Effects of Growth Stages of Pugionium Gaertn. on Soil Microbial Biomass C:N:P Stoichiometric Ratios and Homeostasis in Northwestern China’s Desert Regions

Microbial stoichiometry serves as a fundamental indicator of nutrient limitations in microbial communities. However, the dynamic effects of <i>Pugionium</i> Gaertn. growth on soil microbial C:N:P stoichiometric ratios and their primary driving factors in native desert ecosystems remain poorly understood. This study aimed to clarify the stage-dependent regulation of microbial C:N:P stoichiometry by <i>Pugionium</i> Gaertn. in native desert ecosystems. This study examined representative <i>Pugionium</i> Gaertn. (<i>P. cornutum</i> and <i>P. dolabratum</i>) in northwestern China's desert regions, based on investigations conducted during 2022-2023, conducting systematic analysis of variations in rhizosphere soil microbial biomass C, N, and P levels, C:N:P stoichiometric ratios, fungal and bacterial diversity, soil physicochemical properties, and extracellular enzyme activities (EEAs) across different phenological stages. Results demonstrated that <i>Pugionium</i> Gaertn. growth significantly enhanced microbial biomass C, N, and P accumulation during vigorous growth stages. Simultaneously, stoichiometric ratios (C:N, C:P, N:P) exhibited periodic fluctuations, with P limitation characteristics becoming substantially intensified during the reproductive stage. Total soil nitrogen, total phosphorus, and EEAs significantly regulated microbial C:N:P stoichiometric ratios through their effects on bacterial diversity. In <i>P. dolabratum</i>, distinct response pathways were observed between fungi and bacteria to P limitation, indicating species-specific regulatory mechanisms. These findings provide novel insights into the relationship between <i>Pugionium</i> Gaertn. and soil elemental stoichiometry, as well as its influence on elemental dynamic balance at microbial and community levels. Furthermore, the results support ecological adaptation strategies of <i>Pugionium</i> Gaertn. communities in native habitats, offering scientific evidence for vegetation restoration and soil improvement in desert regions.