Análise de nutrientes solúveis em palhas após aplicação de dejetos líquidos suínos

Abstract

Swine farming is of fundamental importance to the socioeconomic context of southern Brazil; however, environmental concerns have emerged regarding the application of swine liquid manure (SLM), as nutrients such as nitrogen (N), phosphorus (P), copper (Cu), and zinc (Zn) may lead to soil and water contamination. Therefore, the objective of this study was to evaluate the solubilization of N, P, Cu, and Zn after the application of SLM on plant residues (straw) collected post-harvest and during flowering. The determination of water-soluble nutrients was carried out using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) for P, Cu, and Zn, and UV-Visible Spectrophotometry for N. The results showed that most nutrients were solubilized during the first water extraction. The data indicate high nutrient bioavailability immediately after application, which may benefit crop growth but also increases the risk of leaching and surface runoff, especially under rainy conditions. Although the concentrations found were below the limits established by environmental regulations, such as CONAMA Resolution No. 420/2009 and IAP Ordinance No. 223/2014, continuous and excessive application may result in accumulation and progressive contamination. It is concluded that the use of SLM as an organic fertilizer is feasible, provided it is applied with technical planning, proper management, and consideration of soil and climate conditions, ensuring agronomic efficiency without compromising environmental sustainability.