Mineral Content and Yield of Cucumis sativus L. under Substrate Mixtures and Different Salinity Levels of the Nutrient Solution

Abstract

Objective: To evaluate the effects of Steiner nutrient solution salinity and coconut fiber/compost mixtures on the yield, commercial quality, and mineral content (K+, Ca2+, and Mg2+) of leaves and fruits of Cucumis sativus L.

Design/methodology/approach: The study was conducted under greenhouse conditions in Culiacán, Sinaloa, using a completely randomized design with a 3 × 3 factorial arrangement. The evaluated factors were Steiner solution salinity (1.0, 1.5, and 2.0 mS cm⁻¹) and coconut fiber/compost ratios (100/0, 75/25, and 50/50% v/v). The number of fruits per commercial category and the mineral concentration in foliar tissue and fruits were determined 78 days after transplanting by atomic absorption spectrophotometry. Results: Increasing electrical conductivity (EC) to 2.0 mS cm⁻¹ significantly enhanced total yield and the “Super Select” category, with values 40% higher than those recorded at 1.0 mS cm⁻¹. Fruit mineral nutrition reached its highest levels at 2.0 mS cm⁻¹, particularly in interaction with 50% compost, which resulted in the greatest concentrations of K, Ca, and Mg. In contrast, foliar Ca and K stabilized at 1.5 mS cm⁻¹, whereas foliar Mg declined. Study limitations/implications: The results are specific to the Zeus F1 hybrid and to the climatic conditions of the Culiacán Valley. Findings/conclusions: A Steiner solution at 2.0 mS cm⁻¹ optimized fruit yield and mineral quality. The combination of coconut fiber with 50% compost and an EC of 2.0 mS cm⁻¹ is recommended to maximize the commercial competitiveness of cucumber production without compromising nutritional balance.