Silicic acid and potassium bicarbonate application affect fruit quality of strawberry cultivated in a rhizosphere cooling system at tropical lowland conditions

The effect of silicic acid (H4SiO4), potassium bicarbonate (KHCO3), and their equal volume combination on strawberry fruit quality was determined on cultivars Festival and Fortuna when grown in a rhizosphere cooling system (RCS) in a completely randomized design. The RCS kept the plants’ rhizosphere temperature at 18°C while the shoots were exposed to ambient tropical weather conditions. The treatments were applied either by foliar spraying or root drenching; and were selected due to limited evidence on how they affect strawberry fruit quality in the tropics. Analyzing the effects of the treatments using ANOVA showed that the root application of H4SiO4 and foliar application of KHCO3 improved fruit size, mass, and shape of both strawberry cultivars, resulting in better fruit grading under the European Union’s standards for fresh market strawberries. Fruit firmness, sweetness index, sugar content, and total soluble solid contents were also improved when treatments containing H4SiO4 were applied as foliar spray. Conversely, the root application of KHCO3 adversely affected most of the parameters assessed. Our findings suggest that applying H4SiO4 could improve strawberry fruit quality, and root drenching is the most effective method. We therefore recommend root drenching with H4SiO4, or foliar application of KHCO3, for improved strawberry fruit quality.