Quantos dias após a desfolha deve-se adubar com nitrogênio os capins BRS Tamani e BRS Quênia?

Abstract

One of the ways of minimizing nitrogen losses in fertilization of forage grasses is to consider the when that this nutrient should be applied to the soil, in search of the best stage of assimilation by the plant. Thus, the objective was to identify the appropriate moment to perform nitrogen fertilization in BRS Tamani and BRS Kenya grass. The experiments were carried out in a greenhouse, in a completely randomized experimental design, with five treatments and ten replications. The treatments consisted of intervals of days after defoliation for nitrogen fertilization: 0, 2, 4, 6 and 8 days. The evaluations were carried out with interval of 20 days from the standardization cut. three and five evaluations were carried out in the Tamani grass and Quênia grass experiment, respectively. The height, number of tillers (NT), number of leaves (NL), shoot dry mass (SDM), leaf blade (DMLB), stem + sheath (DMCB), residue (DMR) and root (DMRT), dry mass of each leaf blade (LDM), leaves per tiller number (NL:NT), leaf appearance rate (LAR), phyllochron (PHYL) and growth rate (GR). There was an effect of the fertilization season (P <0.05) of the BRS Tamani grass for NT, NL, DMLB and DMCB, since, overall, there was a decrease in the means of BRS Tamani grass. For BRS Quênia grass, the fertilization moment did not influence the evaluated variables, except for height and DMR. Thus, there was an increase in the height of the BRS Quênia grass the later the fertilization and the higher DMR occurred when the grass was fertilized two days after the defoliation. Therefore, there is an interval of up to eight days after defoliation to make the fertilization of BRS Quênia grass and BRS Tamani grass, the fertilization should be carried out as close to the defoliation as possible.