O efeito do silício (Si) na produção de matéria seca de arroz, teor e acúmulo de Si foi avaliado sob condições de casa-de-vegetação. O delineamento experimental foi o inteiramente casualizado em esquema fatorial 5 x 2 com 4 repetições. Os tratamentos foram 5 doses de Si (0; 0,25; 0,50; 0,75 e 1,00 g dm-3) e 2 cultivares de arroz (Conai e Curinga). A aplicação de Si não afetou os componentes de crescimento e produção, com exceção da matéria seca de raiz. Houve um acréscimo da matéria seca de raiz sob aplicação de Si com uma produção máxima de 33,57 g vaso-1 na dose ajustada de 0,38 g dm-3 de Si. O acúmulo e os teores de Si variaram entre os cultivares, os quais responderam de forma linear ao aumento das doses de Si. Já para o acúmulo de Si na parte aérea não houve diferenças significativas entre cultivares.

The effect of silicon (Si) application on dry matter production of rice, as well as on the content and accumulation of silicon was evaluated under greenhouse conditions. The experimental design was a completely randomized design arranged in a 5 x 2 factorial structure with four replicates. The treatments consisted of a combination of five Si levels (0, 0.25, 0.50, 0.75, and 1.00 g dm-3) and two rice cultivars (Conai and Curinga). The Si application did not affect the growth and production components except the root dry matter. There was an increase in the root dry matter under Si application with a maximum production of 33.57 g pot-1 in the dose of 0.38 g dm-3 Si. The content and accumulation of Si varied between the cultivars, increasing linearly with the Si levels, except for Si accumulated in the shoot, where no significant differences were observed between the cultivars.

The solubility of Mn in different fertilizers (MnSO4.H2O-p.a., MnO2-p.a.+MnO-Ind., MnO2-Ind.+MnO-Ind., MnO2-p.a., MnO2-Ind. and MnO-Ind.) was determined using different methodologies: total content and soluble contents in water, 10% H2SO4, citric acid at 20 g L-1, diluted neutral ammonium citrate, (1+9) and DTPA at 0.005 mol L-1. The Mn solubilities in the latter three extractors were assessed after agitation of the sample for one hour and after boiling for 5 minutes. The extraction procedure using neutral ammonium citrate (1+9), at 1:100, with agitation for one hour, was shown to be the most adequate to assess the availability of Mn in fertilizers.