Banca de DEFESA: CAMILLA SANTOS REIS DE ANDRADE DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CAMILLA SANTOS REIS DE ANDRADE DA SILVA
DATE: 31/03/2025
TIME: 08:30
LOCAL: Sala 24 do departamento de solos.
TITLE:

Organic fertilizer produced from gliricidia leaves biomass: agronomic and environmental efficiency.

KEY WORDS:

Nitrogen. Fertilization. Sustainability.

PAGES: 107
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

Organic production systems follow strict standards described in the legislation. Among these standards is the prohibition of the use of synthetic fertilizers, which limits the availability of low-cost standardized fertilizers. One alternative to overcome this limitation is to conduct research that tests inputs adapted for organic systems, aiming to provide good results in the field in a sustainable manner. The pelleted fertilizer, processed from Gliricidia sepium leaves (green N), fits this principle because it is a renewable source derived from biological nitrogen fixation, with nitrogen content suitable for fertilization and accessibility. The general objective of the thesis was to evaluate the agronomic and environmental performance of green N fertilizer. The thesis was divided into three chapters. The objective of Chapter I was to investigate the definition of the spatial arrangement to determine the maximum biomass production of gliricidia, testing three spacings between plants (0.3 m, 0.5 m and 1.0 m) combined with two types of rows (single and double). The objective of Chapter II was to estimate the economic dose of green N (NG) and compare its efficiency in agricultural yield using chicken litter (CL) and castor bean cake (CC) as references, in addition to a treatment without fertilization (control). Chapter III aimed to verify nitrogen (N) losses due to ammonia volatilization and nitrous oxide emissions. The results observed in the first chapter showed that a spacing of 0.3 m is the best, as it allows greater accumulation of gliricidia biomass, with a greater proportion of leaves and thinner stems. In the first chapter, the quadratic model showed that the economic dose of NV was 262 kg of N ha^-1 for the first year and reduced in the second year of evaluation to 249 kg of N ha^-1. Likewise, for the two years of study, lettuce productivity in both cycles under single NV fertilization is equal to CL and CC, and both agree with the productivity of the State of RJ. The amount of nitrogen accumulated in the lettuce shoots was higher in the second agricultural year. The third chapter showed that NV favored low levels of N₂O emissions in accordance with the recommendation of the Intergovernmental Panel on Climate Change (IPCC) in both agricultural years. Depending on the climate conditions, fertilization with TM favors N₂O emission levels higher than those stipulated by the IPCC, as observed in 2022. NG and CF applied on the surface and incorporated manually favored lower N losses due to NH₃ volatilization. In general, with a spacing of 0.3 between plants, it is possible to obtain a production of 20 Mg ha^-1 of gliricidia aerial biomass, making it possible to produce 10 Mg ha^-1 of green N per hectare. Coupled with this, fertilizer proves to be a renewable source of nitrogen with the capacity to provide lettuce production comparable to sources used in organic production systems, with reduced emissions of N₂O and NH₃.

COMMITTEE MEMBERS:
Externo ao Programa - 1104775 - ADELSON PAULO DE ARAUJO - nullPresidente - ***.282.827-** - BRUNO JOSÉ RODRIGUES ALVES - EMBRAPA
Externo à Instituição - CAIO DE TEVES INÁCIO - EMBRAPA
Externo à Instituição - DAVID VILAS BOAS DE CAMPOS - EMBRAPA
Interno - 2213075 - EVERALDO ZONTA