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

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.

草地生态化学计量学（grassland ecological stoichiometry）分析对于通过能量流动与元素平衡评估生态系统质量与健康至关重要。放牧是塑造青藏高原（Qinghai-Tibet Plateau, QTP）高寒草地的主要人类活动，但目前鲜有研究借助根际化学计量学（rhizosphere stoichiometry）探究不同放牧制度下的植物-土壤-微生物互作动态。本研究对比了退化指示种扁蓿豆（Medicago ruthenica）与优势种矮嵩草（Kobresia humilis）的根际化学计量特征变化，实验设置了牦牛放牧（YG）、绵羊放牧（SG）以及牦牛-绵羊比例分别为1:2、1:4、1:6的混合放牧（MG）三种处理。当采用MG(1:2)放牧模式时，扁蓿豆的总氮含量升高、总磷含量降低，其氮磷比显著提升；MG(1:4)处理则使矮嵩草的总氮与总磷含量均有所增加，同时降低了其碳氮比与碳磷比。混合放牧处理下，矮嵩草根际土壤的总碳与总磷含量显著升高。对于矮嵩草而言，混合放牧处理下其根际微生物量碳（MBC）与微生物量氮（MBN）呈现先降低后升高的变化趋势；而所有放牧模式下微生物量磷（MBP）均显著升高，且植物与微生物生物量的氮磷比保持稳定。调控路径因物种而异：单放牧模式下，扁蓿豆通过自身碳氮含量影响微生物量碳、氮、磷，而混合放牧时则通过土壤属性调控微生物量磷；矮嵩草则在单放牧模式下通过土壤属性与自身碳氮磷化学计量特征影响上述微生物指标，混合放牧时仅通过土壤属性发挥调控作用。本研究结果揭示了关键植物物种的化学计量特征对放牧的性状依赖性响应，增进了对高寒草地根际植物-土壤-微生物互作机制的理解，并为青藏高原的可持续放牧管理提供了科学依据。