Banca de DEFESA: ANTONIO LEANDRO CHAVES GURGEL
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.DISCENTE : ANTONIO LEANDRO CHAVES GURGEL
DATA : 14/02/2019
HORA: 08:00
LOCAL: Sala de Reuniões do Grupo de Pesquisa em Produção Vegetal - Embrapa Gado de Corte
TÍTULO:
SOIL-PLANT-ANIMAL INTERACTION IN MOMBAÇA GRASS PASTES UNDER RESIDUAL EFFECT OF NITROGEN.
PALAVRAS-CHAVES:
nitrogen fertilization, Panicum maximum, pasture structure, root system, soil physics.
PÁGINAS: 60
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. 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 (2014/2015, 2015/2016 and 2016/2017). In the year 2017/2018 no nitrogen fertilization was used to characterize the evaluation of the residual effect of N doses. For performance evaluation, 54 male Nelore whole cattle were used. The interaction between the residual effect of the nitrogen doses and the soil depths was not significant for all the variables related to the soil. There was no effect of residual nitrogen doses on soil density with mean values of 1.22 cm-3 and 1.25 g cm-3, under and between the clumps, respectively. In pre-grazing the resistance to penetration (RP) was not influenced by the residual nitrogen doses in any of the depths. In the post-grazing, higher RP (1.97 MPa) was observed in the soil that received 300 kg ha-1 of N for three consecutive years. There was no effect of the residual nitrogen doses for root density and dry mass of roots with mean values of 2.60 kg m-3 and 2.506.0 kg ha-1, 0.941 kg m-3 and 941.2 kg ha-1, under and out clumps, respectively. There was no effect of the residual nitrogen doses for carbon stocks (99.9 Mg / ha) and nitrogen (7.6 Mg / ha). The interaction between the residual nitrogen effect and the grazing cycles was not significant for the pre and post grazing pasture variables. There was no effect of the residual nitrogen fertilization for canopy height and dead material mass (DMM) in pre-grazing. The accumulation rate, forage mass (FM), foliar leaf mass (FLM) and stem mass (SM) were higher in the pastures under the residual effect of 300 kg ha-1 of N, and lower for the residual effect of 100 kg ha-1 of N, with intermediate values for those with 200 kg ha-1 of N. There was no effect of residual nitrogen doses on post-grazing for canopy height, FM, FLM, SM, DMM and leaf blade: with average values of 49.4 cm, 2822.8 kg ha-1 MS, 891.9 kg ha-1 MS, 744.5 kg ha-1 MS, 1186.7 kg ha-1 MS and 1.3, respectively . The residual nitrogen doses did not promote changes in the chemical composition of the morphological components of the Mombasa grass. There was no effect of the residual nitrogen doses for the average daily gain of cattle, with a mean value of 0.490 kg day-1. The stocking rate was higher in the pastures under the residual effect of 300 kg ha-1 of N, and lower in the 100 kg ha-1 of N, with intermediate value for the pastures under a residual effect of 200 kg ha-1 of N. The observed response to stocking rate was repeated for liveweight gain per hectare. The physical characteristics of the soil, carbon and nitrogen stocks and the characteristics of the root system were not influenced by the residual nitrogen doses. The residual doses of 200 and 300 kg ha-1 of nitrogen promoted greater forage accumulation, which allowed for increases in animal productivity.
MEMBROS DA BANCA:
Presidente - 986835 - GELSON DOS SANTOS DIFANTE
Externo à Instituição - ALEXANDRE ROMEIRO DE ARAUJO - EMBRAPA
Externa à Instituição - DENISE BAPTAGLIN MONTAGNER - EMBRAPA
Externo à Instituição - VALÉRIA PACHECO BATISTA EUCLIDES - EMBRAPA