Teores de nutrientes no solo, produção de fitomassa e qualidade da pastagem de Tifton 85, produzida em área submetida à aplicação de dejetos suínos




The utilization of swine dejections as fertilizer in cultivated areas with Tifton 85 pasture, has been a common practice realized by producers in the west of Paraná state, Brazil, however the number of researches dedicated to the evaluation of this practice is still small. This work was carried out with objective of evaluating the effect of the application of swine dejections on the production, pasture quality and on nutrients accumulation and nitrates contents in soil cultivated with Tifton 85, in environments conditions of the area west of Paraná State. The experiment was carried out in a clay oxisoil area. A randomized blocks design with six treatments and four replications was used. The treatments were six doses of swine dejections: 0; 78; 156; 234; 312 and 390 m3 ha-1 year-1, enough for the application of 0; 151; 303; 454; 603; and 757 Kg ha-1 year-1of total nitrogen. These doses were divided in seven applications inside of a period of 12 months (Fev/04 the fev/05). The dry phitomass production and the contents of N, P, K, Ca, Mg, Cu, Zn, crude protein(CP), neutral detergent fiber (NDF) and vitro digestibility of the Tifton 85 dry matter was determined in each of the seven cuts realized during the experimental period. Soil samples were collected in the depths 0 - 10, 10 - 40, 40 - 80, 80 - 120 and 120 - 160 cm and chemically analyzed for evaluation of P, K, Cu, Zn and nitrates contents. After seven cuts, it was verified that the dry phitomass production of the tifton-85 pasture increased lineally with the swine dejections doses. N, P, K, Cu, Zn and crude protein (CP) content increased, while the dry matter content (DM) and Ca content in the dry matter of Tifton 85 decreased with the application of dejections. The NDF content and dry matter in vitro digestibility was little influenced by the application of swine dejections. For all the evaluated variables in the Tifton 85 pasture fertilized with swine dejections, the obtained content were considered appropriate for cattle feeding. For the soil analysis, it can be observed that there was increase, only of P and Zn content in the superficial layer (0 - 10 cm), in function of the doses of swine dejections. For the others nutrients and nitrates contents there were not significant increases for none of the analyzed layers. The agricultural swine dejections utilization in cultivated area with pasture of Tifton 85 with doses of up to 390 m3ha-1 (equivalent up to 753 kg ha-1 year-1de N) and for the environments conditions analyzed of the west Paraná State area, did not present environmental risk of contamination of the water table with nitrates.


suíno - esterco resíduos orgânicos como fertilizantes pastagens - adubos e fertilizantes swine dejections organic wastes as fertilizer pastures - fertilizers and manures

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