Vermicompost Improves Growth of Tree Species in Different Stages of Ecological Succession Under Iron Mine Tailings

Environmental contamination by iron mine tailings occurs worldwide; however, the growth of cultivated tree species in different stages of ecological succession in such areas is not well understood. Over 80 days, with data collected every 20 days, the morphophysiology of three tree species in different stages of ecological succession (Schinus terebinthifolius, pioneer; Cedrela fissilis, secondary; and Cariniana estrellensis, climax) was investigated in a growth room. These were subjected to iron mine tailings from the Fundão Dam (Mariana-MG, Brazil), with the addition of either soil or vermicompost (2%) as an amendment. S. terebinthifolius and C. fissilis had higher quantities of dry matter, exhibited more changes in shoot and root morphology, as well as less variations in chlorophyll a fluorescence, indicating tolerance to the mine tailings. However, C. estrellensis was highly susceptible to these tailings. The pioneer species were more tolerant to mine tailings, suggesting their potential use as an excellent tool for the recovery of contaminated areas. The secondary species were also tolerant to mine tailings, although to a lesser extent. The climax species were found to be more sensitive to the tailings, but field establishment can differ when succession is already in place. The vermicompost showed great potential as an amendment, thereby reducing the bioavailability of Fe and Mn and favoring the growth of S. terebinthifolius and C. fissilis.