Dynamic rhizosphere C:N:P stoichiometry of plants, soils and microbial biomass under different grazing patterns

Abstract Analysing grassland ecological stoichiometry is crucial for evaluating ecosystem quality and health via energy flow and elemental equilibrium. Grazing is a dominant human activity shaping alpine grasslands on the Qinghai–Tibet Plateau (QTP), yet few studies have used rhizosphere stoichiometry to assess plant–soil–microbe interaction dynamics under different grazing regimes. We compared rhizosphere stoichiometric changes of the degradation indicator Medicago ruthenica and dominant Kobresia humilis under yak grazing (YG), sheep grazing (SG) and mixed grazing (MG) with yak‐to‐sheep ratios of MG(1:2), MG(1:4) and MG(1:6). MG(1:2) increased total N and reduced total P in M. ruthenica , significantly elevating its N:P ratio; MG(1:4) increased total N and P in K. humilis , lowering its C:N and C:P ratios. Rhizosphere soil of K. humilis showed significantly increased total C and P under MG. For K. humilis , microbial biomass carbon (MBC) and nitrogen (MBN) initially decreased then increased under MG, while microbial biomass phosphorus (MBP) significantly increased across all grazing patterns, with stable plant and microbial biomass N:P ratios. Regulatory pathways differed by species: M. ruthenica affected MBC, MBN and MBP via plant C and N under single grazing, and MBP via soil properties under MG; K. humilis influenced these microbial indices via soil properties and plant C:N:P under single grazing, and soil properties under MG. Our findings reveal trait‐dependent stoichiometric responses of key plant species to grazing, advance understanding of rhizosphere plant–soil–microbe interactions in alpine grasslands, and provide a scientific basis for sustainable grazing management on the QTP. Read the free Plain Language Summary for this article on the Journal blog.