RESPONSE OF SOYBEAN CROP TO THE SILICON FERTILIZATION ON LEAVES

The objective of this study was to evaluate the effect of the application of silicon in the soybean crop. An experiment was carried out in a red latosol soil from December 2007 to April 2008. The estatistical design of the experiment was complete randomized blocks with four treatments (T(1), untreated plot; T(2), a silicon foliar application; T(3), two silicon foliar applications, and T(4), three silicon foliar applications) with three replicates. Each application was 500 ml per hectare of "Silicio Samarita". The first silicon application was carried out in the stage V8 (46 days after the sowing), the second in R(1) (60 days after the sowing) and the third in R(5.1) (88 days after the sowing). Only the third application of the silicon affected the cumulative dry mass of the plants, except for root dry mass. The plants that received three silicon applications presented thicker leaves with the decrease of the specific leaf area (16%, 17.5% and 9.9%) in relation to T(1), T(2) and T(3), respectively. The conclusion is that only as of the third application (T(4)) the silicon accumulated in adequate levels for the plant and promoted an increase in the accumulatioon of dry weight and productivity, which was over 20, 18 and 20 bags per hectare in relation to treatments T(1), T(2) and T(3), respectively.