Biochar from crop residues mitigates N₂O emissions and increases carbon content in tropical soils

Author(s)

Gabetto, Fernanda Palmeira ; Tenelli, Sarah ; Netto-Ferreira, Julia Barra ; Martins Junior, Joaquim ; Almeida, Octavio Augusto Costa ; Cosenza, Marcela Lamas ; Strauss, Mathias ; Carvalho, Joao Luis Nunes

• Document type: Journal article
• Source: BIOFUELS BIOPRODUCTS & BIOREFINING-BIOFPR; v. N/A, p. 17-pg., 2025-02-02.

Abstract

The application of biochar may offer a cost-effective solution to decrease nitrous oxide (N2O) emissions in agriculture soils while having the potential to enhance soil carbon (C) accumulation. Biochar can be produced primarily from a range of agricultural and woody residual biomass, potentially resulting in biochar types with distinct properties. This study evaluated the effects of four different biochar types on soil N2O emissions, C storage, and diversity of the soil microbial community in a tropical environment. A greenhouse experiment with sugarcane plants was conducted with six treatments: soil only (CTR); soil + N fertilizer (NF); NF + sugarcane straw biochar (NF+SB); NF + sugarcane bagasse biochar (NF+BB); NF + Pinus residue biochar (NF+PB); and NF + eucalyptus residue biochar (NF+EB). Regardless of the origin of the feedstock, all biochar reduced the cumulative N2O emissions by 25% to 50% in comparison with the nitrogen-fertilized treatment. Only NF+EB registered higher N2O emissions than NF+SB. The feedstock material also influenced the chemical properties of biochar, showing a negative correlation between oxidized functional groups and N2O emissions. Variations in the physicochemical properties of biochar did not affect soil C levels or microbial diversity, as all treatments with biochar presented similar results. All biochar types increased soil C levels, but only those derived from wood residues showed higher C content than CTR and NF. Despite biochar having no effects on overall soil microbiome diversity, the amendment tended to increase the abundance of Bacteroidetes and Proteobacteria, while suppressing the ammonia-oxidizing phylum Thaumarchaeota. Biochar application had no significant effect on ammonium availability; however, it exhibited the capacity to retain nitrate. The application of biochar in tropical soils can therefore be considered a nature-based solution to decrease N2O emissions and increase C levels without changing microbial diversity. (AU)

• FAPESP's process: 21/11995-0 - Use of biochar in agriculture: implications for N2O emissions and soil microbial community
• Grantee: Fernanda Palmeira Gabetto
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/50403-2 - Valorizing the decentralized biomass production chain for advanced biofuel production: development and evaluation of thermochemical routes integrated with biomass production and biochemical routes
• Grantee: Antonio Maria Francisco Luiz Jose Bonomi
• Support Opportunities: Research Grants - Research Partnership for Technological Innovation - PITE
• FAPESP's process: 22/07665-7 - Integrated crop-livestock system as a strategy to store and stabilize soil carbon in Brazilian agriculture
• Grantee: Sarah Tenelli
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/10573-4 - Center for Carbon Research in Tropical Agriculture (CCARBON)
• Grantee: Carlos Eduardo Pellegrino Cerri
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 21/02691-7 - Implications of sugarcane-based biochar application on soil N2O emissions and crop yield
• Grantee: Fernanda Palmeira Gabetto
• Support Opportunities: Scholarships in Brazil - Technical Training Program - Technical Training