Optimizing Tomato Cultivation: Impact of Ammonium–Nitrate Ratios on Growth, Nutrient Uptake, and Fertilizer Utilization.

Tomatoes, an essential crop in controlled environments, benefit significantly from the careful use of nitrogen fertilizers, which are crucial for improving both yield and nitrogen efficiency. Using a tomato pot experiment arranged in a facility greenhouse, five treatments were established as follows: a control excluding the application of nitrogen fertilizer (C), and applications of ammonium nitrogen and nitrate nitrogen with nitrogen mass ratios of 0:100 (A₀N₁₀₀), 25:75 (A₂₅N₇₅), 50:50 (A₅₀N₅₀), 75:25 (A₇₅N₂₅), and 100:0 (A₁₀₀N₀), to study the effects of different ratios of nitrogen mass on tomato yield, quality, nutrient accumulation, and nitrogen fertilizer utilization. The results showed that compared with C, the different ammonium–nitrate ratios significantly increased the yield, dry matter mass, N, P, and K accumulation, soluble solids, soluble sugars, and vitamin C content (Vc) of the tomatoes. Among all the treatments, A₇₅N₂₅ tomatoes had the highest dry matter accumulation, nitrogen, phosphorus, and potassium accumulation in fruits, soluble sugar, and soluble solids content. The differences in tomato yield and nitrogen fertilizer utilization between A₇₅N₂₅ and A₁₀₀N₀ were insignificant but their values were significantly higher than those of the other treatments. A₇₅N₂₅ had the highest nitrogen fertilizer utilization rate, 42.1% to 82.3% higher than C, A₂₅N₇₅, and A₅₀N₅₀. Hence, an ammonium-to-nitrate nitrogen mass ratio of 75:25 optimized tomato yield and quality in a controlled environment while minimizing nutrient loss. [ABSTRACT FROM AUTHOR]