Abstract

The experiment was conducted to study the effect of NH4+:NO3- ratio and spraying with seaweed extract on the quality indicators of Swiss chard. Nitrate or ammonium fertilization was used alone at a concentration of 400 mg. L-1, or a balanced combination of both at a ratio of 200:200 mg L-1 in combination with spraying with SWE extract at levels of 0, 3, 6 g L-1. Generally, the results showed that the studied quality indicators were affected differently by different fertilization levels and combinations. As, the results showed that the interaction of NH4+:NO3- ratio (200:200) and seaweed extract at a concentration of 6 g L-1 led to the highest significant increase in leaf content of ascorbic acid to 44.92 mg 100 g-1 fresh weight and protein to 6.62%. However, other qualitative indicators, leaf content of oxalic acid 87.85 mg/100 g-1, oxalic acid/calcium ratio 1.73, and number of calcium oxalate crystals 265.13 crystals, recorded the highest values in the nitrate 400: 0 ammonium treatment in combination with the presence of SWE at a concentration of 3 g/L-1.