Response of Pre-sprouted Sugarcane Seedlings to Foliar Spraying of Potassium Silicate, Sodium and Potassium Silicate, Nanosilica and Monosilicic Acid

Abstract

Silicon (Si) applied via foliar on pre-sprouted sugarcane seedlings is a practical alternative for supplying Si, however, it is necessary to use an adequate Si source and optimal concentration, but this information is unknown. This study evaluates the effect of alternative Si sources applied via foliar spraying at lower concentrations in relation to potassium silicate, on Si accumulation and the beneficial effects on pre-sprouted sugarcane seedlings and initial growth. Two experiments were carried out in a greenhouse, one in the production phase of pre-sprouted seedlings and the other in the initial growth phase of sugarcane grown in pots. Both experimental designs were randomized blocks with treatments arranged in a 4 × 5 factorial scheme, with four Si sources: nanosilica (Si-nano), monosilicic acid stabilized with PEG-400 (Si-acid), sodium and potassium silicate stabilized with sorbitol (Si-alkali) and potassium silicate (Si-K) in five concentrations (0, 0.25, 0.5, 0.75 and 1.0 mmol L−1), and 4 repetitions. The Si syrup pH was adjusted to 5.5 ± 0.2. The foliar spraying of Si on pre-sprouted sugarcane seedlings is feasible since it increased Si accumulation, and benefited seedling production and plant initial growth. Soluble Si sources with stabilizers increased Si accumulation more efficiently compared to potassium silicate (Si-K) and nanosilica (Si-nano). Plants that have been sprayed with the PEG-400-stabilized monosilicic acid (Si-acid) and the sorbitol-stabilized sodium and potassium silicate (Si-alkali) at 0.5 and 0.6 mmol L−1 concentrations, respectively, promote had greater Si accumulation and beneficial effects in the growth of pre-sprouted sugarcane seedlings in production phase. In the initial growth of sugarcane, the sources Si-acid and S-alkali also increase the buildup and beneficial effects, but both sources at 0.6 mmol L−1 concentrations.