Banca de DEFESA: MICHEL DOUGLAS SANTOS RIBEIRO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MICHEL DOUGLAS SANTOS RIBEIRO
DATE: 29/07/2026
TIME: 08:00
LOCAL: Video conferência
TITLE:

Automated irrigation management for tomato crops in verdeponics: development of a control system and effects on production, physiology, and post-harvest quality

KEY WORDS:

Solanum lycopersicum L., irrigation automation, tensiometry, organic fertilization, water use efficiency, post-harvest quality, Greenponics.

PAGES: 90
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Manejo e Tratos Culturais
SUMMARY:

The search for agricultural production systems that reconcile high productivity with environmental sustainability is one of the major challenges of modern agriculture. In this context, this thesis aimed to evaluate the technical and agronomic viability of the "Greenponics" system, which employs uncomposted plant biomass as a nutrient source in conjunction with a low-cost automated irrigation system, for the organic cultivation of the 'Dominador F1' hybrid tomato. To achieve this objective, two field experiments were conducted in Seropédica, Rio de Janeiro, in 2023 and 2024. The first experiment tested different proportions of grass clippings (Paspalum notatum) and Gliricidia leaves (Gliricidia sepium) as nutrient sources, compared to a control treatment using Bokashi compost. The second experiment, utilizing the biomass composition that showed the best productive performance in the first year, evaluated the effect of different irrigation flow rates on the crop, with water management controlled by an automatic irrigation trigger based on tensiometry. The automated irrigation system demonstrated operational robustness, functioning without failure for periods of up to 145 days and accurately recording irrigation events, which allowed for the precise quantification of applied water volumes. Results from the first experiment indicated that the combination of 50% grass clippings and 50% gliricidia leaves, supplemented with thermophosphate, yielded the highest productivity—reaching 121.08 Mg ha⁻¹—surpassing the 83.56 Mg ha⁻¹ observed in the Bokashi treatment. In the second experiment, the maximum productivity observed was 107.49 Mg ha⁻¹ (at a flow rate of 4.0 L h⁻¹), and a quadratic relationship was found between the volume of water applied and productivity, indicating that excessive increases in applied volume did not result in additional yield gains. Water use efficiency varied considerably among treatments, with the highest values recorded in treatments subjected to moderate water deficit, suggesting a differential crop response to water conditions. Regarding post-harvest fruit quality, results showed that physicochemical attributes, such as pH, total soluble solids, titratable acidity, and the soluble solids-to-acidity ratio, were influenced by both the nutritional composition of the biomass used and the volume of water applied. Fruits from treatments with a higher proportion of gliricidia exhibited a higher soluble solids-to-acidity ratio, indicating a sweeter flavor profile, whereas treatments using Bokashi and a balanced mixture of grass and gliricidia showed higher titratable acidity. In the second experiment, fruit pH and titratable acidity varied according to irrigation flow rates; higher pH values were observed in the full irrigation treatment, while higher acidity was noted under moderate water deficit conditions. Total soluble solids showed a quadratic response to irrigation depth, with peak values recorded under both severe water deficit and excess water conditions, suggesting distinct effects related to concentration and fruit metabolism. Thus, it is concluded that the Greenponics system, particularly when utilizing a balanced mixture of grass and gliricida combined with automated irrigation management, represents a viable alternative for organic tomato production. It offers the potential for high yields, efficient water use, and fruit quality attributes that meet commercial standards, although the physiological mechanisms underlying these responses require further detailed investigation.

COMMITTEE MEMBERS:
Presidente - 1224578 - DANIEL FONSECA DE CARVALHO
Externa ao Programa - 3321101 - DINARA GRASIELA ALVES - UFRRJExterno ao Programa - 2136627 - NIVALDO SCHULTZ - UFRRJExterno à Instituição - MARCELO DE ALMEIDA GUIMARÃES - UFC
Externo à Instituição - JHONATAN MARINS GOULART - UFRRJ