Foliar and time of application of silicon and the effect on rice yield components, productivity and seed quality

The application of silicon (Si) has been beneficial to several cultures, mainly those considered Si accumulators, such as rice. Thus, in most cases Si is supplied via soil. However, it has been found that foliar application and small amounts of the element can be a viable alternative for its supply to plants. The objective of the present work was to evaluate the foliar application times of different silicon sources on yield components, productivity and seed quality of irrigated rice. The experiment was conducted in a greenhouse at the Federal University of Pelotas. The experimental design was completely randomized with four replicates. The treatments were: two sources of Si (Caulim®, 50 kg ha-1; and Sifol®, 3 L ha-1), three times of foliar application (tillering, bottling and flowering). Two distinct rice cultivars (IRGA 424 and Puita Inta CL) were used. The production components evaluated were: Seed yield, number of panicles, and number of seeds per plant. For the evaluation of the physiological quality, the seeds were submitted to the tests of germination and first germination count. Seed health test was performed. To cultivate IRGA 424, the use of Caulim® and Sifol® in the drilling phase increased the number of seeds per panicle. Therefore, for both cultivars the use of silicon provided improvements in seed vigor. We conclude that the application of silica via foliar, through the Caulim® and Sifol®, to the cultivar IRGA 424 in the drilling phase, increases the number of seeds per panicle, and for both cultivars, it improves the vigor of the seeds, in addition to reducing the incidence of fungi. Key words: Oryza sativa L., vigor, germination.