Foliar application of silicon on the growth and productivity of table tomatoes

Abstract

The objective of this study was to investigate different doses of silicon (Si), applied via foliar application, on the growth and productivity of tomato plants. For this purpose, tomato plants, Solanum lycopersicum, variety Santa Clara, were grown in plastic pots containing 8 dm³ of substrate inside the greenhouse of the Instituto Federal Catarinense, Campus Videira. The plants grew with the substrate maintained close to field capacity until the end of the experiment, lasting 121 days after transplanting (DAT) of the seedlings into the pots. Irrigation control was performed by the gravimetric method (daily weighing of the pots), adding water until the mass of the pot reached the previously determined value, considering the mass of the soil and water. The application of the Si doses was performed using a manual sprayer with a capacity of 500 mL and a fan-type nozzle for application. Control plants where Si was not applied were sprayed with distilled water. The simple mineral foliar fertilizer potassium silicate (Flex Silício^®) was used at the following doses: 0.0 ml/L (Control), 2.0; 4.0; 6.0 and 8.0 ml/L of potassium silicate, in four applications, carried out at 40, 55, 70 and 85 DAT. The experiment was set up in a completely randomized design, with four replications, at five levels of potassium silicate doses (0.0; 2.0; 4.0; 6.0 and 8.0 ml/L). Each experimental unit consisted of a plastic pot containing one plant. The data were subjected to analysis of variance, and the treatments were compared by Tukey's test at 5% probability, using the R^® software program, version 4.3.2. The determination of height, stem diameter, number of green and ripe fruits, weight of ripe fruits harvested, production per plant and chlorophyll a, b and total indices were carried out in four evaluations of the tomato plant, at 100, 107, 114 and 121 DAT. The dry matter of the root, stem and branches, root and total (leaf, stem and branches; and root) was also evaluated at the end of the experiment, at 121 DAT. To estimate the productivity, a spacing of 100 x 50 cm in one hectare (ha) was considered, accounting for 20 thousand plants/ha. According to the results obtained, it was observed that the supply of Si did not benefit the growth in height and stem diameter, as well as did not contribute to increases in the chlorophyll a, b and total indices. However, the application of Si favored a significant increase in root and total dry matter, mainly at doses of 2.0 and 4.0 ml/L of potassium silicate. The lowest dose of potassium silicate (2.0 ml/L) significantly favored production and estimated productivity in relation to the highest doses used of 6.0 and 8.0 ml/L. There was no significant effect on tomato production by supplying Si at increasing doses of potassium silicate in relation to the control treatment (0.0 ml/L).