Agronomic Evaluation Study: Use of Caiapônia Shale as Magnesium Supplementation for Soybean (Glycine max) and Maize (Zea mays) Cultivation

The soil of the cerrado is acidic, with high levels of iron and aluminum, and has low fertility due to weathering, which removes elements such as magnesium. To increase the availability of magnesium, essential for various plant processes, an alternative is the use of agrominerals rich in this element. The objective of this work was the agronomic evaluation of the use of Caiapônia shale as magnesium supplementation for soybean and corn crops. It is characterized as Magnesium Silicate containing 18% Magnesium Oxide (MgO) in its composition, in addition to the minerals Montmorillonite, Albite and Ilite. The product was screened to 0.425 mm in sieve no. 40. The study was conducted at the School of Agronomy of the Federal University of Goiás, located in the municipality of Goiânia, Goiás, in a greenhouse in two soils- Red Latosol (LV) and Yellow Latosol (LA). The treatments of Caiapônia Shale (CS) were increasing doses (0, 50, 100, 200 and 400 kg. ha-1 of MgO), in addition to the reference agrominerals, Dianutri (SiMg) and Ibar (MgO) and Wollastonite, source of Ca, with addition of MgO. The experimental design was completely randomized, with eight treatments conducted in quadruplicate. The variables analyzed were magnesium and calcium content and pH in the soil. The Caiapônia Shale (CS) released Mg+2, increasing the availability of magnesium, especially in LV in the first year of soybean and residual in corn in the second year, while in LA it was efficient in the first year.