Response of Soil Biological Properties and Bacterial Diversity to Different Levels of Nitrogen Application in Sugarcane Fields

Abstract Field experiments were performed in early March 2019 at the farm of the Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences. Four concentrations of nitrogen application were employed as follows: that is, urea applications 964, 482, 96, 0 kg ha − 1 , respectively. And 300 kg ha − 1 calcium, magnesium, and phosphorus were likewise applied in 4 different treatments. The results showed that the soil microbial biomass carbon and phosphorus were altered significantly by non- and low-nitrogen input. Moreover, the indexes of soil bacterial richness and diversity in the sugarcane field could be significantly improved, even by low nitrogen input. At the genus level, norank_f__SC-I-84 , Mycobacterium , norank_f__Micropepsaceae , norank_f__norank_o__Saccharimonadales , norank_f__norank_o__Subgroup_2 and norank_f__Acetobacteraceae were the unique dominant bacteria in the soil with the high nitrogen input treatment. norank_f__JG30-KF-CM45 and Jatrophihabitans were the unique dominant genera in the moderate nitrogen input treatment. norank_f__norank_o__norank_c__Subgroup_6 , HSB_OF53-F07 , Streptomyces , norank_f__67 − 14 , norank_f__norank_o__SBR1031 and norank_f__norank_o__norank_c__KD4-96 were the unique dominant genera in the low nitrogen input treatment. In contrast, FCPS473 , Actinospica , 1921-2 , Sinomonas , and norank_f__Ktedonobacteraceae were the unique dominant genera in CK (no nitrogen application treatment). It suggested that low nitrogen input was the most significant effect on the soil microbial biomass carbon and phosphorus in the sugarcane field. Moreover, low nitrogen input also can improve the diversity and richness of sugarcane soil bacteria. The dominant bacterial genera of low nitrogen input and the other treatments were different for the compositions of dominant bacteria, and the largest abundance difference of dominant bacterial genera was norank_f__norank_o__norank_c__Subgroup_6 . However, whether low nitrogen stress can improve the yield and quality of sugarcane warrants further research.