Banca de QUALIFICAÇÃO: ANTONIO LEANDRO CHAVES GURGEL
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.DISCENTE : ANTONIO LEANDRO CHAVES GURGEL
DATA : 14/09/2018
HORA: 13:30
LOCAL: Sala GPV - Grupo de Pesquisa Produção Vegetal - Embrapa Gado de Corte
TÍTULO:
RESIDUAL EFFECT OF NITROGEN FERTILIZATION IN SOIL CHARACTERISTICS AND IN THE STRUCTURE OF MOMBAÇA GRASS GRAZING BY CUTTING CATTLE
PALAVRAS-CHAVES:
Nitrogen, Panicum maximum, pasture structure, root system, soil physics
PÁGINAS: 50
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
SUBÁREA: Pastagem e Forragicultura
RESUMO:
The objective of this study was to evaluate the residual effect of nitrogen fertilization on soil characteristics, on the pasture structure of the mombaça grass and on the performance of beef cattle. The experiment was carried out at the Embrapa Gado de Corte, in Campo Grande, Mato Grosso Sul. The experimental period was from 07/11/2017 to 05/22/2018, with a duration of 196 days. Pastures received three annual doses of nitrogen (N) in the form of urea (100, 200 and 300 kg ha-1 of N) for three consecutive years (2015, 2016 and 2017). In the year 2018, nitrogen fertilization was not used to characterize the evaluation of the residual effect of N doses. For defoliation, 54 male Nellore cattle were used. Soil density (SD), penetration resistance (PR) and the Mombasa root system were evaluated in the soil. In the pasture the structural characteristics were evaluated and in the animals the average individual gain and per area and the stocking rate were evaluated. The interaction between the residual effect of N doses and soil depths was not significant for SD, PR and root system characteristics. There was no effect of the residual doses of N to DS, with mean values of 1.22 cm-3 and 1.25 g cm-3, under and outside the clumps, respectively. There was effect of the depths to the SD, under and outside the clumps, the highest values were observed in the depths of 0-10 cm. PR in pre-grazing was not influenced by N doses at any of the depths. The PR differed between doses of N in post grazing, the highest PR (1.97 MPa) was observed in the soil under the residual effect of 300 kg ha-1 of N, with a higher value in the layer of 10 cm (3.60 MPa). There was no effect of the residual N doses for dry mass and density of roots of the mombaça grass, with mean values of 2.60 kg m3 and 2506.0 kg ha-1 0, 941 kg m-3 and 941.2 kg ha-1, under and between clumps, respectively. There was effect of the depths for the density, dry mass and distribution of the mass of roots, under and between clumps. The highest values were observed in the depth of 0-10 cm and the lowest values, in the 30-40 cm depth. The interaction between the residual effect of N and the grazing cycles was not significant for the structural variables of the pasture in pre and post grazing. There was no residual effect of N for canopy height and mass of dead material (MDM) in pre grazing. The forage accumulation rate (FAR), forage mass (FM), foliar leaf mass (FLM) and stem mass (SM) were higher in the pastures with a residual effect of 300 kg ha-1 of N and lower for the residual effect of 100 kg ha-1 of N. There was no effect of the residual N doses for the structural variables of the pasture in post grazing. There is no residual effect of N fertilization on the soil physical characteristics evaluated, nor on the root system of the Mombasa grass. The higher accumulation of forage in the pastures under the residual effect of 200 and 300 kg ha-1 of N promoted an increase in the structural characteristics of the pasture.
MEMBROS DA BANCA:
Presidente - 986835 - GELSON DOS SANTOS DIFANTE
Externo à Instituição - ALEXANDRE ROMEIRO DE ARAUJO - EMBRAPA
Externo à Instituição - DENISE BAPTAGLIN MONTAGNER - EMBRAPA