Critical N-NO3- and chlorophyll levels in lettuce leaves grown hydroponically under forced air pressure

Flores G.S.L.; Yupanqui F.F.R. · Nativa (2026) · DOI: 10.31413/nat.v14i1.20344

Resumen

The production of lettuce (Lactuca sativa L.) under hydroponic systems in the Mantaro Valley requires optimal nitrogen (N) levels to meet quality standards established by the EU Commission Regulation. This study was conducted in the greenhouse of the El Mantaro Agricultural Experimental Station, Jauja, Peru, to determine the critical levels of N-NO3-in petiole sap, in lettuce leaves (cv. Seda), and foliar chlorophyll, as well as identifying the N concentration in the nutrient solution that maximizes yield without exceeding the permissible limits of N-NO3-. Treatments of 0.5, 1, 4, 7, 10, 13, 16, 19, and 22 mmol N L-1 were applied, with six replications. Results indicated that the optimal N concentration in the nutrient solution ranged between 1.25 and 4.0 mmol N L-1, significantly improving crop growth, yield, and quality. The critical levels of N-NO3- were 3347.43 mg kg-1 in fresh leaves, 482.54 mg L-1 in petiole sap, and 2.12 µg g-1 on chlorophyll, complying with the maximum limit of 4500 mg kg-1 of N-NO3- in fresh weight. This study contributes to optimizing nitrogen fertilization in hydroponic systems, ensuring product quality and food safety.

Instituciones: Universidad Nacional del Centro del Perú