FERTILIDADE DO SOLO E ACÚMULO DE METAIS PESADOS EM LATOSSOLO ADUBADO COM DEJETOS DE ANIMAIS

Abstract

The western region of Paraná stands out in the production of pigs and poultry in a confinement system in farms in Brazil. This production system is usually installed on small properties with family labor.Generally, the properties have small extensions of land and normally the residues from the production of pigs and poultry are applied to the soil. However, the application of high amounts and continuously can cause undesirable accumulations of heavy metals in the soil.The objective of this work was to evaluate the soil fertility and the accumulation of heavy metals in an Oxisol fertilized with swine manure and poultry litter. To assess soil fertility, calcium, magnesium, aluminum, potassium, phosphorus, copper, iron, zinc, manganese, boron, sulfur, organic matter and CaCl2 pH values were analyzed.To assess the accumulation of heavy metals, the contents of arsenic, cadmium, lead, barium, cobalt, chromium, nickel, antimony, mercury, total copper and total zinc were analyzed.The experimental design used was randomized blocks, with eight treatments and four replications. The evaluated treatments were three doses of pig manure (S1, S2, S3), three doses of poultry litter (A1, A2, A3), a control and a treatment with mineral fertilizer, with experimental units of 50 m² (5 m x 10 m).The lowest dose was defined to provide the same amount of nitrogen or phosphorus, depending on the crop, as the fertilizer. S1 corresponds to the calculated amount, S2 twice the calculated amount and S3 corresponds to three times the calculated amount, the same calculation was performed for the three doses of poultry litter A1, A2, A3.Data were subjected to analysis of variance and means were compared using Tukey's test at 5% probability. Fertilization with animal and mineral manure did not change the levels of organic matter, boron, aluminum, barium, cobalt and nickel in the soil.The fertilization with poultry litter provided higher values of pH, calcium and potassium in the soil and the one with liquid pig manure, higher levels of phosphorus, sulfur, copper, iron, manganese and zinc. There was an accumulation of arsenic, cadmium, chromium, lead, total copper and total zinc in the soil. This was more evident in the treatment with the highest dose of liquid swine manure, but the levels were below the environmental limits established by the regulatory agencies.