Cost-effective composted municipal waste and sugarcane bagasse for forest seedling production: insights into physiological quality assessment

As a result of the treatment stations' operation, sewage sludge has become a problem on a global scale. Alternatives to a better destination are imperative, highlighting the employment of sewage sludge as a plant subtract. This study evaluated the physiological and chemical status of Maclura tinctoria (L.) seedlings cultivated in a substrate composed of a mixture of sewage sludge and sugarcane bagasse, through the chlorophyll fluorescence technical and the inner metals concentration, aiming to discuss ecologically correct means for waste management and sustainable forestry practices. The results indicated that the treatments with the proposed substrate positively impacted the physical and physiological plants characteristics (p < 0.05). Overdoses provoked increases in the inner concentration of metals (Fe, Zn) and heavy metals (Cu, Cd, Cr, Pb, and Ni). However, the photochemical activity of photosystem II indicates that the phytotoxic risk is lower than expected. The changes observed in the chlorophyll-a fluorescence induction curves, which reflect the photochemical activity of the leaves, corroborate this. In this way, the ability of the substrate to optimize the growth of young plants is highlighted, as well as the need to monitor the accumulation of metals in plant tissues, contributing valuable information on the advantages and ecological consequences of using sewage sludge in forestry and promoting sustainable waste management and reforestation methods. Research involving sewage sludge use is important to avoid the accumulation of this contaminant in landfills. [GRAPHICS]