Dinâmica de nitrato e metais em solos do Estado do Paraná, submetidos a aplicações de dejetos bioestabilizados de suínos

Abstract

The objective of this work was to evaluate the occurrence of the mobility of nitrate (NO3-) and metallic ions (K+, Zn2+, Cu2+, Fe2+, Mn2+) and toxic metals (Pb2+, Cr3+, Cd2+) in soils submitted to applications of biostabilized swine manure. In Chapter I, Article 1 is presented in the form of General Considerations a literature review focusing on the main aspects that characterize the use of pig waste as biofertilizer in agricultural areas. The Chapter II, Article 2 presents the experimental study developed with column lysimeter containing undisturbed samples of soils from four regions of Paraná classified as: (Red Nitosol eutroferric, Sandy Red Latosol dystrophic, Red Latosol dystrophic and Bruno Latosol dystrophic) to evaluate the mobility of NO3- in depth.. The columns were arranged in a completely randomized experimental arrangement (DIC 5x4x3)x3, corresponding to five applications of manure (0, 70, 140, 210 and 420 m3 ha-1) and the simulation of four volumes of rainfall (100, 150 , 200 and 250 mm) with collection of the percolated contributions in three depths (30, 60 and 100 cm) and in three replicates. The percolation tests were carried out in two distinct periods of 114 days, the first one called loading (from september 6 to december 20, 2015), and the second recharging (from march 21 to july 10, 2016). The NO3- concentrations obtained in the percolated contributions were determined by the Cd reduction method using spectrophotometer equipment with wavelength 543 nm. The analytical results showed that in all soils there were successive increases in the concentrations of percolated NO3- as the highest rates of manure and simulated rainfall volumes were applied, especially the Sandy Red Latosol dystrophic which presented the highest concentrations of oxyanion in depth. Also, an evaluation of the mobility of the metals (K+, Zn2+, Cu2+, Fe2+, Mn2+) and toxic metals (Pb2+ +, Cr Total, Cd2+) was carried out, using the same percolation tests. Comparing the contents of these chemical elements present in soils before and after the end of the experimental study period are presented in Chapter III, Article 3 of this work. The percolated concentrations of these chemical elements were determined by atomic absorption spectrometry flame mode (EAA). In general the results of the study characterized the mobility of K+ and Zn2+ in small concentrations by the profile of the studied soils, while the other metallic ions increased their original contents but remained concentrated and worshiped in the superficial layer. On the other hand, the toxic metals did not have their original contents altered with the sequenced application of waste in the soils. In general, the study indicated the need to review and update the legislation of Paraná that regulates the disposal of swine manure in the soil, which should include the mandatory need for periodic agronomic monitoring in order to discipline the rates to be applied in agricultural areas , According to the needs of the agricultural crops, in order to minimize the risks of contamination of the groundwater by the mobility of NO3-.