连作对植烟土壤微生物群落多样性的影响

Effect of Continuous Cropping on Tobacco Soil Microorganism Community Diversity

连作影响土壤健康的微生物学机制分析是当前的研究热点之一。本试验首次采用BIOLOG生态板法从生理代谢水平上分析了烟草连作对土壤微生物多样性的影响。对分别来自重庆黔江和河南洛阳不同连作年限的烟田土样研究结果一致表明:(1)短期连作(连作年限≤3 a)时的土壤微生物平均吸光度值(AWCD)显著高于4 a和5 a的连作土壤,反映出短期连作土壤仍具有较高的微生物活性;(2)短期连作时土壤微生物的Shan-non指数、Simpson指数显著高于4 a、5 a连作,重庆和河南地区的McIntosh指数总体上表现出短期连作高于长期连作,Shannon均一度指数则无显著差异;(3)主成分分析(PCA)结果显示:连作烟田土壤微生物利用的主要碳源是糖类、高分子类和羧酸类,短期连作的土壤微生物具有较高的的碳源利用率。综合研究结果表明:短期连作(连作年限≤3 a)土壤仍保持较高的微生物多样性,但连作4 a、5 a的土壤微生物多样性则急剧降低。本试验结果为烟田土壤健康机制研究的一部分,有助于进一步探讨土壤的可持续利用及土传病害防治新途径。

Effect of continuous cropping on soil microorganism mechanis is one of hot research issues at present. The effect of continuous cropping on soil microorganism diversity was analysed at the metabolic level by using BIOLOG. The tobacco soil from Chongqing and Henan was analysed and the results indicated ： （ 1 ） The average well color development（AWCD） of soil microorganism was significantly higher under short -term continuous cropping（ continuous cropping years ≤3 years） than 4 and 5 years, this reflected that soil microorganism activities were still high under shortterm continuous cropping. （2） The Shannon index and Simpson index of soil microorganism were significantly higher under short-term continuous cropping, the McIntosh index of Chongqing and Henan had the similar law as a whole, the difference of Shannon uniformity index was not significant. （3） The results of principal component analysis（PCA） indicated that carbohydrates, carbohydrates and carboxylic acids which were the main carbon resources were utilized by soil microorganism of continuous tobacco cropping, the soil microorganism had a higher utilization rate of carbon resource under short-term continuous cropping. The synthetical study indicated that the soil microorganism diversity was higher under short-term continuous cropping, and sharply declined after 4 and 5 years. The test was a part of the research of soil health mechanism, and can provide new ways for sustainable use of soil and control of soil-borne dieases.