Table 5: Multifactor analysis of statistical differences in P, Cu, and Zn concentrations as affected by soil types, sewage source, mixing rate, and incubation time.

Source Soils Sewages Rates Incubation periods Amendments Soils*sewages*rates*incubation periods*amendments P DF 1 1 1 1 8 8 ratio 949.08 8.23 3.79 10.37 620.57 3.39 Prob > <0.01* 0.04* 0.05 0.01* <0.01* 0.01* Zn DF 1 1 1 1 8 8 ratio 278.49 90.99 3.49 216.33 894.80 1.15 Prob > <0.01* <0.01* 0.06 <0.01* <0.01* 0.32 Cu DF 1 1 1 1 8 8 ratio 1.23 1.01 1.01 0.96 0.99 0.99 Prob > 0.26 0.31 0.31 0.32 0.43 0.43