覆盖对连作半夏根际土壤微生物多样性的影响

Effects of Mulching on Soil Microbial Diversity in Continuous Cropping of Pinellia ternata

目的:探讨了覆盖措施对连作半夏根际土壤微生物多样性的影响,旨在为寻求半夏连作障碍的缓解措施提供理论依据。方法:设置了常规栽种(T1)、稻草覆盖(T2)、玉米秆覆盖(T3)、对照未栽种(CK)4个处理,采用末端限制性片段长度片段多态性(T‐RFLP)技术分析土壤细菌、真菌菌群结构及多样性。结果:不同覆盖措施间,半夏根际土壤细菌、真菌的多样性分别表现为T2>T3>CK>T1、T1>T3>T2>CK;细菌群落中214 bp菌种在连作后消失,经秸秆覆盖后重新出现并成为优势菌种;真菌群落中317 bp菌种成为连作后的优势菌种,经秸秆覆盖后原优势菌种恢复其优势地位。RDA分析表明,不同处理半夏根际土壤中细菌、真菌群落结构均与土壤氮具有极显著相关性。结论:连作半夏根际土壤细菌多样性水平下降,真菌多样性水平升高,土壤微生物出现从“细菌型”向“真菌型”转化的趋势;玉米秆或稻草覆盖对连作半夏土壤微生物菌群的改变具有调节作用,对连作土壤微生态失衡具有一定缓解效果;土壤中氮含量对根际土壤细菌和真菌群落结构具有显著影响,土壤氮是影响微生物生长和发育的重要环境因素。

Objective:This study explored the effects of mulching measures on rhizosphere soil microbial diversity of continuous cropping Pinellia ternata,aiming to provide a theoretical basis for seeking mitiga‐tion measures of continuous cropping obstacles in P.ternata.Method:Four treatments,including conven‐tional planting(T1),straw mulching(T2),corn stalk mulching(T3)and control without planting(CK)were set,and terminal restriction fragment length polymorphism(T-RFLP)was used to analyze soil bac‐terial and fungal community structures.Result:Among different mulching measures,the diversity of rhi‐zosphere soil bacteria was T2>T3>CK>T1,and the diversity of fungi was T1>T3>T2>CK.The 214 bp original dominant strain in bacterial community disappeared after continuous cropping,and reap‐peared when straw mulching and became dominant bacteria.In the fungal community,317 bp strain be‐came the dominant strain after continuous cropping,and the original dominant strain restored its domi‐nant position after straw mulching.RDA analysis showed that the bacterial and fungal community struc‐tures in rhizosphere soil of P.ternate under different treatments were highly significantly correlated with soil nitrogen.Conclusion:The level of bacterial diversity in rhizosphere soil of continuous cropping P.ternata decreased,and the level of fungal diversity increased.Soil microorganisms showed a trend of transformation from bacterial type to fungal type.Corn stalk or straw mulching had a certain regulatory ef‐fect on the change of soil microbial flora in continuous cropping P.ternata,and had a certain mitigation effect on the imbalance of soil microbial ecology in continuous cropping.Soil nitrogen content had a signif‐icant impact on the rhizosphere soil bacterial and fungal community structure.It was an important environ‐mental factor affecting the growth and development of microorganisms.