Influence Of Fertilization On Community Structure Of Arbuscular Mycorrhizal Fungi In Maize Fields And The Factor Analysis In North China Plain

The North China Plain (NCP) is one of the most important regions for grain production in China. Yield increase and sustainable land use is of great significance for the development of national economy. Large amount of chemicals such as fertilizer is supplied to increase the yields of cereals. Excessive and inappropriate fertilizer application caused a series of environmental problems. As one group of important soil microbial groups, arbuscular mycorrhizal fungi (AMF) deliever multi-functions in the agroecosystems. Understanding the community structure of arbuscular mycorrhizal fungi in response to fertilization is of great significance for sustainable agriculture. Terminal restriction fragment length polymorphism (T-RFLP) and clone-sequencing methods were employed for comprehensive study of AMF community in response to fertilization included N experiment (Opt. N:193kg N ha-1, V3stage45kg, V6stage56kg, V10stage92kg; Con. N:250kg N ha-1,100kg as base fertilizer and150kg as topdressing in V6stage; CK treatment), P experiment (High. P:100kg P ha-1; Low. P:25kg P ha-1and CK), long-term organic manure experiment (High. O: compost15000kg ha-1; Low. O:compost7500kg ha-1; Con. F:conventional chemical fertilization and CK treatment), chemical-organic fertilizer application experiment (Org:manure9000kg ha-1High. C:296.4kg N ha-1,177.3kg P ha-1,287.8kg K ha-1; Low. C:74.1kg N ha-1,44.3kg P ha-1,71.9kg K ha-1and CK treatment) in an typical intensive maize agroecosystem in NCP. Vertical distribution of AMF community was determinaed. The results were as follows:Appropriate N management was important to mitigate the decline in diversity of AMF in the conventional N treatment in the surface soil.22OTUs covering7AMF genera (such as Glomus, Funneliformis, Diversispora. etc) were detected. Significant differences in AMF community structure were observed between control and N application treatments but not between the two N application strategies. Certain AMF taxa showed different responses to N management, including species showing positive (F. caledonius and D. celata/aurantid), negative (G. indicum) or no response (Glo2, Uncultured Glomus) to N additions. Some AMF taxa were sensitive to N strategies. For example189bp (Glomus indicum/Funneliformis constrictus) had higher relative abundance in Opt. N and258bp (G/o7/8) was in Con. N treatment. Deeper soils supported diverse and rich AM fungal species. Soil pH and Nmin contents were the major factors affecting soil AMF community while vertical distribution of the fungal community was significantly influenced by soil electrical conductivity.Phosphorus fertilizer application increased diversity and evenness index of AMF community, implying reduced AMF competition and the effect was obvious in the surface soil.27OTUs covering7AMF genera such as Glomerales (Glomus Group A/B) and Diversisporales were detected. AMF taxa responded differently to P application. For example Glo1(Uncultured Glomus), Septoglomus constrictum showed positive response to P application while F. mosseae/caledonium, G. indicum showed negative response. T-RFLP fingerprint showed similar results. The relative abundance of189bp and258bp were increased by P application,141bp and116bp were suppressed by high P input. Deeper soils supported diverse AM fungal species. Soil Olsen-P and exchangeable K were the major soil properties affecting the AMF community among the P treatments while vertical distribution of the fungal community was mainly influenced by soil Olsen-P and Na+concentration.The impact of organic fertilizer applications on soil AMF community structure was complicated. Long term application of organic fertilizers decreased the diversity and evenness indexes of AMF community while the richness of AM fungi was not significantly affected. In contrast, short term application of organic fertilizers had no significant influence on diversity of AMF community.28and31OTUs were detected in long-term and short-term organic fertilizer experiments respectively. AM fungi belonged to Glomerales (Glomus Group A/B) and Diversisporales. Some AMF taxa for example F. caledonius was stimulated by organic fertilizer application while Sclerocystis sinuosa was positive response to Low.O treatment and Acal(Uncultured Acaulospora) was sensitive to High.O application. Similar results were also obtained from T-RFLP fingerprint analysis. The relative abundance of116bp (Glol1/12/13/15; Fun2/3/4; Rhil) increased in organic fertilizer treatment and140bp (Uncultured Glomus) was mainly stimulated by chemical fertilizer both in long-term and short-term organic fertilizer experiments. Short-term fertilization stimulated the relative abundances of141,142and169bp (belonging to Diversisporales), but the effect was not detected in the long-term organic fertilizer experiment. Soil pH contributed greatly to AMF community in the short-term organic fertilizer experiment. Whereas in the long-term organic fertilizer experiment, compared to pH, soil fertility (soil TC, TN, OM, Olsen-P. etc) had a greater impact on the fungal community...