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)
TreatmentShootRootsPod husks

Additional treatments
 Control15.66a13.99a10.66a
 Mineral fertilization15.32a12.65a 9.66a
Sewage sludge
 Pb rate (mg kg−1)
 314.99b15.99b12.16b
 2118.99ab24.49ab16.50b
 4219.99a34.85a28.00a
Time of application
 30 d before sowing17.88a25.11a17.44a
 At the day of sowing18.10a23.10a20.33a

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 (%)16.2631.4024.10

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.