草木灰对烤烟根际土壤微生物群落结构及代谢功能多样性的影响

施用草木灰旨在改善土壤微生物群落结构，减少由土壤自身衰退而引发的土传病害，更好的维持土壤生态系统的平衡。通过田间小区试验，采用平板培养法和BIOLOG技术研究施用草木灰对烤烟根际土壤微生物数量和功能多样性的影响。研究结果表明：施用草木灰显著增加了烤烟根际细菌、放线菌和微生物总量(P＜0.05)，真菌数量虽略有降低但差异并不明显；移栽后35、55、75天的3个时间段均有一致规律。同时，上述3个时间段烤烟根际微生物群落碳源利用率(AWCD)和对6类碳源的利用程度也以施用草木灰处理显著高于对照。施用草木灰后，烟株各时期根际土壤微生物群落Shannon 指数(H)、Simpson指数(D)、均匀度指数(E)、丰富度指数(S)(P＜0.05)均有所提高，其中移栽后35天时差异显著。根际微生物群落的PCA分析表明，增施草木灰处理和对照在主成分坐标体系中差异十分明显，草木灰处理集中在第1主成分正方向，而未施用的对照则集中在第1主成分负方向，表明土壤微生物功能多样性差异显著。上述说明增施草木灰在改善烟株根际土壤微生物群落结构及功能多样性方面有明显效果。

Effect of applying plant ash on rhizosphere soil microbial quantity and functional diversity of flue-cured tobacco

The application of plant ash is aimed at improving the soil microbial community structure, reducing the soil-borne diseases caused by the degeneration of the soil itself and better maintaining the balance of the soil ecosystem. A field experiment was conducted to explore the effects of applying plant ash on rhizosphere soil microbial quantity and functional diversity of flue-cured tobacco using plate culture method and Biolog technique. The results showed that the application of plant ash all significantly increased the amounts of bacteria, actinomycetes and the total microbes in rhizosphere of flue-cured tobacco, while the number of fungi decreased slightly at 35 d, 55 d and 75 d after transplanting respectively, the difference was not significant. Meanwhile, the utilization of carbon sources (AWCD) and six types of carbon sources in rhizosphere microbial communities of flue-cured tobacco was also significantly higher than that of the control during the periods mentioned above. The diversity indices (Shannon index, Simpson index, Evenness index and Richness index) of the rhizosphere soil microbial treated by plant ash were increased in all periods, and the difference was significant at 35 days after transplanting. Principal component analysis also suggested that the difference between the plant ash treatment and the control was obvious in principal component coordinate system with the plant ash treatment distributing in positive direction of PC1 while the control distributing in negative direction, indicating significant differences in soil microbial functional diversity. The above results showed that applying plant ash significantly improved the microbial community structure and functional diversity in rhizosphere soil of tobacco plants.