This study aimed to investigate the effects of a biological nitrification inhibitor on nitrous oxide emission and rice yield quality in paddy soils and its effects on denitrifying the bacteria of nosZ, nirK, and nirS types. Two treatments were performed: (1) using a local conventional fertilizer as the control CK; (2) using the partial application of a conventional fertilizer + biological nitrification inhibitor as SW. N2O emission was measured using gas chromatography; qPCR amplification was performed using primers for the targeted functional genes, nosZ, nirS, and nirK, and denitrifying functional gene abundance and denitrifying microbial community structure were analyzed using fluorescence quantification and high–throughput sequencing, respectively. The results reveal that the biological nitrification inhibitor resulted in a 41.83% reduction in N2O, relative to the normal fertilizer treatment. Meanwhile, rice yield increased by 15.45% and related quality indexes were also improved. This can promote the reproduction of bacteria with the nosZ gene while inhibiting the growth of bacteria with nirS and nirK genes. The core bacteria, Nitrosospira, Rhodanobacter, Bradyrhizobium, Tardiphaga, Rhodopseudomonas, and Paracoccus, positively correlated with N2O emissions, while core bacteria Azospirillum, Burkholderia, and Mesorhizobium negatively correlated with N2O emissions. Therefore, the application of a biological nitrification inhibitor could be an effective measure to promote rice yield and quality, reduce N2O emissions, and affect key denitrifying bacteria.

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Characterizing the rhizosphere microbial community composition associated with enhanced crop yield and (or) greenhouse gases is an important first step towards understanding the role of the microbiota in rice paddies. This research aimed to decipher the influence of straw tea composting product combined with dicyandiamide amendment on greenhouse gas emission and microbial community in rice paddies.The results indicated that amendment of biological nitrification inhibitors can mitigate gas emissions and significantly increase rice yield by 41.70%, and improve the growth and development of the root system. Furthermore, composting product can mitigate greenhouse gas emissions, and bionitrification inhibitor combined with straw compost tea can effectively increase the growth and development of rice, the number of panicles, which are respectively 9.75% and 18.34%. However, the biological nitrification inhibitor impacted the communities of nitrogen-fixing bacteria (Proteobacteria), bacteria capable of eliminating nitrogen (Nitrospirae) as well as Verrucomicrobia known to be one of the most common and diverse phyla in soil habitats. As with bacteria, a distinct community structure and distribution patterns for archaea were observed in soils; however, the abundance, richness, regularity and diversity of archaea communities were significantly less in the different samples. In addition, biological nitrification inhibitors have had an impact in Euryarchaeota, responsible for the elimination of methane.

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This study aimed to explore the effects of straw compost with different proportions as replacement to chemical fertilizer on soil microorganisms as well as rice growth yield and quality. The rice variety Quan9you 063 in Fengyang, Anhui province was employed as the research subject. Four experimental treatments were set: local conventional fertilization as a control (CK) and compost substituting chemical fertilizer at 10% (T1), 20% (T2), and 30% (T3) to investigate the effects of straw composting. Our findings revealed that T1 treatment had the best rice yield-increasing effect (p < 0.05). Compared with CK, the rice yield, grain number per panicle, and rice polishing rate increased by 6.43%, 21.60%, and 0.47%, respectively; the chalkiness and chalky grain rate decreased by 25.77% and 55.76%, respectively. The T1 treatment achieved significantly higher relative abundance of β-Proteobacteria, Sideroxydans, Methanoregula, and Candidatus Nitrosocosmicus, indicating that the compost replacing 10% chemical fertilizer notably increased the microbial diversity. Hence, the replacement of 10% of chemical fertilizers with compost can enhance the rice yield.