Response of alfalfa growth and rhizosphere properties to soil phosphorus supply and mowing in a salt-affected soil

P application significantly improved plant height and branch number, with the highest levels observed when P application rate was 180 kg ha^-1. Crude protein content was also improved (13.3%-23.3%) with increasing P application rates and reached the maximum when P application rate was 240 kg ha^-1. The yield of alfalfa increased with higher shoot P concentration. Furthermore, mowing significantly reduced rhizosphere carboxylates concentration (30.4%-100%) and APase activity (39.8%-75.0%) across all P treatments. However, these reductions were less pronounced when the P application rate exceeded 120 kg ha^-1. In contrast, rhizosphere pH was unaffected by mowing across different application rates. Overall, this study demonstrates that P fertilization not only promotes alfalfa growth and quality in salt-affected soil but also mitigates the adverse effects of mowing on rhizosphere carboxylates concentration and APase activity. This highlights the potential of P fertilization to reduce P fixation and enhance P uptake by regulating rhizosphere-activated soil P dynamics after mowing. These findings provide a basis for enhancing the P utilization rate after mowing. The research results provide a basis for improving P utilization after mowing, enabling farmers to formulate scientific mowing strategies in production, thereby enhancing the yield and quality of alfalfa.