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.

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.

This study was designed to investigate the effect on wheat yield of applying organic fertilizers (OF) with five different selenium (Se) concentrations. The mineral nutrients, cadmium (Cd) content, and the distribution of Se in wheat plants were also measured. The results showed that wheat yields reached a maximum of 9979.78 kg ha⁻¹ in Mengcheng (MC) County and 8868.97 kg ha⁻¹ in Dingyuan (DY) County, Anhui Province, China when the application amount of selenium-containing organic fertilizer (SOF) was up to 600 kg ha⁻¹. Among the six mineral nutrients measured, only the calcium (Ca) content of the grains significantly increased with an increase in the application amount of SOF in the two regions under study. Cd content showed antagonistic effects with the Se content of wheat grains, and when the SOF was applied at 1200 kg ha⁻¹, the Cd content of the grains was significantly reduced by 30.1% in MC and 67.3% in DY, compared with under the Se0 treatment. After application of SOF, the Se content of different parts of the wheat plant ranked root > grain > spike-stalk > glume > leaf > stem. In summary, SOF application at a suitable concentration could increase wheat yields and significantly promote the Ca content of the grains. Meanwhile, the addition of Se effectively inhibited the level of toxic Cd in the wheat grains.

Harnessing an ammonia-oxidizing microbiome has become an increasingly attractive form of management for mitigating greenhouse gas emissions in rice paddies; however, the relationship between greenhouse gas emissions and ammonia-oxidizing microbiomes, using a nitrogen application and irrigation regime, has not been well investigated. To decipher which of (and how) the specific mmonia-oxidizing bacterial species drive the greenhouse gas CH₄ and N₂O emissions, a field experiment with varying nitrogen application and irrigation regimes was initiated to investigate the succession of key bacterial consortia associated with GHG emissions. The results showed that water-saving irrigation (AWD) significantly increased NO₃-N and NH₄⁺-N concentrations, compared with conventional irrigation (FDF), whereas (total nitrogen) TN was little higher in FDF (1.38 g kg⁻¹) compared with the AWD (1.36 g kg⁻¹). During the rice-growing season, CH₄ emissions ascended speedily, and emissions peaked at maximum values of 3.32 and 4.41 ug mg⁻² h⁻¹ on day 5 in FDF and AWD irrigation regimes, respectively, and then they rapidly decreased during the midseason period, maintaining a relatively low emission rate until the rice was harvested. The patterns of N₂O emission fluxes had the same tendencies with N fertilization. Putative key taxa, such as Flavobacterium, Massilia, Arenimonas, Novosphingobium, Pseudomonas, exhibited significant positive relationships with higher GHG emissions, suggesting that they make particularly obvious contributions to N₂O emissions. These putative taxa should be considered when designing a high nitrogen application and irrigation strategy. As such, the nitrogen application of N180, and the irrigation regimes of water-saving irrigation, are recommended methods for N conservation and the mitigation of greenhouse gas emissions in rice paddies.