Soil Physicochemical Properties and Rhizosphere Microorganisms Mediates the Growth of Cigar Tobacco Across Different Ecoregions in Yunnan, Southwest China

Abstract

The quality of cigar tobacco is influenced by various factors, among which the ecological environment plays a crucial role. However, it remains uncertain whether Yunnan, known for its diverse ecological environment, is suitable for the growth of cigar tobacco. Therefore, the objective of this study was to investigate the disparities in soil physicochemical properties and soil microbial community across three ecoregions in Yunnan, namely Longyang, Ruili and Tengchong, located in southwest China. Furthermore, we aimed to analyze the correlation of these factors with tobacco growth. The results showed that Longyang exhibited higher values in soil pH (7.78±0.11), available potassium (735.72±198.96), cellulase (1.07±0.23) and polyphenol oxidase (0.39±0.001) compared to Ruili and Tengchong, promoting the growth of cigar tobacco (P<0.05). Additionally, Longyang demonstrated greater soil fungal diversity but lower soil bacterial diversity (P<0.05). Correlation analysis and structural equation modeling further confirmed that soil pH was the primary factor influencing tobacco growth (r=0.802, P< 0.01). Moreover, bacteria exhibited higher sensitivity to soil physicochemical properties compared to fungi, with bacterial structure significantly influencing plant growth (P< 0.05). In summary, the alkaline soil in Longyang, enriched with organic matter and available potassium, exhibited favorable conditions for promoting the soil microbial community and thereby proved more suitable for the growth of cigar tobacco.