The bottom ash used in this study was generated in moving grate furnaces and did not contain fly ash. This is a major difference from fluidized bed combustors, which produce an ash mix. The analysis thus revealed lower concentrations of N, P, K, Mg, and S than those reported by other authors (Ohno and Erich 1990; Korpilahti et al. 1998; Demeyer et al. 2001; Miller et al. 2002; Solla-Gullon et al. 2006). In accordance, heavy metal concentrations were relatively low compared with those of other waste products used in agriculture, e. g., slurry from wastewater treatment plants and coal ash (Arvidsson and Lundkvist 2002; Hytonen 2003).

Fig. 6.5 This figure is a result of Pinus radiata D. Don for plots over migmatites. Control untreated, WA application of 4.5 Mg wood ash ha-1 for three consecutive years (2003, 2004, 2005), WAP single applications of 4.5 Mg wood ash ha-1 and 0.1 Mg P2O5 ha-1. In the repeated measures analysis, the sphericity assumption was not valid and therefore values of P-Huynh Feldt were used in univariate tests of their interactions