Análise comparativa das propriedades químicas do solo em sistemas de manejo orgânico e convencional

Abstract

This study aimed to compare the chemical properties of soils under predominantly organic and conventional management systems, with emphasis on macronutrient availability, acidity, organic matter, and fertility attributes. Initially, the conceptual foundations of soil fertility were presented, highlighting the influence of macronutrients, pH, and organic matter on plant nutrition processes. Soil samples were collected from agricultural areas under different management systems and prepared according to standard procedures of air-drying, disaggregation, sieving, and chemical analysis following Embrapa protocols, including determinations of pH, phosphorus, potassium, calcium, magnesium, aluminum, organic matter, and multivariate statistical analyses (PCA and HCA). The results showed marked differences between the systems. The predominantly organic soil exhibited higher pH values, absence of exchangeable aluminum, higher levels of phosphorus, potassium, calcium, magnesium, and organic matter, as well as greater sum of bases (SB), cation exchange capacity (CEC), and base saturation (V%). In contrast, the conventional soil showed high acidity, elevated exchangeable aluminum levels, and low concentrations of essential nutrients, indicating low overall fertility. PCA and HCA analyses reinforced the clear separation between the systems, demonstrating that predominantly organic management favors improvements in soil chemical and structural quality. It is concluded that organic practices provide greater stability, nutrient retention, and acidity reduction, promoting more favorable conditions for plant development.