Fungos micorrízicos arbusculares em solos e raízes de mudas e plantas de áreas degradadas na base petrolífera geólogo ‘Pedro de Moura’ em Urucu, município de Coari, AM

Abstract

The recovery of degraded areas in Amazonia is the main problem to be solved caused by human occupation in the region. For the already devastated areas can contribute to sustainable development, both in agriculture and other economic use, they must be used with plant species that can develop in these soils which are often poor and degraded. The soils of Urucu gaps serve as reference for the development of technologies for recovery of all occupied areas of the Amazon, where agriculture and livestock account for the majority of regional deforestation. The aim of this study was to evaluate the importance of mycorrhizal fungi (AMF) in soil components that suffer direct and indirect impacts of oil exploration, from the analysis of eight clearings and deposits Urucu levels of root colonization by mycorrhizal fungi cultivated species in degraded areas and also to evaluate the conditions of 40 mycorrhizal seedlings of forest and fruit species used in environmental regeneration and symbiotic characteristics of populations of mycorrhizal fungi from soils of these clearings and adjacent forest. For the analysis of root colonization were chosen gaps / deposits RUC 40, LUC 22, JAZ 5, RUC 37H, JAZ 21, JAZ 14, RUC 21/24 and 44 JAZ, where samples were collected from soil and roots in the rhizosphere of 17 forest species in and on the edges of clearings / deposits in the months of May and November 2010. The soils were highly acidic, with low and medium levels of K, Ca and Mg due to fertilization with these elements. The Fe contents were satisfactory, while the Zn and Mn were low. As for the contents of P, it was observed high in JAZ 5, indicating its application in the form of fertilizer. Colonization by arbuscular mycorrhizal fungi in the roots of the species within the clearings / deposits in the rainy season ranged from 0.0% to 44.4%. With respect to fungal structures, rates of colonization by hyphae did not exceed 10% and with vesicles ranged between 0.0% and 44.4%. The roots sampled in the same period, but on the edges of clearings / deposits did not exceed 7.0% rate of colonization. The root colonization by AMF in the dry season within the clearings / deposits ranged between 4.0 and 58.0%, but with few roots showing hyphae; collections made in the margins of clearings colonization rate was 5.4% to 12.0%. The low rates of fungal hyphae in the roots suggest that fungi are giving little or no contribution to the ability to absorb water and nutrients from the soil by plants in those climatic conditions. To assess whether the problem of mycorrhizal plants begins in the nursery, we evaluated also the potential for colonization by mycorrhizal fungi in the roots of seedlings selected from the nursery, as well as statistical analysis of the diameter, height, dry biomass of roots was taken and shoots of the selected seedlings. The root colonization by AMF in January 2010 were very similar to those observed in June 2009, where their rates of colonization by hyphae were zero or close to this value, indicating that the problem of little or no root colonization by AMF also occurs in seedling nurseries.