Banca de DEFESA: MAICON WILLIAM DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MAICON WILLIAM DA SILVA
DATE: 29/05/2025
TIME: 13:00
LOCAL: Remoto via Google Meet
TITLE:

Soil Reaction and Methods for Estimating the Liming Requirement in Acid Soils of Rondonia

KEY WORDS:

Soil acidity, Liming methods, Incubation assay, Tropical soils, Agricultural sustainability.

PAGES: 32
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

This study aimed to evaluate the efficiency of lime requirement estimation methods and the reactivity of commercial limestone in acidic soils of Rondonia, Brazil. Four predominant soil orders—Plinthosol, Oxisol, Ultisol, and Inceptisol—were selected, representing distinct pedological, mineralogical, and geochemical characteristics of the region. Soil samples from surface and subsurface layers were incubated with increasing doses (0-125% of recommended rates) of analytical-grade calcium carbonate (CaCO₃) and a commercial limestone (85% Relative Neutralizing Power, PRNT). The pH dynamics, exchangeable aluminum (Al³⁺), and base saturation were monitored to validate traditional lime recommendation methods, including base saturation, aluminum neutralization, and acidity potential approaches.

The results demonstrated that current lime recommendation methods, particularly those based on base saturation (V%) and aluminum neutralization, effectively estimated lime requirements for most soils. However, regional calibration was critical due to the high buffering capacity and mineralogical diversity of Rondonia’s soils. For instance, the Plinthosol required 60% of the recommended lime dose to elevate pH to 6.24, while the highly weathered Oxisol demanded 80% of the dose to reach pH 6.0, reflecting its strong acidity buffering. The commercial limestone exhibited comparable efficiency to pure CaCO₃, achieving target pH levels (5.7-6.5) with minimal deviations, thus validating its use as a cost-effective local alternative.

Quadratic regression models (R² = 0.90-0.99) effectively described the dose-response relationships, highlighting the predictability of pH adjustments across soil types. The Argissol, with inherent eutrophic properties, showed rapid pH elevation (from 5.56 to 5.95 with 40% lime dose), emphasizing its lower dependency on lime compared to more acidic soils. Conversely, the Cambisol required higher lime inputs due to its variable cation exchange capacity and organic matter content. Statistical analyses confirmed significant differences (p < 0.05) in lime efficacy among methods, underscoring the need for multicriteria evaluations to address systematic biases in traditional models.

The study concludes that while established lime recommendation methods are broadly applicable, their precision in Rondonia hinges on accounting for local soil variability, particularly organic matter content and mineralogy. The commercial limestone’s performance, nearly equivalent to pure CaCO₃, offers agricultural stakeholders a viable, regionally sourced input to enhance soil fertility and crop productivity sustainably. These findings contribute to optimizing lime management strategies, reducing costs, and minimizing environmental impacts in Amazonian agroecosystems.

COMMITTEE MEMBERS:
Presidente - ***.454.498-** - PAULO GUILHERME SALVADOR WADT - UFV
Externa ao Programa - 2283698 - ELAINE ALMEIDA DELARMELINDA - UNIRExterno à Instituição - MARCOS GERVASIO PEREIRA - UFRRJ
Externo à Instituição - DOUGLAS MARCELO PINHEIRO DA SILVA - UNESP