Biomass and Yield of Peanut Grown on Tropical Soil Amended with Sewage Sludge Contaminated with Lead

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.