Response of ammonia-oxidizing microbial community to irrigation water salinity and nitrogen application in grey desert soil of cotton field in Xinjiang
Irrigation water salinity and nitrogen application were used in this experiment.Two levels of irriga-tion water salinity were set as 0.35 dS·m-1(fresh water)and 8.04 dS·m-1(saline water),and two levels of nitro-gen application were set as 0(no nitrogen application)and 360(nitrogen application)kg·hm-2(represented by FWN0,FWN360,SWN0 and SWN360,respectively).In this study,cotton soil with saline water drip irrigation was used as material to measure the physicochemical properties and biological indexes,and the results showed that:(1)Saline water drip irrigation significantly increased soil EC 1∶5 and NH4-N contents by 457.74％and 73.02％,but significantly decreased NO3--N content by 35.88％;Nitrogen application significantly increased the contents of EC1∶5,NO3--N and NH4+-N in soil by 32.09％、668.33％and 39.88％.(2)Saline water drip irrigation significantly reduced the nitrification potential of soil,which was 28.97％lower than that of freshwater treatment.Nitrogen application significantly increased the nitrification potential of soil,which was 317.27％higher than that without nitrogen application.(3)Saline water drip irrigation significantly decreased the gene copies number of am-monia-oxidizing bacteria(AOB)and the A branch(amoA-clade-A)and B branch(amoA-clade-B)of complete ammonia oxidizing bacteria by 81.27％,73.49％and 62.51％,but significantly increased the gene copies number of ammonia-oxidizing archaea(AOA)by 487.94％.Nitrogen fertilizer application significantly increased the gene copies number of ammonia oxidizing microorganisms by 511.20％(AOA),958.13％(AOB),72.66％(amoA-clade-A)and 31.18％(amoA-clade-B).(4)The dominant bacteria genera of ammonia oxidizing microorganisms were Pseudomonas,Candidatus nitrosocosmicus,Nitrosospira,Bradyrhizobium,Streptomyces,Nitrospira,Stenotroph-omonas,Methylovorus,Chelatococcus,Cystobacter,Nitrosomonas,Rhodopseudomonas,Bacillus and Ramlibacter.(5)Saline water drip irrigation decreased the diversity and abundance of AOA and the diversity of amoA-clade-A but increased the abundance and diversity of AOB and amoA-clade-B,and the abundance of amoA-clade-A.Ni-trogen application significantly decreased the abundance of AOA and AOB,and the abundance and diversity of amoA-clade-A but increased the abundance and diversity of amoA-clade-B.In conclusion,salinity was the main driving factor affecting the community structure of ammonia-oxidizing microbial community,ammonia-oxidizing ar-chaea were the dominant species of soil ammoxidation,and ammonia-oxidizing bacteria and the A branch of com-plete ammonia oxidizing bacteria were the dominant microbial populations of ammoxidation in saline water drip irri-gation cotton fields.
saline water irrigationnitrogen applicationcotton fieldammonia oxidizing microbial communityRDA analysis
万方数据
维普
