Community structure of total bacteria and methane emission-related prokaryotes in the rice fields applied with urea and biofertilizer

Rice fields are a source of methane emissions. Urea fertilization is considered to increase methane emission in rice field. Reduction in amount of urea applied with addition of biofertilizer, consisting of methanotrophic and N2O-reducing bacteria, is presumably to become an innovative fertilization technique to decrease methane emission from rice field. This current work aimed to investigate the community structure of total bacteria and methane emission-related prokaryotes in rice field soil treated with urea and biofertilizer at the vegetative and generative of rice stage. Two treatments were set up in the field experiment, i.e., 100% urea (250 kg/ha) without biofertilizer (B0) and 50% urea (125 kg/ha) with biofertilizer (B1). We used Illuminabased sequencing to investigate the soil microbial community in each treatment. Results showed that the soil bacterial community had minor changes in the two treatments throughout the rice growing period. Application of 50% urea with biofertilizer (B1) did not change the dominant bacterial phyla in rice field soil, i.e., Proteobacteria. However, there were differences in bacterial composition among the two treatments. Bacterial communities were partitioned into two clusters by the treatments (B0 and B1) rather than the rice growth phase. In addition, methanogens:methanotrophs ratio in the B1 treatment was lower than that of the B0 treatment.