Wastewater and substrates on the growth of Anadenanthera colubrina L. seedlings

ABSTRACT The production of seedlings of forest species for reforestation of biomes is a practice that restores the conditions of the environment, but water and substrates that favor the growth of seedlings are required. However, in the semi-arid region, water is a limiting factor, requiring the use of alternative sources such as treated domestic sewage. In this context, the objective was to evaluate the growth of Anadenanthera colubrina L. seedlings produced in substrates (soil + bovine manure and soil + coconut fiber) fertilized with treated domestic sewage effluent diluted in public-supply water in proportions (100, 75, 50 and 25% of domestic effluent) and using water from the supply network as a control. The treatments were arranged in a completely randomized design, in a split-plot with three replicates. The treated domestic effluent (TDE) used in the experiment came from the domestic sewage treatment plant of the decanter-digester type of the Projeto de Assentamento Milagre Apodi/RN. The study was conducted in a seedling production nursery at UFERSA, with growth and vigor evaluations at 30, 60, 90 and 120 days after transplanting. The production of seedlings fertigated with domestic effluent caused differences in all growth variables, with improvement in phytomass production. Seedlings fertigated with a dilution of 50% TDE and 50% water supply showed better results when produced with substrate composed of soil and coconut fiber. The seedlings showed good quality, and those cultivated with 50% and 75% of wastewater showed better quality after 120 days of cultivation.