Use of MSW compost, dried sewage sludge and other wastes as partial substitutes for peat and soil

Comparison between pine bark and coconut husk sorption capacity of metals and nitrate when mixed with sewage sludge

“…The porosity of the substrates decreased with the sludge addition, and it was higher for coco fibres media than for pine bark substrates. This fact was also reported by several authors (Ingelmo et al, 1998;Guerrero et al, 2002) for peat-and pine bark-sewage sludge substrates. Substrates with sludge showed higher microporosities than the pine bark and coconut fibre substrates.…”

“…Particle and bulk densities increased with the addition of sludge, as found in previous studies (Ingelmo et al, 1998;Chen et al, 2002;Guerrero et al, 2002;Hernandez-Apaolaza et al, 2005, and present higher values for pine bark (PB) than for the coconut fibre (F). When bulk density increases, the number of larger pores is reduced, and the root forces necessary for the deformation and displacement of substrate particles readily become limiting, and root elongation rates decrease (Taylor and Ratliff, 1969).…”

“…Waste products such as biosolids (Gouin, 1993;Ingelmo et al, 1998;Guerrero et al, 2002) and wood wastes (Hicklenton et al, 2001;Chen et al, 2002) have been frequently used in container production of ornamental trees, shrubs and perennial plants. Nowadays other materials have been used as substrate, for example coconut fibres, because they have many characteristics in common with peat (Lennartsson, 1997).…”

Chemical and physical properties of organic residues

“…The characteristics of plant residues vary depending on the plant species, plant tissues, and soil chemical and physical properties, but are generally nutrient-poor and have lower EC than animal or municipal wastes (Abad et al, 2002;Garcia-Gomez et al, 2002;Benito et al, 2003;Benito et al, 2005;Benito et al, 2006;Domeño et al, 2009;Bernal et al 1998;Ingelmo et al, 1998;Hernández-Apaolaza et al, 2005;Bardhan et al, 2008;Ostos et al, 2008). Benito et al (2006) concluded that composts obtained from pruning must be mixed with other ingredients rich in nutrients, to compensate the low-nutrient level.…”

“…Cattle manure have high salinity levels (Bardhan et al 2008), and, depending on its proportion in the substrate, can affect EC in the mixture with other materials and therefore restrict their amount. Sewage sludge, depending on the chemical composition, can not be the exclusive or dominant component in residue mixtures, since it can increase the content of heavy metals and electrical conductivity (Ingelmo et al, 1998;Bardhan et al, 2008;Ostos et al, 2008). The imbalance of nutrients in view of the plant demand and the variability in nutrient contents (Westerman & Bicudo, 2005), as well as other properties, of chemical and physical nature, may limit the agricultural use of organic residues.…”