Department of Plant Sciences

Several classes of soils in Brazil have been used for sugarcane cultivation, inclusive soils with low soluble silicon contents. The objectives were to evaluate silicon availability in soils and the relationship between availability and uptake. Therefore, we assessed the dry matter yields of sugarcane cultivated in three soil types, with and without silicon fertilization. The experiment was set up in a completely randomized factorial scheme (4 x 3 x 2) with four silicon rates (0, 185, 370 and 555 kg ha-1 Si) as Ca-Mg silicate and three soils: Quartzipsamment (RQ), Rhodic Hapludox (LV) and Rhodic Acrudox (LVdf), in four repetitions. All plots (100 L) received same Ca and Mg quantities with additions of dolomitic lime and or MgCl2. The LVdf soil showed the higher soluble silicon concentration, followed by LV and RQ. Added Si applied increased the amounts of soluble content in all soils but Si uptake in leaves of sugarcane were just increased to RQ and LV. However, addition of Si to the soils did not promote changes in dry matter yields and Si uptake on stalks of sugarcane.