Doses e fontes de nitrogênio na recuperação das características estruturais e produtivas do capim-marandu

Abstract

Doses e fontes de nitrogênio na recuperação das características estruturais e produtivas do capim-marandu 1Rates and sources of nitrogen in the recovery of the structural and productive characteristics of marandu grass ABSTRACT -To replenish soil fertility is one of the ways of recovering the productive capacity of degraded pasture. Nitrogen fertilisation is fundamental to increasing forage production, especially when it comes to the recovery of pasture. With this in mind, the objective of this work was to evaluate the structural characteristics and dry matter (DM) accumulation of the leaf blades and sheathed stems of marandu-grass pasture at a moderate stage of degradation, for different dosages and sources of nitrogen, during a three-year period. The experiment was carried out from July, 2003 to March, 2006 at the Model Farm of the Goiás State University (UEG), over an area of 882 m 2 with plots of 20 m 2 and usable area of 6 m 2 . The experimental design was of randomized blocks with three replications. The treatments in the plots were characterized by a 2 x 4 factorial, being two nitrogen sources (ammonium sulphate and urea) and four nitrogen dosages (0; 100; 200 and 300 kg ha -1 yr -1). For each sub-plot, treatments were represented by the years (2004, 2005 and 2006), as relating to the time of the recovery of the pasture. Nitrogen fertilization was divided into three applications, following each harvesting of the grass for forage evaluation. The results showed that nitrogen fertilisation influenced the structural characteristics and dry matter accumulation of marandu grass, and hence its recovery. The dosage of 300 kg ha -1 yr -1 of ammonium sulphate resulted in greater values for plant height, tiller density and leaf-blade dry matter.

Residue of Phosphorus Sources Broadcast and Applied on Rows in Forages during Off-Season Crops

“…This higher leaf-culm ratio can be justified by the lower development of culms of forage sorghum plants fertilized with BRP, which presented a greater leaf development ( Figure 3C). The leaf-culm ratio is very relevant in studies of forage grasses since the higher number of leaves over culms indicates a better adaptation of plants to grazing and cuttings (Silva et al, 2013). Passos et al (1997) evaluated the effects of phosphorus sources (magnesium thermophosphate and triple superphosphate) on two potted grasses (Brachiaria and Andropogon) and found that phosphorus sources did not differ regarding the number of tillers per Brachiaria pot, imilar result was found in the present study.…”

Soil dynamic alterations and use efficiency of nitrogen by Brachiaria species

“…This may reduce the production costs, avoid natural resources degradation and increase the crops yield (Costa et al, 2009). Besides, the N has an important function in structural characteristics of the plants, which could positively influence the Brachiaria's production (Silva et al, 2013) and improve the management when this forage is used to animal production. As already mentioned, the N use efficiency was higher on the "single cut" management, regardless of the specie (Table 8).…”

Tifton 85 grass responses to different nitrogen levels and cutting intervals

“…N limits biomass production and influences the amount of other nutrients necessary to sustain production. It also influences the nutritional value of forage, plant health, and plant recovery after grazing, and may affect animal performance (SOLLENBERGER, 2008;SILVA et al, 2013). N fertilizer must be applied regularly because the amount available in the soil is insufficient to support high productivity and forage quality (REZENDE et al, 2015).…”