Composição química de capim-tanzânia adubado com nitrogênio e fósforo

Abstract

RESUMO -Avaliaram-se os teores de matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), nutrientes digestíveis totais (NDT), cálcio (Ca), fósforo (P) e magnésio (Mg) na parte aérea do capim-tanzânia (Panicum maximum) adubado com nitrogênio e fósforo durante o período de verão/outono. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 4 × 3, com quatro doses de nitrogênio (0, 100, 200 e 300 kg/ha/ano) e três doses de pentóxido de difósforo (P 2 O 5 ) (0, 50 e 100 kg/ha/ano), com três repetições. Foram realizados três cortes a 40 cm do solo, a cada 35 dias. Após cada corte, foi realizada adubação, aplicando-se o P 2 O 5 de uma só vez no corte de uniformização e o nitrogênio parcelado em três vezes. As doses de nitrogênio não afetaram os teores de magnésio e reduziram os teores de matéria seca, cálcio e fósforo, enquanto a adubação fosfatada aumentou o teor de fósforo. A adubação teve efeito quadrático nos teores de PB, FDN e NDT, melhorando a qualidade da forragem conforme aumentaram as doses, principalmente de nitrogênio.Nas condições edafoclimáticas estudadas, recomenda-se que o capim-tanzânia seja adubado com 300 kg de N/ha e 100 kg de P 2 O 5 /ha. Palavras-chave: fibra em detergente neutro, forrageira, matéria seca, minerais, Panicum maximum, proteína bruta Chemical composition of Tanzania grass fertilized with nitrogen and phosphorusABSTRACT -It was evaluated in this work the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), total digestible nutrients (TDN), calcium (Ca), phosphorus (P) and magnesium (Mg) in the aerial section of the Tanzania grass (Panicum maximum), fertilized with nitrogen and phosphorus during the summer and autumn. The experimental design was complete randomized, with a 4 × 3 factorial scheme, and four N rates (0, 100, 200, and 300 kg/ha/year), and three pentoxide diphosphorus (P 2 O 5 ) rates (0, 50, and 100 kg/ha/year), with three replicates. Three cuts were made at 40 cm of the soil, every 35 days. After each cut, the fertilization was accomplished, and P 2 O 5 was applied only once on the uniformed cut and N was parceled in three times. Nitrogen rates did not affect contents of magnesium and they reduced contents of dry matter, calcium and phosphorus, while phosphate fertilization increased levels of phosphorus. Fertilization

Agricultural answers and chemical composition of Massai grass under different nitrogen doses and urea sources

“…Reductions in DM content due to the increase in nitrogen fertilization in all seasons were due to the effect of nitrogen fertilization combined with the management cut by 95% light interception to promote faster plant growth and consequently increase the frequency of cutting, resulting in more tender plants, i.e., renewal of younger tissues with more soluble components. This effect is probably characterized by the higher proportion of leaves (mean of 82.0%) in relation to the total forage produced in the present experiment (Table 2), which corroborates the results of Sousa et al (2010), who also observed a reduction in dry matter contents with increased leaf participation under increasing doses of N.…”

What is the best fertilizer for Marandu and Xaraes palisadegrass production in the short term?

“…These results are in concordance with other studies, where the TDN of Marandu palisadegrass was higher with N supply and declined with the successive cuts (Benett et al, 2008). Similarly, higher rates of N and P resulted in higher TDN of Tanzania guineagrass (Sousa et al, 2010).…”

“…The increase in energetic content of Marandu palisadegrass due to urea application may be associated with greater amounts of rapidly degraded polymers such as cellulose, due to the high rate of N (Van Soest, 1994), whereas 08-28-16 application resulted in greater P availability, that performs important functions in the transference of energy in plant cells (Sousa et al, 2010). The TDN, DE and ME content in leaves and stems of Marandu palisadegrass fertilized with urea, Super N and 30-00-20 decreased in the two last cuts in comparison to the first cut (Table 3), possibly because of an increase in the fibrous fractions of low degradability content and CP content reduction.…”

Animal performance, production, and quality of Tanzania grass fertilized with nitrogen

“…The levels of CP obtained were lower than those reported by França et al (2007), who observed variations of 57.8-142.8 g kg -1 of CP, and by Sousa et al (2010), who found CP levels of 130 g kg -1 in Tanzania grass using 300 kg N ha -1 .…”