The Characteristic Of Bacterial And Fungal Community Under Long-term Different Fertilization In Chinese Typical Croplands

As the typical cropland from Chinese North to South,the quality of phaeozem,Cambisol and Acrisol decides Chinese food production.However,in recent decades,high-intensive cultivation and unreasonable fertilization led to soil acidification and destroyed soil microbial community,which further brought in the decrease of soil quality and the destruction of agricultural sustainability.Soil exists highest microbial diversity in geosphere,microbe play an indispensable role in global biochemistry cycling.Among microorganism,the quantity of bacteria and fungi accounts for 80%,which play key role in agricultural nutrient cycling,and their community intensively relate to soil quality.Using high-throughput sequencing technology,we research the soil bacterial and fungal community of phaeozem,Cambisol and Acrisol respectively from Haerbin,Laiyang and Qiyang long-term fertilization trials,and following four treatments were sampled:un-fertilized control?CK?,chemical nitrogen fertilizer?N?,manure only?M?and M plus N?MN?.Moreover,we analyzed the soil properties to decipher the driving factors of bacterial and fungal community.The results as follows:?1?According to the analysis of soil nutrients,yield and bacterial diversity,the results demonstrated MN treatment was the optimal fertilization regime for all three soil types in terms of soil nutrients,crop yields,and bacterial diversities.By applying long-term MN fertilization,the abundance of Erysipelotrichia and?-Proteobacteria were significantly enhanced respectively compared with CK and M,while the relative abundances of Acidobacteria subgroup Gp6 and Plancomycetia were commonly higher in MN than N in all three typical soils.The changes of those groups were significantly associated with the changes of soil pH values.The variation partitioning analysis?VPA?revealed that soil properties,fertilizer types,and their interaction contributed most?54%?to the soil bacterial communities,indicating pH,grit content,available N,available potassium and ammonium contents were the driving factors in determining the bacterial community in all three types of fertilized soils.?2?Relating to the analysis of bacterial and fungal community from Phaeozem,the results predicated that compared with CK,long-term N fertilizer had no significant influence on bacterial abundance,but significantly decreased bacterial diversity by 13.2–48.5%.Fungal abundance was increased 24 times while the diversity was decreased 4.6–80.3%with N fertilization.Additional manure to N fertilization,bacterial abundance and diversity were enhanced by 2 times and8.1%-46.6%,respectively.Fungal quantity was declined by 14.2%,while fungal diversity was increased by 62%-237%,comparing MN with N only fertilizer.The abundance of Acidobacteria_Gp1,Gp3 and?-Proteobacteria?bacterial classes?were significantly increased,and the abundance of Agaricomycetes?fungal class?even was enhanced by 41 times in N fertilization than in CK.Compared with in N treatment,the bacterial abundance was kept constant in MN treatment;while the abundance of?-Proteobacteria,Acidobacteria_Gp1 and Gp3 were decreased by 26%,97%and 81%,respectively;and Acidobacteria_Gp4,GP6 and Plancomycetes abundance were increased by 11,9 and 2 times,respectively with long-term M treatment.Bacterial community structure for MN and N treatments appeared similar,which were significantly different from CK and M treatments.Fungal community structure for CK,M and MN treatments were similar and significantly different from N treatment.Soil pH?6.07?and available potassium(125.5g·kg^-1)were the principal factor for the difference of bacterial community and fungal community,respectively.Soil organic matter explained both bacterial and fungal community structure alternations while the criteria was different as 28.4 g·kg^-1 for bacteria and 30.8 g·kg^-1 for fungi.?3?The analysis of soil bacterial and fungal community from Cambisol,indicating that compared with CK,manure application significantly changed bacterial community or fungal community,while no significant change with long-term N treatments.A uniform analysis of bacterial community and fungal community,the MRT result predicated the key driving factor commonly influencing bacterial and fungal community is total phosphorus(0.89g·kg^-1).Additional manure significantly increased soil organic matter and yield,which influenced soil phosphorus content,and phosphorus further correlated intensively to bacterial community and fungal community;while no significant correlation and pathways were discovered with long-term NoM treatment?N and CK treatments?.AM treatments strengthen the connection of inter-microbes and appeared the fungal populations as nods,while no fungal population participated in NoM treatment.Adding manure could effectively regulate the fungal community,then further strengthen the connection of inter-microbes.The phylogenetic tree about hubs in network analysis also indicated the whole microbial community in Cambisol correlated closely to soil phosphorus transformation.The response of bacterial and fungal community variation to long-term different fertilization indicated that some dominant microbial populations could be the biological index predicating soil quality.In different soil types,the driving factor of influencing soil bacterial or fungal community is different.Therefore,it is possible to artificially regulate a high yield and high efficiency microbial community by reasonable fertilization.