Objective This study aimed to investigate the effects of various mulching films on agronomic traits, yield, economic value, and volatile metabolites of flue-cured tobacco variety 'Yueyan 97', providing theoretical basis for the precise selection of mulching films in Nanxiong tobacco-growing areas.

Method The dominant flue-cured tobacco cultivar 'Yueyan 97' widely cultivated in Guangdong tobacco-growing regions was used as the experimental material. Four mulching film treatments were established, including black-transparent film (BW, transparent in the middle with black edges), fully transparent film (W), silver-transparent film (YGW, transparent in the middle with silver edges), and pure silver film (YG). The application effects were comprehensively evaluated by measuring agronomic traits at maturity, grading yield and value, and analyzing volatile components in tobacco leaves.

Result In terms of agronomic traits, plant height of the W treatment was significantly higher than that of YG, and the maximum leaf length in the BW treatment was significantly lower than YG. There were no significant differences in the number of effective leaves and maximum leaf width among the four mulch treatments. The YG treatment possessed the optimal position of the maximum leaf and the most uniform population growth. In terms of yield and output value, YG had the highest proportion of upper leaves, yield and output value, while treatment W presented the worst comprehensive production performance. A total of 89 volatile compounds from eight chemical groups were identified by GC-MS. The range of relative content of esters was 16.630%, which was affected most obviously by mulch types, whereas alkenes showed the weakest response. Principal component analysis (PCA) demonstrated that YG and W shared similar metabolic profiles, while BW and YGW formed separate clusters. The contents of core aroma substances including esters, trans, trans-farnesol and α-ionone in BW tobacco leaves were significantly higher than those of other treatments, with the lowest concentration of harmful myosmine. Geraniol also reached the highest level under BW treatment, with no significant difference compared with the YGW treatment. Treatment YG accumulated high levels of alcohols and dihydroactinidiolide, but its characteristic aroma components were relatively low and the myosmine content was higher. The W and YGW treatments had certain advantages in ketone accumulation without prominent comprehensive performance.

Conclusion Comprehensively considering agronomic performance, economic output and aroma quality, BW treatment slightly reduced the maximum leaf length but significantly elevated the contents of aroma compounds and decreased harmful components in tobacco leaves, making it the optimal mulch film for high-quality flue-cured tobacco production in Nanxiong tobacco-growing areas. The YG mulch film is suitable for tobacco cultivation targeting stable plant growth and high accumulation of alcohol compounds, while W and YGW treatments show no obvious comprehensive advantages.