A valorization analysis towards agricultural application of biochar prepared using maize straw grown using organic or chemical fertilizers

Jining Zhang ^1,2,3,4, Li-Ao Ge ⁵, Xianxian Zhang ^1,2,3

⁰Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China.

Scientific Reports +

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April 3, 2025

View abstract on PubMed

Summary

Biochar from maize straw, created using organic or chemical fertilizers, shows potential as a fertilizer. Higher pyrolysis temperatures increase carbon content and soil residence time, with organic fertilizer biochar richer in potassium and phosphorus.

Area Of Science

Agricultural Science
Environmental Science
Soil Science

Background

Biochar, a carbon-rich material derived from biomass pyrolysis, is increasingly recognized for its potential in soil amendment and nutrient management.
The properties of biochar are significantly influenced by the feedstock and pyrolysis conditions, impacting its effectiveness as a fertilizer and soil conditioner.
Understanding the comparative benefits of biochar produced from different fertilization regimes (organic vs. chemical) is crucial for optimizing its application in agriculture.

Purpose Of The Study

To evaluate the potential of biochar-based fertilizers derived from maize straw cultivated under different fertilization strategies.
To analyze the impact of pyrolysis temperature on biochar properties, including carbon content, pH, and mean residence time (MRT).
To compare the nutrient content (potassium and phosphorus) and overall quality of biochar produced from organically and chemically fertilized maize straw.

Main Methods

Maize straw from plants treated with organic or chemical fertilizers (200 kg N hm⁻², 180 kg P₂O₅ hm⁻², 180 kg K₂O hm⁻²) was pyrolyzed at temperatures ranging from 300-700 °C.
The resulting biochar was analyzed for total carbon (C) content, pH, mean residence time (MRT), and concentrations of potassium (K) and phosphorus (P).
Biochar quality was assessed against the industry standard for biochar-based organic fertilizer (NY/T 3618-2020).

Main Results

Increasing pyrolysis temperatures (300-700 °C) consistently elevated biochar's total C content, pH, and MRT.
Biochar from chemically fertilized maize exhibited higher total C content (61.3-74.4 wt%) and MRT (232.5-1473.6 year) compared to organically fertilized maize biochar (54.7-59.1 wt%, 126.7-714.5 year).
Biochar derived from organically fertilized maize showed significantly higher potassium (43.6-113.8 g kg⁻¹) and phosphorus (9.5-12.3 g kg⁻¹) content than that from chemical fertilization (14.5-49.6 g kg⁻¹ K, 5.5-10.5 g kg⁻¹ P). All samples met the NY/T 3618-2020 standard.

Conclusions

Biochar produced from maize straw, regardless of the initial fertilization method, demonstrates potential as a nutrient carrier and soil amendment.
Pyrolysis at 500 °C is identified as a suitable condition for producing biochar that can effectively sequester carbon in soil.
Organic fertilizer-derived biochar offers superior potassium and phosphorus enrichment, while chemical fertilizer-derived biochar provides enhanced carbon stability and soil residence time.

Keywords:

Biochar Chemical fertilization Maize straw Organic fertilization Pyrolysis temperature