Banca de QUALIFICAÇÃO: JOHNNY JEAN

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: JOHNNY JEAN
DATA: 30/06/2026
HORA: 09:00
LOCAL: DCS10
TÍTULO:

TECNOLOGIAS CONSERVACIONISTAS E RECONDICIONAMENTO FÍSICO E QUÍMICO DO SOLO: BIOCHAR E PLANTAS DE COBERTURA.

PALAVRAS-CHAVES:

Edaphic and vegetative practices, environmental and agricultural sustainability, regenerative agriculture, soil quality and health.

PÁGINAS: 2
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Manejo e Conservação do Solo
RESUMO:

Soil physical degradation caused by water erosion compromises the sustainability of tropical agricultural systems, especially on highly erodible soils such as Cambisols. Coffee husk biochar has emerged as a promising soil amendment; however, its interaction with cover crops for reconditioning soil physical quality in tropical erosion-prone soils remains underexplored. This study evaluated the short-term effects on soil structure of coffee husk biochar (0, 5, 10, and 20 Mg ha^-1) combined with two cover crops: Brachiaria ruziziensis (Brachiaria) and Crotalaria ochroleuca (Crotalaria) on the B horizon of a Cambisol. A greenhouse experiment was conducted using a completely randomized 4 x 2 factorial design and three replicates over two crop cycles. The following variables were measured: particle density, bulk density (BD), total porosity, macroporosity, microporosity, soil moisture, water retention curve, water permeability, aggregate stability, and penetration resistance. Data were analyzed by ANOVA and polynomial regression. BD remained unchanged across treatments (1.09–1.26 g cm^-3). Soil water permeability peaked at the lower biochar dose of 5 Mg ha^-1 with Crotalaria (16–17 mm h^-1). Brachiaria combined with high biochar rates (20 Mg ha^-1) increased microporosity and plant available water but reduced macroporosity and aggregate stability. These structural changes were associated with improved plant performance, increasing biomass production and Brachiaria tillering through improved permeability, pore-size distribution, and plant-available water. Coffee husk biochar was effective as a physical soil conditioner, but the optimal application rate varies according to the cover crop species and the specific restoration goal, whether prioritizing immediate biomass productivity or long-term reconditioning of degraded horizons. The 5 Mg ha^-1 dose combined with Crotalaria optimized water permeability, but higher rates for increasing water retention require careful monitoring due to structural trade-offs such as reduced macroporosity and increased soil penetration resistance.

MEMBROS DA BANCA:
Interno - RENATA ANDRADE REIS (Membro)
Externo ao Programa - PEDRO MARANHA PECHE - DAG/ESAL (Suplente)
Presidente - JUNIOR CESAR AVANZI (Membro)
Externo à Instituição - FLÁVIO PEREIRA DE OLIVEIRA - UFPB (Membro)
Interno - BRUNO MONTOANI SILVA (Membro)