Banca de DEFESA: VICTOR HENRIQUE RODRIGUES DIAS

QUALITY OF A KAOLIN MINING TECHNOSOL UNDER DIFFERENT DIFFERENT TECHNIQUES FOR RECOVERING DEGRADED AREAS IN THE EASTERN AMAZON

soil quality index, carbon stock, microbiological indicators, liming, nucleation,
Miyawaki method.

Technosol is an alternative for recovering areas degraded by mining, as the topography of the relief
is reconstructed with tailings from mining and processing, thus creating an environment for fauna
and flora and waste disposal. However, to fulfill the ecosystem services of natural soil, the
Technosol must be of good quality. With this in mind, the study aimed to assess whether the
chemical, physical, and biological indicators of a Technosol are altered by different methods of
recovering degraded areas after three years in a given site condition. The experiment was set up at
the IRCC mine in 2020 with the following treatments: nucleation (NU), dense planting (PA), forest
planting (PF), forest planting with liming (PFC), and a native forest (FN) as the reference
ecosystem. To carry out the sampling, the treatments and FN were divided into four plots (25 x 25
m), which were collected in July 2023 at depths of 0–10 cm and 10–20 cm. First chapter: in this
chapter, the following indicators were assessed: pH, organic matter (MO), potassium (K),
phosphorus (P), calcium (Ca), magnesium (Mg), aluminum (Al), potential acidity (PA), sum of
bases (SAB), cation exchange capacity (CTC), base saturation (V), and aluminum saturation (m).
The physical indicators were: soil density (DS), total porosity (PT), penetration resistance (RP),
sand, silt, and clay, and the soil quality index (IQS). The physical indicators were little altered in the
Technosol, except for RP, which was positively affected by PA, while the chemical indicators in the
PFC treatment showed higher pH, Ca, Mg, SB, and V values, and lower Al and m values. Higher
PT and lower DS and RP were observed in the FN. In addition, the FN had higher MO, AP, CTC,
P, K, Al, and m values. The IQS in the PFC was higher in the Technosol, but not lower when
compared to the FN. Therefore, the treatments hardly altered the physical quality of the Technosol,
while the chemical characteristics were positively changed by liming. However, the characteristics
studied in the third year of recovery are still not close to those of the FN. Second chapter: this
chapter covers oxidizable carbon (COx), organic carbon (CO), microbial biomass carbon (CBM),
basal respiration (RBS), organic carbon stock (E-CO), microbial quotient (QMIC), and metabolic
quotient (QCO). CO was not influenced by the treatments, while E-CO and COx were altered, with
NU and PA having the highest values. For CBM and RBS, the highest values were at a depth of
10–20 cm in NU and 10–20 cm in PA in CBM and PA=NU in RBS. For QMIC, at 0–10 cm, it was
highest in NU and PFC and 10–20 cm in PA. QCO was higher in PF at a depth of 10–20 cm. As a
result, the quality of the Technosol for the variables studied is not yet equal to that of the native
forest. However, nucleation stands out from the other treatments in Technosol.