Disponibilidade e transferência de nitrogênio, fosforo e potássio em um argissolo submetido à aplicação de fontes de nutrientes

Abstract

The swine and cattle activities are of great economic and social importance in Brazil in the southern region, but generate of large volumes of waste, that when applied to the soil can be mineralized and part of the nutrients released can be absorbed by plants or transferred by runoff or percolation. The aimed of this study was to evaluate the rate of mineralization, availability and transferences of nitrogen (N), phosphorus (P) and potassium (K) for the solution runoff and percolation in the profile in a Sandy Typic Hapludalf under application of nutrient sources. Two experiments were carried out at the Federal University of Santa Maria (UFSM), in Santa Maria (RS). For the experiment 1, soil samples of a Sandy Typic Hapludalf were collected in October 2010, prepared and carried the following treatments: soil, soil + pig slurry, soil + deep-litter; soil + cattle slurry and soil + mineral fertilizer. These soils were incubated during 0, 20, 35, 58, 73 and 123 days and then, samples were collected and submitted to analysis of mineral-N (N-NH4 + e N-NO3 -), P extracted by exchanged anion resin and K by exchanged cation resin. The experiment 2 was installed in 2004, at the experimental area of the Department of Soils of UFSM. The treatments were: control, pig slurry, deeplitter, cattle slurry and mineral fertilizer. Each source of manure has been applied to provide the N demand of corn (Zea mays L.) and oat (Avena strigosa Schreb.). From May 2010 to February 2011, samples of runoff and percolated in the profile solution were collected; the volume was measured and the content mineral- N (N-NH4 + e N-NO3 -), P e K in the solution was analyzed. The highest rate of N mineralization occurred in soil under the application of pig slurry and increased availability of P and K was observed with the application of litter of pigs. The greatest transfer of N, P and K occurred in the soil under the application of deeplitter