化肥配施有机肥对花生根际细菌群落结构及共存网络的影响

Effects of Chemical Fertilizer Combined with Organic Manure on Peanut Rhizosphere Bacterial Community Structure and Co-occurrence Network

为评估化肥配施有机肥对花生根际细菌群落的影响,田间试验条件下研究了不施肥(CK)、施化学氮磷钾肥(NPK)和化学氮磷钾肥+有机肥配施(NPKM)对花生根际细菌群落多样性、结构和共存网络的影响。结果表明:NPKM处理下花生根际土养分状况明显改善,特别是有效磷的含量,较CK和NPK处理分别提高了5.31倍~12.16倍和3.24倍~6.50倍;而NPK处理下花生根际土养分状况并没有明显提升;SourceTracker分析显示,NPKM处理下根际细菌群落中只有2.1%~5.5%的物种来源于有机肥自身,但其花生根际细菌群落多样性在生育期前期要明显高于CK和NPK处理,而CK和NPK处理下根际细菌群落多样性差异不大;限制性主成分分析(CAP)显示,施肥措施和生育期均对根际细菌群落结构产生了显著影响,NPKM处理下花生根际土中富集了属于根瘤菌目(Rhizobiales)、梭菌目(Clostridiales)和芽孢杆菌目(Bacillales)这一类根际促生菌,根际细菌共存网络结构更加复杂,且网络中重要连接点的比例要也明显高于CK和NPK处理网络。可见,化肥配施有机肥有助于构建一个健康稳定的根际细菌群落。

To evaluate the effects of different fertilization on peanut rhizosphere bacterial community,three fertilization treatments were conducted in the field plot experiments.The treatments include no fertilizer(CK),nitrogen,phosphorus and potassium fertilizer(NPK),and application of NPK plus manure(NPKM).The diversity,community composition,and co-occurrence network of the rhizospheric bacteria were studied.The results showed that NPKM significantly improved the nutrient status in peanut rhizosphere soil,especially for the content of available phosphorus,which was 5.31–12.16 and 3.24–6.50 times higher than those of CK and NPK,respectively.However,NPK did not significantly improve the nutrient status of peanut rhizosphere soil.The results of SourceTracker showed that only 2.1%–5.5%of the bacteria community in NPKM potentially originated from organic manure.In the early growth stage,NPKM had a significantly higher bacterial community diversity as compared with CK or NPK.However,no significant differences of bacterial community diversity were detected between the CK and NPK.Partial canonical analysis of principal coordinates(CAP)corroborated that both growth stages and fertilization regimes had significant effects on the assembly of rhizosphere bacterial communities.A number of beneficial bacterial OTUs classified to Rhizobiales,Clostridiales,and Bacillales,were significantly enriched under NPKM.Rhizosphere bacterial co-occurrence network was most complex under NPKM,and the proportion of connectors was also highest under NPKM.The results indicate that chemical fertilizer combined with organic manure could help to build a healthy and stable rhizosphere bacterial community.