Análises ecofisiológicas e nutricionais em plantas de Cabreúva (Myroxylon peruiferum L.f.) cultivadas em diferentes proporções de rejeitos oriundos do rompimento da barragem do Fundão

Abstract

In 2015, approximately 55 million m3 of iron ore tailings from the collapse of the Fundão dam, located in the Iron Quadrangle region of the State of Minas Gerais, southeastern Brazil, formed an avalanche of tailings and water that covered a total of 663 km, causing destruction along the Doce River. The sea of mud caused the biggest socio-environmental problem of the mining sector in the country, with the burial of vegetation and the silting up of water bodies, causing impacts in the entire Rio Doce basin. The natural process of ecological succession in this ecosystem is unlikely to be re-established without anthropic interference. In this context, aiming at the preservation of natural resources, actions to recover and conserve the remaining areas of riparian forest and the recovery of the areas directly impacted are necessary. From an ecological point of view, one of the fundamental steps for the success of environmental recovery is the identification of native tree species capable of establishing and developing in the impacted riparian areas. As part of this initiative, the present study analyzed the ecophysiological and biochemical responses and the accumulation of mineral elements in the tissues of Cabreúva (Myroxylon peruiferum L.f.) plants, as well as the physical and chemical conditions of the substrates used, before and after growing the species for 40 months in pots prepared from a mixture of tailings/fertile substrate, in the proportions of 0, 25, 50, 75 and 100% of tailings from the Fundão dam. The contribution of tailings in the substrates, especially at the 100% level, negatively influenced the performance of the species. The low fertility and reduced levels of organic matter, and especially the physical-structural characteristics of the substrates formed were limiting factors for plant establishment. However, even so, the species maintained its leaf structures and photosynthetic rates stable, developing, in the observed period, over low nutrient levels, storing most of the Fe and Mn in its roots and stems. These characteristics are important for the inclusion of Cabreúva plants in reclamation projects in areas affected by the Fundão iron ore dam disaster