| Abstract: According to the growth law of lettuce, three formulas of top dressing were selected to explore the effect of different formulas on the yield, quality and economic benefit of lettuce. The results showed that the average yield of T2 treatment was the highest in three test sites, and the biological yield and economic yield reached 69.2, 49.7 t/hm2, respectively. The economic coefficient of T2 was the highest, reaching 0.72. Compared with T1 and T3, T2 increased soluble sugar content by 0.4 and 0.1 percentage point, and decreased nitrate content by 4.0% and 4.8%, respectively. The average nitrogen partial factor productivity and phosphate fertilizer partial productivity of T2 were the highest, which were 7% and 5% higher than that of T1 and T3, respectively. Therefore, considering the yield, quality and fertilizer productivity of lettuce, the recommended formula of top dressing water-soluble fertilizer was 22-8-22. |