Technosol made with urban and industrial waste: Potential for improving soil quality and growing tree seedlings

Abstract

This study evaluated the use of waste materials to produce Technosol, a "tailor-made" soil consisting of construction and demolition waste (CDW), solid waste from stone mining (WSM), natural soil (NS), and compost from plant pruning (CPP), for improving soil quality in forest recovery projects. Samples of CDW were characterized using X-ray fluorescence and X-ray diffraction. The potential of the Technosol as a substrate was assessed using a mixture of "Class A" CDW, WSM, NS, and CPP in the following proportions: (a) 10 % CDW + 42.5 % WSM + 42.5 % NS + 5 % CPP, (b) 20 % CDW + 37.5 % WSM + 37.5 % NS + 5 % CPP, and (c) natural soil as a control. A randomized block design was used with nine treatments and three replications using 5.5 L pots. The experimental treatments consisted of two proportions of mixtures, natural soil, and three tree species: pioneer, Cecropia pachystachya, secondary, Handroanthus impetiginosus and climax, Copaifera langsdorffii. The activity of the enzymes β-glucosidase and arylsulfatase was determined in the Technosol and natural soil at the end of the experiment. During 180 days, the height of the plants and the diameter of the stem were determined at intervals of 30 days and, at the end of the experiment, the aerial part dry mass (leaves and trunk) and roots were evaluated. The Technosol constructed from the mixture (a) proved to be viable for improving soil quality, as indicated by a greater enzymatic activity compared to other soils, and for the growth of H. impetiginosus seedlings, showing the capacity to gain plant height over 180 days after planting.