Banca de DEFESA: LUCERO SARABIA SALGADO
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : LUCERO SARABIA SALGADO
DATA : 21/02/2019
HORA: 09:00
LOCAL: Departamento de Solos
TÍTULO:
Nitrogen dynamics and soil emissions of N2O and CH4 in a star grass pure pasture and in a silvipastoral system with leucaena for dairy production
PALAVRAS-CHAVES:
Animal intake, Forage quality, Milk production, Nitrogen Balance, N2O Emissions.
PÁGINAS: 114
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Fertilidade do Solo e Adubação
RESUMO:
In the southeast region of Mexico conventional livestock is the most common monoculture system, where the main species are native grasses or African grasses, with the biomass production being limited by rainfall seasonality and low soil fertility. In animal production systems, pasture degradation is associated with soil N depletion, requiring nutrient replacement. For the establishment of more productive pastures in these areas, silvopastoral systems (SPS) have been recommended, especially with the use of tree legumes, but are still little studied about their impact on the nitrogen cycle. Thus, the objective of this work was to quantify N fluxes in the soil-plant-animal system as a means of comparing the sustainability of an SPS with leucaena (Leucaena leucocephala) in a stargrass (Cynodon nlemfuensis) pasture with a pure pasture of star grass (SM). The average milk yield for two seasons was similar in both systems, with 7.1 and 6.3 kg UA-1 (1 UA = 450 kg live weight) day-1 for SM and SPS, respectively. The mean N intake by the animals in the two seasons was 171.9 and 215.7 g N UA-1 day-1 for SM and SPS, respectively, highlighting the importance of the legume in the supply of protein to the animals. The N deposited in the animal excreta was 138.1 and 184.9 g N UA-1 day-1 for SM and SPS, respectively, being higher in dung than in urine. N2O fluxes were higher in SM, with peaks of 1623.9 and 755.9 ug N-N2O m-2 h-1 for SM and SPS, respectively, originating from the urine treatment. The highest direct emission factors (FE) of N2O were observed in the rainy season, when denitrification was favored, being 0.05 and 0.01% for dung, and 0.52 and 0.17% for urine, in SM and SPS, respectively. In the dry season, FE was lower. It is concluded that the presence of legume in SPS allows to maintain the milk production observed in SM, fertilized with N, but with a lower intensity of N2O emission, contributing to the sustainability in livestock production.
MEMBROS DA BANCA:
Presidente - 681.282.827-00 - BRUNO JOSE RODRIGUES ALVES - EMBRAPA
Interno - 1104775 - ADELSON PAULO DE ARAUJO
Interno - 058.898.198-28 - SEGUNDO SACRAMENTO URQUIAGA CABALLERO - USP
Externo à Instituição - FRANCISCO JAVIER SOLORIO SANCHEZ
Externo à Instituição - MARCIO DOS REIS MARTINS - EMBRAPA