Objective The bioavailability of potassium (K) sorbitol chelate is high. Investigating the effects of different foliar K application concentrations on celery growth, nutrient absorption, and K utilization efficiency could provide scientific basis and technical references for high-quality celery production.

Method Under greenhouse conditions, K sorbitol chelate, synthesized independently in the laboratory, was used as the K fertilizer for the experiment, and regular celery was the test crop. On the basis of conventional fertilization, six foliar application concentrations were set up (in terms of potassium ions, unit g L⁻¹): 0 (CK, water control), T1 (10), T2 (15), T3(20), T4 (25), and T5 (30). The effects of each treatment on yield at harvest, growth indicators, quality indicators, K content and accumulation in various organs, and soil available P content were analyzed.

Result Different foliar application concentrations significantly affect celery yield, quality, and the K content in plant-soil systems. Specifically, compared to control treatment. ① Foliar application of 10 g L⁻¹ K sorbitol chelate could promote photosynthesis in celery, as evidenced by increased SPAD values, plant height, petiole thickness, and yield. ② The application of K sorbitol chelate could significantly reduce the nitrate content in the edible parts of celery. When the application concentration is 10-20 g L⁻¹, the soluble protein and soluble solid contents in celery are significantly increased. The soluble solid content increased by 26.50%, 36.60% and 24.40% at application concentrations of 10 g L⁻¹, 15 g L⁻¹, and 20 g L⁻¹, respectively. ③ When the application concentration is 25-30 g L⁻¹, the K content and accumulation in various organs of celery at harvest, as well as the soil available K content, were significantly increased, with the most pronounced effect at 25 g L⁻¹. ④ Correlation analysis of economic benefits indicated that celery yield and net profit were positively correlated with K fertilizer utilization efficiency, K accumulation in celery leaves and roots, and leaf nitrate content, but negatively correlated with soil available K content. Economic benefit analysis showed that the benefits were better when the application concentration is 10-15 g L⁻¹.

Conclusion In conclusion, during the vigorous growth period of celery, the recommended foliar application concentration of K sorbitol chelate is 10-15 g L⁻¹. This concentration effectively enhances celery yield, quality, and K absorption and utilization.