Abstract:Ammonia oxidizing microorganisms in the soil affects the conversion of nitrogen and indirectly affect crop nutrient absorption and nitrogen utilization. Therefore, this study investigated the banana plant growth and the community composition and abundance of ammonia oxidisers in soils after application of different nitrogen form fertilizers. The banana plants were cultivated in pots with soil collected from Ledong coast.(NH4)2SO4 and Ca(NO3)2 were applied as N fertilizers. Plant growth and nutrient contents were determined. Soil ammonia oxidizing amoA gene clone library was constructed and analyzed. The results indicated that the copy number of the AOB amoA gene under (NH4)2SO4 treatment was significantly higher than the control and Ca(NO3)2 treatment, the copy number of AOA amoA was the lower than the control andCa(NO3)2 treatment. But the absolute number of ammonia-oxidizing archaea AOA in general were much higher than the number on the AOB. Community diversity and richness of AOB amoA also increased significantly under (NH4)2SO4 treatment. However, the administration of Ca(NO3)2 did not change significantly. The community structure of AOA was similar between the (NH4)2SO4 and Ca(NO3)2 treatments, but the richness and diversity were higher than the control without fertilization. From fertilization effect, compared with ammonium sulfate, calcium nitrate significantly increased biomass and nitrogen content of banana plants. These results indicated that, in the south acidic soils with AOA predominate, the application of ammonium nitrogen fertilizer can promote AOB abundance and diversity, but is likely to inhibit the number of AOA. Therefore, in the littoral soil after application of ammonium nitrogen fertilizer, through nitrification can’t meet the needs of banana absorbing nitrate, and nitrate fertilizer should be applied directly to promote the growth of bananas.