Perfilhamento e valor nutritivo de pastagens de capins marandu e xaraés[BRACHIARIA BRIZANTHA (HOSCHST EX A. RICH.) STAPF.] sob manejo intermitente e doses de nitrogênio e potássio
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2010-08-05
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Universidade Federal de Goiás
Resumo
The pastures are formed by a population of plants and each plant is
formed by basic units called tillers. Management practices
allow the knowledge of the processes of tillering. The nutritional value of
pasture is determined by chemical composition of the plant and its
digestibility may be affected by nutrient supply, the station
year and the grazing management. An experiment was conducted at Embrapa
Rice and Beans-Midwest Center for Dairy Research, in order to evaluate the
tillering and nutritive value of grasses and Marandu Xaraés fertilized with
nitrogen (N) and potassium (K) (0, 100, 200 and 300 kg / ha / year),
from December 2007 to May 2008. The experiment was
complete block design with three replications. Data Tiller
were grouped in four seasons during the trial period for the
variable tiller density (DPP) and three times for
other variables (TAP, TSP, and TMP IEP). The evaluation of tillering was
held in an area demarcated by tillers known. From the
initial population, each grazing were identified new populations of
tillers, marked with different colored wires. For the value data
nutrition were evaluated in the dry season and water. The collection of samples was
performed by simulated grazing were analyzed and the CP, NDF,
ADF, lignin and IVDMD. In the review of DPP, there were dose effect
(P = 0.0510) and age (P <0.0001), and after the grazing periods, the DPP is
stabilized. No differences were found between seasons for the rate
of tillers (TAP) to treat 300 kg of N and K / ha / year. In
rainy season, the mortality rate of tillers (TMP) were lower
the dose of 300 kg N and K / ha / year. The survival rate of tillers (TSP) was
higher in water at a dose of 300 kg N and K / ha / year and 200 kg of N and
K / ha / year, not different from the other doses. The stability index of tillers
(IEP) remained above 1.0 in all treatments and times. For capimxaraés,
the linear increase in fertilizer levels stimulated tillering with
the increase in DPP to 300 kg of N and K / ha / year. Waters, the dose of
100 kg of N and K / ha / year showed higher TAP. The other doses and times not
differed. In the waters between 0 and 100 kg of N and K / ha / year yielded the highest
TMP. However, the dose of 100 kg of N and K / ha / year did not vary from 200 kg N and
K / ha / year, with intermediate values. At a dose of 300 kg of N and K / ha / year were
observed the lowest TMP. It was observed that the pastures fertilized
300 kg of N and K / ha / year had the highest TSP in relation to
too, for the waters. The highest values were found in the TSP
dry seasons. The stability index of tillers (IEP) remained above
1.0 in all treatments and times. At a dose of 300 kg of N and K / ha / year was
observed the highest TSP during the rainy season, although the highest values have been in the dry season. The NDF, ADF and lignin were not
influenced by fertilization, but the ADF (33.40 and 31.20%
respectively) and lignin (3.93% and 2.97, respectively) were higher in
the rainy season. The average CP of pastures were not affected by
fertilization, except for CP content pastures fertilized with 200 kg N and
K / ha / year was higher (P = 0.0353) during the rainy season. The concentration of NDF
pastures fertilized with N were 7.7 and 7.1% lower (P = 0.0368) than
Unfertilized, in times of rainy and dry seasons, respectively. The levels
Average ADF were not affected by fertilization, but the average content
FDA pastures in the rainy season was lower (P = 0.0933) than during the
drought. The average content of lignin pastures fertilized with 200 kg of N and K / ha / year
was higher (P = 0.0547) than in pastures fertilized with 100 N and K / ha / year (2.27
and 3.86% respectively). The average IVDMD of pasture was higher Unfertilized
(P = 0.0476) than that of pastures fertilized with 200 kg of N and K / ha / year, and in
rainy season, the IVDMD of pasture was not fertilized greater than that of
fertilized pastures. In the pastures fertilized with 300 kg of N and K / ha / year, IVDMD
in the rainy season was higher (P = 0.0155) than in the dry season. Pastures
xaraés unfertilized grass are prone to susceptibility
degradation in the short term and it is recommended fertilization rates above 200 kg
N and K / ha / year. Grazing management based on light interception
proved valid for pastures that receive manure. Pastures are fertilized
more stable compared to the dynamics of tillering. There was no variation
IVDMD significantly due to fertilization rates and periods studied with
always harvested forage in the same physiological maturity. When the pasture
was managed based on IL fertilization affected only the CP. Fertilization
did not affect the nutritional value of grass xaraés subjected to grazing management
IL-based.
Descrição
Palavras-chave
Adubação nitrogenada , Aparecimento de perfilho , composição
bromatológica , estabilidade de perfilhos , interceptação luminosa , mortalidade de
perfilhos , Nitrogen , tillers composition , chemical , stability of tillers , light interception , mortality
tillers , 1.Adubação nitrogenada 2.Perfilhos - aparecimento 3.Composição bromatológica 4.Interceptação luminosa 5.Perfilhos - mortalidade
Citação
AMARAL, Alliny das Graças. Tillering and nutritive value of pastures and Marandu xaraés [Brachiaria brizantha (A. Rich HOSCHST EX.)
STAPF.] Under management and intermittent doses of nitrogen and potassium. 2010. 138 f. Dissertação (Mestrado em Ciências Agrárias - Veterinaria) - Universidade Federal de Goiás, Goiânia, 2010.