In Brazil, upland rice is cultivated mainly on cerrado soils, which, due to their highly weathered degree, present low pH, low base saturation and low ratio of Si oxides of Fe and Al. A greenhouse experiment was conducted to evaluate the response of upland rice to calcium silicate as well as its effect on correcting soil acidity. The treatments consisted of six levels of SiO2 (0; 125; 250; 375; 500 and 625 mg kg-1 of soil) as of wallastonite, Wansil-10 (50% of SiO2, 44 of CaO and 1.48 of MgO) and three upland rice cultivars (Caiapo, Carajas, and Confiança).The experimental design was completely randomized with four replications. Rice response to SiO2 was linear, showing significant positive correlation with Si and Ca content of soil, derived from application of calcium silicate. The application of SiO2 also increased the pH, exchangeable Ca and Mg and soluble Si in the soil.
Oryza sativa L.; Oxisol; soil ammendment; nutrient absorption