不同土壤处理对烤烟根际土壤生物学特性的影响

Effects of different soil treatments on biological characters of rhizosphere soil of flue-cured tobacco(Nicotiana tabacum L.)

为研究土壤特性对烤烟生长及其根际土壤生物学特征的影响,在大田条件下,通过壤土掺沙和壤土掺泥处理,分析烤烟根际微生物群落和土壤酶活性的变化。根际土壤微生物PLFAs多样性指数分析表明,不同土壤处理中壤土各多样性指数都相对较高。微生物生长分析表明,壤土有利于以糖类、脂肪酸类、氨基酸及酚酸类为碳源的微生物生长,掺沙后土壤则有利于以羧酸类、胺类为碳源的微生物生长,掺泥后土壤的微生物功能多样性则表现最差。土壤酶活性分析表明,蔗糖酶活性以壤土最高;过氧化氢酶活性为壤土掺沙﹥对照﹥壤土掺泥;脲酶活性为壤土掺泥﹥对照﹥壤土掺沙。综合认为,壤土特性条件下土壤通透性能好,烤烟根际微生物结构与功能多样性丰富,且有利以酚酸为碳源微生物类群的繁殖,加之相应的土壤酶活性协调,因而最有利烟草生长。生产上可以通过适当客沙或客泥来改良土壤,以改善土壤生物学特性,促进烤烟生长。

Diversity of soil microbial community and enzyme activities in rhizosphere was investigated by mixing loamy soil with sand and mud treatments.Effects of different soil texture on growth of tobacco and its rhizosphere biological characters were studied.Community diversity indexes analysis indicated that the Shannon-Wiener index（H）,Richness index（S）,Pielou index（J） and Simpson index（D） of loamy soil were relatively higher,reflecting better microbial community structure diversity.BIOLOG analysis showed that loamy soil was conducive to growth of microbial flora feeding on carbohydrate,fatty acid,amino acids and phenolic acid as carbon sources.Loamy soil mixed with sands was of great benefit to growth of microbial flora using carboxylic acids and amine as carbon sources.Loamy soil mixed with mud showed the poorest microbial functional diversity.Consequence analysis of enzyme activity in rhizosphere soil illustrated that loamy soil had the highest sucrose activity.Activity of catalase ranked as：soil mixed with sands 〉 loamy soil 〉 soil mixed with mud.Activity of urease ranked as：soil mixed with mud 〉 loamy soil 〉 soil mixed with sands.In summary,the texture of loamy soil is most suitable for growing tobacco.Heavy clay soil should be mixed with sands and over-sandy soil mixed with mud moderately can improve biological characters in rhizosphere soil and enhance tobacco growth.