Differential response of soil microbial communities involved in N-cycling to short-term N input depends on the history of N application.

This study focuses on investigating the response mechanism of nitrogen cycling microorganisms to nitrogen addition gradients in yellow soil with and without long-term nitrogen application, in order to optimize nitrogen fertilizer management strategies in yellow soil areas. The results showed that nitrogen addition significantly affected the alpha diversity index, gene relative abundance, and species relative abundance of nitrogen cycling microorganisms in soils with a history of long-term nitrogen application. Among the treatments, high nitrogen addition contributed the most to differences in community structure. In contrast, nitrogen cycling microorganisms in soils without long-term nitrogen application exhibited weaker responses to short-term nitrogen addition. Redundancy analysis indicates that differences in soil chemical properties are important drivers of differences in soil nitrogen cycling microbial community composition, and long-term nitrogen application history determines the specificity of microbial responses to short-term nitrogen gradients.