CONDUCTIVIDAD ELÉCTRICA DE LA SOLUCIÓN NUTRITIVA Y SU EFECTO EN COMPUESTOS BIOACTIVOS Y RENDIMIENTO DE PIMIENTO MORRÓN (Capsicum annuum L.)

Summary

This randomised experimental study examined how electrical conductivity of hydroponic nutrient solutions affects both yield and nutritional quality of bell pepper (Capsicum annuum L.). Results demonstrated a trade-off: whilst increasing EC from 2.0 dS m⁻¹ onwards enhanced bioactive compound accumulation (vitamin C, phenols, carotenoids, capsaicinoids, and antioxidant activity), it simultaneously reduced commercial yield and fruit firmness. The findings suggest that nutrient solution management is critical for optimising either fresh-market yield or functional food quality, with implications for precision nutrient management in soilless production systems.

Regional applicability

Although this study was conducted in Mexico, the findings are applicable to United Kingdom protected horticulture and commercial glasshouse bell pepper production. UK growers using hydroponic or soilless systems could use these EC thresholds to inform nutrient strategy, though local cultivar selection, climate control, and market preference (yield vs. micronutrient density) would influence optimal EC choice. The methodology and nutrient solution approach (based on Steiner) are internationally transferable.

Key measures

Electrical conductivity (1.5, 2.0, 2.5, 3.0 dS m⁻¹); fruit yield; fruit firmness; vitamin C content; total phenols; lycopene; β-carotene; total capsaicinoids; antioxidant activity

Outcomes reported

The study measured fruit yield, firmness, and bioactive compounds (phenolic compounds, vitamin C, lycopene, β-carotene, and antioxidant activity) in bell pepper grown under varying electrical conductivity (EC) of hydroponic nutrient solutions. Higher EC (≥2.0 dS m⁻¹) increased bioactive compound concentrations but reduced yield and fruit firmness.

Supporting research

Soilless bell pepper on Steiner solution at EC 1.5 to 3.0 dS/m: from EC 2.0 upward vitamin C, phenolics, lycopene, beta-carotene and capsaicinoids rose while yield and firmness fell.

Limits: One bell pepper cultivar in one season under one greenhouse; EC was varied by concentrating the whole solution, so single-nutrient effects cannot be separated.

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