No‐Till Improved Peanut Flavour Quality and Aroma Through Soil Nitrogen–Microbiome Regulation

ABSTRACT Peanut ( Arachis hypogaea L.) flavour quality is an important determinant of its market value and consumer acceptance. No‐tillage (NT), a widely adopted conservation agricultural practice, reduces soil disturbance and alters soil microbial communities, potentially influencing the accumulation of flavour‐related compounds in peanut. However, the mechanisms linking NT management to peanut flavour quality, particularly through soil nitrogen dynamics and microbial processes, remain poorly understood. This study investigated the effects of NT versus conventional tillage (CT) on soil physicochemical properties, microbial community function, and flavour quality of peanut in the red soil region of Southern China. Results showed that, compared to CT, the NT substantially increased the soil pH, total nitrogen, and ammonium (NH 4 + ) nitrogen content, while decreasing nitrate (NO 3 − ) nitrogen. NT also substantially enhanced the abundance of nitrification functional genes that is, AOA ‐amoA and AOB ‐amoA and reduced cumulative CO 2 emissions and global warming potential, but increased CH 4 and N 2 O emissions. Notably, NT substantially improved the content of six key fatty acids, including oleic and linoleic acids, and modulated amino acid metabolism by significantly elevating umami‐related amino acids (glutamic acid, asparagine) and aromatic amino acids, while reducing the bitter amino acids. Furthermore, GC–MS analysis detected 344 volatile compounds whereas orthogonal partial least squares discriminant analysis (OPLS‐DA) identified 23 differentially abundant substances under NT. Among these, the levels of terpenoids such as (E,Z)‐2,6‐nonadienal (cucumber‐like odour) and (E,E)‐2,6‐nonadienal (fruity/melon‐like odour) were significantly higher, constituting the primary characteristics of the ‘fresh, clear aroma’ and ‘umami’ notes of peanut under NT. In addition, Mantel test revealed significant positive correlations between amino acid/fatty acid components and the abundance of Proteobacteria/AOA ‐amoA gene, confirming that NT improved the peanut flavour and quality through coordinated shifts in soil microbial community composition and nitrification function.