Synergistic effects of Pseudomonas stutzeri NRCB010 and organic fertilizers on soil N2O emission reduction and microbial community structure in greenhouse vegetable fields

Agricultural soils, particularly intensively managed greenhouse vegetable fields, are a significant source of the potent greenhouse gas nitrous oxide (N2O). While organic fertilization is essential for soil health, it can exacerbate N2O emissions. This microcosm study evaluated the efficacy of the denitrifying bacterium Pseudomonas stutzeri NRCB010, applied with three organic fertilizers (mushroom residue organic manure, high-temperature pretreated compost, and hydrochar organic manure), to mitigate N2O emissions and alter the microbial community. The results showed that inoculation with strain NRCB010 significantly decreased cumulative soil N2O emissions (p < 0.05). Among them, the mushroom residue organic manure inoculation treatment achieved the most significant emission reduction, with a mitigating rate of 46.5%, followed by the hydrothermal carbon organic manure inoculation treatment (27.8%) and the high-temperature pretreated compost inoculation treatment (26.3%). Soil N2O emissions showed a significant negative correlation with the abundance of the nosZI gene (p < 0.05), a key factor in decreasing N2O emissions, and a significant positive correlation with nitrate nitrogen content, pH, and electrical conductivity (EC). Furthermore, amplicon sequencing showed that inoculation significantly shifted the soil microbiome, increasing Pseudomonadota and decreasing Verrucomicrobiota, with the bacterial inoculant having a greater impact on microbial community structure than the type of organic fertilizer. It was concluded that the synergistic application of MR and P. stutzeri NRCB010 presents a robust, microbiome-mediated strategy for achieving significant N2O mitigation and ecological sustainability in protected agriculture.