Parâmetros morfogênicos e produtividade do capim-Pioneiro submetido a doses de nitrogênio

Abstract

ResumoObjetivou-se por meio deste trabalho avaliar o efeito de nitrogênio sobre a morfogênese e rendimento forrageiro do capim-elefante cv. Pioneiro. O delineamento experimental utilizado foi em blocos casualizados com cinco repetições, totalizando 20 unidades experimentais. Os tratamentos corresponderam a quatro doses de nitrogênio (100, 200, 300 e 400 kg ha -1 ano -1 ). O experimento foi mantido sob condições irrigadas. Foram realizados cortes avaliativos a 50 cm do solo com valores de interceptação luminosa (95%) sem intervalos pré-definidos. Observou-se que a adubação nitrogenada aumentou significativamente (P<0,05) a produção de matéria seca por hectare, taxa de aparecimento foliar (folhas dias -1 perfilho -1 ), taxa de alongamento foliar (cm folha -1 dia -1 ) e taxa de alongamento de colmo (cm perfilho -1 dia -1 ). O processo de senescência foliar nesta forrageira é acelerado com o aumento das doses de nitrogênio e taxa de aparecimento foliar, consequentemente reduzindo o filocrono. É necessário um estudo sobre a viabilidade econômica de doses mais elevadas de nitrogênio em pastos de capim elefante cv. Pioneiro. Palavras-chave: Alongamento de colmo, aparecimento foliar, filocrono, Pennisetum purpureum AbstractObjective of this work by evaluating the effect of nitrogen on forage yield and morphogenesis of elephant grass cv. Pioneer. The experimental design was randomized blocks with five replications, totaling 20 experimental units. Treatments consisted of four nitrogen levels (100, 200, 300 and 400 kg ha -1 yr -1 ). The experiment was conducted under irrigated conditions. Evaluative cuts were made at 50 cm soil with values of light interception (95%) without pre-defined intervals. It was observed that N fertilization increased significantly (P<0.05) the production of dry matter per hectare, leaf appearance rate (leaves days -1 tiller -1 ), leaf elongation rate (cm tiller -1 day -1 ) and stem elongation rate (cm day -1 ). The process of

Agronomic and nutritional responses of Carajas elephant grass fertilized with protected and non-protected urea

“…Under conditions of low luminous intensity, tropical grasses may prioritize stem yield to allow light to reach the base of the canopy (HODGSON; SILVA, 2002). Lobo et al (2014) verified the positive effect of nitrogen enrichment rate on SER in elephant grass 'Pioneiro' and showed an increase of 0.001 cm til -1 day -1 when there was an increase of 1 kg of nitrogen.…”

“…According to Skinner and Nelson (1995), leaf elongation is restricted to the dividing zone at the base of the expanding leaf, and this zone is a site with great demand for nutrients, mainly nitrogen. Lobo et al (2014), evaluating the response of elephant grass 'Pioneiro' to doses of nitrogen (100, 200, 300, and 400 kg ha -1 year -1 ) observed an increase in LER of 17.67% between the lowest and the highest fertilization doses they used. In the present study, an increase of 58.99% was observed between the treatment with no fertilization and that with a dose of 800 kg N ha -1 year -1 .…”

Variation of Morpho-Agronomic and Biomass Quality Traits in Elephant Grass for Energy Purposes According to Nitrogen Levels

“…Nitrogen management is complex recommendation which is subject, dependent on soil and climatic conditions, occurring losses by leaching, volatilization, denitrification erosion due to multiplicity of chemical and biological reactions [13]. Due to the importance of agriculture to elephant grass, more information about economic and rational use of fertilizers is needed [14]. Because of the importance of agriculture to elephant grass, more information about economic and rational use of fertilizers is needed [15], in addition to actually check for production increases with increasing nitrogen dose or as a dose of production remained stable (maximum point).…”

Forage accumulation, tillering and bromatological characteristics of Brachiaria grass under nitrogen fertilization

“…Increases in forage production through nitrogen fertilization of pasture are mentioned by several authors (Lopes et al, 2013;Lobo et al, 2014).…”

“…Every 50 kg of N applied increases DMAR by 11.1 kg ha -1 day -1 . Forage DMAR is an important variable, since it reflects the balance in the dynamics of the plant growth and senescence rates (Fagundes et al, 2005;Lobo et al, 2014). Maranhão et al, (2010) obtained a 109% increase in the daily forage production of Brachiaria grass in response to the application of 200 kg ha -1 year -1 of N in relation to the treatment without fertilization.…”