长期定位不同施肥类型对烟田土壤nifH细菌群落结构的影响

  目的  解析长期施肥对烟田土壤中含nifH细菌群落结构和丰度的影响。  方法  通过田间定位试验，研究了长期单一施用化肥（T1）、化肥+稻草回田（T2）和化肥+稻草回田+饼肥（T3）3个处理对烟田土壤无机氮及烟株根际土壤nifH细菌多样性的影响。  结果  ① 长期采用稻草回田并施用饼肥有利于提高植烟土壤无机氮含量；②稻草回田或再增加饼肥处理的烟田土壤中细菌α多样性均高于单施化肥处理；③在细菌群落组成中变形菌门（Proteobacteria）和该菌门下物种的相对丰度最高，且稻草回田并添加饼肥处理最高；④植烟土壤微生物LEf Se进化分支图表明单施化肥、化肥+稻草回田和化肥+稻草回田+饼肥的烟田土壤的细菌优势种群主要是披毛菌目（Gallionellales）、根瘤菌目（Rhizobiales）和柄杆菌目（Caulobacterales）的物种。  结论  长期定位施肥条件下，稻草回田并增加饼肥能够改善烟田土壤无机氮含量，提高细菌群落结构组成和相对丰度。 

Effects of long-term fertilization on nifH bacterial community structure in flue-cured tobacco field

The objective of this study is to analyze the impact of long-term fertilization on nifH bacterial community structure and abundance in flue-cured tobacco field. The effects of long-term single application of chemical fertilizer (T1), chemical fertilizer + rice straw returning (T2) and chemical fertilizer + straw returning + cake fertilizer (T3) on soil inorganic nitrogen and bacterial diversity in flue-cured tobacco rhizosphere were studied through field positioning experiments. The results showed that long-term application of rice straw and cake fertilizer increased the content of inorganic nitrogen in tobacco plantng soil. The bacterial α-diversity a in tobacco soil treated with rice straw returning + cake fertilizer were higher than that treated with chemical fertilizer alone. The relative abundances of Proteobacteria and the subphyla of Proteobacteria in bacterial community were the highest. The LEf Se phylogenetic cladistics of tobacco planting soil showed that the dominant bacterial populations in the tobacco soil under the 3 treatments of chemical fertilizer alone, chemical fertilizer + straw returning and fertilizer + straw returning + cake fertilizer were mainly gallionellales, rhizobiales and caulobacterales. In conclusion, straw returning +cake fertilizer can increase the inorganic nitrogen content and improve bacterial community structure and abundance in tobacco field under long-term fertilization.