Reatividade de fontes de silício e sua eficiência na absorção e acumulação na cultura do arroz irrigado

Abstract

Silicon Fertilization in agriculture has proportionate innumerable benefits, specially as fertilizing and corrective action. To evaluate the agronomic efficiency of different silicon sources, three studies were conducted, two of then were an incubation study using two types of soil, a sandy and a clay soil, and a biological study using flooded rice. The incubation study was carried out at times and distinct soil. The first study, was used a sandy soil and for the second study was used a clay soil, evalueting 7 silicon sources. The silicates were applied at dose: 200 mg kg-1 of Si, Wollastonita was the standard silicon source at doses : 50, 100, 200, 400 mg kg-1 of Si. After 60 and 120 days of incubation, a soil sample was analyzed to determine Si, pH, Ca and Mg. The most efficient sources in avalable Si using a sandy soil, was Siligran and Wollastonita during 60 and 120 days of incubation. Analyzing Ca availability the best silicon sources to supply Ca in a sandy soil were Wollastonita and siligran AWM, for Mg supply were pode- ciclone and siligran AWM. The best sources to raise the pH, in sandy soil, were pode- ciclone and siligran AWM. Siligran and siligran AWM, with the Wollastonita, were more efficient in availability Si in a clay soil, with 60 and 120 days of incubation. Analyzing the clay soil, siligran AWM and siligran, were more efficient to available Ca, Mg and pH. The biological study was carried out in pots, with flooded rice, (cv Rio Formoso), using granulated and powdered, siligran and silicon as silicon sources, at dose 200 mg kg-1 of Si. The Wollastonita also was used as standard silicon source at doses: 50, 100, 200 and 400 mg kg-1 of Si. The soil was sampled to analyze: Si acid acetic 0.5 mol L-1 and 0.01 calcium chloride mol L-1. Aerial part of the plant was analyzed to determine; dry matter, panicle mass and grains; Si in aerial part, rind and Si accumulation. The differents rates of Wollasytonita increased Si in the soil. The rice answered positively with increasing rates of Wollastonita, as well with siligran and siligran AWM. The biggest Index of Efficiency Agronomic (I.E.A.), considering Si in the aerial part and Si accumulated, was gotten by siligran granulated.