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.

Bacillus amyloliquefaciens -modified bio-organic fertilizer (BOF) has shown great potential in improving crop yields and soil quality in degraded or reclaimed soils. However, the underlying microbial mechanisms remain unclear. This study conducted field experiments in reclaimed rice soil to compare the effects of chemical fertilizer (CF), organic fertilizer (OF), and BOF on rice yield and rhizosphere microbial community dynamics. The rice yield of BOF treatment increased by 9.6%, from 7.79 to 8.54 t ha ⁻¹ compared with CF, and significantly improved critical soil properties by alleviating acidification, as indicated by an increase in pH from 6.10 to 6.65, achieved a 15.7% rise in organic matter accumulation. Available phosphorus increased by 24.5% and available potassium by 14.4%. High-throughput sequencing revealed that bio-organic fertilizer application markedly altered rhizosphere bacterial communities, enriching sulfur-oxidizing taxa and beneficial plant-associated genera including Sphingomonas . Quantitative analysis indicated a significant positive correlation between the abundance of B. amyloliquefaciens and Sphingomonas , and both were associated with improved soil nutrient status and crop performance. Metabolic pathway analysis based on KEGG showed enrichment of the citric acid cycle (1.8-fold) and amino acid biosynthesis (2.3-fold) pathways, which promote nutrient mobilization and microbial interactions. These findings provide new insights into the synergistic interactions between introduced bacteria and native bacterial communities and establish a mechanistic foundation for designing targeted microbial formulations to promote sustainable rice production in improved soils.

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.

Soil reclamation is a crucial strategy for restoring degraded land and improving agricultural productivity, yet the underlying microbiological mechanisms that drive soil quality improvement remain inadequately understood. To address this, a rice field experiment under chemical fertilizer (CF), organic fertilizer (OF), and B. subtilis -enriched bio-organic fertilizer (BOF) was conducted to assess the impact of different fertilization treatments on rhizosphere soil bacterial community by targeted sequencing in reclaimed paddy soil. The results revealed that BOF significantly enhanced rice yield and improved soil attributes, including a reduction in soil pH and an increase in microbial diversity. Compared with the CF and OF, BOF exhibited a more pronounced effect on the enrichment of indigenous Bosea spp. in the rhizosphere. Metabolomic analysis further revealed that the relative abundance of Bosea was positively associated with increased levels of aromatic compounds such as benzoic acid and tropolone , which are potentially linked to improved soil functionality. These findings suggest that the synergistic interaction between B. subtilis and native Bosea populations may enhance soil health and promote sustainable crop productivity by altering microbial community structure and activating beneficial metabolic pathways. Collectively, this study provides further insight into the role of bio-organic fertilizers in promoting ecological restoration and sustainable agriculture in reclaimed soils.

Compost produced by straw and livestock and poultry manure under the action of micro-organisms is one of the main forms of organic alternative fertilizers at present. The present study explored the effects of compost substitution on soil greenhouse gas emissions, soil microbial community changes, and wheat yield to determine the best substitution ratio for reducing greenhouse gas emissions and soil microbial community changes and increasing wheat yield. Using the single-factor randomized block trial design, four treatments were employed, the characteristics of greenhouse gas emission, yield and yield components, and the changes of soil microbial community under different compost substitution ratio in the whole wheat growing season were determined by static box-gas chromatography. During the wheat season, both CO₂ and N₂O emissions were reduced, whereas CH₄ emission was increased. That all treatments reduced the Global Warming Potential (GWP) and Greenhouse gas emission intensity (GHGI) in wheat season compared with T0. Compost substitution can alleviate the global warming potential to some extent. Under the condition of compost substitution, the wheat yield under T2 and T3 increased significantly compared with that under the control; however, the spike number and 1000-grain weight did not differ significantly among the treatments. When compost replacement was 30%, the yield was the highest. Under different ratios of compost substitution, the microbial communities mainly comprised Proteobacteria, Actinobacteria, Firmicutes, Patescibacteria, Chloroflexi, Acidobacteria, Bacteroidetes, Gemmatimonadetes, and Verrucomicrobia. The soil microbial community structure differed mainly due to the difference in the compost substitution ratio and was clustered into different groups. In conclusion, to achieve high wheat yield and low greenhouse gas emissions, compost replacement of 30% is the most reasonable means for soil improvement and fertilization.