Abstract: To more efficiently guide scientific fertilization for crops and determine the appropriate nutrient concentration in soil solution, cucumber (Cucumis sativus L.), a crop with high water and fertilizer requirements, was selected as the test material. A pot experiment was conducted to investigate the variations in soil solution nutrients and their correlations with soil chemical properties and cucumber yield under seven fertilization concentrations (0, 0.5, 1.0, 2.0, 4.0, 6.0, and 8.0 g/L, based on total fertilizer application). The results showed that the trends of soil solution nutrient indicators and soil nutrient indicators were generally consistent under different fertilization concentrations, and a highly significant positive correlation (P<0.01) was observed between them, indicating that soil solution nutrient measurement could replace soil nutrient analysis to evaluate soil nutrient supply intensity. The yield per plant increased with increasing fertilization concentration when it was below 2.0 g/L. When the fertilization concentration exceeded 2.0 g/L, further increases in fertilizer concentration led to a continuous decline in yield, accompanied by severe accumulation of nutrients and salts in the soil solution. By fitting regression equations, the appropriate fertilization concentration range targeting higher than 95% of the maximum yield was quantified, and the results showed that the yield range was 1.34-1.41 kg per plant, the corresponding suitable fertilization concentration was 1.03-1.87 g/L, and the corresponding soil solution electrical conductivity, inorganic nitrogen, available phosphorus, and available potassium were 2.27-3.64 mS/cm, 216.7-438.0 mg/L, 18.3-24.6 mg/L, and 172.6-359.0 mg/L, respectively.

Key words: fertilizer concentration, cucumber (Cucumis sativus L.), soil solution, nutrient, greenhouse