抄録
Phosphorus (P) supply strongly influences yield formation in high-yield drip-irrigated wheat, yet how P availability coordinates biomass production with nitrogen (N)–P allocation and utilization during yield formation remains insufficiently resolved. A two-year field experiment with contrasting P application rates was conducted in drip-irrigated spring wheat (Triticum aestivum L.) in northern Xinjiang, China, to determine how P supply regulates dry matter production, assimilate remobilization, and N–P utilization efficiency. Grain yield showed a nonlinear response to P supply, with an intermediate P level maximizing yield by sustaining dry matter accumulation, promoting pre-anthesis assimilate remobilization, and enhancing the coordinated accumulation and redistribution of N and P to grains. Excessive P application, however, produced diminishing yield returns because additional biomass and nutrient accumulation were not proportionally translated into grain formation, resulting in lower P utilization efficiency. The integrated physiological responses indicated that yield advantage under optimal P supply depended not on maximizing biomass or nutrient accumulation per se, but on synchronizing continuous biomass production with coordinated N–P acquisition and efficient assimilate and nutrient remobilization during grain filling. These findings establish a P-regulated resource-allocation framework in which yield formation emerges from the coordination of biomass production, N–P coupling, and post-anthesis redistribution, providing a mechanistic basis for shifting high-yield drip-irrigated wheat from input-driven P management toward efficiency-oriented nutrient regulation.
