditions, soil properties and management practices. This review synthesizes recent advances in biochar research (2019–2026), examining how production variables determine biochar physicochemical properties and how these properties subsequently influence soil functioning, plant performance and long-term agricultural sustainability. The review integrates evidence on feedstock selection, pyrolysis technologies, biochar modification strategies and the relationships between biochar properties and soil physical, chemical and biological processes. Particular attention is given to crop productivity, nutrient use efficiency, stress mitigation, contaminant immobilization, greenhouse gas mitigation and long-term soil resilience. Across the literature, the most consistent agronomic benefits were observed when biochar was applied to degraded or resource-limited soils and integrated with complementary management practices, whereas responses were often limited under fertile soils, low application rates or short experimental periods. Rather than identifying a universally superior biochar, the evidence indicates that agronomic performance depends on matching biochar characteristics to specific production objectives and environmental conditions. Based on these findings, this review proposes a transition from generalized biochar application towards optimized deployment strategies supported by standardized characterization, long-term multi-site validation and integrated environmental and economic assessments. This synthesis provides a comprehensive framework for guiding future research and facilitating the effective implementation of biochar within sustainable and regenerative agricultural systems.
Ágata Cristiana Correia, C. Pessoa, P. Legoinha et al.· The Scientist· 0 citations
Controlled environment agriculture (CEA), including hydroponics, vertical farming (VF), and soilless cultivation, is expanding rapidly as food production shifts toward resource-efficient and climate-resilient systems. However, conventional substrates such as rockwool, peat, coco coir, and perlite present limitations related to nutrient buffering, structural stability, and environmental sustainability. Biochar has emerged as a promising alternative substrate component due to its porous structure, surface functionality, and ability to modify root-zone conditions. This review synthesizes current knowledge on the role of biochar in controlled cultivation systems, focusing on its physicochemical properties, substrate interactions, and plant physiological responses. Biochar incorporation influences water retention, aeration, nutrient availability, and microbial activity within confined root environments, thereby improving root architecture, photosynthetic performance, crop quality, and plant uniformity. Applications across hydroponic, VF, and soilless cultivation systems demonstrate improved moisture regulation, nutrient buffering, and substrate stability. Biochar interactions with conventional media such as coco peat, perlite, and peat moss further highlight its role in engineered growing substrates. Despite these advantages, challenges remain, including feedstock variability, pH and electrical conductivity effects, lack of standardized specifications, and limited long-term performance data in recirculating systems. Emerging research areas such as engineered biochar, nano-biochar, microbial integration, and precision cultivation technologies offer opportunities to optimize biochar performance in controlled environments. Overall, biochar represents a versatile and sustainable substrate component for CEA, with potential to enhance crop productivity, substrate durability, and resource efficiency. Future research should focus on material standardization, system-specific optimization, and large-scale validation to support commercial adoption.
Nora Baldoni, S. Cocco, Giuseppe Corti et al.· Agronomy· 0 citations
Sustainable agriculture is increasingly challenged by soil degradation, environmental pollution, and climate change, necessitating the pragmatic and eco-friendly approach. This review systematically synthesizes the role of biochar as multifunctional soil management strategy in enhancing soil health and sustainable environmental management, with particular emphasis on the critical roles of feedstock type and pyrolysis conditions in governing biochar performance. To address existing knowledge gaps, we comprehensively evaluate recent available literature on biochar-based environmental remediation, focusing on key indicators of agricultural sustainability, including nutrients availability, soil biological activity, climate change mitigation, biochar-assisted phytostabilization, and crop productivity. Current evidence indicates that biochar application can achieve a net negative carbon footprint, mitigate greenhouse gas emissions and heavy metal contamination, and improve soil structure, fertility, and overall crop productivity on sustainable-basis. However, these benefits largely depend upon the various important biochar production factors including feedstock source, pyrolysis temperature, biochar stability, residence time, rate of application, and soil pH. Beyond its function as a soil amendment, biochar also serves as a multifunctional resource contributing to bioenergy production, waste reduction, and long-term carbon sequestration. At the same time, this review identifies critical research gaps, including the long-term field performance of biochar, mechanisms underlying the interactions between biochar and agronomic practices, and the environmental and human health risks associated with large-scale agricultural applications. Overall, this work highlights the importance of feedstock selection and pyrolysis parameters in designing biochar for environmental remediation and outlines future research directions to refine biochar engineering, application guidelines, and risk assessment frameworks for its sustainable use.
Ismail Khan, Faming Wang, Abdul Rehman et al.· International journal of phy...· 0 citations
Biochar has emerged as a multifunctional soil amendment with the potential to mitigate soil degradation, nutrient loss, and water scarcity. However, its effectiveness depends strongly on feedstock type and production conditions, limiting consistent application across agroecosystems. This review focuses on Paulownia leaf-derived biochar (PLB) as a promising feedstock for sustainable soil management. Current knowledge on its production, physicochemical properties, and mechanisms of interaction with the soil environment is synthesized, with emphasis on nutrient storage, water dynamics, and plant responses. To link process-based understanding with practical application, a case-based approach integrates literature evidence with a previously published experimental study evaluating PLB in turfgrass systems under different fertilization and irrigation regimes. The case study illustrates how feedstock-specific properties, including alkaline pH, high cation exchange capacity, mineral enrichment, and a developed pore structure, contribute to enhanced soil functions and turfgrass performance. The combined evidence indicates that PLB may enhance nutrient storage, water availability, and fertilizer-use efficiency, particularly in intensively managed systems. Overall, this review provides an integrated framework for understanding how the physicochemical properties of Paulownia leaf-derived biochar are translated into soil functions and agronomic responses, supporting the targeted selection and application of biochar for sustainable soil management.
M. Koprivica, Marija Simić, Jelena Dimitrijević et al.· Plants· 0 citations
Soil salinization has become a major constraint on sustainable agricultural development and the improvement of crop productivity. However, the effects of biochar combined with different organic amendments on the microbial ecology of saline–alkaline soils and crop performance remain insufficiently understood. This study evaluated the effects of different amendment strategies, including sole applications of fulvic acid (FA), organic fertilizer (OF), and biochar (BC), as well as their combinations. Soil bacterial community composition, richness, and diversity, oat agronomic traits, hay yield, and forage quality indicators were assessed. Spearman correlation analysis and the Mantel test were employed to examine the relationships among soil physicochemical properties, microbial communities, and crop performance. Combined applications exerted stronger effects on modulating soil bacterial community composition than sole applications, while FA, BC, or their combinations significantly enhanced bacterial richness and diversity. Crop responses exhibited distinct functional differentiation among combined treatments. The biochar combined with fulvic acid (BC + FA) treatment showed the greatest potential for promoting oat growth and increasing yield, with plant height and stem diameter reaching 99.20 cm and 3.99 mm, respectively, and hay yield increasing by 48.5% compared with the control treatment. In contrast, the biochar combined with organic fertilizer (BC + OF) treatment significantly increased crude protein content (CP) and reduced acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents, indicating improved forage quality. Although the crude fat content was numerically higher under BC + OF, no significant differences were observed among treatments. Correlation analyses further revealed that changes in soil physicochemical properties were associated with variations in several dominant bacterial genera, which were correlated with oat agronomic traits and forage quality indicators. Overall, the combined application of biochar with fulvic acid or organic fertilizer improved saline-alkaline soil microbial characteristics and showed potential for enhancing forage oat yield and quality, with BC + FA primarily improving yield production and BC + OF mainly enhancing forage quality.
Teng Wang, Zhen Li, Shilan Shao et al.· Land· 0 citations
Biochar, a carbon-rich solid produced through oxygen-limited pyrolysis of biomass, is increasingly considered a soil amendment for sustainable soil fertility management. Indian agriculture faces continuing pressure from soil degradation, declining soil organic carbon, nutrient depletion, crop-residue burning and climate variability, all of which constrain productivity and resource-use efficiency. This review synthesises literature and field-based evidence relevant to the use of biochar in Indian soil-crop systems. It discusses biochar production through slow, fast and flash pyrolysis using crop residues, woody biomass, and livestock or poultry manure at 300–700 °C, and relates these production conditions to key properties, including porosity, specific surface area, alkaline pH, fixed carbon content and nutrient composition. The review also examines the principal mechanisms through which biochar improves soil fertility, including modification of bulk density, water-holding capacity, aggregate stability, cation exchange capacity, soil reaction, nutrient retention and microbial activity. Evidence reviewed here indicates that biochar can reduce nutrient leaching, influence nitrogen and phosphorus dynamics, contribute to soil carbon sequestration, and mitigate selected greenhouse gas emissions, although responses depend on feedstock, pyrolysis conditions, soil type and crop requirement. Field observations from India suggest that applications within the range of 5–20 t ha⁻¹ can improve the productivity of rice, wheat, maize, legumes, oilseeds, plantation crops and vegetables, with stronger responses generally reported in acidic, sandy and degraded soils. The review further identifies practical constraints to adoption, including production cost, inconsistent product quality, limited standardisation, insufficient extension support and variable soil-crop compatibility. Integrating biochar with integrated nutrient management and decentralised residue management may support more sustainable soil fertility strategies in India.
Manoj Kumar, A. Pandey, Ashutosh Singh et al.· International Journal of Env...· 0 citations