Synergistic Mechanisms of Plant Phosphorus (P) Resorption and Microbial P‐Limitation Affecting Soil P During Grassland Vegetation Succession

Abstract Phosphorus (P), a crucial element for all life forms on Earth, is often insufficiently available in terrestrial ecosystems. The interaction and feedback between plants and soil microorganisms are crucial links integrating above‐ and below‐ground ecosystems. However, changes in soil P fractions in response to plant‐microbe interactions during vegetation succession remain poorly understood. This study investigated the trends and relationships between plant resorption, microbial properties, and soil P fractions in the transformation interface soil layer (TIS) and underlying topsoil layer (UTS) during grassland vegetation succession. The results point to a combination of soil properties, alongside microbial and plant factors driving soil P changes. However, the TIS and UTS layers differ, with phosphorus dynamics in the TIS layer primarily influenced by microorganisms. Microorganisms are co‐limited by C and P in both the TIS and UTS layers. Under microbial P‐limitation, microorganisms produce alkaline phosphatases (AP), while C deficiency stimulates the production of C‐acquiring enzymes, subtly regulating soil P dynamics through organic matter decomposition. Plant P resorption efficiency and microbial P‐limitation exhibit synergistic variations, reaching their lowest levels during the mixed Bothriochloa ischaemum and Stipa bungeana Trin ( Bo.I + St.B ) stage. This study emphasizes that P cycling is influenced by plant‐microbe‐soil interactions and feedback. Plants and soil microorganisms jointly regulate soil nutrient effectiveness and partitioning in the ecosystem.