Banca de DEFESA: GABRIEL ARAÚJO PAES FREIRE

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : GABRIEL ARAÚJO PAES FREIRE
DATA : 24/02/2021
HORA: 09:00
LOCAL: PORTO VELHO, EMBRAPA RONDÔNIA
TÍTULO:

PHOSPHATE ADSORPTION IN SOUTH-WESTERN AMAZONIA 2:1 MINERALOGY SOILS

PALAVRAS-CHAVES:

Tropical soils. Langmuir isotherm. Soil mineralogy

PÁGINAS: 39
GRANDE ÁREA: Outra
ÁREA: Ciências Ambientais
RESUMO:

The low availability of phosphorus (P) in Amazonian soils is a result of the soil's poverty in this element, but mainly due to the fixation processes (precipitation and phosphate adsorption) in the soil. In view of this, the use of phosphate fertilizer is required to increase crop productivity, increasing production costs. This often occurs on weathered soils. However, in the Amazon there have been reports of high phosphate adsorption even in poorly developed soils, with the presence of 2: 1 clay minerals. To evaluate this phenomenon, five representative soils collected in the south of the Brazilian Amazon were selected for the adsorption study, where concentrations of P ranging from 0 to 320 mgP L^-1 in the form of KH₂PO₄ in CaCl2 solution at 0.01M were used. The obtained adsorption values were adjusted to the Langmuir isotherm, being evaluated the maximum phosphorus adsorption capacity (MPAC), phosphorus adsorption energy (PAE) and the maximum phosphate buffering capacity (MPBC) as a function of P values -absorbed, and the P-desorbed calculated through extraction via CalCl₂ at 0.01M. MPAC values ranged from 677.09 to 1346.08 mgP kg^-1, where the greatest adsorption was attributed to the interaction of type 2:1 minerals such as smectite and vermiculite with interlayered hydroxy-Al. The Langmuir linear model was adequate for the data obtained, evidenced by the determination coefficients (r²> 0.95). The acidic soils, with 2: 1 clay minerals, showed a high P adsorption capacity. Desorption was lower in soils containing iron oxides and type 2:1 clay minerals, being less than 20%, showing a high phosphorus fixation in the studied soils.

MEMBROS DA BANCA:
Presidente - 060.454.498-78 - PAULO GUILHERME SALVADOR WADT - UFV
Externo ao Programa - 2283698 - ELAINE ALMEIDA DELARMELINDA HONORE
Externo à Instituição - VALDOMIRO SEVERINO DE SOUZA JÚNIOR - UFRPE
Externo à Instituição - ALAERTO LUIZ MARCOLAN - EMBRAPA
Externo à Instituição - JOSÉ MARQUES JÚNIOR - UNESP