Fauna do solo, fungos micorrízicos arbusculares e bactérias diazotróficas em áreas de mineração de bauxita no Noroeste do Pará revegetadas com dendê

Abstract

The Mining is considered the activity can cause a great impact in the environment, involving the vegetation and subsoil layers remove. After the finish of mineral sources, mandatorily these areas require recovery measures. This study aimed to evaluate the initial establishment of three genotypes of palm oil: C2501, C2301 and C2528, indicated by Embrapa Amazônia ocidental, in area of mining in the northwest Pará. Was also evaluated the soil fauna, the occurrence of nitrogen fixing bacteria and arbuscular mycorrhizal fungi associated with culture. The establishment of culture was evaluated for survival, height, number of leaves and nutritional status of plants and soil fertility. The impact on soil fauna was evaluated with samples in the experimental area and in areas of reforestation and forest adjacent to it. To determine the presence of mycorrhizal fungi and diazotrophic bacteria samples were taken from roots and soil in the palm oil. The amount of the plant N derived from BNF was determined with the natural abundance of 15N technique. The mortality of the plants was low, but growth was not strong, this may be related to low P in soil and periods of drought. In this initial stage of establishing the symbiosis with diazotrophic bacteria was inefficient where only the genotypes C2501 and C2528 were 4,5 and 4,8% respectively of N derived from BNF, with great variability in the population of bacteria. The mycorrhizal fungi no showed differences in sampled areas and this result may be related to water deficit and sampling period in the dry season. The composition of soil fauna not differ in the areas of palm oil plantation with and without green manure, and conventional reforestation, however not present the same diversity of the forest.