Silicon (Si) is a beneficial element to many agricultural crops. We found improved horticultural traits in our preliminary Si supplementation research on floricultural greenhouse crops produced in soilless substrates. The objective of this study was to establish optimum Si rates based on previous results and investigate the relationship of Si tissue and substrate content. Potassium silicate (KSiO3) weekly drenches (0, 50, 100, 150 mg·L-1 SiO2), media-incorporated KSiO3 flakes (0, 280, 400, 520 g·m-3 SiO2), and ashed rice hulls (0, 200, 270, 360 g·m-3 SiO2) were provided to Helianthusannuus`Ring of Fire'. Leaf, stem, and flower tissues as well as soilless substrate samples were collected for Si analysis. Several Si treatments resulted in plants with increased flower and stem diameter compared to untreated controls (P ≤ 0.05). Weekly drenches with KSiO3 (150 mg·L-1 SiO2), KSiO3 flakes (280 g·m-3 SiO2), and ashed rice hulls (360 g·m-3 SiO2) were the most efficient treatments based on the increased quality characteristics. Leaf tissue had the highest Si content, followed by flower, then stem tissue. Correlation analysis indicated that leaf and flower Si content was positively correlated with saturated media extract substrate samples (correlation coefficients r= 0.75 and 0.63, respectively).
If the inline PDF is not rendering correctly, you can download the PDF file here.