Dose-response evaluation of chitosan, nanostructured silicon and micronutrient microcapsules on the yield of Cucumis sativus L. under greenhouse conditions

Abstract

The low efficiency of conventional fertilization limits nutrient use in intensive horticultural crops; therefore, microencapsulated bioinputs represent an alternative to improve cucumber productivity under greenhouse conditions. This study aimed to evaluate the dose-dependent response of growth, productive components and yield of Cucumis sativus L. to foliar application of chitosan and micronutrient microcapsules with SiO₂ nanoparticles. The experiment was carried out under greenhouse conditions at the Technical State University of Quevedo, Ecuador, with a mean internal temperature of 27.9 °C. A completely randomized design was used with four treatments and four replications: T1, control with basal fertilization and no foliar spraying; T2, 1,000 mg.L⁻¹; T3, 1,500 mg.L⁻¹; and T4, 2,000 mg.L⁻¹, sprayed at 12, 25 and 35 days after sowing with 100 mL.plant⁻¹ per application. Plant height, stem diameter, days to flowering, number of fruits per plant, fruit length, fruit diameter, fruit weight and yield per plot were assessed. The 2,000 mg.L⁻¹ dose showed the most consistent response, with 456.25 cm plant height at 60 days, 8.00 mm stem diameter, 3.00 fruits per plant, 30.28 cm fruit length, 5.67 cm fruit diameter and 6.72 kg per plot, equivalent to a projected 42.0 t.ha⁻¹ against 24.8 t.ha⁻¹ in the control. The 2,000 mg.L⁻¹ dose showed the best agronomic performance under the evaluated conditions, although validation in additional cycles is required.