2.4. Statistical methods
The statistical analysis was based on the Univariate Linear
General Model (LGM), ANOVA procedures, in order to evaluate the
effect of the variables considered: type of compost, proportion of
compost in the mixture and plant species. The Tukey-b test was
used (p < 0.05) to compare the differences obtained. The ShapiroWilk
and Levene tests were carried out prior to performing the
ANOVA, to evaluate the normality and variance homogeneity,
respectively. The SPSS v. 18.0 statistical software package was used
for the data analysis.