Results of the PCA of the soil chemical properties measured at the end of the experiment are shown in Fig. 1 (details are given in Table 3). The compost and vermicompost treatments were clearly separated from the mineral treatment along the first axis, which explained 57% of the total variance. The compost and vermicompost treatments were characterized by higher C and N, higher pH and CEC, and lower available P, NH4+ and NO3− than the mineral treatment.