Growth and phytoextraction in forest species after addition of tannery sludge in substrate.
This study aims to evaluate the use of tannery sludge as a component of commercial substrate, to produce seedlings for reforestation of four native species: (Anadenanthera colubrina; Anadenanthera macrocarpa; Schinus mole; Guanzuma ulmifolia) and one exotic species: Eucalyptus urophylla; and also to evaluate the removal of nutrients and chromium from the substrate. This study evaluated the incorporation of five doses (5, 10, 15, 20 and 25%) of tannery sludge used in commercial substrate for growth of different native and exotic species suitable for reforestation. The experiment was conducted in greenhouse seedling growth. After sowing into substrate in tubes, each treatment was examined for plant development for 120 days, with periodic assessment of height and final evaluation of biomass (roots and shoots) in plants; contents of macro and micronutrients and accumulation of chromium in the leaf tissue was also examined. Three forest species responded positively to the addition of up to 25% of tannery sludge on the substrate to produce seedlings. Schinus mole showed a high absorption of chromium into the shoot and also provided the best growth in response to sludge addition on the substrate. Chromium content in the substrate was reduced after cultivation of forest species, with emphasis on the performance found by eucalyptus seedlings.