Soil Chemical Attributes and Foliar Nutrient Contents of Native Species in Rehabilitation Chronosequence after Iron Ore Mining

The mineland rehabilitation can be a challenge due to high soil density and low levels of organic matter and nutrients. This study assessed soil chemical attributes and leaf nutritional contents of two native species (Mimosa acutistipula var. ferrea and Vismia baccifera) grown in an iron waste pile under environmental rehabilitation in the Carajas Mineral Province, Eastern Amazon, Brazil. Soil samples were collected close to plant species in three different chronosequences of rehabilitation. Regardless of the rehabilitation stage, the soils have low levels of phosphorus, potassium, calcium, magnesium, and boron. A tendency of organic matter accumulation was observed at the advanced stage (5-8 years after the onset of rehabilitation process) and it was correlated with other soil nutrients. The leaf nutrient' contents of M. acutistipula and V. baccifera tend to be distinct from each other, which could indicate that the studied species have different nutritional requirements. The V. baccifera presented higher leaf concentrations of sulfur, copper, and zinc, while M. acutistipula stood out for presenting a higher leaf nitrogen content, which is possibly related to its nitrogen-fixing capacity. In general, an improvement of soil chemical attributes was achieved with the advance of the rehabilitation stages, showing the efficiency of the procedures performed to rehabilitate the studied areas.