套作蚕豆对梨园土壤肥力和微生物群落结构的影响

The impact of intercropping faba beans on soil fertility and microbial communities in pear orchards

为探讨套作蚕豆对梨园土壤肥力及微生物的影响,本研究于蚕豆的苗期、开花期和成熟期,分别采集不套作(对照,CK)、套作苏蚕3号(CT1)、套作苏蚕4号(CT2)和套作慈蚕1号(CT3,本地品种)处理土壤,对土壤理化性质和微生物活性及群落结构变化进行研究。结果表明:套作蚕豆后苗期土壤硝态氮(NO_(3)^(-)-N)和有效磷(OlsenP)含量有所增加,开花期土壤电导率、可溶性有机碳(DOC)、可溶性有机氮(DON)和NO_(3)^(-)-N含量显著增加,pH和OlsenP含量显著降低;套作蚕豆增加了土壤微生物量碳(MBC),成熟期CT1和CT2土壤MBC含量分别较CK显著增加36%和51%(P<0.05);套作蚕豆还降低了与碳氮磷降解相关的水解酶活性。此外,套作蚕豆增加了细菌微生物丰富度指数和香农指数,其中增加了浮霉菌门(1.5~1.7个百分点)、厚壁菌门(0.9~3.4个百分点)、芽单胞菌门(0.7~1.1个百分点)和疣微菌门(0.3~0.5个百分点)细菌相对丰度,降低了变形菌门(1.3~2.7个百分点)、放线菌门(1.9~2.8个百分点)和酸杆菌门(0.1~1.1个百分点)细菌相对丰度。Mantel和CCA分析结果显示,pH和NO_(3)^(-)-N是微生物活性的重要驱动因子,MBC是影响细菌群落结构的重要因子。研究表明,套作蚕豆有助于提高土壤微生物量及其群落结构多样性,对维持土壤微生态多样性具有重要的保育作用。

To investigate the effects of intercropping faba beans on soil fertility and microbial communities in pear orchards,soil samples were collected from no intercropping(CK),intercropped Sucan 3 Hao(CT1),intercropped Sucan 4 Hao(CT2),and intercropped Cican 1 Hao(CT3,local variety)treatments during the seedling stage,flowering stage,and maturity stage.The samples were analyzed for soil physicochemical properties,microbial activity,and community structures.The results showed that after intercropping with faba beans,the nitrate nitrogen(NO_(3)^(-)-N),and available phosphorus(Olsen P)increased during the seedling stage.During the flowering stage,soil electrical conductivity,dissolved organic carbon(DOC),dissolved organic nitrogen(DON),and NO_(3)^(-)-N contents significantly increased,while pH and Olsen P contents significantly decreased.Intercropping with faba beans increased soil microbial biomass carbon(MBC),especially CT1 and CT2 increased by 36%and 51%,respectively at the maturity stage compared with CK(P<0.05),and decreased the activity of hydrolytic enzymes related to the degradation of carbon,nitrogen,and phosphorus.Additionally,intercropping with faba beans increased the bacterial richness index and the Shannon index.It also increased the relative abundances of bacteria from the Planctomycetota,Firmicutes,Gemmatimonadetes,and Verrucomicrobia phyla,while decreasing the relative abundances of bacteria from the Proteobacteria,Actinobacteria,and Acidobacteria phyla.Mantel and CCA analyses indicated that pH and NO_(3)^(-)-N were important driving factors for microbial activity,and MBC significantly affected the bacterial community structures.Our results indicates that long term intercropping of faba beans helps to increase soil microbial biomass and diversity,playing a crucial role in maintaining soil micro ecological diversity.