Role of biochar in sustainable agriculture: Effects on soil properties and plant growth

Introduction

Sustainable agriculture has came up as an analytical method to satisfy the growing global food demand without environmental degradation and while preserving natural resources [1] . Due to conventional agriculture soil degradation, nutrient depletion, and increased greenhouse gas emissions affect the long-term productivity and ecosystem stability [2] . The integration of carbon rich biochar into agricultural systems has emerge as a promising strategy for enhancing soil structure and nutrient retention [3] . Biochar, a solid carbon rich material produced through the pyrolysis of Biomass, has emerged as a promising amendment for improving soil fertility and mitigating agriculture stressors [4] . As the biochar was derived from various sources like agricultural residues, forestry waste, and animal manure which leads to unique physicochemical properties of Biochar which is highly suitable for soil application [5] . Once biochar was applied in soil it has been reported to enhance soil physical, chemical, and biological properties. It improves soil structure, increases water retention capacity, and enhances nutrient availability [6] . Biochar also assist microbial activity and stabilize organic carbon in soil, which is essential for long-term soil productivity. All this improvement help in plant growth and increase crop yield and help in surviving under too much environmental stress (draught , salinity) [7] .Biochar also help in mitigating the climate change through carbon sequestration and reduction of greenhouse gas emissions [8] . The properties of Biochar depend on various factor (feedstock type, production conditions, and application rate). Nanobiochar was synthesized using Rice husk via pyrolysis (600 °C for 2h) continued with ultra sonication and centrifugation. This process yield 27.5% Biochar and 0.9% nanobiochar. Nanobiochar act as maximum dye removal for waste water dye remediation [9] . Silver embedded wheat straw biochar was produced using pyrolysis at 450-500 °C. In this silver is also extracted from Ligustrum lucidum leaf. It act as an efficient green nano-adsorbent for phenol removal from wastewater through adsorption and sonoadsorption processes [10] .

What is Biochar?

Biochar is a recalcitrant, carbon-rich amendment produced through pyrolysis of diverse biomass feedstock, which holds significant potential for optimizing soil physiochemical properties and enhancing agricultural sustainability hence gaining considerable attention in recent years [11] . Biochar-specific properties such as high porosity and large surface area, facilitate improved soil aeration, water retention and bulk density modulation, which are critical for optimal root system development. It is a strong carbon material with a high degree of aromatization [12] .

Precursor of Biochar

Biochar was mainly produced via wide range of biomass which has strong impact on physicochemical properties of Biochar and effectiveness in agricultural applications [13] . There are so many common feedstocks include agricultural residue like rice husk, wheat straw, corn stover, and sugarcane bagasse, These option are widely available and cheap in cost. There are few residue from forest like wood chips, bark, and sawdust it is mainly used due to presence of high percentage of lignin content [14] . There are few more option for precursor of biochar like animal manure including poultry litter and cattle dung will produce nutrient rich biochar with high concentration of Nitrogen, Phosphorus, Potassium. If we compare both plant based biochar and manure based biochar, in plant based biochar it having high carbon stability and other having nutrient availability [15] . Production Methods of Biochar Nowadays biochar production increased using biomass due its various application. There are various method for production of biochar like pyrolysis, gasification, hydrothermal carbonization and torrefaction [11] . Biochar produce via pyrolysis (Pyro means fire and lysis means breakdown) is a process defined by the thermochemical decomposition of biomass in oxygen-limited environments, yields a highly porous, carbon rich material capable of sequestering carbon while mitigating soil degradation [17] .

There are mainly two type of pyrolysis (Slow pyrolysis and Fast pyrolysis) In slow pyrolysis, the process temperature is between 300-500C with longer times, it help to produce high yield of biochar with high stability carbon and high porosity. It promote sustainable agricultural productivity. In fast pyrolysis, the process temperature are too high, and have short residence time, this process help for bio-oil production instead of Biochar [18] . There are various other types of pyrolysis like flash pyrolysis, vaccum pyrolysis and intermediate pyrolysis [11] . Other than pyrolysis there is another technique named Gassification, This process occur in High temperature always more than 700 °C with presence of gasification agent oxygen. But in this technique also syngas was produced and biochar as side product (in small quantity). Syngas includes Carbon monoxide, Carbon dioxide, Methane, Hydrogen [19] . One more technique is torrefaction which is a hydrothermal process where heating at 200-300 °C in low oxygen environment, in this 70% of Biomass remain as solid biochar and remaining came out as gases and condensable side product [43] . Biochar yield and quality totally depend on production parameter like Temperature, Heating rate, residence time. During pyrolysis high temperature was provided, It usually help in increasing surface area and aromaticity and functional group [20] . Hydrothermal carbonization is a technique occur in 180-300 °C with a residence time 1-16 h. Via this technique biochar production was around 50-80% and bio-oil and syngas produce as side product [21] . Biochar nanodot synthesized from soyabean straw and cattle manure via pyrolysis and continued with hydrothermal treatment using nitric and sulphuric acid. After characterization of nanodot sizes are confirmed as about 4-5nm. It showed potential application in environmental remediation, water treatment, and sustainable agriculture [22] .,Biochar is synthesized using rice husk by hydrolysis under ambient temperature and pressure with an acid catalyst (H2SO4). This technique used as alternate conventional pyrolysis. SiO2 is a byproduct in this process [23] . Biochar was produced using hydrothermal carbonization under optimized condition (187 °C, 8 h reaction time, and 1.19 mol/L H₃PO₄ concentration). The synthesized biochar showed improved adsorption capacity and achieved about 46% removal of 2,4-dichlorophenol (2,4-DCP) from wastewater [24] . Fast pyrolysis 500-1000 1-24 h

Biochar-12 Bio-oil-75 Syngas-13 [40] Hydrothermal carbonization 180-300 1-16h

Biochar-50-80 Bio-oil-5-20 Syngas-2-5 [41] Gasification 700-900 10-20 sec Biochar-10 Bio-oil-5 Syngas-85 [42] Torrefaction 200-300 10-60 min Biochar-80 Bio-oil-0 Syngas-20 [43] Flash carbonization 300-600 More than 30 min Biochar-37 Bio-oil-Syngas- [44] Physicochemical Properties of Biochar Biochar is a solid substance produced via carbonization of biomass. It is cahracterized by a highly porous structure and diverse array of surface functional groups, which fundamentally dictate its interaction with soil matrices and nutrient retention capacity. It will be having Higher carbon content and Energy value and lower hydrogen and oxygen content [25] .

Physical property

Biochar has high porosity and it contain macro, meso and micro pores, it act like a sponge. In macropore the pore size is more than 50 nm, these function as pathway for root penetration and habitat for soil microbe . In mesopore the pore size is 2 to 50 nm it usually act as storage space for liquid water and nutrient molecule. In micropore the pore size is less than 2 nm [26] . Biochar have specific surface area, mechanical strength and physical stability, The physical structure of biochar is highly stable due to rigid aromatic carbon matrix so biochar maintain shape in soil for long period of time. Biochar has high water retention property, it trap water within the pores, it help to reduce soil runoff.

Biochar also help in reduce soil compaction and improve root aeration [27] .

Chemical property

Biochar is alkaline in nature (7 to 10), due to this basic nature it is very helpful in neutralizing acidic soils for cultivation. Lime is globally used to manage the acidic soil. High cost and its scarcity reduced the usage in many area.

To overcome this issue biochar produced using rice husk and corn cob is very much helpful to tackle soil acidity [28] . Biochar are having high cation exchange capacity, it hold on positively charge nutrient like Calcium, magnesium and potassium. It also contain functional group like hydroxyl group, carboxyl group, phenolic group. It has high carbon content, it consist fixed carbon. Biochar contribute nutrient to the soil, it also adsorbs toxic substance like heavy metals.

In one study it was seen that biochar synthesis using peanut shell and cattle manure are very much helpful in decrease in exchanging Al and H ion and increase the cation exchange capacity [29] . Biochar synthesis using pecan shell at temperature below 700 °C having neutral pH (7.2) and high surface area (222 m²/g), with 92% carbon content [45] .

Table 3: Properties of Biochar [30] Property

Effect of Biochar on Soil Fertility

Biochar refine soil fertility by boost the physical, chemical, and biological properties of soil. If we talk about physical improvement. Biochar application in soil upgrade the structure of soil, increase porosity, bulk density reduce and aeration will improve and filteration of water. For sndy soil, Biochar help to hold water and maintain the nutrient and for clay soil biochar help in improving the drainage and reduce compaction [31] .

Chemically, Biochar help in maintaining soil pH because pH of biochar is alkaline so it help in neutralizing the pH of soil especially in acidic soil [28] . Even Biochar help reducing aluminum toxicity and improving nutrient availability. Biochar also help improving cation exchange capacity, which help soil maintain essential nutrients such as potassium (K), calcium (Ca), magnesium (Mg), and ammonium (NH₄⁺). Biochar has ash and mineral nutrient which support soil fertility [29] . Biologically, Biochar support favourable environment for beneficial soil microorganisms (nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and mycorrhizal fungi). The micropores in biochar act as microhabitat for growth and nutrient cycle of microorganisms by protecting them from environmental stress and predators [32] . Microbial activity improve soil health and fertility by improving decomposition and nutrient mineralization. Biochar application in soil increase microbial biomass and diversity. Biochar also improve soil enzyme activity in carbon, nitrogen, and phosphorus cycling. Better soil enzyme activity increase decomposition and nutrient mineralization processes [33] . As biochar adsorb toxic chemical and heavy metal, it help microbe for there growth by providing more favourable environment and reducing stress [34] .

Effect of Biochar on Plant Growth and Crop Yield

Effect of biochar application on plants show positive effect through multiple mechanism. Biochar improve nutrient availability, better water retention, enhanced microbial activity, and improved soil structure which sustain healthy plant growth [35] . Biochar enhance seed germination by holding up the water, maintaining moisture in soil and aeration condition. Biochar also help in root development by reducing soil compaction. Root growth allow palnt to absorb water and nutrient. Soil with poor nutrient, after biochar application in soil lead to yield improvement [36] . Biochar is a effective tool for carbon sequestration and climate change mitigation [37] . Biochar is produced through a thermochemical process by converting biomass into stable carbon-rich material under no or less oxygen [17] . In this process few portion of carbon becomes resistant to microbial decomposition, due to this biochar remain in soil for a very long period of time. Biochar application in soil act as a long-term carbon sink by hindering the fast release of CO 2 into environment. Biochar can reduce the emission of greenhouse gases (Methane, nitrous oxide). So Biochar contribute to climate mitigation [38] .

Biochar for Carbon Sequestration and Climate Change Mitigation

Conclusion

To solve the agriculture land issue Biochar came up as a best solution that fulfil the gap between productivity and environment safekeeping. Biochar benefit are not only limited to agriculture field. Biochar improve soil fertility and crop performance to mitigating climate change through carbon sequestration. The material which is once accepted as waste can now be transformed into valuable resource with lot of benefit as supporting future food security. Biochar is a one stop resolution for all different issue.

Acknowledgement

AcknowledgementsThe authors gratefully acknowledge the support and academic facilities provided by Vikrama Simhapuri University, Nellore-524324, and Signova Agro Management Private Limited, Hyderabad-500082, which facilitated the preparation and completion of this review article. The authors also extend their sincere thanks to colleagues, faculty members, and research staff for their valuable suggestions, encouragement, and support during the compilation of the literature and manuscript preparation. International Journal of Advanced Biochemistry Research https://www.biochemjournal.com

References

1. Smit B, Smithers J. Sustainable agriculture: interpretations, analyses and prospects. Can J Reg Sci. 1993;16(3):499-524.
2. Srivastava RK. Conservation tillage practices on GHG emissions, soil health and overall agricultural sustainability. Soil Use Manag. 2025;41(2).
3. Atkinson CJ, Fitzgerald JD, Hipps NA. Potential mechanisms for achieving agricultural benefits from biochar application to temperate soils: a review. Plant Soil. 2010;337(1):1-18.
4. Rathinapriya P, Maharajan T, Jothi R, Prabakaran M, Lee IB, Yi PH, et al. Unlocking biochar impacts on abiotic stress dynamics: a systematic review of soil quality and crop improvement. Front Plant Sci. 2025;15:1479925.
5. Kalus K, Koziel JA, Opaliński S. A review of biochar properties and their utilization in crop agriculture and livestock production. Appl Sci. 2019;9(17):3494.
6. Blanco-Canqui H. Biochar and soil physical properties. Soil Sci Soc Am J. 2017;81(4):687-711.
7. Singh BP, Cowie AL. Long-term influence of biochar on native organic carbon mineralisation in a low-carbon clayey soil. Sci Rep. 2014;4(1):3687.
8. Gupta DK, Gupta CK, Dubey R, Fagodiya RK, Sharma G, Kumar A, et al. Role of biochar in carbon sequestration and greenhouse gas mitigation. In: Biochar Applications in Agriculture and Environment Management. Cham: Springer International Publishing; 2020. p. 141-165.
9. Aziz S, Uzair B, Ali MI, Anbreen S, Umber F, Khalid M, et al. Synthesis and characterization of nanobiochar from rice husk biochar for the removal of safranin and malachite green from water. Environ Res. 2023;238:116909.
10. Khan MN, Siddique M, Mirza N, Khan R, Bilal M, Riaz N, et al. Synthesis, characterization, and application of Ag-biochar composite for sonoadsorption of phenol. Front Environ Sci. 2022;10:823656.
11. Shyam S, Ahmed S, Joshi SJ, Sarma H. Biochar as a soil amendment: implications for soil health, carbon sequestration, and climate resilience. Discov Soil. 2025;2(1):18.
12. Rizwan M, Murtaza G, Zulfiqar F, Moosa A, Iqbal R, Ahmed Z, et al. Sustainable manufacture and application of biochar to improve soil properties and remediate soil contaminated with organic impurities: a systematic review. Front Environ Sci. 2023;11:1277240.
13. Mukherjee A, Patra BR, Podder J, Dalai AK. Synthesis of biochar from lignocellulosic biomass for diverse industrial applications and energy harvesting: effects of pyrolysis conditions on the physicochemical properties of biochar. Front Mater. 2022;9:870184.
14. Xu J, Xie Y, Yao Q, Lv L, Chu H. Advances in sustainable nano-biochar: precursors, synthesis methods and applications. Nanoscale. 2024;16(32):15009-15032.
15. Kalus K, Koziel JA, Opaliński S. A review of biochar properties and their utilization in crop agriculture and livestock production. Appl Sci. 2019;9(17):3494.
16. Jha S, Gaur R, Shahabuddin S, Tyagi I. Biochar as sustainable alternative and green adsorbent for the remediation of noxious pollutants: a comprehensive review. Toxics. 2023;11(2):117.
17. Luo L, Wang J, Lv J, Liu Z, Sun T, Yang Y, et al. Carbon sequestration strategies in soil using biochar: advances, challenges, and opportunities. Environ Sci Technol. 2023;57(31):11357-11372.
18. Brown TR, Wright MM, Brown RC. Estimating profitability of two biochar production scenarios: slow pyrolysis vs fast pyrolysis. Biofuels Bioprod Biorefin. 2011;5(1):54-68.
19. You S, Ok YS, Chen SS, Tsang DC, Kwon EE, Lee J, et al. A critical review on sustainable biochar system through gasification: energy and environmental applications. Bioresour Technol. 2017;246:242-253.
20. Zhao B, O'Connor D, Zhang J, Peng T, Shen Z, Tsang DC, et al. Effect of pyrolysis temperature, heating rate, and residence time on rapeseed stem derived biochar. J Clean Prod. 2018;174:977-987.
21. Ojewumi ME, Chen G. Hydrochar production by hydrothermal carbonization: microwave versus supercritical water treatment. Biomass. 2024;4(2):574598.
22. Guo F, Bao L, Wang H, Larson SL, Ballard JH, Knotek-Smith HM, et al. A simple method for the International Journal of Advanced Biochemistry Research https://www.biochemjournal.com synthesis of biochar nanodots using hydrothermal reactor. MethodsX. 2020;7:101022.
23. Li F, Xu J, Xie Y, Yao Q, Hu F, Lv L, et al. Fast synthesis of biochar by hydrolysis with an acid catalyst for efficient low-temperature SCR of NO. ACS Omega. 2025;10(29):32301-32309.
24. Mubashir S, Ba-Abbad MM, Ewis D, El-Naas MH. Synthesis of biochar from tamarind seed: experimental optimization using response surface methodology design. Chem Pap. 2025;79(6):3587-3600.
25. Kuryntseva P, Karamova K, Galitskaya P, Selivanovskaya S, Evtugyn G. Biochar functions in soil depending on feedstock and pyrolyzation properties with particular emphasis on biological properties. Agriculture. 2023;13(10):2003.
26. Cao Y, Zhang K, Liu S, Wang Y. A review of advancements in the theory and characterization of soil macropore structure. PeerJ. 2024;12.
27. Chia CH, Downie A, Munroe P. Characteristics of biochar: physical and structural properties. In: Biochar for Environmental Management. Routledge; 2015. p. 89-109.
28. Huang K, Li M, Li R, Rasul F, Shahzad S, Wu C, et al. Soil acidification and salinity: the importance of biochar application to agricultural soils. Front Plant Sci. 2023;14:1206820.
29. Gondek K, Mierzwa-Hersztek M, Kopeć M, Sikora J, Głąb T, Szczurowska K. Influence of biochar application on reduced acidification of sandy soil, increased cation exchange capacity, and the content of available forms of K, Mg, and P. Pol J Environ Stud. 2018;28(1):103-111.
30. Sorrenti G, Masiello CA, Dugan B, Toselli M. Biochar physico-chemical properties as affected by environmental exposure. Sci Total Environ. 2016;563:237-246.
31. Mukherjee A, Lal R. Biochar impacts on soil physical properties and greenhouse gas emissions. Agronomy. 2013;3(2):313-339.
32. Bardhan S, Chanda DK, Barrili S. Effects of biochar on biochemical cycles. In: Biochar as Remediation Tools for Pollutant Removal. 2026. p. 307-346.
33. Ali A, Jabeen N, Chachar Z, Chachar S, Ahmed S, Ahmed N, et al. The role of biochar in enhancing soil health and interactions with rhizosphere properties and enzyme activities in organic fertilizer substitution. Front Plant Sci. 2025;16:1595208.
34. Manikandan SK, Pallavi P, Shetty K, Bhattacharjee D, Giannakoudakis DA, Katsoyiannis IA, et al. Effective usage of biochar and microorganisms for the removal of heavy metal ions and pesticides. Molecules. 2023;28(2):719.
35. Khan S, Irshad S, Mehmood K, Hasnain Z, Nawaz M, Rais A, et al. Biochar production and characteristics, its impacts on soil health, crop production, and yield enhancement: a review. Plants. 2024;13(2):166.
36. Adesoyin AE, MacCarthy DS, Adiku GSK, et al. Interactive effects of soil compaction, biochar application, and soil water regime on the growth, yield, and water use efficiency of upland rice. Sci Afr. 2023;21.
37. Lorenz K, Lal R. Biochar application to soil for climate change mitigation by soil organic carbon sequestration. J Plant Nutr Soil Sci. 2014;177(5):651-670.
38. Yin Y, Yang C, Li M, Zheng Y, Ge C, Gu J, et al. Research progress and prospects for using biochar to mitigate greenhouse gas emissions during composting: a review. Sci Total Environ. 2021;798:149294.
39. Babu KKBS, Nataraj M, Tayappa M, Vyas Y, Mishra RK, Acharya B. Production of biochar from waste biomass using slow pyrolysis: studies of the effect of pyrolysis temperature and holding time on biochar yield and properties. Mater Sci Energy Technol. 2024;7:318334.
40. Brewer CE, Hu YY, Schmidt-Rohr K, Loynachan TE, Laird DA, Brown RC. Extent of pyrolysis impacts on fast pyrolysis biochar properties. J Environ Qual. 2012;41(4):1115-1122.
41. Liu Z, Quek A, Hoekman SK, Balasubramanian R. Production of solid biochar fuel from waste biomass by hydrothermal carbonization. Fuel. 2013;103:943-949.
42. You S, Ok YS, Chen SS, Tsang DC, Kwon EE, Lee J, et al. A critical review on sustainable biochar system through gasification: energy and environmental applications. Bioresour Technol. 2017;246:242-253.
43. Potnuri R, Rao CS, Surya DV, Sridevi V, Kulkarni A. Two-step synthesis of biochar using torrefaction and microwave-assisted pyrolysis: understanding the effects of torrefaction temperature and catalyst loading. J Anal Appl Pyrolysis. 2023;175:106191.
44. Köves M, Madár V, Ringer M, Kocsis T. Overview of traditional and contemporary industrial production technologies for biochar along with quality standardization methods. Land. 2024;13(9):1388.
45. Li S, Harris S, Anandhi A, Chen G. Predicting biochar properties and functions based on feedstock and pyrolysis temperature: a review and data syntheses. J Clean Prod. 2019;215:890-902.