Effects of green manure planting on soil ammonium oxidizing microorganisms in citrus orchards
Planting experiments with three types of green manure,which were natural grasses(NG),Vicia villosa var.glabrescens,a legume single planted(LP),and V.villosa var.glabrescens mixed planted in the NG(NL),were conducted in a long-term positioning fertilization experimental base in Fenghuangshan,Dangyang.Plant communities and soil physical and chemical properties were surveyed and measured,and the functional gene abundance and community structure of ammonium oxidizing microorganisms for soil samples were analyzed using qPCR amplification and Illumina MiSeq High-Throughput Sequencing.Next,the relationships between ammonium oxidizing microorganisms and plant community factors and soil properties were clarified by a Mantel test and redundant analysis with hierarchical partitioning(RDA-HP).The results showed that:Compared with the NG,the LP and NL had different effects on the abundances of AOA-amoA and AOB-amoA:the LP reduced the amounts of AOA-amoA and AOB-amoA,while the NL decreased AOA-amoA but increased AOB-amoA.The Ace indice and Chao indice of AOA in LP and NL were significantly higher than those in NG.Simultaneously,the Shannon index of AOB in LP was significantly higher than that in NG,and the β diversity among the three treatments differed significantly.In the three treatments,119 OTUs of AOA were obtained,with the dominant phylum and genus being Crenarchaeota and norank—Crenarchaeota,respectively;meanwhile,142 OTUs were obtained for AOB,with the dominant phylum and genus being Proteobacteria and Nitrosospira,respectively.The relative abundance of Nitrosospira was significantly higher in LP(45.87%).According to the Mantel test and RDA-HP,the abundance,composition,and diversity of ammonium oxidizing microorganisms were closely related to plant factors(plant height,cover,and diversity,shoot and root biomasses,and carbon and nitrogen contents in roots)and soil properties(pH,soil water content,total carbon and nitrogen contents,and ammonium,nitrate,and available phosphorus contents).The study indicates that green manure planting in citrus orchards alters the plant community and soil physicochemical properties and modifies the abundance and community structure of soil ammonium oxidizing microorganisms.Within the three ground cover treatments,NL has a markedly higher abundance of ammonia-oxidizing microorganisms,thus promoting soil nitrification and improving the ecological environment of the orchard.Therefore,intercropping legumes with NG in orchards is recommended for practical applications.
万方数据
维普
