Morphological characteristics of aruana grass under different nitrogen levels

Abstract

Morphological characteristics of Aruana grass under cut in greenhouse under different N levels were evaluated. A completely randomized design with three nitrogen levels (125; 250 e 375mg/dm³ of N) plus control (no fertilization) and six replicates was used. The leaf transpiration rate and the leaf photosynthesis rate presented linear response to the N fertilization. It was observed increment of 14.52% to the 375 mg/dm³ of N in relation to 0 mg•dm-³ of N on internal CO2 concentration. It was observed the linear crescent and decrescent response on the leaf elongation rate and phylochron, respectively. There was no effect of nitrogen fertilization on senescence rate leaves remaining before cut, however the senescence rate leaves remaining after cut presented linear crescent effect under nitrogen fertilization levels. The net herbage accumulation, the tiller population density and the leaf/culm ratio were not affected by N levels. There was linear effect of nitrogen fertilization on plant height, number of leaves per tiller, forage production rate, total forage biomass, senescent forage biomass, green forage biomass, green leaf biomass and green culm biomass. The morphological characteristics of Aruana grass are favored by nitrogen fertilization at the highest levels.