Biochar amendments to tropical paddy soil increase rice yields and decrease N2O emissions by modifying the genes involved in nitrogen cycling

Summary

This 2023 field study investigated how biochar amendments to tropical paddy soils influence rice productivity and greenhouse gas emissions by modifying the microbial genes governing nitrogen cycling. The research suggests that biochar application increases grain yields whilst simultaneously reducing N2O emissions through shifts in the abundance or expression of nitrification and denitrification genes. The findings indicate a potential mechanism by which soil carbon amendment could enhance both agronomic performance and climate mitigation in rice-growing regions.

Regional applicability

This study was conducted in a tropical paddy rice system, which differs substantially from United Kingdom climate and crop production systems. However, the underlying mechanisms of biochar effects on soil nitrogen cycling genes and emissions reduction may be transferable to temperate cereal and grassland systems, though effects on yield and emission rates would require validation under UK growing conditions. Biochar amendments are increasingly studied in UK soil health and carbon sequestration contexts.

Key measures

Rice yield (tonnes per hectare or similar), N2O flux (ng N m⁻² h⁻¹ or equivalent), abundance of nitrogen cycling genes (likely via qPCR or metagenomic sequencing of genes such as amoA, nirK, nirS, nosZ)

Outcomes reported

The study measured rice grain yields, soil N2O emissions, and changes in the relative abundance of genes involved in nitrogen cycling (nitrification and denitrification) in tropical paddy soil amended with biochar. As suggested by the title, the research evaluated whether biochar modifications alter microbial gene expression related to nitrogen transformations.

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