Abstract:In order to investigate the effects of tobacco-rice rotation on the physical and chemical properties of soil aggregates, aggregates composition, yield and quality of tobacco leaves, field surveys were conducted in the tobacco growing areas in Chizhou and Xuancheng, located in the Yangtse plain of southern Anhui Province. In total 9 tobacco-growing fields in Chizhou and Xuancheng were surveyed and sampled, including single cropping rice (0 a), tobacco-rice rotation of 2 a, 4 a and 9 a in Chizhou; tobacco-rice rotation of 1 a, 3 a, 5 a, 8 a and 12 a in Xuancheng. The results showed that 2-5 mm aggregate content in Chizhou increased initially and then decreased with the increase of rotation year; 2-5 mm aggregate content of 1 a rotation soil in Xuancheng was significantly higher than those of other rotation years, and the proportion of 2-5 mm aggregates was negatively correlated with rotation year. With the increase of rotation year, tobacco yield decreased, but chlorine content decreased in middle and upper leaves and K/Cl ratio in upper leaves increased in Chizhou; Sugar-alkali ratio in middle and upper leaves of other rotation years in Xuancheng was higher than that of 1 a rotation, and 5-8 a rotation were suitable for high quality tobacco production. The scores of irritability and dryness of upper leaves in Chizhou showed a downward trend with the increase of rotation year, while the scores of aroma characteristics of upper leaves in Xuancheng increased with the increase of rotation year. There was a significant positive correlation between 2-5 mm aggregate content and tobacco yield in Chizhou and Xuancheng, and the yield was significantly affected by pH of 2-5 mm aggregates in the two areas. There was a significant positive correlation between the content of 2-5 mm aggregates and the content of total sugar in tobacco leaves in Chizhou. The content of total sugar in tobacco leaves in Chizhou was significantly affected by the content of soil available nitrogen. The content and physicochemical properties of 2-5 mm aggregates play an important role in yield and quality of tobacco in southern Anhui. It is necessary to apply straw, organic fertilizer and soil amendments in the farmlands in order to effectively cultivate soil aggregates, improve soil aggregate structure, improve soil quality, and ensure the appropriate, stable, high-quality and unique flavor of flue-cured tobacco in southern Anhui.