Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: PAULO HENRIQUE DALTO
DATA: 27/02/2026
HORA: 10:00
LOCAL: Urucui - Piaui - IFPI - https://meet.google.com/eyr-hysa-uay
TÍTULO: FERTILITY, MICROBIAL ACTIVITY, AND CARBON STOCKS ALONG A CULTIVATION CHRONOSEQUENCE IN THE BRAZILIAN CERRADO
PALAVRAS-CHAVES: Soil microbial activity, Soil Carbon stocks, Soil fertility, Nutrient leaching, Carbon sequestration, Sandy soils
PÁGINAS: 84
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
RESUMO:

The growing demand for food has driven the conversion of native areas into arable land, a process that has significantly impacted the Cerrado biome (Brazilian Savanna) in recent years, bringing important implications for the soil carbon (C) balance. In Cerrado soils, typically acidic, nutrient-poor, and usually sandy, the development of cropping systems that promote C accumulation is crucial for agricultural sustainability. In this regard, this study evaluated a cultivation chronosequence (native vegetation vs. 12, 18, and 24 years of cultivation) to identify temporal changes in fertility, microbial activity, and C stocks in the upper 0.5 m of a Oxisol (Latossolo Amarelo Distrófico) under the Cerrado biome in the state of Piauí, Brazil. Total organic carbon (SOC), microbial biomass carbon (MBC), basal soil respiration (C-CO₂), microbial quotient (qMic), metabolic quotient (qCO₂), soil acidity (pH), and stocks of C, Ca, Mg, K, P, S, Fe, Mn, Zn, B, and Cu, as well as CO₂ sequestration, were analyzed at five depths (0.0-10, 10-20, 20-30, 30-40, and 40-50 cm). No significant differences were observed among the areas for MBC, qMic, and qCO₂, however, there was an increase in SOC content, C-CO₂, and C stocks as cultivation time extended. Improvements relative to the native area occurred down to a depth of 50 cm in the sum of bases, base saturation, and stocks of C, Ca, and S. For cation exchange capacity and stocks of Mg and K, the improvement was restricted to the upper 30 cm. Al reduction and pH changes reached 20 cm, while the increase in P stocks and micronutrients (Cu, Mn, Zn, and B) was limited to the surface layer (0.0-10 cm). CO₂ sequestration rates were 0.96, -0.06, and 1.69 Mg ha⁻¹ year⁻¹ for the areas cultivated for 12, 18, and 24 years, respectively. Overall, cultivation time increased microbial activity (providing CO₂ sequestration), chemical fertility, and C and nutrient stocks down to a depth of 50 cm. On average for the profile (0-50 cm), after 24 years of cultivation, base saturation increased by 429% and the sum of bases by 660%. These results indicate that the study of local management systems is fundamental for long-term agricultural sustainability, considering that regional environmental and climatic characteristics directly influence the effectiveness of implemented agricultural practices and their outcomes.

MEMBROS DA BANCA:
Presidente - 1081793 - RONNY SOBREIRA BARBOSA
Interno - 2232167 - YURI JACQUES AGRA BEZERRA DA SILVA
Externo ao Programa - 2058762 - ARTENISA CERQUEIRA RODRIGUES
Externo ao Programa - 2141503 - VANESSA MARTINS
Externo à Instituição - PAG694152 - ANTONIO RAFAEL SÁNCHEZ RODRÍGUEZ - UCO
Externo à Instituição - 056.***.***-00 - JOÃO DE DEUS FERREIRA E SILVA - USP

Cadastrada em: 23/02/2026