Metodologías de recomendação de uso de gesso agrícola em diferentes sistemas de produção

Abstract

The use of integrated agricultural production systems has been widespread in agriculture in order to prevent wear or soil degradation, with the benefits of accumulation of organic matter and physical conditioning of the soil and, for this, the use of gypsum becomes an interesting resource, because it can be used as a source of sulfur (S) and calcium (Ca) and as a subsurface conditioner, resulting in greater root development of crops. Thus, the objective is to evaluate which of the methodologies for recommending the use of gypsum in different sustainable production systems offers better conditions for the structuring of sandy soil in the Cerrado region. The methodologies of Raij et al. (1996), Sousa, Lobato and Rein (2005) and Caires and Guimarães (2016) were analyzed in three agricultural production systems: no-tillage system (SSD), agro-pastoral system (SAP) and conventional pasture (PAST). The following evaluations will be carried out: density, porosity and soil aggregation in the layers 0-0.05, 0.05-0.20 and 0.20-0.40 m, laser granulometry - laser diffraction method, specific surface, elemental analysis of C, N and C/N ratio and FTIR spectroscopy with preprocessed data in the 0-0.10 m layer. There was no effect of gypsum for C, N and C/N ratio, nor for soil particle size. The no-tillage system stood out for increasing C and N contents and less oxidation of organic matter, and conventional pasture for improving aggregation. In the no-tillage system, the gypsum methodology proposed by Caires and Guimarães (2016) improved soil aggregation. In the agro-pastoral system and conventional pasture, the application of gypsum, regardless of the gypsum methodology used, provided physical improvements in the soil. According to the theories of Mie and Franhoufer, the no-tillage system presents a higher concentration of coarse sand fraction and, the agro-pastoral system, a higher concentration of fine sand. The no-tillage system and the agro-pastoral system present higher levels of total sand when compared to conventional pasture.