Table 6: Lead content in peanut as a function of Pb rates applied to soil with sewage sludge, time of sewage sludge application, mineral fertilization, and control.

Pb content (mg kg−1) Treatment Shoot Roots Pod husks Additional treatments  Control 15.66a† 13.99a 10.66a  Mineral fertilization 15.32a 12.65a 9.66a Sewage sludge  Pb rate (mg kg−1)  3 14.99b 15.99b 12.16b  21 18.99ab 24.49ab 16.50b  42 19.99a 34.85a 28.00a Time of application  30 d before sowing 17.88a 25.11a 17.44a  At the day of sowing 18.10a 23.10a 20.33a Analysis of variance Source of variation F test‡ Additional treatments NS NS NS Pb rate * * ** Time of application NS NS NS Pb rate × time of application NS NS NS Sewage sludge × additional treatments NS ** * CV (%) 16.26 31.40 24.10

†Means followed by same letter in column within additional treatments and each factor of factorial do not differ significantly by Tukey test at P < 0.05. ‡NS: not significant. *, **significant at P < 0.05 and P < 0.01, respectively.