Composição e Efeito do Lithothamnium como Corretivo de solo

Abstract

Soil acidity is a major limitation on plant development and increased productivity. It is known that managing soil acidity increases crop performance, making it possible to extract a large part of its productive potential. Limestone has been the most used soil acidity corrector worldwide, expressing a high benefit/cost ratio. Replacing limestone with other correctives is justified when there are financial or nutritional gains, such as an increase in other nutrients, in addition to Ca and Mg. In this sense, Lithothamnium is a product derived from calcareous algae, mainly composed of calcium carbonate, however, products based on this material have been recommended as soil conditioners, with possible effects on increasing the availability of nutrients in the soil. Thus, the objective of the work was to evaluate Lithothamnium, in terms of composition, reactivity in the soil as a corrective and as a chemical conditioner. The reactivity of Lithothamnium was evaluated by measuring the pH of soils with contrasting textures (clayey and sandy) incubated with different amendments, including Lithothanium, at different incubation times (0, 15, 21 days). The material was also characterized for its ability to neutralize acidity, through an acid-base reaction with HCl, followed by titration with NaOH. The mineralogical composition was determined by X-ray diffraction (XRD). The chemical composition for some elements was determined using energy dispersive X-rays (EDX) coupled to scanning electron microscopy (SEM), EDX-ME. Lithothamnium has neutralizing power and reactivity close to CaCO3 P.A, due to its predominant mineralogical composition being based on calcite and being finely ground. There is no evidence of any effect of Lithothanium as a soil conditioner, beyond the corrective effect of acidity and source of Ca, Mg.