AbstractThe 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.
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