AVAILABILITY OF SILICON FOR RICE CROP ACCORDING TO SOURCES, INCUBATION TIME, AND SOIL CLASSES

Abstract

Rice is a silicon accumulator, what benefits its growth and development, reducing cuticular transpiration and increasing the plant tolerance to pests and pathogens attacks. This study aimed to evaluate the incubation time effects of silicate sources on the Si availability and absorption and on rice plants growth. The experimental design was randomized blocks, in a 5x2x3 factorial scheme, with four replications, two silicate sources (calcium silicate and steel slag), five incubation times (1, 14, 35, 63, and 98 days), and three soils classes. The silicon dose used in the soil was 300 mg dm^-3. The levels of soluble Si extracted by calcium chloride were evaluated in the soil, and, for plants, the dry matter of shoot and root, plant height, Si content and accumulation of the aerial part were evaluated. For all soil classes, the root dry matter yield was not influenced by silicon fertilization. The shoot dry matter index was higher with the application of calcium silicate. The highest shoot silicon accumulation occurred between the second and third incubation time, with higher concentration for the Oxisol.