Characteristic Functional Genera (CFG) Mediate Nitrogen Priming Effect in the Microbiome of Saline-Alkaline Farmland

This study aimed to investigate the impact of nitrogen priming effect on the makeup of the maize rhizosphere microbial community structure in saline-alkali agriculture, focusing on characteristic functional genera. In 2020, three nitrogen levels of 60 kg·ha^-1 (N1), 180 kg·ha^-1 (N2), and 300 kg·ha^-1 (N3), along with a control group, were established in the meadow saline-alkali soil farmland of Daqing in Heilongjiang Province. The maize cultivar was Xianyu 335. Rhizosphere soil was taken for nutritional analysis and high-throughput sequencing of the microbial population. The findings indicated that the bacterial community structure in the N1 and N2 treatment groups was comparable; however, the N3 treatment dramatically altered the community structure (p < 0.01). A notable disparity existed between the fungal nitrogen application group and the control group. Screening identified ten genera, including Lysobacter and Coniophora, as characteristic functional genera, with their habitats and functions dramatically altered during nitrogen priming effect. Nitrogen priming effect enhanced bacterial functionality for nitrogen source augmentation but diminished the capacity for nitrogen transformation, while also altering the nutritional preferences of fungus. Soil nitrogen and organic matter content showed distinct responses to different nitrogen application rates and exhibited significant interactions with the microbial community. The impacts of low, medium, and high nitrogen treatments on microbial and soil indicators varied, suggesting that effective nutrient management necessitates the regulation of microbial community function and accurate nitrogen administration. The research findings hold substantial importance and promotional potential for the sustainable advancement of saline-alkali agriculture.