The construction of hydroelectric power plants in the world is based on increasing demand for energy and river flood control. At the national level they are alternatives due to the great Brazilian hydroelectric potential. The Tucuruí Hydro-Power Complex is located in the Tocantins-Araguaia Basin and over 1,100 islands have been formed from the filling of the reservoir, inhabited by some 6,500 people, most of whom have vegetable extraction and animal husbandry as their source of income. Among these islands, one can highlight the Germoplasma Island, which is a permanent preservation area (APP) and is located 3 km from the Tucuruí
dam. This island was created in order to guarantee the conservation of the plant genetic material of the region flooded by the dam. On the island of germplasm, some forest matrices planted on the courts are perishing. In other courts the productivity of the forest species is decreasing. This problem can hinder the extraction of seeds for seedling production and propagation. The purpose of this research was to determine the physical and chemical attributes of the soil and characterize the area in situ (PC3), shade planting (Q18) and full sun planting (Q17) ex situ area of the germplasm island located in the lake of the Tucuruí hydroelectric power station. Deformed composite samples were collected from 10 to 30 sub-samples in each area at depths
of 0-10cm and 10-20cm. The samples were then prepared and analyzed in the Civil Engineering Laboratory of the Federal University of Pará at the Tucuruí University Campus. The chemical and physical results of the soils were submitted to the Tukey statistical test at 5% probability, Hierarchical Grouping Analysis (HCA) and Principal Component Analysis (PCA). The results of the soil chemical and physical analyses made it possible to understand the characteristics of the germplasm island areas. The highest levels of calcium and magnesium were found in Q17, due to the management performed in the plantation. Moreover, it presents high weathering and low organic matter content, and therefore, low Cation Exchange Capacity. In relation to the Q17 and Q18 planting areas, the shading planting provides the best conditions for the development of plant species and maintenance of soil quality, as it showed similarity between the chemical attributes of the natural vegetation area. From the data obtained and statistical analysis, there was greater similarity between the areas PC3 and Q18. Through the results of the Principal Component Analysis (PCA) it was possible to visualize the contribution of soil chemical attributes in the characterization of the studied areas. The soil chemical attributes that contributed the most were: ∆pH (-0.333), Al3+ (-0.332) and pH H2O (0.323), H+ (-0.534), Fe2+ (0.410) and AP (-0.379). Hierarchical Component Analysis (HCA) confirmed the results obtained in Principal Component Analysis (PCA).
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